Prenatal and intrapartum strategies to
prevent prematurity: A case study
Caitlin O’Connor, MSN, RN, CPNP
Susan Gennaro, RN, PhD, FAAN
Contact hours: 2.5 contact hours are available for this activity through 11/15/18. Continuing nursing
education (CNE) credit may be extended past this date following content review and/or update.
Accreditation: March of Dimes Foundation is accredited as a provider of continuing nursing
education by the American Nurses Credentialing Center s Commission on Accreditation.
Disclosures: Caitlin O’Connor and Susan Gennaro have no financial, professional or personal
relationships that could potentially bias the content of this module.
Article purpose
The purpose of this article is to provide an overview
of the risk factors, pathophysiology and management
of preterm labor and premature birth.
Questions in the study help readers apply module
content to Cynthia’s condition to identify and
help reduce her risk for premature birth and offer
appropriate nursing interventions.
Objectives
Premature birth
After reading this article, the learner will be able to:
1. Identify and outline the evidence of who is most at
risk for preterm labor and premature birth.
2. Discuss the etiology of preterm labor and
premature birth.
3. Analyze the state of the science to diagnose,
manage and provide care for women experiencing
preterm labor and premature birth.
Case study
This article reviews known risk factors for
spontaneous or indicated premature birth. Given the
presence of certain risk factors, the ability to predict
who will experience a premature birth can help nurses
effectively provide care for mothers and their infants.
The article presents a case study of Cynthia, a
41-year-old pregnant woman. The case study
builds throughout the content to include Cynthia’s
medical history as well as obstetric, demographic,
sociobehavioral, biologic and physiologic risk factors
that may contribute to her overall pregnancy health.
© 2015 March of Dimes Foundation. All rights reserved.
Premature or preterm birth, defined by the World
Health Organization (WHO) as a live birth occurring
before 37 weeks gestation, affects more than 15 million
babies globally each year (WHO, 2014).The rate of
premature birth in the United States has steadily declined
from a high of 12.8 percent in 2006 to 11.5 percent in
2012 (Figure 1). However, it is still well above the March
of Dimes (2014) goal of 9.6 percent by 2020.
Table 1 identifies sequelae associated with preterm
birth. Because premature birth is a leading cause of
perinatal mortality, it is imperative for health care
professionals to understand the etiology behind it so
they may adequately diagnose, manage and care for
women and their babies.
•
•
•
•
Table 1. Sequelae associated
with preterm birth
Growth restrictions
Neurodevelopment issues
Learning disabilities
Visual and hearing problems
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Prenatal and intrapartum strategies to prevent prematurity: A case study
Figure 1. Preterm births, United States,
2003 to 2013
Percent of live births
National Center for Health Statistics (NCHS), 2014
Part of the challenge in identifying who is at risk for
premature birth lies in the unclear etiology and the
combination of maternal, fetal, physiological and
environmental factors that are at play. Approximately
30 to 35 percent of premature births are medically
indicated and result either from maternal or fetal
health concerns (Goldenberg, Culhane, Iams
& Romero, 2008). Another 40 to 45 percent of
premature births are a result of spontaneous preterm
labor, which is manifested by regular contractions
of the uterus resulting in cervical change prior to 37
weeks gestation (American College of Obstetricians
and Gynecologists [ACOG], 2012a, 2014b; Iams,
Romero, Culhane & Goldenberg, 2008). The interval
between preterm labor and premature birth can
be days to weeks, with many women experiencing
multiple episodes of preterm labor before giving birth.
However, with appropriate management, as little as
10 percent of women who present with preterm labor
experience a premature birth within 7 days (ACOG,
2012a), and up to 70 percent go on to deliver at term
(McPheeters et al., 2005).
Risk factors for premature birth
Table 2 identifies risk factors associated with
premature birth.
Obstetric risks
One of the strongest risk factors for premature birth
is a previous premature birth (ACOG, 2012b; Muglia
& Katz, 2010). Women who have had a previous
premature birth are up to 50 percent more likely
than women who haven’t given birth prematurely to
experience a recurrent preterm delivery (Goldenberg
et al., 2008).
2
Table 2. Risk factors associated
with preterm birth
Obstetric
• Previous premature birth
• Non-medically indicated
inductions and cesarean births
• Multiple gestations
• Short interpregnancy interval
Demographic
• Race
• Younger than 17 or older than
40
• Low socioeconomic status
• Unmarried
• Less educated
Sociobehavioral • Substance use/abuse
• Work environment
• Stress, anxiety or depression
• Preconception weight
• Intrapartum weight gain
Biologic
• Genetics
• Pre-existing infections, diseases
or obstetric conditions
• Short stature (between 5 feet
and 5 feet 2 inches
Physiologic
• Short cervix
• Uterine abnormalities
Important factors in the rise of the preterm birth
rate in the United States between 1989 and 2004
are non-medically indicated labor induction and
cesarean delivery (Chang et al., 2013). Elective
deliveries before 39 weeks are common and increase
the risk for premature birth and infant morbidity
and mortality. While there are specific indications
for labor induction before 39 weeks gestation,
ACOG and the Society for Maternal-Fetal Medicine
(SMFM) (2013) strongly assert that a non-medically
indicated early-term delivery is not appropriate, even
with mature fetal lung studies. Approximately 10 to
15 percent of births in this country are the result of
non-medically indicated elective early-term deliveries
between 37 0/7 and 38 6/7 weeks gestation (Jensen,
White & Coddington, 2013). Despite their size,
infants born in this gestational range have a higher
likelihood of respiratory distress syndrome (RDS),
transient tachypnea of the newborn , pneumonia,
hypoglycemia, admission to the neonatal intensive
care unit (NICU) and death than infants born at
39 to 40 weeks gestation (ACOG & SMFM, 2013).
In recent years, numerous strategies have been
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Prenatal and intrapartum strategies to prevent prematurity: A case study
employed to reduce rates of non-medically indicated
inductions and cesarean births, including education
for nurses, doctors, pregnant women and the general
public about the avoidable risks of early elective
deliveries, institutional policies that make it difficult
to impossible to schedule a non-medically indicated
near-term induction, insurance pressures and quality
accrediting agencies.
Multiple gestations (twins, triplets or more) are at
increased risk, almost 10-fold, for premature birth
(Aboulghar & Islam, 2013; Goldenberg et al., 2008;
March of Dimes, Partnership for Maternal, Newborn
& Child Health, Save the Children & WHO,
2012.) This increased risk is believed to be caused
by overdistention which leads to contractions and
preterm premature rupture of membranes (PPROM).
PPROM is rupture of membranes before 37 weeks of
pregnancy.
Short interpregnancy intervals, especially intervals
<6 months between pregnancies, are associated with
up to 2 times the risk for premature birth (CondeAgudelo, Rosas-Bermúdez & Kafury-Goeta, 2006;
Smith, Pell & Dobbie, 2003). Goldenberg and
colleagues (2008) postulated that this increased risk
may be related to the time necessary for the uterus
to return to normal size after delivery. The risk is
even greater for women with complications, such as
a premature birth or intrauterine growth restriction
(IUGR), in a previous pregnancy coupled with
demographic factors like age, education, marital
status and race.
Demographic risks
Significant racial disparities in preterm birth exist,
with black women in the United States experiencing
the highest rate (Figure 2). While the mechanisms
behind this phenomenon are unknown, researchers
hypothesize that black women may be poorer, less
educated and more likely to be unmarried, three
characteristics that are linked to increased risk of
premature birth (Gennaro, 2005; Goldenberg et
al., 2008; Muglia & Katz, 2010). Minority women
of low socioeconomic status are more likely to live
in crowded, disadvantaged neighborhoods (Kent,
McClure, Zaitchick & Gohlke, 2013) where air
pollution is higher (Ponce, Hogatt, Wilhelm & Ritz,
2005; Wu, Ren, Delfino, Chung, Wilhelm & Ritz,
2009; Yorifugi, Naruse, Kashima, Murakoshi & Doi,
2015). Chronic stressors, like poverty and racism, may
result in neuroendocrine changes that ultimately lead
to premature birth (Lyndon, 2006).
3
Figure 2. Preterm by race, United States,
2011 to 2013 average
Percent of live births
NCHS, 2015
Married women experience lower levels of premature
birth compared to their unmarried counterparts.
Being married and having a committed partner is
associated with social and financial support and
stability (El-Sayed, Tracy & Galea, 2012; Zain, Low
& Othman, 2014); thus, these women experience less
stress and anxiety than single women. Unmarried
women with lower socioeconomic status and lower
levels of education experience higher levels of
psychological stress, depression and substance abuse,
which may contribute to greater risk for premature
birth (Masho, Chapman & Ashby 2010; Shiozaki et
al., 2014; Zain et al., 2014).
Women younger than 17 are at higher risk for a
premature birth than older women (Vaughan, Clearly
& Murphy, 2013). Pregnant teenagers are more likely
to be poor, less educated and unmarried (El-Sayed
et al., 2012; Thomson, Bender, Lewis & Watkins,
2008). Poor pregnancy outcomes can be associated
with physiologic immaturity of the uterine or cervical
blood supply as a result of becoming pregnant at a
young age (Al-Haddabi et al., 2014; Chen et al., 2007).
Inadequate weight gain during pregnancy is a risk as
the teenage mother’s growing body competes with the
fetus for nutrients (Fraser, Brockert & Ward, 1995).
The smaller size of the uterus and pelvic bones, due
to physiologic immaturity, may play a part in the
increased risk of premature birth in teenage mothers
(Lao & Ho, 2000; Moerman, 1982). On the other
end of the spectrum, women older than 40 are at
significantly higher risk for premature birth than
younger women (Laopaiboon et al., 2014; Seoud,
Kazma, Khalil, Melhem, Nassar & Usta, 2002).
Increased incidence of congenital fetal anomalies or
comorbid chronic diseases in older mothers may be
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Prenatal and intrapartum strategies to prevent prematurity: A case study
related to the increased risk (Auger, Abrahamowicz,
Wynant & Lo, 2014).
Premature birth is a global problem. An estimated
60 to 85 percent of premature births worldwide occur
in Africa and Asia (Beck et al., 2010; Blencowe et
al., 2012) due to higher frequency of premature birth
among women of African descent and the large number
of births in Asia. In lower-income countries, such as
Pakistan and Indonesia and the sub-Saharan countries
of Botswana, Zimbabwe and Mozambique, 11.8 percent
of births are considered preterm, supporting that poorer
families are at greater risk (Blencowe et al., 2012).
4
Sociobehavioral risks
Sociobehavioral characteristics are becoming
increasingly important when assessing premature
birth. Women who are underweight before pregnancy
are at risk for premature birth caused by low blood
volume and uterine blood flow, vitamin deficiencies
and increased infection risks (Goldenberg et al.,
2008). Overweight and obese women are at risk for
pregnancy complications, including preeclampsia,
gestational diabetes and fetal anomalies, all of which
increase the risk of premature birth (ACOG, 2013c;
Cnattingius et al., 2013). Obesity, which is associated
with systemic inflammation, can significantly increase
Case study part 1: Cynthia
Cynthia (G5 T1 P2 A1 L3) is a 41-year-old African-American woman who presents on April 1 to the clinic
for prenatal care. She is approximately 14 weeks pregnant by her last menstrual period (LMP).
Past medical history
• Hypertension (HTN) diagnoses 2 years ago after the birth of her last child.
Currently not medicated: “I keep it in control with my diet.”
• BMI of 41
Past surgical history
None
Obstetric history
• 2005 First-trimester termination of pregnancy
• 2009 Full-term vaginal delivery post induction of labor for preeclampsia,
3,400 g
• 2011 Preterm normal spontaneous vaginal delivery (NSVD) at estimated
gestational age (EGA) 31 weeks, reported spontaneous contractions,
hospitalized with cervical change and delivered within 2 days
• 2013 Preterm NSVD at EGA 355/7 weeks, reported spontaneous contractions
with spontaneous rupture of membranes, hospitalized and delivered within 5
days
Social history
• Smoked one pack per day (PPD) prior to pregnancy, “cut down
dramatically” to 1/4 PPD when learned of this pregnancy
• Denies alcohol or drug use
• Denies domestic violence/intimate partner violence
• Works as a nurse’s aid at a local nursing home; worries because she heard
facility is making cutbacks to the work force
• Recently separated from husband of 14 years
• Associate’s degree
• Mother: Essential HTN, type 2 diabetes mellitus, obese
Family history
• Father: Deceased at age 70 from myocardial infarction
• Sister: History of preterm birth
• Height 66 inches, weight 253 pounds
Evaluation
• BP 136/80 HR 102
• Uterine size 15 weeks consistent with LMP and singleton pregnancy
• + fetal heart rate
• + clue cells on wet mount
Question for nurses: Describe Cynthia’s risk factors for premature birth.
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Prenatal and intrapartum strategies to prevent prematurity: A case study
the likelihood of delivering a premature baby even
in women who do not have chronic diseases, such as
hypertension, that often are associated with obesity
(Smith, Hulsey & Goodnight, 2008).
Insufficient and excessive intrapartum weight gain
both are associated with premature birth (Wise,
Palmer, Heffner & Rosenberg, 2010). Table 3
identifies guidelines for appropriate weight gain
during pregnancy.
Table 3. Guidelines for appropriate
intrapartum weight gain
BMI before pregnancy
Suggested weight gain
Underweight (<18.5)
28 to 40 pounds
Normal (18 to 24.9)
25 to 35 pounds
Overweight (25.0 to 29.9)
15 to 25 pounds
Obese
11 to 20 pounds
Institute of Medicine and National Research Council,
2009
Women who experience high levels of anxiety, stress
and depression are at greater risk for premature
birth than other women (Ding et al., 2014; Ibanez
et al., 2012; Lobel, Cannella, DeVincent, Graham,
Meyer & Schneider, 2008). The risk is exacerbated by
associated behaviors, including smoking, using drugs
and drinking alcohol, that increase the likelihood of
premature birth (Goldenberg et al., 2008). Nicotine, a
vasoconstrictor, is associated with placental damage
and decreased uteroplacental blood flow, resulting
in restrictions in fetal growth (Goldenberg et al.,
2008). The relationship between alcohol consumption
and premature birth is associated with elevated
prostaglandins and initiation of labor. Maternal binge
drinking accounts for 1.75 percent of premature births
across all sociodemographic groups, with women age
40 to 44 experiencing the highest incidence (Truong,
Reifsnider, Mayorga & Spitler, 2012).
Excessive physical workload and standing more than
8 hours a day have been linked to negative health
symptoms, such as lower back pain, swelling of lower
extremities and fatigue, as well as poor pregnancy
outcomes (March of Dimes et al., 2012). Occupations,
such as retail sales, nursing and hairdressing, that require
prolonged periods of standing increase a woman’s
risk for premature birth (Waters & Dick, 2014).
Biologic risks
Genetics may play a role in the risk of premature
birth. Studies have shown an increased rate of
5
premature birth among women who were born
preterm themselves (Dizon-Townson, 2000) or
whose sisters or other female family members have
experienced premature birth (Mattison, Damus,
Fiore, Petrini & Alter, 2001).
Women with infections, chronic diseases or uterine
bleeding during pregnancy experience higher rates of
premature birth than other women (ACOG, 2012b;
Blencowe et al., 2012; Hossain, Harris, Lohsoonthorn
& Williams, 2007). Intrauterine infections are
associated with up to 40 percent of premature births
(Goldenberg et al., 2008). Infection of the uterus,
placenta, amniotic fluid, urinary tract and peritoneal
cavity are all related to risk of premature birth
(Hillier et al., 1995; Romero et al., 2007). Women
with bacterial vaginosis (BV), an imbalance of
vaginal flora, have a higher likelihood of delivering
preterm (Donders et al., 2009). Additionally, systemic
infections like malaria and periodontal infections are
associated with an increased risk of premature birth
(ACOG, 2012a; Espinoza, Erez & Romero, 2006).
Chronic health conditions, such as diabetes,
hypertension, rheumatoid arthritis and thyroid and
autoimmune disorders, are associated with poor
pregnancy outcomes, including premature birth
(Dunlop, Jack, Botallico, Lu, Shellhaas & Prasad,
2008). Likewise, certain obstetric conditions, such
as preeclampsia, pregnancy-induced hypertension,
gestational diabetes and intrauterine growth
restriction, can result in premature birth for maternal
or fetal indications (Goldenberg et al., 2008).
Preeclampsia is an obstetrical condition experienced
by 2 to 8 percent of pregnant women (Barton &
Sibai, 2008; Duvekot, Pijnenborg, Steegers & von
Dadelszen, 2010; Haedersdal et al., 2013). It is a
systemic syndrome characterized by hypertension
and other signs that a woman’s organ systems are
not working normally (ACOG, 2013, 2014a) and is
associated with an increase in premature birth (Duley,
2009). Preeclampsia in a previous pregnancy, in
addition to other risk factors like obesity or advanced
maternal age, increases the risk for preeclampsia and
premature birth in subsequent pregnancies (Connealy
et al., 2014; Hutcheon, Lisonkova & Jospeh, 2011).
Light first-trimester bleeding can be normal
during pregnancy; it occurs in up to 24 percent of
pregnancies that deliver at term (Edwards, Baird,
Hasan, Savitz & Hartmann, 2012). However, firstor second-trimester vaginal bleeding, characterized
by long duration, heavy flow or deep red color,
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Prenatal and intrapartum strategies to prevent prematurity: A case study
6
Case study part 2: Cynthia
Cynthia is at significant risk for premature birth
not a sexually transmitted disease (STD), it
in her current pregnancy. Her previous preterm
frequently develops after intercourse with new or
births, African-American race and advanced
multiple sex partners. However, routine treatment
maternal age are her greatest risk factors.
of sexual partners is not recommended (CDC,
Additional factors that increase Cynthia’s risk for
2014). Nurse Anne talks with Cynthia about her
early birth include:
separation from her husband, and reviews the
importance of having safe sex with new partners,
especially using condoms to protect against STDs
• Being separated from her husband
that can have adverse effects on her baby.
• Her job as a nurse’s aid that requires standing for
extended periods of time
At her 18-week prenatal care visit, Cynthia has
• Stree from potential layoffs at work
an ultrasound that confirms her dates. Given her
• Smoking, obesity, hypertension and BV
history, she is worked up for her hypertension with
• Family history of premature birth
labs and gets an EKG. The attending obstetrician
recommends weekly 17P injections for her risk
At her initial prenatal visit, Cynthia’s provider
of recurrent preterm labor and birth. She is set
prescribes a 7-day course of Flagyl® to treat her BV
up with a visiting nurse who will administer the
and tells her that a follow-up is not necessary if her
injections at Cynthia’s home for convenience and
symptoms resolve (Centers for Disease Control and
compliance. The nurse can rotate injection sites to
Prevention [CDC], 2010).
minimize Cynthia’s pain.
Nurse Anne explains to Cynthia that BV is a
bacterial imbalance in the vagina, and though it is
Question for nurses: What nursing assessments do you consider for Cynthia? What follow-up would
you offer at Cynthia’s next visit?
is associated with an increased risk of premature
birth (Ramaeker & Simhan, 2012). Hemorrhage
and vascular placental lesions also are risk factors
(Committee on Understanding Premature Birth and
Assuring Healthy Outcomes, Board on Health Science
Policy, 2007). The mechanism that links bleeding
to premature birth is unknown but may be related
to coagulation and platelet activation and placental
ischemia (Edwards et al., 2012; Simmons, Rubens,
Darmsadt & Gravett, 2010).
Women of short stature experience premature birth
at significantly higher rates than women of average
height (Han, Lutsiv, Mulla & McDonald, 2012). The
measurement that defines short stature varies across
studies but is generally characterized between 153 to 157
centimeters, or 5 feet to 5 feet 2 inches. The mechanism
behind premature birth in short-stature women
may be related to small pelvic structure or limited
nutritional intake leading to restricted fetal growth.
Physiologic risks
A short cervix, measured by transvaginal ultrasound,
is linked to an increased risk of premature birth.
Cervical length <25mm any time before 34 weeks
gestation signifies higher risk, with the shorter
the cervix the greater the risk (Moroz & Simham,
2012). Other abnormalities, such as scar tissue or
adhesions due to trauma, uterine surgery or certain
gynecological procedures (loop electrosurgical
excision procedure and dilation and curettage), can
cause cervical insufficiency or incompetency, also
associated with premature birth (ACOG, 2012a;
Goldenberg et al., 2008).
Etiology of premature birth
Identifying women at risk for premature birth is
crucial because its etiology is not fully understood.
While we continue to investigate the mechanisms
that underline preterm labor and birth, nurses are
responsible for the challenging task of providing
appropriate care to patients. Understanding what
triggers the cascade of events that leads to preterm
labor and birth helps health care providers target
interventions and treatment strategies effectively.
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Prenatal and intrapartum strategies to prevent prematurity: A case study
The first step in thinking about targeted interventions
is identifying whether a premature birth is
spontaneous or indicated. Spontaneous premature
birth results from preterm labor or preterm premature
rupture of membranes (PPROM); indicated
premature birth is medically initiated as a result of
maternal or fetal complications. Preterm birth is
classified as early preterm (before 32 weeks gestation)
(ACOG, 2011a) or late preterm (34 to 36 weeks
gestation) (ACOG, 2013b).
The most common cause of early preterm birth is
infection (chorioamnionitis or urogenital) (Simhan
& Krohn, 2009). Infections lead to an immune
cascade where proinflammatory cytokines increase,
triggering increased prostaglandins which lead
to cervical changes and the onset of contractions.
Inflammation occurs as a result of biologic or
psychosocial stress and is a major cause of early
preterm birth (Kramer et al., 2012; Shapiro, Fraser,
Frasch & Seguin, 2013). Stress, like infection triggers
the proinflammatory cascade (Muglia & Katz, 2010;
Shapiro et al., 2013; Simmons et al., 2010) resulting
in increased prostaglandins, cervical changes and
contractions. Infection and inflammation both cause
increased production of stress hormones, including
corticotrophin releasing hormone (CRH) by the
placenta and brain, which has been associated with
premature birth (Holzman, Jetton, Siler-Khodr,
Fisher & Rip, 2001; Wadhwa, Garite, Porto, Glynn,
Chicz-DeMet, Dunkel-Schetter, 2004).
With many chronic diseases, such as diabetes
and hypertension, and with obstetric conditions,
such as preeclampsia, placenta previa and other
hemorrhagic disorders, the uterus can become a
hostile environment in which preterm birth is a better
alternative than continuation of the pregnancy. Late
preterm birth often is a result of indicated delivery
for maternal complications (Loftin, Habli, Snyder,
Cormier, Lewis & DeFranco, 2010). Late spontaneous
preterm birth may result from chronic diseases that
cause vascular changes that cause problems with
placental function. When the fetus becomes stressed,
either because of inadequate oxygen or nutrition
(both sequeli of inadequate placental function), the
fetus produces hormones that begin the inflammatory
cascade leading to preterm labor (Mattison et al.,
2001). When the fetus contracts an infection later
in pregnancy, the same inflammatory cascade can
lead to late spontaneous preterm birth. Uterine
distension as a result of multifetal pregnancies often is
a leading cause of late preterm birth (Simmons et al.,
2010). 7
One of the difficulties in adequately managing
premature birth is that the etiology often is
multifactorial, leaving no single intervention strategy
as best effective. For example, a woman with a
short cervix and increased stress hormones is more
likely to deliver prematurely than a woman with a
normal-length cervix and increased stress hormones
(Moroz & Simhan, 2014). Uterine size and subsequent
stretching play a role in premature birth in multiples
but are of greater concern in a woman with a smaller
uterus and pelvic girth. Marriage has been shown to
be protective for preterm birth due to the added social
support; however, an 18-year-old married woman is
at greater risk for premature birth due to her young
age than a married woman at age 34 (El-Sayed, et
al., 2012), once again demonstrating the complexity
of preterm birth etiology. Like all multifactorial
conditions, preventing and treating premature birth
can only be accomplished with multiple solutions.
Preventing premature birth
Preconception care
Preconception care focuses on a helping a woman
achieve a healthy lifestyle and manage chronic
conditions before conception. This includes, but is
not limited to, ensuring a woman is up-to-date with
immunizations, maintains a healthy pre-pregnancy
weight through a nutritious food and exercise
regimen, gets adequate sleep and takes appropriate
steps for smoking and alcohol cessation (Atrash,
Johnson, Adams, Cordero & Howse, 2006). Family
planning is an important part of preconception
care, as short interpregnancy intervals have been
associated with an increased risk for premature
birth. Preconception care also encompasses maternal
psychosocial factors, such as psychological wellbeing, family support and counseling. Preconception
care can help reduce prenatal risk factors and
decrease adverse pregnancy outcomes; however,
preconception care is not provided to all women
(Atrash et al., 2006; Chandranipapongse & Koren,
2013).
Prenatal care
Prenatal care helps decrease premature birth by
identifying women with medical or obstetric problems
that, when undiagnosed, often lead to premature
birth, such as infections, hemorrhagic conditions and
chronic medical conditions (Alexander & Kotelchuck,
2001; Moos, 2006; Van Dijk, Anderko & Stetzer,
2011). Unfortunately, prenatal care that addresses
demographic and sociobehavioral factors that lead to
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Prenatal and intrapartum strategies to prevent prematurity: A case study
premature birth are just beginning to be incorporated
in prenatal care, and there is much work left to do.
Receiving prenatal care does help prevent premature
birth by ensuring that a pregnant woman knows
the signs and symptoms of preterm labor and by
emphasizing that she seek prompt care when preterm
labor is suspected so appropriate interventions can
be initiated (Stringer, Gennaro, Deatrick & Founds,
2008).
Smoking during pregnancy is one of the most
common risk factors for adverse maternal and
fetal outcomes, including premature rupture of
membranes, placental abruption, low birthweight,
premature birth and sudden infant death syndrome
(SIDS) (Wendell, 2013). Unfortunately, routine
assessment of smoking habits does not occur in
routine prenatal care. Melvin and Gaffney (2004)
report that at least half of obstetricians surveyed did
not discuss smoking cessation with their pregnant
patients. ACOG supports the use of the 5A’s (Ask,
Advise, Assess, Assist and Arrange) as an effective
intervention for smoking cessation in pregnant
women (ACOG, 2011c). Nursing care that uses the
5A’s to assess smoking and support cessation in
pregnant women is certainly warranted.
Another crucial prenatal nursing assessment is
assessing how patients cope with stressors in their
life. Stress, anxiety and depression contribute to
premature birth and low birthweight, emphasizing
the importance of assessing both the physical
and psychological well-being of pregnant women
(Dunkel-Schetter & Tanner, 2012). This assessment
allows for appropriate referrals to mental health care
providers or interventional services.
Predicting premature birth
Given the variety of risk factors, mechanisms and
etiology behind premature birth, it is essential to
have diagnostic criteria and preventative measures
to combat its occurrence. Because it is difficult to
pinpoint one specific causative agent, it is challenging to
determine the best mode of diagnosis and management.
Cervical length
One of the most frequently used and clinically reliable
methods of predicting premature birth is determining
cervical length via transvaginal ultrasound. The
predictive value of this measurement varies by
gestational age. When measured between 20 and 23
weeks, a cervical length of ≤25mm indicates a strong
predictive risk of premature birth; a cervical length
8
measuring <25mm at any point in gestation before 34
weeks indicates a high predictive risk of premature
birth (Goya et al., 2012). Bolt and colleagues (2011)
state that a cervix of ≤15mm is indicative of a
50-percent chance of premature birth before 32 weeks.
However, false-positives are common, and many
women classified as having a short cervix deliver at
term. Serial measurements, starting in the second
trimester and continuing every 2 weeks, are suggested
to increase sensitivity (Moroz & Simhan, 2012). Every
1mm of cervical length shortening correlates with
a 3-percent increase in the risk of premature birth
(Moroz & Simhan, 2012).
Fetal fibronectin (fFN)
fFN is a protein found in cervical and vaginal
secretions from the uterus when there is separation
between the fetal membranes and the maternal
decidua. It is collected by sterile speculum exam, is
most useful between 22 and 35 weeks gestation and
should only be considered in the absence of bleeding,
semen and ruptured membranes. fFN is most
clinically useful for its high negative predictive value.
A negative result, a concentration of <50ng/mL,
indicates that the risk for impending preterm birth
is <1 percent (Bolt et al., 2011). This is an important
factor in assessing patients and ruling out those who
are not at imminent risk for premature birth who can
be sent home without further intervention.
When used together, cervical length and fFN
can provide a clear picture of women at risk for
premature birth. A woman with an fFN result of
≥50ng/mL is 30 percent more likely to give birth
before 30 weeks gestation; when this result is coupled
with a short cervix of <25 mm, her chances of
delivering preterm increase to 50 to 60 percent
(Bolt et al., 2011). When both cervical length
measurement and fetal fibronectin results are used,
the two positive results are notably more reliable.
When only one of the two methods is positive, fFN
is more sensitive than cervical length for predicting
premature birth (DeFranco, Lewis & Odibo, 2013).
Interventions
While no single method has been found to be effective
in preventing premature birth, providers use a number
of interventions that show promise in delaying birth
and improving outcomes.
Preterm labor
Educating at-risk pregnant women about the signs
and symptoms of preterm labor (Table 4) can
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Prenatal and intrapartum strategies to prevent prematurity: A case study
9
Case study part 3: Cynthia
Cynthia presents to the prenatal clinic for routine
Midwife Maggie also asks Cynthia about how
care at 22 weeks gestation. At this visit, her
she is coping with life at home with three small
cervical length measures 35mm. She confirms that
children now that she is separated from her
she continues to receive her weekly progesterone
husband. Cynthia admits she feels overwhelmed at
injections from the visiting nurse without incident.
times by the demands of her kids. She is concerned
Midwife Maggie reviews her health and medical
about money and how to afford caring for a new
record and is concerned about her history of
baby. She has heard that her company has been
smoking and the presence of multiple stressors in
making cutbacks and that a number of employees
her life.
have been laid off. Midwife Maggie recommends
that Cynthia meet with a social worker to discuss
Midwife Maggie uses the 5A’s with Cynthia
these concerns and to learn about community
and learned that she smoked one pack per day
resources that may be available for financial and
before pregnancy but has cut down to ¼ pack
social support groiups. Other women have praised
per day. She advises Cynthia that her continued
the Mom’s Group offered at the local community
smoking can be harmful to her baby and that she is
center for helping them meet other mothers facing
exposing her other children to harmful secondhand
similar challenges.
smoke. Cynthia admits that she would like to try
to quit (because cigarettes are expensive), but she
When Cynthia confides that she often feels sad
is not confident she can give it up completely.
when thinking about how different life is without
Midwife Maggie provides Cynthia with a list
her husband, Midwife Maggie encourages her to
of support groups and resources for smoking
consider speaking with a therapist to discuss her
cessation, and they discuss goals and an ideal time
feelings and help her develop coping mechanisms
for Cynthia to quit smoking. Midwife Maggie
to deal with them.
assures Cynthia that she will follow up with her in
4 weeks to see how she is managing.
Questions for nurses: What nursing assessments do you consider for Cynthia? What follow-up would
you offer at Cynthia’s next visit?
facilitate timely assessment and care. Nurses can
talk to women about the importance of seeking
medical care if they experience signs or symptoms of
preterm labor, as early care provides the opportunity
for caregivers to intervene appropriately (Stringer,
Gennaro, Deatrick & Founds, 2008).
•
•
•
•
•
•
Table 4. Signs and symptoms
of preterm labor
Contractions that make your belly tighten up
like a fist every 10 minutes or more often
Change in the color of your vaginal discharge, or
bleeding from your vagina
The feeling that your baby is pushing down.
This is called pelvic pressure
Low, dull backache
Cramps that feel like your period
Belly cramps with or without diarrhea
March of Dimes, 2013
Admission to the hospital and thorough evaluation
are essential for a woman experiencing preterm
labor and PPRO. Preterm labor and PPRO must
be managed efficiently; hospitalization allows for
constant monitoring and the administration of
tocolytics, antibiotics and/or corticosteroids. Staff
can notify the NICU if labor cannot be halted and
premature birth is inevitable.
Progesterone
Prophylactic treatment with progesterone is
a therapeutic intervention that has been used
antenatally to delay delivery and prevent premature
birth due to its ability to decrease inflammation and
soothe uterine activity (Dodd & Crowther, 2009;
Society for Maternal-Fetal Medicine Publications
Committee & Berghella, 2012). While we do not
completely understand how progesterone works, it
may have an anti-inflammatory effect on the uterus.
Recommendation for progesterone’s mode of
administration and dose depend on the level of
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Prenatal and intrapartum strategies to prevent prematurity: A case study
identified risk. Vaginal progesterone, 90-100mg gel or
200 mg capsule, is the preferred administration for a
woman with a clinically diagnosed short cervix and
has been frequently used in high-risk pregnancies,
including multiple gestation (Romero et al., 2012).
Cetingoz and colleagues (2011) found that 100mg
of micronized progesterone administered daily by
vaginal suppository significantly reduced the rate
of premature birth as compared to placebo. In the
same study, the rate of preterm birth for women who
received progesterone was lower for those with a
history of premature birth and with a twin pregnancy,
as compared to a placebo group.
ACOG (2012b) guidelines recommend that
women with a history of premature birth be given
progesterone supplementation to prevent recurrent
preterm birth. Intramuscular administration of
17-hydroxyprogesterone caproate (17P) at a dose
of 250mg per week has demonstrated a decrease in
recurrent premature birth and the associated negative
infant outcomes but has not been proven effective
when used with multiple gestations (Society for
Maternal-Fetal Medicine Publications Committee
& Berghella, 2012). Nursing care is essential in
facilitating this intervention. The use of visiting nurse
services can help with adherence to this regimen by
allowing a woman to receive injections in the comfort
and convenience of her own home.
Case study part 4: Cynthia
At EGA 29 weeks, Cynthia presents to the labor
and delivery unit with complaints of episodic
pelvic pressure, a change in her vaginal discharge
and lower back pain. She denies vaginal bleeding
and reports ++ fetal movements. She is placed
on an electronic fetal monitor and over an hourlong interval has 10 uterine contractions. The
fetal heart rate is within normal parameters for
a fetus at 29 weeks gestation. Midwife Mary
determines it is not necessary to repeat a cervical
length measurement at this time as Cynthia’s
midpregnancy measurement of 35mm indicated
low risk, and she has no history of cervical
insufficiency. Her fetal fibronectin is positive,
and her exam reveals her to be dilated 2cm, 50
percent effaced, fetal station -3.
Question for nurses: What additional
assessments do you recommend for Cynthia at
this time?
10
Tocolytics
Tocolytic agents are administered in attempt to halt
symptoms and slow progression of preterm labor.
Though they do not prevent premature birth, they
can delay delivery anywhere from 48 hours up to 7
days (ACOG, 2014b; Rozenberg et al., 2012). Table 5
identifies classes of tocolytics and their agents.
•
•
•
•
Table 5. Tocolytics and their agents
Betamimetics (terbutaline)
Prostaglandin inhibitors (indomethacin)
Calcium channel blockers (nifedipine)
Magnesium sulfate
Before selecting a specific tocolytic agent, it is
important to consider gestational age, current risk
factors and side effects. While several agents are
currently approved by ACOG and used for acute
tocolytic purposes, there are no agents approved
by the FDA solely for tocolytic use. Therefore, the
preferred course of treatment varies by facility, with
no single agent identified as the gold standard. In
addition to progesterone and magnesium sulfate,
nifedipine and indomethacin have been shown to have
favorable responses in regards to delayed delivery
and maternal and fetal outcomes (Conde-Agudelo,
Romero & Kusanovic, 2011; Haas, Caldwell,
Kirkpatrick, McIntosh & Welton, 2012; Markham &
Klebanoff, 2014).
Tocolytic agents are given so that other medications,
like corticosteroids or magnesium sulfate, can be
administered for lung function and neuroprotection in
infants. By delaying delivery, tocolytics provide time
for the mother to be transferred to a facility that has
the resources to care for a premature birth, including
a NICU. Though proven effective in inhibiting
ontractility, some tocolytic agents (nifedipine, for
example) should be discontinued once labor has
subsided as long-term administration does not show
any effect on fetal outcomes (ACOG, 2012a). Oather
agents (progesterone, for example) can be continued
for maintenance tocolysis.
Magnesium sulfate
Magnesium sulfate has been used for its tocolytic effect
as a means to halt labor, though it is imperative to
monitor for negative side effects like nausea, headaches,
flushing and respiratory depression. Magnesium
sulfate has not been found to be an effective tocolytic in
preventing premature birth (Han, Crowther & Moore,
2013), but it does seem to be neourprotective for infants
when given antenatally to women in preterm labor.
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Prenatal and intrapartum strategies to prevent prematurity: A case study
Premature birth can cause deficiencies or damage
to a baby’s brain, resulting in deafness, blindness,
physical or mental impairments and cerebral
palsy (Doyle, Crowther, Middleton, Marret &
Rouse, 2010). Magnesium sulfate is commonly
administered to women at risk for premature
birth to reduce damage to a premature baby’s
brain and the risk of cerebral palsy. Doyle
and colleagues (2010) found an absolute risk
reduction of 1.6 percent for cerebral palsy in
infants whose mothers were treated antenatally
with magnesium sulfate compared to those who
were not. Given intravenously with a loading
dose of 4 to 6g followed by hourly doses of 1
to 3g for up to 24 hours, magnesium sulfate
demonstrates a significant reduction in cerebral
palsy (ACOG, 2010). ACOG (2013b) supports the
use of magnesium sulfate as both a tocolytic and a
neuroprotective agent.
Calcium channel blockers
Nifedipine, a calcium channel blocker, is a commonly
used tocolytic agent that has the capability to
delay delivery up to 7 days and prevent premature
birth before 34 weeks (Wisanskoonwong, Fahy &
Hastie, 2011). Nifedipine is relatively well tolerated
and has been shown to improve infant outcomes,
including RDS, necrotizing enterocolitis (NEC) and
intraventricular hemorrhage (IVH) (Conde-Agudelo
et al., 2011). Nifedipine is initially administered orally
at a dose of 20mg, followed by another 20mg orally
if contractions persist after 30 minutes. Additional
20-mg doses can be given orally every 3 to 8 hours for
2 to 3 days.
Prostaglandin inhibitor
Indomethacin is a nonsteroidal anti-inflammatory
drug used as a tocolytic agent. It is recommended only
for women who present with preterm labor before 32
weeks (ACOG, 2012a). Its duration is not to exceed
48 hours due to its potential for negative fetal side
effects (Haas, Caldwell, Kirkpatrick, McIntosh &
Welton, 2012).
Bed rest
Evidence does not support the use of bed rest for
prevention of premature birth. Bed rest has been
associated with negative adverse effects, such as
increased incidence of thromboembolism, a decrease
in maternal muscle mass and low birthweight (Biggio,
2013; Maloni, 2011; McCall, Grimes, Lylery, 2013;
McCarty-Singleton & Sciscione, 2014). Additionally,
neither pelvic rest nor intravenous fluids have
demonstrated any statistically significant results in
11
reducing the rate of premature birth in women who
experience preterm labor (McCarty-Singleton &
Sciscione, 2014; Stan, Boulvain, Pfister & HirsbrunnerAlmagbaly, 2013). However, while no formal guidelines
have been established, other behavioral interventions,
such as limiting strenuous activities and reducing the
number of hours spent standing (March of Dimes
et al., 2012) are thought to be beneficial. SaurelCubizolles and colleagues (2004) found that women
who spent more than 6 hours a day standing are at
significantly higher risk for premature birth.
Antibiotics
Intervention for women experiencing PPROM
includes antibiotic administration as the first line
of defense against infection. Though PPROM
may be the result of maternal infection, the use of
antibiotics has demonstrated success in preventing or
reducing the risk of neonatal infections. Antibiotics
are recommended for women who test positive
for group B streptococcus (GBS), to prevent
transmission to the infant during delivery (ACOG,
2011b). Antibiotics do not decrease the risk of
premature birth (except in women who have had a
previous premature birth or women who have BV
in their current pregnancy) (Wisanskoonwong et
al., 2011). They do, however, improve outcomes for
women with PPROM or infections, such as GBS.
Evidence suggests that this low-cost, efficacious
intervention is effective in preventing infections
and reducing complications, such as sepsis, RDS,
IVH, NEC and neonatal death (Cousens, Blencowe,
Gravett & Lawn, 2010). Frequently used agents
include ampicillin, erythromycin, clindamycin,
penicillin and amoxicillin with varying doses and
duration of therapy.
Antenatal corticosteroids (ACS)
ACS are given to women starting as early as 24
weeks gestation (ACOG, 2012a), when the risk
for premature birth is high and early delivery is
expected. These medications cross the placenta
to augment development and maturation of the
baby’s lungs, brain and other organs. The two most
commonly used corticosteroids are betamethasone
and dexamethasone. Betamethasone is given
intramuscularly in two 12-mg doses 24 hours apart,
and dexamethasone is given intramuscularly in 6-mg
doses 12 hours apart for a total of four doses in each
course of treatment (ACOG, 2012a).
Cerclage
Cervical cerclage is an intervention used to prevent
premature birth in singleton pregnancies before 34
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Prenatal and intrapartum strategies to prevent prematurity: A case study
weeks gestation in women diagnosed with a short
cervix (Wisanskoonwong et al., 2011). Studies
show that the use of a cerclage, coupled with the
administration of 17P, may reduce the rate of
premature birth in women with high-risk pregnancies
(Temming, Kirkland, Kullstam, Rozario, Mitra &
Joy, 2013). The use of a cerclage is not without risks,
however, and women may experience increased rates
of premature rupture of membranes or infections,
such a chorioamnionitis (Wisankoonwong et al.,
2011).
Case study part 5: Cynthia
Cynthia is admitted to the hospital and started
on the tocolytic agent nifedipine to halt her labor.
She is set up for a consult with an attending
maternal fetal medicine physician. She is given
magnesium sulfate intravenously with a loading
dose of 6g and an hourly dose of 2g for 24 hours
for neouroprotection. She receives two 12-mg
intramuscular doses of betamethasone 24 hours
apart for fetal lung maturity.
Cynthia’s labor subsides and she is discharged
from the hospital 2 days later. Her obstetrician
assures her that bed rest is not neccesary and
will not prevent her from experiencing another
episode of preterm labor. Her doctor tells her
that she may return to her normal activities,
including work; however she should assume a
reduced workload, limiting her heavy lifting and
reducing time standing on her feet. Her doctor
tells her to re-start her weekly progesterone
injections with the visiting nurse and to contact
her midwife if she starts experiencing signs of
early labor again.
Question for nurses: The doctor’s
recommendations may increase Cynthia’s stress.
How can you help Cynthia incorporate the
recommendations into her day?
Conclusion
Health care providers prefer to prevent preterm labor
and birth rather than treat their consequences. The
multifactorial etiology of premature birth contributes
to the extensive list of risk factors that nurses need to
be aware of when caring for pregnant women; it also
provides challenges for prevention.
12
Coordinated nursing care identifies women at risk
for preterm labor, and nurses seek to help decrease a
woman’s risk factors whenever possible. Nurses are
responsible for teaching women to recognize the signs
and symptoms of preterm labor and emphasizing
the importance of seeking care promptly when if
they have signs or symptoms. Early care of these
women allows for appropriate interventions to be
administered to reduce the sequelae of preterm labor
and premature birth.
In many cases, with appropriate antepartum care and
labor management, delivery can be delayed. Seeking
care promptly after the onset of preterm labor signs
and symptoms allows providers time to enhance lung
development with corticosteroid administration and
ensure neuroprotection with magnesium sulfate, if
appropriate. However, in scenarios where premature
birth is imminent, appropriate resources must be
available, such as a NICU or antibiotics, to reduce
perinatal mortality.
Case study part 6: Cynthia
At 39 weeks, Cynthia gave birth to a healthy 6
pound, 11 ounce baby girl.
Question for nurses: What nursing
interventions contributed to this positive birth
outcome?
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