Prevalence of Developmental and
Inflammatory Lesions in Nonmolar
First-Trimester Spontaneous Abortions
RAYMOND W, REDLINE, MD, MICHAEL ZARAGOZA,
AND TERRY HASSOLD, PHD
The management of patients with first-trimester spontaneous
abortions is handicapped by two problems: difficulty in recognizing
conceptions that abort because of abnormal karyotypes and an
incomplete understanding of what causes abortions with normal
karyotypes. Our goals in this study were to define features useful in
distinguishing normal from abnormal karyotype and to identify
pathological processes contributing to abortions with a normal
karyotype. The study population consisted of 668 well-characterized
first-trimester spontaneous abortions derived from a larger study of
1,054 consecutively karyotyped spontaneous abortions. Clinical factors increased in specimens with normal karyotype were maternal age
younger than 20 years (P = .0003) and autoimmune markers
(P = .0474). Developmental features associated with abnormal karyotype were developmental stage less than 6 weeks (P = .0017), hydropic villi greater than 1 mm (P = .0004), and villi with two or more
dysmorphic features (P = .0001). Developmental stage greater than
11.5 weeks was increased with normal karyotype (P = .0001). Histological features increased in specimens with a normal karyotype were
chronic intervillositis (P = .0003), increased perivillous fibrin deposition with intermediate trophoblast (P = .0006), decidual plasma cells
(P --- .0040), deciduitis without plasma cells (P = .0660), and chronic
villilis (P = .1581). Overall, 19% of samples with a normal karyotype
versus 8% with abnormal karyotype had one or more of these findings
(P < .0001). Autoimmune markers, chronic intervillositls, and increased perivillous fibrin with intermediate trophoblast all had
positive predictive values greater than 85% for normal karyotype,
whereas dysmorphic villi had a positive predictive value of 90% for
abnormal karyotype. Patients with recurrent spontaneous abortion
and normal karyotype were more likely to have one or more of the
histological features listed above (31%) than patients with normal
karyotype and no prior abortions (13%) and patients with recurrent
abortion and abnormal karyotype (11%). HUM PATHOL 30:93-100.
Copyright © 1999 by W.B. Saunders Company
Key words: chromosomal anomalies, chronic intervillositis, perivillous fibrin, plasma cells, recurrent abortion.
S p o n t a n e o u s a b o r t i o n s are i m p o r t a n t causes o f
r e p r o d u c t i v e loss that are p o o r l y u n d e r s t o o d a n d difficult to treat. 1-5 O n e p r o b l e m limiting progress in this
area is the difficulty in subclassifying patients into
a p p r o p r i a t e t r e a t m e n t groups. T h e first a n d m o s t fundam e n t a l distinction b e t w e e n p a t i e n t g r o u p s is karyotype,
yet it is n o t practical to karyotype all a b o r t i o n specimens. C o n c e p t u s e s with a b n o r m a l karyotypes are intrinsically a b n o r m a l a n d have little o r n o c h a n c e o f reaching term. T h o s e with n o r m a l karyotype a b o r t f o r a
variety o f reasons, i n c l u d i n g n o n c h r o m o s o m a l a n o m a lies, e x p o s u r e to teratogens, u n d e r l y i n g m a t e r n a l disease, o r failure o f the m o t h e r to a c c o m m o d a t e the fetal
allograft. Major progress in p r e v e n t i n g s p o n t a n e o u s
a b o r t i o n is unlikely until these latter processes are
clearly distinguished a n d b e t t e r u n d e r s t o o d .
We analyzed data f r o m a large p o p u l a t i o n - b a s e d
study o f 1,054 consecutively k a r y o t y p e d s p o n t a n e o u s
abortions accessioned in o u r d e p a r t m e n t over a 43m o n t h period. O u r goals were to d e t e r m i n e the prevalence, significance, a n d predictive value o f specific
clinical a n d p a t h o l o g i c a l factors in karyotically d e f i n e d
subsets o f abortions. Particular emphasis was placed o n
identifying patterns distinguishing patients with c h r o m o somally n o r m a l abortions a n d a history o f r e c u r r e n t
miscarriage.
MATERIALS AND METHODS
Study Population
The Case Western Reserve University Spontaneous Abortion Survey was a population-based study of 1,054 consecutively karyotyped spontaneous abortions of 20 weeks of gestation or less accessioned in the Pathology Department of
University Hospitals of Cleveland over a 43-month period
from August 20, 1993 to March 26, 1997. 6 University hospitals
and its affiliates serve a well-defined multiracial population of
private and staff patients from the Eastern Cuyahoga County
region. All patients in the system with threatened, incomplete,
or missed abortions had curettage performed in the clinics,
outpatient department, or operating rooms of the hospital,
and all of these specimens were submitted to Pathology.
Specimens were examined before fixation by a single pathologist (R.W.R.) and a trained technician, who separated the
tissue into fetal, villous, and endometrial fractions. All specimens had three or more tissue blocks submitted for paraffin
embedding, after which routine hematoxylin and eosin-stained
slides were prepared. One slide corresponded to the tissue submitted for karyotype (exclusively villous), and the remaining
slides contained a mixture of fetal, villous, and maternal tissues.
From the Departments of Pathology and Genetics, Case Western
Reserve, Cleveland, OH. Accepted for publication October 13, 1998.
Supported by a grant from the National Institutes of Health (R01
HD21341).
Address correspondence and reprint requests to Raymond W.
Redline, MD, Department of Pathology, University Hospitals Health
System, University Hospitals of Cleveland, 11100 Euclid Ave, Cleveland, OH 44106.
Copyright © 1999 by W.B. Saunders Company
0046-8177/99/3001-0017510.00/0
Cytogenetics
Villous tissue was processed by standard methods for
karyotypic analysis. Cells harvested after 1 to 3 weeks of
culture were stained for standard Q banding, and 10 or more
cells per culture were analyzed for most cases. Mosaicism was
defined as two or more identical nonmodal cells amongst the
10 or more cells analyzed. Karyotype was successful in 832 of
93
HUMAN PATHOLOGY
Volume 30, No. 1 (January 1999)
1,054 cases (79%), 778 of which aborted in the first trimester
of pregnancy (earlier than 14 weeks developmental age). The
following cases were excluded: complete and partial moles
(n = 7 and 21, respectively), samples with insufficient villous
tissue for histological analysis (n = 60), and samples with
46,XX karyotype having more than 20% maternal tissue on
the slide, which corresponded to the tissue submitted for
karyotype (n = 22). Molar gestations were excluded because
their unique phenotype made them difficult to compare with
nonmolar conceptuses. Phenotypic characterization of our
molar cases has been previously published. 6~ The remaining
668 cases (86% of successfully karyotyped first-trimester abortions) formed the basis for this study. The 350 cases with
abnormal karyotypes were separated into five groups: nonmosaie single and double trisomies (n = 215 and 10, respectively), nonmolar triploidy (n = 43), monosomy X (n = 15),
tetraploidy (n = 15), and others (n = 33; nine mosaic trisomies, nine simple translocations, two autosomal monosomies,
and 13 cases with a variety of other abnormalities including
marker chromosomes and complex karyotypes),
vessels containing a mixture of hydropic and hyalinized villi;
group 2--involuting abortions with numerous fetal vessels +fetal tissue; and group 3--fresh abortions with well-preserved
villi _+ fetal tissue. Group 3 cases were generally associated
with hemorrhagic or necrotic gestational endometrium and a
clinical history of threatened, complete, or incomplete abortion. The presence or absence of fetal tissue was defined by
histology and excluded extraembryonic fetal structures such
as umbilical cord, yolk sac, amnion, or circulating fetal blood
cells. Although not a specific focus of this study, many
first-trimester cases with abnormal karyotypes had embryonic
anomalies, as did a number of second-trimester cases with
normal karyotype. Only three cases of first-trimester abortion
with normal karyotype had anomalies (one club foot, one
nodular disorganized embryo, one dysmorphic facies). Dysmorphic villi were defined by the presence of at least two of
the following four elements: irregular villous contour, multiple villous trophoblast inclusions, villous stromal karyomegaly
(nucleus more than 3 times larger than adjacent nuclei), and
mazelike branching fetal vascular pattern. 6 Hydropic villi were
defined as r o u n d t o oval edematous villi measuring larger
than 1 m m in maximum diameter as measured on the
microscopic slide.
Clinical Features
Maternal age was available in all cases. Obstetric data
(previous spontaneous abortions, preterm deliveries, and
infertility problems) and medical history (diabetes, chronic
hypertension, autoimmune markers) were obtained from
requisitions accompanying study specimens. Relevant data
was provided with most specimens but analyses stratified for
history of previous spontaneous abortion were limited to cases
in which the presence or absence of prior spontaneous
abortions was explicitly specified.
Histological Features (Data
From Kaplan et a114and Redline 15)
Chronic villitis (vi!litis of unknown cause) was defined as
lymphohistiocytic infiltration of villous stroma with fibrosis or
necrosis and negative bacterial stains. Chronic intervillosifis
cases lacked villitis and were separated into two groups: diffuse
chronic intervillositis consisting of a monomorphic population of monocyte-macrophages diffusely packing the intervillous space with or without accompanying fibrin and focal
intervillositis consisting of a less extensive and mixed inflammatory infiltrate, including lymphocytes, monocyte-macrophages, and neutrophils: Cases with mixed inflammatory
infiltrates were stained for bacteria and spirochetes using
silver impregnation techniques as previously discussed. 16 Diffuse perivillous fibrin with intermediate trophoblast was
defined as a uniform near-total obliteration of the intervillous
space by a combination of inflammatory cells and fibrin-like
material, with the latter predominating. Controversy exists
regarding the exact nature of this fibrin-like material. It may
represent true fibrin, extracellular matrix proteins, or a
combination of both. For the purposes of clarity, it is referred
to as fibrin in this report. This fibrin is characteristically
heavily infiltrated by intermediate trophoblast and overlaps
with maternal floor infarction as defined for second- and
third-trimester placentas. Many of the patients with perivillous
fibrin in our study also had either chronic intervillositis or
chronic villitis. Decidual plasma cells were identified in the
maternal endomyometrium by typical cytological features.
Deciduifis (other) consisted of clusters of mononuclear cells,
often surrounding decidual arteries, and subjectively greater
in extent than that normally seen with first-trigAester gestation.
Pathological Analysis
Pathological features were assessed by a single pathologist
(R.W.R.). To obtain an estimate of intraobserver variation, we
compared the final evaluation of cases done after completion
of the study with an earlier set of observations p e r f o r m e d on
100 cases early in the specimen collection phase of the study.
Developmental Phenotype
Assignment of developmental stage (<6.0 weeks, 6.0 to
11.5 weeks, and 11.5 to i4.0 weeks from the last menstrual
period) was based on a staged set of elective abortion
specimens available in our laboratory, the diameter of the
chorionic sac, and a variety of other developmental criteria
that have previously been described in detail. 6 The stages used
c o r r e s p o n d to primary vasculogenesis and secondary villous
formation (<6.0 weeks),9,10 branching of primitive mesenchymal villi (6.0 to 8.5 weeks),11 presence of immature intermediate stem villi and apposition of amnion to chorion (8.5 to 11.5
weeks), 9,11 and establishment of the definitive placenta with
polarization of the chorion laevae and complete maternal
arterial perfusion of the intervillous space (>11.5 weeks);9,12
The relationship between our assessment of developmental
stage and clinically estimated gestational age has been discussed previously.6 For the purposes of this study, we combined the 6.0- to 8.5- and 8.5- to ll.5-week stages, which are
the most difficult to distinguish from one another, into a
single group.
Spontaneous abortions also were classified into three
major groups based on criteria developed by Rushton. is In
brief, these groups were defined as follows: group 1--anembryonic abortions ("blighted ova") with rare or absent fetal
Statistical Analysis
Chi-square analysis or Fisher's exact tests were used for
group data. Significance was set at P = .05. Positive and
negative predictive values of clinical and pathological variables for predicting karyotype were calculated as true positives/
total positives and true negatives/total negatives, respectively,
94
SPONTANEOUSABORTIONAND KARYOTYPE(Redline et al)
and a positive predictive value of 85% or greater was arbitrarily chosen as useful.
P = .0017), dysmorphic villi ( P = .0001), and villous
hydrops (>1 m m diameter, P = .0004) (Tables 2 and
3). Early developmental stage was most c o m m o n with
trisomy and tetraploidy. Dysmorphic and hydropic villi
were increased in all subgroups of chromosomal abnormality. The association of dysmorphic villi with abnormal karyotype was equally strong after exclusion of
triploid cases (P < .0001, 87% positive predictive value).
The p r o p o r t i o n of cases in each Rushton group (see
Materials and Methods) and the presence or absence of
fetal tissue by histological examination differed little in
specimens with normal versus abnormal karyotype. Of
the developmental features evaluated, only the presence of dysmorphic villi had a high positive predictive
value (90%) for abnormal karyotype.
RESULTS
Clinical History
Normal karyotype was m o r e frequent in the spontaneous abortion specimens of mothers younger than 20
years of age (P = .0003) and in those with a u t o i m m u n e
markers ( P = .0474) (Tables 1 and 2). T h e specific
a u t o i m m u n e markers in the six patients with normal
karyotype were frank systemic lupus erythematosus
(two patients), positive antinuclear antibody (three
patients), and antiphospholipid antibodies (one patient). Patients with a history of prior spontaneous
abortion were m o r e likely to have a n o r m a l karyotype
(5.0% v 2.6%) and age greater than 35 was m o r e
c o m m o n in patients with an abnormal karyotype (35%
v 24%), but neither finding reached statistical significance. The increase in patients older than 35 years of
age in cases with abnormal karyotype was attributable to
trisomic cases (43% over 35 years of age for trisomy v
24% for normal karyotype and 26% for abnormal
karyotypes o t h e r than trisomy, P < .0001). Adverse
obstetric factors other than prior spontaneous abortion
(infertility, prior p r e t e r m delivery, or uterine malformation) and a history of either diabetes or essential
hypertension were u n c o m m o n and equivalent in the
two groups. A u t o i m m u n e markers had a positive predictive value of 86% for normal karyotype, whereas the
positive predictive value of o t h e r clinical variables was
poor. A general finding applicable to all variables
studied was that absence of a feature had little or no
predictive value (ie, low predictive value of the negative,
Table 2).
Idiopathic Chronic Inflammation
a n d Fibrin Deposition
The presence of one or more histological abnormalities indicative of chronic inflammation or fibrin
deposition was significantly increased in abortions with
a normal karyotype (19% v 8%, P < 0.0001, Table 4).
Individual lesions significantly increased with normal
karyotype were chronic intervillositis, increased perivillous fibrin with intermediate trophoblast, and decidual
plasma cells. Deciduitis without plasma cells (P = .0660)
and chronic villitis (P = .1581) were increased but did
not reach statistical significance. The predictive value of
a positive result was highest for chronic intervillositis
(93%) and increased perivillous fibrin with intermediate trophoblast (85%) (Table 2). These two lesions are
shown in Figure 1. Finally, in the limited n u m b e r of
cases in which prior spontaneous abortion status was
known (n = 50), the prevalence of one or more histological abnormalities was 31% in r e c u r r e n t aborters
with normal karyotype versus 13% in first-time aborters
with a normal karyotype, 11% in r e c u r r e n t aborters
with an abnormal karyotype, and 0% in first-time
aborters with an abnormal karyotype (Table 4). These
results did not achieve statistical significance because of
small numbers.
Developmental Features
Normal karyotype was significantly more c o m m o n
in abortion specimens of late developmental stage
(>11.5 weeks, P = .0001). Abnormal karyotype was
associated with early developmental stage ( < 6 weeks,
TABLE ].
Clinical History of Women With Nonmolar First-Trimester Spontaneous Abortions by Karyotype
Maternal Age (y)
Karyotype
Normal
46,XY
46,XX
Total
Abnormal
Trisomy
Triploidy
Monosomy X
Tetraploidy
Others
Total
Clinical History
N
<20
20-35
>35
Previous
SAB*
Obstetric
(Other) *
Hypertension
or Diabetes
145
173
318
18
21
39 (12)t
101
103
204 (64)
26
49
75 (24)
6
10
16 (5)
2
4
6 (2)
1
4
5 (2)
3
3
6 (2)
225
43
34
15
33
350
5
4
5
0
1
15 (4)
124
35
22
11
18
212 (61)
96
4
6
4
13
123 (35)
7
1
0
0
1
9 (3)
4
1
0
0
2
7 (2)
3
0
0
0
1
4 (1)
1
0
0
0
0
1 (<1)
*Obstetric (other) = infertility, previous preterm delivery, or uterine malformation.
tNumber of patients (percentage of total).
Abbreviation: SAB, spontaneous abortion.
95
Autoimmune
Markers
HUMAN PATHOLOGY
Volume 30, No. 1 (January 1999)
TABLE 2. Prevalence, Significance, and Predictive Values of Clinicopathologic Factors by Karyotype
Karyotype
Normal (%)
A. Clinical History
Age <20 y
Autoimmune markers
B. Developmental phenotypes
Stage
< 6 wks
>11.5 wks
Dysmorphic villi
Hydropic villi
C. Histologic abnormalities
Any
Chronic intervillositis (any)
Perivillous fibrin
Plasma cells
Deciduitis (other)
Chronic villitis
Predictive Value
Abnormal (%)
Negative
3.0
.6.7
.0003
.0474
72
86
54
53
7.2
16.7
2.2
8.5
12.9
6.3
17.4
17.7
0.5
3.0
0.1
0.4
.0017
.0001
.0001
.0004
66
71
90
70
51
45
48
50
19.2
4.4
5.4
9.1
7.2
1.3
8.0
0.3
0.9
3.7
4.0
0.3
2.7
16.1
6.5
2.6
1.9
4.4
<.0001
.0003
.0006
.0040
.0660
.1581
69
93
85
69
62
80
44
47
47
46
47
47
assess their reproducibility. 22 In our study, objective
criteria were established before the analysis using previous data from the literature. All observations were made
by a single pathologist who was blinded to the clinical
history and karyotype. Reproducibility was estimated by
comparison of the final diagnoses with a preliminary
reading done by the same observer after ascertainment
of the first 100 cases. Intraobserver agreement ranged
from 91% to 100% for all criteria measured. The use of
a single observer ensures uniform application of criteria but fails to address the issue of interobserver
variation. Previous studies of fetoplacental diagnosis
have shown that good interobserver variation can be
achieved with strict definitions and a period of training
to learn how to apply criteriaY These latter issues,
though important, were outside of the scope of this
study.
Only two clinical factors were significantly increased in abortions with a normal karyotype, age
younger than 20 years and autoimmune markers. Of
Developmental Phenotype of Nonmolar First-TrimesterSpontaneous Abortions by Karyotype
Rushton Groupt
Developmental Stage*
Normal
46,XY
46,XX
Total
Abnormal
Trisomy
Triploidy
Monosomy X
Tetraploidy
Others
Total
Positive
4.3
0.3
Previous studies comparing pathological features
to karyotype in spontaneous abortions have been handicapped by one or more of the following factors: small
sample sizes, referral bias based on using only cases
submitted to a cytogenefics laboratory, lack of clinical
history, or limited histological analysis. 17-21 Our study
included all spontaneous abortions occurring in patients managed by physicians associated within a large
primary health care system over a 43-month period.
Clinical history was derived from pathology requisitions, which included maternal age in all cases and
gestafional age, mode of presentation, and relevant
clinical history in most cases. Although information
derived from these requisitions may underestimate the
overall prevalence of some conditions, there is no
reason to assume any ascertainment bias relative to
karyotype, which was the major focus of this study.
Any study evaluating the utility of pathological
diagnoses should clearly define diagnostic criteria and
Karyotype
P
12.3
1.9
DISCUSSION
TABLE 3.
Odds
Ratio
N
<6
6-11.5
>11.5
1
2
3
Fetal
Tissue
Dysmorphic
Villi++
Hydropic
Villi§
145
173
318
9
14
23 (7)]]
150
118
268 (84)
33
20
53 (17)
44
76
120 (38)
71
55
126 (40)
30
42
72 (23)
56
40
96 (30)
4
3
7 (2)
9
18
27 (9)
225
43
34
15
33
350
28
8
1
5
3
45 (13)
188
26
27
10
28
283 (81)
9
5
6
0
2
22 (6)
100
10
5
11
18
144 (41)
65
18
19
2
10
114 (33)
60
11
10
2
5
88 (25)
32
16
13
0
8
69 (20)
39
13
5
2
2
61 (17)
48
4
2
2
6
62 (18)
*Developmental stage = estimated gestational age weeks from last menstrual period by morphology.
tRushton group 1, anembryonic/involuted; 2, partially involuted with fetal vessels; 3, well-preserved villi.
++Twoor more of the following: irregular villous contour, trophoblast inclusions, atypical stromal cells, abnormal fetal vessels.
§Greater than 1 mm. maximum diameter.
][Number of patients (percentage of total).
96
SPONTANEOUS ABORTION AND KARYOTYPE(Redline et al)
TABLE 4.
Histological Chronic Inflammation and Fibrin Deposition by Karyotype in Patients
With and Without Previous Spontaneous Abortions
Specific Abnormalities$
Intervillositis
N
Any
Abnormality~
Chronic
Villitis
Diffuse
Focal
Perivillous
Fibrin
Plasma
Cells
Deciduitis
(Other)
>1
16
5 (31)
0
2
1
3
4
1
1
15
2 (13)
0
0
0
0
1
1
287
318
9
10
331
350
54 (19)
61 (19)§
l (11)
0 (0)
27 (8)
28 (8)
4
4
0
0
1
1
5
7
0
0
1
1
6
7
0
0
0
0
14
17
1
0
2
3
24
29
0
0
13
13
21
23
1
0
13
14
SAB*
Status
Karyotype
Normal
Abnormal
Unknown
Total
>1
1
Unknown
Total
*SABStatus: >1 = previous spontaneous abortion; 1 = no previous spontaneous abortions.
mAnyabnormality: any one of the specific abnormalities listed.
++SeeMaterials and Methods for details.
§Number of patients (percentage of total).
f r o m the seven p a t i e n t s i n the study with a u t o i m m u n e
m a r k e r s h a d histological features o f c h r o n i c i n f l a m m a t i o n or f i b r i n d e p o s i t i o n . A u t o i m m u n e disease a n d
a n t i p h o s p h o l i p i d a n t i b o d i e s have b e e n associated previ-
these, o n l y a u t o i m m u n e m a r k e r s h a d a g o o d predictive
value (86%) for n o r m a l karyotype. This result s h o u l d
b e r e g a r d e d with c a u t i o n b e c a u s e o f the small n u m b e r
o f cases involved. O n l y o n e o f the a b o r t i o n s p e c i m e n s
FIGURE 1. Histological features of massive intervillositis and diffuse perivillous fibrin deposition with intermediate trophoblast
("maternal floor infarction"). (A) Massive chronic intervillositis is characterized by diffuse infiltration of the intervillous space by
monomorphic monocytoid cells in association with patchy fibrin deposition (cytological features of the infiltrate are shown in the
inset at the top left). The villi themselves are generally spared (ie, lack chronic villitis), and intermediate trophoblast are not present.
(B) Diffuse perivillous fibrin deposition with intermediate trophoblast consists of obliteration of large segments of the intervillous
space by the deposition of fibrin in association with intermediate trophoblast. Inflammatory cells are often present but are not a
major component of the lesion. (H&E-stained sections, original magnification x26.)
97
HUMAN PATHOLOGY
Volume 30, No, 1 (January 1999)
ously with recurrent abortion, but karyotype data have
not routinely been available. 2~-25
A n u m b e r of clinical factors commonly thought to
be predictive of karyotype were similar in the two
groups. 2~3°Advanced maternal age was increased in the
subset of cases with trisomy but not in the abnormal
karyotype group as a whole. In part this may reflect a
trend toward delayed childbearing resulting in a general increase in older mothers. Obstetric factors such as
recurrent abortion and infertility and maternal medical
conditions such as diabetes or hypertension also were
not overrerpresented in either group. The finding that
chromosomal abnormalities are not infrequent in patients with recurrent abortion and infertility has been
reported previously. 26,31 Possible explanations include
genetic predisposition to abnormal gametogenesis or
defects in the normal surveillance mechanisms that
eliminate abnormal conceptuses at a stage before recognition of pregnancy. No good data exist to support
either of these suggestions.
In our analysis of developmental features, we found
that abortions with abnormal karyotype were more
likely to occur at an early developmental age (<6
weeks), whereas those with normal karyotype were
more likely to abort later (>11.5 weeks). There was
considerable overlap between the two groups, and the
ability of developmental age to predict karyotype was
low. A second measure of developmental phenotype
separates abortions into groups based on the timing of
fetal/embryonic loss. is Group 1 abortions are anembryonic gestations with changes suggesting either failure of
embryonic development or very early embryonic death.
Group 2 gestations show changes roughly paralleling
those seen in intrauterine fetal deaths at later gestations, and Group 3 abortions have changes suggesting
very recent death. The proportion of cases in each
group was virtually identical for abortions with normal
and abnormal karyotype. Previous data suggesting that
groups 2 and 3 were more c o m m o n in abortions with
normal karyotype may be due to the inclusion of
second-trimester abortions, which usually have a normal karyotype and are virtually never anembryonic.
Hydropic villi greater than 1 m m in diameter were
significantly increased with abnormal karyotype, especially in trisomic conceptuses, but approximately 10%
of the normal karyotype group also had hydropic villi,
and the predictive value of this feature was low.
The only developmental feature predictive of abnormal karyotype was villous dysmorphism. Dysmorphic
villi were useful when present (17% with abnormal
karyotype v 3% with normal karyotype), but most cases
with chromosomal abnormalities lacked this feature. A
standard definition of dysmorphic villi does not exist,
but most observers would agree on some combination
of irregular villous contour, trophoblast inclusions,
atypical stromal cells, and an abnormal fetal vascular
pattern. 17-22These patterns tend to cluster together, and
we required that at least two of the four criteria be
present for diagnosis. Previous studies have found an
association between dysmorphic villi and abnormal
karyotype, but some have argued that this relationship
is entirely accounted for by the triploid subgroup. 2° In
our study, dysmorphic villi were significantly associated
with and strongly predictive of abnormal karyotype,
even after the exclusion of triploid gestation. The
specific karyotypes other than triploidy that most commonly had dysmorphic villi in our study were trisomies
7, 8, 13, 16, and 18 and monosomy X (data not shown).
Finally, in what we consider to be the most important result of the study, we found that a group of
partially overlapping histological findings indicative of
chronic inflammation or perivillous fibrin deposition
were significantly increased in patients with normal
karyotype. These findings affected only a subgroup
(19%) of cases and wereparticularly frequent in patients with recurrent spontaneous abortion (31%). The
increased prevalence of these findings in patients with
previous abortions was limited to cases with a normal
karyotype, arguing against nonspecific changes related
to prior curettage. Chronic inflammation of the decidua was more c o m m o n but less specific for normal
karyotype than lesions of intervillous space and villous
stroma, which were seen almost exclusively with normal
karyotype. Although chronic inflammatory lesions have
been previously reported in as many as 13% of firsttrimester abortions, 17 to our knowledge only one previous study has correlated these changes with karyotype. 19
This latter study identified chronic intervillositis and
decidual perivasculitis as increased in chromosomally
normal abortions. Chronic inflammation or fibrin deposits in spontaneous abortions also could relate to nonchromosomal genetic defects in either the mother or
fetus. Two recently described molecular defects that
potentially could lead to early pregnancy losses associated with chronic inflammation and fibrin deposition
are abnormalities in tryptophan metabolism and factor
V Leiden mutations. 32,3~
In our study, decidual inflammation was associated
with normal karyotype only in the presence of plasma
cells. Endometrial plasma cells are a well-recognized
indicator of persistent antigenic stimulation in the
uterus of both pregnant and n o n p r e g n a n t patients.
Patients with endometrial plasma cells often present
with uterine bleeding and infertility, and they have an
increased incidence of chronic villitis during pregnancy. 1~,s4,35 Our finding of decidual plasma cells in
patients with recurrent abortions correlates with a
recent flow cytometric study that showed an increased
proportion of decidual B-lymphocytes in these patients. ~6
Diffuse perivillous fibrin with intermediate trophoblast, also known as maternal floor infarction, is strongly
associated with recurrent reproductive failure but has
usually been described at later gestational ages. 37 The
term maternal floor infarction is unfortunate, because
there is no evidence to suggest that the lesion has any
relationship to ischemia or vascular occlusion. Patients
with maternal floor infarction often have a history of
prior first-trimester abortions. The underlying cause of
maternal floor infarction is unknown, but an associa-
98
SPONTANEOUS ABORTION AND KARYOTYPE(Redline et al)
tion with maternal a u t o i m m u n e disease has been f o u n d
in some studies. 38 The exact nature of the perivillous
fibrin remains controversial and may vary from case to
case. Most observers agree that it consists of some
combination of true fibrin and trophoblast-derived
extracellular matrix products. 39
Idiopathic diffuse or massive chronic intervillositis
has b e e n r e p o r t e d in occasional patients with r e c u r r e n t
abortion and may represent an inappropriate i m m u n e
response to trophoblast antigens. 4°,41 Intervillositis is
believed to occur in association with increased local
levels of t u m o r necrosis factor-alpha and gamma interferon. 41,42 Interestingly, both of these cytokines have
been shown to increase the expression of leukocyte
adhesion molecules on trophoblast in vitro. 43 Both
cytokines are also markedly elevated in placental blood
samples from women with placental malaria, which is
also characterized by diffuse chronic intervillositis. 44
The eight patients with diffuse chronic intervillositis
r e p o r t e d in this study are a subset of 14 patients that we
have identified in our institution with this lesion. Eight
of the 14 patients have a history of r e c u r r e n t spontaneous abortion, and several of the others have a history of
intrauterine growth retardation or second-trimester loss
(unpublished results). None of the patients in our
series have any indication of underlying infections as
d e t e r m i n e d by special stains, elevated white blood cell
counts, or other clinical history.
To summarize our study, we f o u n d that abortion
with normal karyotype occurs more frequently in young
patients at late developmental stages. These abortions
lack dysmorphic villi and are occasionally associated
with maternal a u t o i m m u n e abnormalities. A distinct
subgroup of specimens, many of whom are from patients with r e c u r r e n t abortion, have histological indicators of chronic inflammation or fibrin deposition.
Further investigation of these latter patients will be of
interest to see whether they respond to various immunomodulatory therapies currently u n d e r investigation such
as intravenous immunoglobulin administration or progesterone supplementation.
Acknowledgment. T h e a u t h o r s t h a n k D e b r a Ozan, Elise
Milley, a n d L u A n n J u d i s for t e c h n i c a l assistance.
REFERENCES
1. Bennett MJ, Edmonds DK: Spontaneous and recurrent abortion. Chicago, IL, Blackwell Scientific Publications, 1987
2. Stirrat GM: Recurrent miscarriage l: Definition and epidemiology. Lancet 336:673-675, 1990
3. Stirrat GM: Recurrent miscarriage II: Clinical associations,
causes, and management. Lancet 336:728-733, 1990
4. Coulam CB: Epidemiology of recurrent spontaneous abortion. A m J Reprod Immunol 26:23-27, 1991
5. HemminkiE: Treatment of miscarriage: Current practice and
rationale. Obstet Gyneco191:247-253, 1998
6. Redline RW, Hassold T, Zaragoza MV: Prevalence of the
partial molar phenotype in triploidy of maternal and paternal origin.
HuM PATHOL28:505-511, 1998
7. Keep D, Zaragoza M, Hassold T, et al: Very early complete
hydatidiform mole. HUM PATHOL27:708-713, 1996
99
8. Zaragoza MV, Keep D, Genest DR, et al: Early complete
hydafidiform moles contain inner cell mass derivatives. Am J Med
Genet 70:273-277, 1997
9. Hertig A. Human Trophoblast. Springfield, IL, CC Thomas,
1968, p 137
10. Kalousek DK, Neave C: Pathology of abortion, the embryo,
and the previable fetus, in Wigglesworth JS, Singer DB (eds):
Textbook of Fetal and Perinatal Pathology. Boston, MA, Blackwell
Scientific Publications, 199l, pp 123-160
11. Benirschke K, Kaufmann P: Pathology of the Human Placenta (ed 3). NewYork, NY, Springer-Verlag, 1995, pp 28-33
12. Jaffe R, Jauniaux E, HustinJ: Maternal circulation in the first
trimester human placenta: Myth or reality: Am J Obstet Gynecol
176:695-705, 1997
13. Rushton DI: The classification and mechanisms of spontaneous abortion. Perspect Pediatr Pathol 8:269-287, 1984
14. Kaplan C, Lowell DM, Salafia C: College of American
Pathologists Conference XIX on The Examination of the Placenta:
Report of the Working Group on the Definition of Structural Changes
Associated with Abnormal Function in the Maternal/Fetal/Placental
Unit in the Second and Third Trimesters. Arch Pathol 115:709-716,
1991
15. Redline RW: Disorders of the placental parenchyma, in Lewis
S, Perrin E (eds) : Pathology of the Placenta: Contemporary Issues in
Surgical Pathology (ed 2). NewYork, NY, Churchill Livingston, 1998,
pp 161-184
16. Redline RW: Recurrent villitis of bacterial etiology. Pediatr
Pathol 6:995-1002, 1996
17. Ornoy A, Salamon-Arnon J, Ben-Zur Z, et al: Placental
findings in spontaneous abortions and stillbirths. Teratology 24:243252, 1981
18. Novak R, et al: Histologic analysis of placental tissue in first
trimester abortions. Pediatr Pathol 8:477-482, 1988
19. Salafia C, Maier D, Vogel C, et ah Placental and decidual
histology in spontaneous abortion: Detailed description and correlations with chromosome number. Obstet Gyneco182:295-303, 1993
20. Van Lijnschoten G, ArendsJW, Leffers P, et al: The value of
histomorphological features of chorionic villi in early spontaneous
abortion for the prediction of karyotype. Histopathology 22:557-563,
1993
21. Genest GR, Roberts D, Boyd T, et al: Fetoplacental histology
as a predictor of karyotype: A controlled study of spontaneous first
trimester abortions. HUM PATHOL26:201-209, 1995
22. Vanlijnschoten G, Arends JW, Delafuente, et al: Intraobserver and inter-observer variation in the interpretation of histological features suggesting chromosomal abnormality in early abortion
specimens. Histopathology 22:25-29, 1993
23. Out HJ, Bruinse HW, Derksen RMWM: Anti-phospholipid
antibodies and pregnancy loss: Review. Hum Reprod 6:889-897, 1991
24. Nayar R, Lage JM: Placental changes in a first trimester
missed abortion in maternal systemic lupus erythematosus with
antiphospholipid syndrome: A case report and review of the literature. HUM PATHOL27:201-206, 1996
25. Iijima T, Tada H, HidakaY, et ah Effects of autoantibodies on
the course of pregnancy and fetal growth. Obstet Gyneco190:364-369,
1997
26. Cowchock FS, Gibas Z, Jackson LG: Chromosome errors as a
cause of spontaneous abortion: The relative importance of maternal
age and obstetric history. Fertil Steri159:1011-1014, 1993
27. Tulppala M, Paluosa T, Ramsay T, et al: A prospective study of
63 couples with a history of recurrent spontaneous abortion: Contributing factors and outcome of subsequent pregnancies. Hum Reprod
8:774-770, 1993
28. Hakim RB, Gray RH, Zacur H: Infertility and early pregnancy
loss. AmJ Obstet Gyneco1172:1510-1517, 1995
29. Coulam CB, Wagenknecht D, McIntyreJA, et al: Occurrence
of other reproductive failures among women with recurrent spontaneous abortion. A m J Reprod Immunol 25:96-98, 1991
30. Miodovnik M, Lavin JR Knowles HC, et ah Spontaneous
abortion among insulin-dependent diabetic women. Am J Obstet
Gyneco1150:372-376, 1984
31. Coulam CB, Stephenson M, Stern U, et ah Immunotherapy
HUMAN PATHOLOGY
Volume 30, No. 1 (January 1999)
for recurrent pregnancy loss: Analysis of results from clinical trials.
AmJ Reprod Immuno135:352-359, 1996
32. Munn DH, Zhou M, Attwood JT, et al: Prevention of
allogeneic fetal rejection by tryptophan metabolism. Science 281:11911193, 1998
33. Ridker PM, Miletich JP, Buring JE, et al: Factor V Leiden
mutation as a risk factor for recurrent pregnancy loss. Ann Intern
Med 128:1000-1003, 1998
34. Rotterdam H: Chronic endometritis: A clinicopathologic
study. Pathol Annu II:209-222, 1978
35. Czernobilsky B: Endometritis and infertility. Fertil Steril
30:119-130, 1978
36. Lachapelle MH, Miron P, Hemmings R, et al: Endometrial T,
B, and NK cells in patients with recurrent spontaneous abortion:
Altered profile and pregnancy outcome. J Immunol 156:4027-4034,
1996
37. Andres RL, Kuyper W, Resnik R, et al: The association of
maternal floor infarction of tile placenta with adverse perinatal
outcome. AmJ Obstet Gynecol 163:935-938, 1990
38. Mandsager NT, Bendon R, Mostello D, et al: Maternal floor
infarction of placenta: Prenatal diagnosis and clinical significance.
Obstet Gyneco183:750-754, 1994
39. Frank HG, Malekzadefi F, Kertschanska S, et al: Immunohistochemistry of two different types of placental fibrinoid. Acta Anat
150:55, 1994
40. Jacques SM, Qureshi F: Chronic intervillositis of the placenta. Arch Pathol Lab Med 117:1032-1035, 1993
41. Doss BJ, Greene ME Hill J, et al: Massive chronic intervillositis associated with recurrent abortions. HUM PATHOL 26:1245-1251,
1995
42. Hill JA, Melling GC, Johnson PM: Immunohistochemical
studies of human uteroplacenta] tissues from first-trimester spontaneous abortion. A m J Obstet Gynecol 173:90-96, 1995
43. Xiao J, Garcia Lloret G, Winklerlowen B, et al: ICAM-1mediated adhesion of peripheral blood monocytes to the maternal
surface of placental syncytiotrophoblasts: Implications for placental
villitis. AmJ Patho1150:1845-1860, 1997
44. Fried M, Muga RO, Misore AO, et al: Malaria elicits type 1
cytokines in the h u m a n placenta: IFN-y and TNF-a associated with
pregnancy outcomes.J Immuno1160:2523-2530, 1998
100