Human Reproduction, Vol.26, No.8 pp. 2092– 2100, 2011
Advanced Access publication on May 5, 2011 doi:10.1093/humrep/der127
ORIGINAL ARTICLE Psychology and counselling
During IVF treatment patient
preference shifts from singletons
towards twins but only a few patients
show an actual reversal of preference
Audrey A.A. Fiddelers 1,*, Fred H.M. Nieman 1, John C.M. Dumoulin 2,
Aafke P.A. van Montfoort 2, Jolande A. Land 3, Johannes L.H. Evers 2,
Johan L. Severens 1,4, and Carmen D. Dirksen 1
1
Department of Clinical Epidemiology and Medical Technology Assessment, Research Institute Grow and Development (GROW)
and Care and Public Health Research Institute (CAPHRI), PO Box 5800, 6202 AZ Maastricht, The Netherlands 2Department of Obstetrics
and Gynaecology, Academic Hospital Maastricht, PO Box 5800, 6202 AZ Maastricht, The Netherlands 3Department of Obstetrics and
Gynaecology, University Medical Centre Groningen, Groningen, The Netherlands 4Department of Health Organisation, Policy, and
Economics, Maastricht University, PO Box 616, 6200 MD Maastricht, The Netherlands
*Correspondence address. E-mail: audrey.fi[email protected]
Submitted on August 13, 2009; resubmitted on February 24, 2011; accepted on March 25, 2011
background: Knowledge of patients’ preferences for elective single embryo transfer (eSET) or double embryo transfer (DET) and for
singletons or twins is of great importance in counselling for embryo transfer (ET) strategies. In this study, the stability of IVF patients’ preferences over time for either a healthy single child or healthy twins was measured and we investigated which factors could explain preference
shifts.
methods: Infertile women (n ¼ 177) who participated in an RCT comparing one cycle eSET with one cycle DET were included. A satisfaction questionnaire was developed to measure patient preferences and attitudes at two moments in time, i.e. at 2 weeks before ET and at
2 weeks following ET, after the results of the pregnancy test. Regression analysis examined the effect of several variables on preference shifts.
results: Before ET, most patients expressed a preference for a singleton, whereas most patients were indifferent 2 weeks after ET,
resulting in an overall preference shift towards twins (P ¼ 0.002; n ¼ 145). Overall, 62% of patients showed a preference shift. Preference
shifts were explained by patients’ global satisfaction of the information given by the fertility clinic staff received by the fertility clinic staff, and
an interaction between the occurrence of pregnancy and transfer policy (eSET or DET).
conclusions: In general, patients’ preferences for a singleton or twins are not stable during IVF treatment. Possible explanations of a
shift in preference are that pregnant patients attuned their preferences to what they expect their pregnancy to result in, whereas non-pregnant patients shifted towards a preference for twins in order to be able to fulfil their ultimate child wish.
Key words: IVF / singletons / twins / patient preferences
Introduction
Multiple pregnancies are considered a serious complication of assisted
reproduction technology because of the relative high incidence in
maternal, perinatal and childhood morbidity and mortality (Land and
Evers, 2003). In Europe, during 2005, the distribution of singleton
and multiple deliveries for both IVF and ICSI was 78.2 and 21.8%,
respectively (Nyboe Andersen et al., 2009), which means that
40% of IVF children are multiples. The only successful way to
reduce the incidence of twin pregnancies to naturally occurring
levels (i.e. 1.2%) is to transfer only one embryo. In the past few
years, several effectiveness and cost-effectiveness studies have been
performed, comparing elective single embryo transfer (eSET) to
double embryo transfer (DET) (Wolner-Hanssen and Rydhstroem,
1998; Gerris et al., 1999, 2004; Martikainen et al., 2001; De Sutter
et al., 2002, 2003; Gardner et al., 2004; Thurin et al., 2004; Lukassen
et al., 2005; Fiddelers et al., 2006, 2009; van Montfoort et al., 2006;
Bhatt and Baibergenova, 2008; Polinder et al., 2008; Veleva et al.,
2009). These studies show that DET is both more effective and
more expensive than eSET under all circumstances. However, the
& The Author 2011. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved.
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Changes in preference for singleton or twins during IVF
question of which transfer strategy is to be preferred (Fiddelers et al.,
2006, 2007, 2009) depends on more conditions and circumstances
than costs and effectiveness only. Knowledge of patients’ preferences
and attitudes towards either eSET or DET and towards singletons
versus twins are at least as important in deciding how many
embryos to transfer. The assessment of patient preferences for
embryo transfer (ET) policy (Murray et al., 2004; Blennborn et al.,
2005; Hojgaard et al., 2007; Newton et al., 2007, Ryan et al., 2007;
Twisk et al., 2007; Hope and Rombauts, 2010) or for outcomes of
IVF treatment (Gleicher et al., 1995; Grobman et al., 2001; Kalra
et al., 2003; Pinborg et al., 2003; Child et al., 2004; Ryan et al.,
2004; Hojgaard et al., 2007) has already received much attention.
Most studies focusing on patients attitudes have shown that patients
generally have a preference for DET over eSET (Murray et al., 2004;
Hojgaard et al., 2007; Newton et al., 2007; Ryan et al., 2007; Twisk
et al., 2007), except when pregnancy rates for eSET are equal or
higher compared with those of DET (Murray et al., 2004; Ryan
et al., 2007; Twisk et al., 2007). Also, patients tend to prefer twins
over a singleton (Gleicher et al., 1995; Grobman et al., 2001;
Pinborg et al., 2003; Hojgaard et al., 2007).
A general characteristic of these studies is that they all have determined patient preferences at one moment in time, mostly before the
start of IVF treatment (before ET) (Child et al., 2004; Murray et al.,
2004; Ryan et al., 2004; Hojgaard et al., 2007; Newton et al., 2007;
Twisk et al., 2007). Only two studies assessed patients’ preferences
after the birth of one or more children (Pinborg et al., 2003; Ryan
et al., 2007): these studies point to a preference for either DET or
twins (Gleicher et al., 1995; Pinborg et al., 2003; Ryan et al., 2004;
Murray et al., 2004; Hojgaard et al., 2007; Newton et al., 2007;
Twisk et al., 2007). However, it has been shown in the literature
that several factors, such as the physicians’ opinion and way of counselling of the patient, and also changes in patient perceptions and
changes in time, may influence patients’ preferences. As a result, preferences may not be stable over time (Jansen et al., 2000; Schwartz
et al., 2006; de Lacey et al., 2007). No study has addressed this
issue in IVF.
The aim of this study was to document the stability of patients’ preferences for either a ‘healthy’ single child or ‘healthy’ twins in infertile
women during their first cycle of IVF. Furthermore, we wished to
investigate which factors may explain preference shifts in these
patients. The setting of the study was a clinical trial in which unselected
infertile women were randomly allocated to either eSET or DET. For
the purpose of this study, preferences were measured at two
moments in time, i.e. 2 weeks before ET (before ET) and 2 weeks
after ET when the results of the pregnancy test were known. In
case of a positive pregnancy test, patients were still unaware
whether it concerned a singleton or multiple pregnancy.
Materials and Methods
Several terms originating from social and cognitive psychology (such as
perceptions, expectations and evaluations) were used as a variable list
of possible predictors to be measured and used in predicting and explaining the preferences of patients (e.g. Fishbein and Ajzen, 1975). In order to
discover the true preference without interference from or confounding by
other arguments (for example, the subjective notion of risks of complications), we offered patients the theoretical option for a ‘healthy’ singleton
or ‘healthy’ twins. Furthermore, we were interested in the effect of several
background characteristics on preferences, whether or not a pregnancy
occurred, transfer strategy, quality of life (QOL) [measured by the
World Health Organization-QOL questionnaire (WHOQOL, 1998)],
patient perceptions, evaluations of treatment, expectations, feelings
and fears on preference shifts. The following research questions were
formulated for this study:
(1) Do patients prefer to have either a healthy singleton or healthy twins
before ET?
(2) Are preferences for either a healthy singleton or healthy twins stable
during IVF treatment (i.e. do preference shifts occur)?
(3) If not stable, which factors explain these preference shifts?
Study design
From January 2002 until December 2004, a prospective RCT was performed at the Maastricht University Medical Centre, the Netherlands.
The main goal of this trial was to compare pregnancy rates and costs of
eSET (irrespective of age and embryo quality) versus DET in the first
IVF treatment cycle in an unselected group of patients. In the following
cycles, standard treatment policy was performed (i.e. eSET in patients
,38 years of age with at least one good quality embryo, and DET in
the remainder of patients). In the first cycle, the one or two best
embryo(s) were transferred. This does however not necessarily mean
that a good quality embryo was available in the randomized eSET (or
DET) group (Fiddelers et al., 2006; van Montfoort et al., 2006).
Randomization was performed immediately prior to ET. After transfer,
patients were informed about the number of embryos transferred (van
Montfoort et al., 2006).
Parallel to this trial, a study on patients’ preferences was carried out in
the same groups of patients. For this purpose, a written satisfaction questionnaire was developed, which was administered after inclusion but
before ET and another questionnaire 2 weeks following ET, after the
results of the pregnancy test had become available to the patient. For
the patients’ preference study, only a subgroup of nulliparous women
who started their first IVF treatment was included, since several questions
were not relevant for patients who already had one or more children.
Satisfaction questionnaire
Items of the newly constructed satisfaction questionnaire were collected in
close co-operation with IVF experts, and were tested for face validity and
content validity. The final version of the baseline questionnaire consisted
of 52 items on six domains related to relevant themes with respect to
IVF. The six domains were: (1) preferences for the desired number of children (healthy single child or healthy twins), (2) the patient’s perception of
the impact of childlessness, (3) the patient’s global satisfaction about the
way the information on the IVF process was provided by the fertility
clinic staff, (4) expectations regarding the burden of treatment (expected
pain at ovum retrieval or expected physical burden and/or psychological
stress) and alleged benefits and drawbacks of having either one or two
embryos transferred, (5) feelings of despondency and feelings of powerlessness and (6) fears for typical problems caused by pregnancy by IVF
(fear for allegedly disabled children, if twins). Furthermore, two separate
follow-up questionnaires were developed, one for the subgroup of pregnant patients and one for the subgroup of non-pregnant patients, as the
psycho-social situation (and so the beliefs and feelings) of a pregnant
patient was expected to be different from that of a non-pregnant one.
Non-pregnant patients were given approximately the same items as in
the baseline questionnaire. Pregnant patients, however, were also provided with items related to fears about the continuation of the pregnancy.
2094
Each item was phrased as a general statement (measured as a five-point
Likert scale), with which respondents could ‘very much agree’, ‘agree’,
‘disagree’ or ‘very much disagree’; a fifth, neutral stance was provided
for patients who ‘neither agreed, nor disagreed’ with the statement. Furthermore, an extra scale position was allowed in case respondents either
said that the statement ‘did not apply’ to their situation, or that they had
‘never even thought about’ the issues raised within the statement (no
opinion whatsoever).
Fiddelers et al.
only refer to preference reversals (i.e. a change in preference from a singleton to twins and vice versa) or a movement towards or away from the
indifference position, but also imply changes in the strength of the preference shift. Repeated measures analysis of variance was performed to
analyse patients’ preferences for a singleton or twins in the first IVF treatment cycle, and to analyse preference shifts.
Research question 3: explanation of preference shifts
Measurement of preferences
Both in the baseline and follow-up questionnaire, patients’ preferences for
either a healthy singleton or healthy twins were measured by two items,
formulated as follows:
(1) ‘If I could choose, I would rather have a healthy singleton than healthy
twins’.
(2) ‘If I could choose, I would rather have healthy twins than a healthy
singleton’.
For readability in the remainder of this paper, healthy singletons and
healthy twins are further referred to as singletons and twins, respectively.
Statistical analysis
Analysis of covariance (using dummy-regression analysis) examined and
tested the effects of several patient background parameters and/or baseline scales of the satisfaction questionnaire on preference shifts. Next to
this, effects of QOL, measured by the WHO-QOL questionnaire, on preference shifts were determined. To find the final best-fitting regression
model for preference shifts, all possible parameters and possible interactions were tested for statistical significance by using the forward selection technique.
A P-value of ,0.05 was considered to reflect statistical significance. All
data analyses were performed using the Statistical Package for the Social
Sciences (SPSS-pc, version 15.0). For the statistical analysis, only those
patients who responded to both the baseline questionnaire and the
follow-up questionnaire were included.
Satisfaction questionnaire
First, frequencies of all items were inspected for skewness of distribution
and discriminatory power. Initially, items of the newly developed questionnaire were uniquely ascribed to six domains. Four separate runs of principal components analysis were performed, one for perceptions (domain 2),
one for evaluations (domains 1 and 3), one for expectations (domain 4)
and one for negative feelings and fears (domains 5 and 6). Listwise deletion
of missing cases was performed throughout each type of analysis. Items
scoring on more than one component or having component loadings
below +0.50 (or above 20.50) were removed from further analysis.
Oblique rotation was used to find more interpretable component loadings. Next, internal consistency of items clustered together in each resulting component was assessed by Cronbach’s alpha. Only components with
a minimal alpha of 0.70 were used in further data analysis. Finally, if items
performed satisfactorily on the criteria above, additive scales were constructed for each component with equal weighting of items involved.
Final scale scores were defined within the same range as the original
items (1– 5).
Research question 1: preferences before ET
To determine the preference for either a singleton or twins before ET, the
scores of both five-point Likert scales measuring preference were subtracted from each other, because items were reversed in the direction
of the statement. The resulting total scale was an eight-point scale,
running from 24 to +4, in which ‘24’ stands for a strong preference
for healthy twins, ‘0’ stands for no preference at all and ‘+4’ for a
strong preference for a healthy singleton. If scores were missing for one
item or if both scores were absent, the total preference scale was set
as missing. The same procedure was used for the measurement after
the results of the pregnancy test.
Results
Study population
Of the 308 patients who had been included in the RCT, 79.5% were
nulliparous. The satisfaction questionnaire was developed when the
RCT-part of the study had already started and was, after approval
of the Medical Ethics Committee of the Maastricht University
Medical Centre, first administered 1 year after the start of the inclusion
for the RCT. Of the 177 patients that received the satisfaction questionnaire, 175 filled in and returned the questionnaire before ET, and
158 returned the questionnaire after results of the pregnancy test. Of
the 177 original patients, 90 (50.8%) had been randomized to receive
eSET and 87 (49.2%) to receive DET. Thirty-one percent of the
patients had a positive pregnancy test after eSET, compared with
39% of the patients after DET. After results of the pregnancy test,
19 of 177 patients (10.7%) did not return the follow-up questionnaire,
of which 10 had received eSET and 9 had received DET. Concerning
the two items regarding preferences for a singleton or twins, the preference before ET could be determined in 167 patients, whereas the
preference after results of the pregnancy test could be determined in
153 patients. Ultimately, full data analysis could be performed in
145 patients, as these patients completed both measurements
before ET and after results of the pregnancy test. Of the 32 missing
patients, 19 received eSET and 13 received DET. Table I shows the
baseline characteristics of the patients. The mean age of the included
patients was 32 years (SD 3.3, range 19– 40) and the duration of infertility was on average 3.5 years (range 0.31 –15).
Research question 2: stability of preferences
Baseline scale scores
A preference shift was defined as a score change of a preference measurement after results of the pregnancy test minus preference measurement
before ET deviant from zero. A positive change score (e.g. from 24
to 23; change score is +1) is further defined as a shift towards a preference for a singleton, whereas a negative change score (e.g. from +4 to
+3; change score is 21) is further denoted as a shift towards a preference
for twins. Change scores ranged from – 8 to +8. Note that shifts do not
Table II shows the baseline scale scores from the satisfaction questionnaire (after analysis consisting of nine scales, including preference
scale) and from the WHO-QOL questionnaire. After the factor analysis of the satisfaction questionnaire, several items to measure expectations did not correlate sufficiently and tended to diverge to other
factors in the solution.
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Changes in preference for singleton or twins during IVF
Table I Baseline characteristics of an unselected group
of patients undergoing a first IVF treatment cycle
(n 5 177).
Mean (SD)
Range
Missing
........................................................................................
Female age (years) at ovum
retrieval
31.97 (3.28)
Duration of infertility (years)
3.48 (1.83)
19–40
0
0.31–15
3
School education
Lower education level
24 (15.2%)
Average education level
70 (44.3%)
Higher education level
64 (40.5%)
Missing: 19
was moderate to high. In general, patients did not feel despondent,
but they felt moderately powerless. Furthermore, in case of pregnancy
they expected few developmental problems in their child because of
IVF treatment, and they felt that becoming pregnant is quite often
something that has to do with one’s destiny or fate. Finally, the
QOL of the patients can be described as moderate to high (3.23–
4.10 on a scale from 1– 5, with 1 ¼ low QOL and 5 ¼ high QOL).
Research question 1: preferences before ET
Before ET, 44.8% of the patients expressed a preference for a singleton, 33.8% were indifferent and 21.4% expressed a preference for
twins (Table III). The mean score was 0.52 (SD 1.947; n ¼ 167),
which indicates that on average patients showed a small preference
for a singleton.
Research question 2: stability of preferences
Table II Baseline QOL, as measured by the World
Health Organization-QOL questionnaire (WHO-QOL),
and satisfaction scales.
Mean (SD)
........................................................................................
Satisfaction questionnaire
Perception seriousness problema
2.94 (0.86)
Evaluation of information given by the IVF staffb
1.61 (0.53)
Expectations of transferring one or two embryosc
3.48 (0.61)
Expected burden of treatmentd
2.72 (0.75)
e
Despondency
3.76 (0.71)
Powerlessnessf
3.01 (0.86)
Fears for problems with babyg
4.08 (0.64)
Feelings about fate/destinyh
3.21 (0.87)
WHO-QOLi
Physical health
3.66 (0.52)
Psychological health
3.78 (0.37)
Degree of independence
3.88 (0.42)
Social relationships
4.09 (0.55)
Environment
4.10 (0.36)
Spirituality
3.23 (0.75)
General QOL and health
4.07 (0.57)
All scores between 1 and 5.
a
The higher the score, the lower the seriousness of the problem.
b
The higher the score, the worse patients evaluate the information given by IVF staff.
c
Low score means positive feelings for DET, high score means positive feelings for
eSET.
d
The higher the score, the less burden patients expected.
e
The higher the score, the less despondent patients are.
f
The higher the score, the less powerless patients are.
g
The higher the score, the less patients are afraid that their child will have
developmental problems because of IVF treatment.
h
The higher the score, the less dependent patients are on higher powers.
i
The higher the score, the higher the QOL with regard to the specific domain.
In general, patients experienced being childless as a moderate
problem, and they generally evaluated the information given by the
IVF staff as good. Patients did not consider eSET as a disadvantage
compared with DET. Their average expected burden of treatment
After results of the pregnancy test, 2 weeks after ET, 31.7% preferred
a singleton, 43.4% were indifferent and 24.8% preferred twins
(Table III). The mean value at follow-up was 0.10 (SD 1.701;
n ¼ 153), reflecting again an overall—but weaker—preference for a
singleton. The overall preference shift towards twins was significant
(Paired t-test: t ¼ 3.18, P ¼ 0.002; n ¼ 145).
Fifty-nine patients (40.7%) shifted towards a preference for twins
(i.e. 21 to 28), 55 patients (37.9%) showed no shift at all and
31 patients (21.4%) showed a shift towards a preference for a singleton (i.e. +1 to +8). Of the 90 patients (62.1%) who showed a preference shift, 29 (32.2%) shifted within their original preference, 54
(60%) showed either a movement towards or a movement from the
indifferent option and 7 (7.8%) showed an actual preference reversal.
Research question 3: explanation of
preference shifts
Using ‘preference shift’ as a dependent variable in regression analysis,
the search for a best-fitting regression model resulted in a final model
containing four explanatory variables, i.e. two conditional states and
two subjective patient perceptions or evaluations. Overruling the
interpretation of two of the four main effects, one first-order interaction effect was also present in the final model (Table IV). Variance
explained by the final model was 0.408. In order of relative importance
(as given by the t-values in the regression model), the following results
can be reported.
First, the observed, originally expressed, preference for a singleton
or twins at baseline was significantly related to the shift in preferences
(b ¼ 2 0.551; P , 0.001). Women who originally preferred a singleton shifted towards a preference for twins, and vice versa. This result
can be seen as a regression-to-the-mean effect that is only relevant to
correct for effects of other explanatory variables within the final
model. Second, women who highly appreciated the information
given by the fertility clinic staff shifted their preference towards
twins, but women who had a more critical stand towards this information shifted towards preferring a singleton (b ¼ 0.148; P ¼
0.027). Finally, pregnant patients who had received eSET tended to
shift towards a preference for a singleton, whereas non-pregnant
patients who had received eSET shifted significantly towards a preference for twins (Table V). Irrespective of being pregnant or not,
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Fiddelers et al.
Table III Patients’ preferences for a healthy singleton or twins, before ET and after results of the pregnancy test.
Preference for a healthy singleton
before ET (scores 11 to 14)
Indifferent before ET
(score 5 0)
Preference for healthy twins before
ET (scores 21 to 24)
Total
before ET
.............................................................................................................................................................................................
Preference for a healthy singleton after pregnancy test
Shift towards twin
16
Stable (no shift)
16
Shift towards singleton
3
Total
35
9
2
46 (31.7%)
Indifferent
25
29
9
63 (43.4%)
Preference for healthy twins after pregnancy test
Shift towards twin
2
Stable (no shift)
10
Shift towards singleton
8
Total
5
Total after pregnancy test 65 (44.8%)
11
20
49 (33.8%)
31 (21.4%)
Table IV Results of the final regression analysis model
with preference shifta as dependent outcome variableb.
Unstandardized
coefficients
Standardized
coefficients
Significance
........................................ .........................
B
SE
b
t
........................................................................................
Constant
20.92 0.36
Preference before
ET (single
child ¼ 0/
twins ¼ 1)c
20.45 0.05 20.55 28.37 ,0.001
22.54
0.01
Pregnancy (0/1)d
0.75 0.33
0.22
2.27
0.03
Evaluation of
information IVF-staff
(1–5)e
0.46 0.21
0.15
2.23
0.03
ET; eSET ¼ 0 or
DET ¼ 1f
20.11 0.27 20.03 20.4
0.69
Pregnancy * ET
((0/1)*(0/1))
21.05 0.45 20.26 22.34
0.02
a
Preference shift scores ranging from 28 (shift towards a preference for twins) to
+8 (shift towards a preference for a singleton).
b
Variance explained by the final model: 0.408; n ¼ 145.
c
Preference for a healthy singleton, scores +1 to +4; indifferent, score 0;
preference for healthy twins, scores 21 to 24.
d
Non-pregnant, score 0; pregnant, score 1.
e
Scores between 1 and 5. The higher the score. The poorer the patients evaluate the
quality of the information given by the fertility clinic staff.
f
eSET, score 0; DET, score 1.
patients who had received DET shifted significantly towards a preference for twins (b ¼ 20.264, P ¼ 0.021), although this shift was more
prominent in pregnant patients.
In Table VI, a description is given of the scales and items of the satisfaction questionnaire after PCA. It, therefore, does not list the total
set of 52 items that we developed in the original questionnaire.
36 (24.8%)
145 (100%)
Discussion
This is the first study in female IVF patients of preferences both before
ET and after results of the pregnancy test for a healthy singleton or
healthy twins, and that investigated whether these preferences were
stable over time. We also examined which components could
explain preference shifts.
Before ET, most nulliparous, first time IVF patients expressed a preference for a singleton, resulting in an overall, but modest preference
for a singleton (44.8% of patients preferred a singleton, 33.8% were
indifferent and 21.4% preferred twins). This is in line with the
studies of Kalra et al. (2003) and Ryan et al. (2004), in which a
similar proportion of women preferred to have twins (21.1 and
20.3%, respectively) before the start of IVF treatment. However,
most other preference studies found a preference for twins to
occur more frequently before the start of IVF treatment (59 –90%)
(Gleicher et al., 1995; Pinborg et al., 2003; Hojgaard et al., 2007).
The discrepancy of our study findings with others is notable, mainly
because of a huge variation in study design between preference
studies. Furthermore, in our study, preferences for either a ‘healthy’
singleton or ‘healthy’ twins were investigated. Ruling out the subjective
notion regarding complications, and because in our study only nulliparous women were included, it was expected that more patients would
have a higher probability for preferring twins. On the other hand, our
study was performed in patients who had only recently agreed to participate in an RCT comparing one cycle of eSET with one cycle of
DET. It may well be that eligible patients with an outspoken preference for either a singleton or twins (or for eSET or DET) were less
likely to agree to participate in the RCT. In total, 43% of patients
who were assessed for eligibility were willing to participate in the
RCT (van Montfoort et al., 2006). Therefore, our results might have
been more comparable to the other studies had our preference
study been performed in the entire IVF population. As a consequence,
our results cannot be generalized to the total population qualifying for
IVF. In the questionnaire, only two questions on preferences for a
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Changes in preference for singleton or twins during IVF
Table V Mean values of preference shift for subgroups of pregnant patients.
Preference for a singleton/twinsa
Number of patients
Baseline
Follow-up
P-value
.............................................................................................................................................................................................
Overall
145
0.5241
0.0966
eSET Pregnant patients
23
0.0870
0.6087
0.002
0.149
eSET non-pregnant patients
48
0.7292
0.1667
0.035
DET pregnant patients
29
0.6552
20.2759
0.008
DET non-pregnant patients
45
0.4444
0.0000
0.007
Baseline, before ET; follow-up, after pregnancy test.
a
Score between 24 and 4; 24 means strong preference for twins, 4 means strong preference for a singleton.
singleton or twins were included. So, the questionnaire was not
designed with the a priori objective to study patients’ preferences
for either a singleton or twins, but to investigate overall satisfaction
with IVF. This may have influenced the outcomes of the preference
study, in that patients may have answered the two ‘preference’ questions as being merely two out of many questions.
In this study, 62% of patients showed a preference shift over time;
so we may confidently state that preferences for either a singleton or
twins are generally not stable during IVF treatment. However, it should
be noted that only a few patients showed an actual preference reversal. Most shifts concerned a change in preference for either a singleton
or twins into indifference, or vice versa. Whether these changes
should also be regarded as preference reversals is open for discussion.
Although the shifts were statistically significant, the question remains
whether these shifts are also clinically relevant. Therefore, data analysis was also performed on categorized preference changes, only
including shifts towards or from indifference, and preference reversals:
the results (data not shown) were similar to results from the
regression model shown in Table IV (R-square: 0.408), although its
R-square (0.061) was much lower owing to self-provoked measurement error induced by the categorization.
A limitation of our study might be that the preferences after results
of the pregnancy test were measured only 2 weeks after ET, after
patients had been tested for pregnancy but still were unaware
whether it was a singleton or multiple pregnancy. A more suitable
moment for measuring preferences after results of the pregnancy
test might be after birth, although patients would then probably
prefer the outcome obtained (Salkeld et al., 2000). This was also
shown by the study of Pinborg et al. (2003), who found that the
only predictive factor of wish for twins in IVF/ICSI-twin mothers
and IVF/ICSI-singleton mothers was actually being a mother of twins.
The shift in preferences found in our study is mainly explained by a
regression-to-the-mean effect, which is a common statistical phenomenon resulting in the finding that women who originally preferred a singleton shifted towards a preference for twins, and vice versa.
Low scores on the test before ET were partly low because of random
fluctuations in a patients’ score. After the results of the pregnancy test,
these scores are likely to rise. For the same reason, high scorers on the
test before ET are likely to have lower scores after the results of the pregnancy test. Patients who are indifferent before ET are equally likely to
have higher or lower scores after the results of the pregnancy test; so,
on average, the scores do not change (Schouten, 1999; Kirkwood and
Sterne, 2003; www.socialresearchmethods.net). Studies with repeated
measures on preference shifts should be aware of this statistical
phenomenon. Furthermore, the evaluation of information given by the
IVF staff had a significant impact on the shift in preferences. Surprisingly,
women who highly appreciated the information showed a shift towards a
preference for twins, whereas the opposite was expected. A possible
explanation may be that the high appreciation is related to a less critical
attitude towards twin pregnancies, whereas more critical women prefer
singletons. Hojgaard et al. (2007) found that ‘feeling well informed’ about
the IVF treatment was not associated with a preference for twins.
Pregnant patients who received eSET shifted significantly towards a
preference for a singleton, whereas pregnant patients who received
DET shifted significantly towards a preference for twins. This may
be explained by a reduction of the cognitive dissonance, which is an
uncomfortable feeling caused by holding two contradictory ideas simultaneously. The theory of cognitive dissonance proposes that people
have a motivational drive to reduce dissonance by changing their attitudes, beliefs and behaviour, or by justifying or rationalizing their attitudes, beliefs and behaviour (Festinger, 1957). In this case, patients’
preferences may thus differ from those they had before IVF treatment
started, as a result of psychological adaptation mechanisms.
On the other hand, non-pregnant patients who had received DET
shifted towards a preference for twins. For non-pregnant patients
who had received eSET, the shift towards twins was also observed
but this was not significant. A possible explanation is that nonpregnant women perceived their chances of ever getting pregnant to
be much lower in the measurement after results of the pregnancy
test compared with the measurement before ET. This may result in
a preference shift towards twins in order to be able to fulfil their ultimate child-wish, which is not just giving birth to a single child, because
most women want more than one child (Gleicher and Barad, 2009).
This explanation is substantiated by recent studies that found that
women waiting for IVF treatment generally viewed a twin pregnancy
as being more desirable than having no child at all (Borkenhagen
et al., 2007), even if associated with adverse pregnancy outcomes
(Scotland et al., 2007).
The present study may be useful for clinicians in the following ways.
Before IVF treatment starts, the fertility clinic staff might explain to the
patient that her preference may change during the coming IVF treatment. So, patients who at first hold a strong preference for twins
should realize that their preference may shift towards a preference
for a singleton, if they have only one embryo transferred. However,
in this study, this finding only applied to pregnant patients, as nonpregnant patients shifted their preferences towards twins irrespective
2098
Fiddelers et al.
Table VI Satisfaction questionnaire.
Scales and items after principal component analysis
.............................................................................................................................................................................................
Scale 1. Perception of the severity of the problem of childlessness
Lately I worry a lot about not being able to have children
My life is completely overshadowed because of the fact that I cannot have children
I think it is horrible that I was not able to have children until now
I think childlessness is the worst thing that can happen to people
I am very insecure about not getting pregnant
Sometimes I become very powerless about the idea of not having children
Lately I become very sad of the fact that I still do not have a child
That I was not able to have children until now keeps me busy all day
I can only be completely happy after the birth of a healthy child
Scale 2. Evaluation of the information on the IVF process provided by the fertility clinic staff
I think I received enough information of the doctors until now
I think the information about the IVF treatment was unsatisfactory
I think the explanation I got from doctors and nurses was very clear
I think the explanation about the IVF treatment was sometimes rather vague
I have complete trust in the expertize of the IVF-doctors
Scale 3. Preference as to the desired number of children (singleton/twins)
If I could choose, I would rather have a healthy singleton instead of healthy twins
If I could choose, I would rather have healthy twins instead of a healthy singleton
Scale 4. Alleged benefits and drawbacks on having one or two embryos
I think it is a big disadvantage to receive only one embryo for transfer, because then I have a smaller chance of having a baby
I think it is a big advantage to receive two embryos for transfer, because the probability of me getting pregnant is higher
Two embryos transferred makes me pregnant much sooner
One embryo transferred makes me pregnant not so soon
I seriously wonder if I ever will get pregnant if only one embryo is transferred
Scale 5. Expectations about the burden of treatment
I think I will find the ovum pick-up very painful
I think I will find the IVF treatment psychologically very aggravating
I think I will find the IVF treatment physically very aggravating
Scale 6. Feelings of despondency
Someway having children does not seem to be my share
I am afraid getting pregnant is not in it for me
Whatever I do, I suspect I will never get pregnant
Lately, I am convinced that, no matter what I do, I will not get pregnant
Often, I am afraid that having a baby will not succeed, whatever the doctors will do
I believe that whatever medical science will do, I will not become pregnant
I think that I, whatever the doctors will invent, will not become pregnant
Whatever the doctors do, I think I will never become pregnant
I do not dare hope anymore that the IVF treatment will lead to the birth of a child
Scale 7. Feelings of powerlessness
Lately I feel powerless, because I will not succeed getting pregnant
Often I am afraid that I will never have a child, whatever I do about it
Often, I have moment that I seriously doubt if I ever will become pregnant
I am very afraid of getting disappointed again after this treatment
Lately, I feel my heart sink into my boots, because I will not become pregnant
Continued
2099
Changes in preference for singleton or twins during IVF
Table VI Continued
Scales and items after principal component analysis
.............................................................................................................................................................................................
Scale 8. Fears for typical problems caused by pregnancy via IVF
I am afraid that my child will be less strong because of the IVF treatment
I am afraid that my child will have problems learning later on because of the IVF treatment
Scale 9. Feelings about fate/destiny concerning pregnancy
I think it is predestined if I will or will not become pregnant
If I ever will become pregnant is mainly determined by higher powers according to me
I believe often it is life’s destiny, that determines if you ever will or will not become pregnant
Description of scales and items after principal component analysis.
of whether they had received eSET or DET. Clinicians should be aware
of this and incorporate it in their baseline (i.e. before the start of IVF
treatment) counselling of patients. One way to do so would be to
stress the positive aspects of the eSET policy, even after an unsuccessful IVF attempt.
In conclusion, patients’ preferences for either a singleton or twins
are generally not stable during IVF treatment. We found that pregnant
patients attune their preferences to what they expect their pregnancy
to result in, being a singleton after eSET or twins after DET. Nonpregnant patients shift towards a preference for twins in order to
play safe and increase the chances that their family ultimately will
consist of the number of children they desire.
Authors’ roles
A.A.A.F., F.H.M.N. and C.D.D. designed the study, performed data
analysis, interpreted the data and drafted the article. A.P.A.M. collected the data and revised the manuscript. J.C.M.D., J.A.L., J.L.H.E.
and J.L.S. contributed to the interpretation of data and revised the
manuscript. All authors have approved the final version of the
manuscript.
Funding
This study was supported by a research grant (number 945-12-014)
from the Dutch Organization for Health Research and Development
(ZonMw) and the Dutch Health Insurance Board (CvZ) in a joint
research program on health technology assessment of infertility.
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