Fetal Reduction From Twins to a Singleton

Clinical value of high-intensity focused ultrasound in fetal reduction

Complex twin reduction surgery is a common but challenging procedure that aims to reduce the risks and complications of multiple pregnancies. The search for safer and more effective methods has led to the development of high-intensity focused ultrasound (HIFU) technology in the field of fetal reduction. This technology utilizes high-energy sound waves to focus precisely on specific areas, achieving non-invasive therapeutic effects. This paper discusses the principles and features of HIFU technology, as well as its application in complex twin reduction surgery. The paper aims to elucidate the important role of this technology in improving surgical outcomes and reducing risks, explore the current limitations of the modality, and propose directions for future development. Through these investigations, it is hoped to improve overall understanding of HIFU, and thereby promote the application of this technology in the field of fetal reduction.

The initial number of fetuses in multiple pregnancy before reduction affects perinatal outcomes

OBJECTIVE

In this study, we aimed to evaluate the perinatal outcomes of dichorionic diamniotic (DCDA) twin pregnancies reduced by the fetal reduction (FR) procedure and cases with continuing DCDA twin pregnancies without FR.

MATERIALS AND METHODS

FR performed in a university hospital in the last 10 years was evaluated. Pregnancies reduced to DCDA twin pregnancies by reduction from three or more pregnancies and pregnancies that started with DCDA twins and continued with DCDA twins were compared in terms of perinatal outcomes. In the subgroup analysis, those who were reduced from three-chorionic three-amniotic (TCTA) triplets to DCDA twins and those who were reduced to DCDA twin pregnancies from four or more were compared in terms of perinatal outcomes.

RESULTS

A total of 119 pregnant women were included in the study, 36 patients underwent FR, while 83 patients were DCDA twins who did not undergo FR. The groups were similar in terms of preterm delivery (p = 0.370). There was a higher rate of miscarriage (21.4% vs. 0.0%, p = 0.019) in the group that was reduced to DCDA twins from quadruplet and above pregnancies compared to the group that was reduced from TCTA triplets to DCDA twins. The gestational week at birth was lower in the group reduced to DCDA twins from quadruplets and above pregnancies (31.00 ± 4.31 vs. 34.64 ± 2.88, p = 0.019).

CONCLUSION

The study's results show that the perinatal outcomes of multiple pregnancies with and without FR are the same As the number of reduced fetuses increases, the rates of preterm birth and miscarriage also increase.

Fetal reduction, moral permissibility and the all or nothing problem

There is an ongoing debate about whether multifetal pregnancy reduction from twins to singletons (2-to-1 MFPR) is morally permissible. By applying the all or nothing problem to the cases of reducing twin pregnancies to singletons, Räsänen argues that an implausible conclusion seems to follow from two plausible claims: (1) it is permissible to have an abortion and (2) it is wrong to abort only one fetus in a twin pregnancy. The implausible conclusion is that women considering 2-to-1 MFPR for social reasons ought to abort both fetuses rather than just one. To avoid the conclusion, Räsänen suggests that it is best to carry both fetuses to term and give one for adoption. In this article, I argue that Räsänen's argument fails for two reasons: the inference from (1) and (2) to the conclusion rests on a bridge principle that does not work in certain circumstances, and there is good reason to reject the claim that it is wrong to abort only one fetus.

Fetal reduction for everyone?

Infertility treatments have benefited millions of couples to have their own children; however, the complication of multiple pregnancies with their increased morbidity and mortality has created significant problems. Fetal reduction (FR) was developed to ameliorate these issues. Over 30 years of publications show that FR has been highly successful in substantially reducing both mortality and morbidity. As with most radically new techniques, initial cases were in the "nothing to lose" category. With experience, indications liberalize, and quality of life issues increase as a proportion of cases. Overall risks for twins are not twice as those for singletons, but they are approximately 4- to 5-fold higher. In experienced hands, the combination of genetic testing by CVS followed by FR has made most multiples behave statistically as if they were originally the lower number. The use of microarray analysis to better determine fetal genetic health before deciding on which fetus(es) to keep or reduce further improves pediatric outcomes. With increasing experience and lower average starting numbers, the proportion of FRs to a singleton has increased considerably. Twins to a singleton FR now constitute an increasing proportion of cases performed. Data on such cases show improved outcomes, and we believe FR should be at least discussed and offered to all patients with a dichorionic twin pregnancy or higher. eSET is not a panacea because of the resultant monochorionic twins.

Fetal reduction of triplet pregnancies to twins vs singletons: a meta-analysis of survival and pregnancy outcome

OBJECTIVE

This systematic review and meta-analysis aimed to compare the fetal survival rate and perinatal outcomes of triplet pregnancies after selective reduction to twin pregnancies vs singleton pregnancies.

DATA SOURCES

PubMed, Web of Science, Scopus, and Embase were systematically searched from the inception of the databases to January 16, 2022.

STUDY ELIGIBILITY CRITERIA

Studies comparing the survival and perinatal outcomes between reduction to twin pregnancies and reduction to singleton pregnancies were included. The primary outcomes were fetal survival, defined as a live birth at >24 weeks of gestation. The secondary outcomes were gestational age at birth, preterm birth at <32 and <34 weeks of gestation, early pregnancy loss (<24 weeks of gestation), low birthweight, and rate of neonatal demise (up to 28 days after birth).

METHODS

The random-effect model was used to pool the mean differences or odds ratios and the corresponding 95% confidence intervals. To provide a range of expected effects if a new study was conducted, 95% prediction intervals were calculated for outcomes presented in >3 studies.

RESULTS

Of note, 10 studies with 2543 triplet pregnancies undergoing fetal reduction, of which 2035 reduced to twin pregnancies and 508 reduced to singleton pregnancies, met the inclusion criteria. Reduction to twin pregnancies had a lower rate of fetal survival (odds ratio, 0.61; 95% confidence interval, 0.40-0.92; P=.02; 95% prediction interval, 0.36-1.03) and comparable rates of early pregnancy loss (odds ratio, 0.89; 95% confidence interval, 0.58-1.38; P=.61; 95% prediction interval, 0.54-1.48) and neonatal demise (odds ratio, 0.57; 95% confidence interval, 0.09-3.50; P=.55) than reduction to singleton pregnancies. Reduction to twin pregnancies had a significantly lower gestation age at birth (weeks) (mean difference, -2.20; 95% confidence interval, -2.80 to -1.61; P<.001; 95% prediction interval, -4.27 to -0.14) than reduction to singleton pregnancies. Furthermore, reduction to twin pregnancies was associated with lower birthweight and greater risk of preterm birth at <32 and <34 weeks of gestation.

CONCLUSION

Triplet pregnancies reduced to twin pregnancies had a lower fetal survival rate of all remaining fetuses, lower gestational age at birth, higher risk of preterm birth, and lower birthweight than triplet pregnancies reduced to singleton pregnancies; reduction to twin pregnancies vs reduction to singleton pregnancies showed no substantial difference for the rates of early pregnancy loss and neonatal death.

Fetal reduction and twins

Infertility treatments have allowed millions of couples to have their own children, but resultant multiple pregnancies with their increased morbidity and mortality have been a significant complication. Fetal reduction was developed to ameliorate this issue. Over 30 years of publications show that fetal reduction has been highly successful in substantially reducing both mortality and morbidity related to multiple pregnancies. As with most radically new techniques, initial cases were in the "nothing to lose" category. With experience, indications liberalize, and quality of life issues gain relevance. The overall risks of twin pregnancy are not twice that of singleton pregnancy; they are about 4 to 5 times higher. In experienced hands, the combination of genetic testing by chorionic villus sampling followed by fetal reduction has made the outcomes of most multiple pregnancies statistically equivalent to those of pregnancies with lower fetal numbers. Use of microarray analysis to better determine fetal genetic health before deciding on which fetus(es) to keep or reduce further improves pediatric outcomes. With increasing experience and lower average starting numbers, the proportion of fetal reductions to a singleton has increased considerably. Twins to a singleton fetal reductions now constitute an increasing proportion of cases performed. Data on such cases show improved outcomes, and we believe fetal reduction should be at least discussed and offered to all patients with a dichorionic twin pregnancy or higher. With the increasing reliance on elective single-embryo transfers, monochorionic twins, which have much higher complication rates than dichorionic twins, have increased substantially. Furthermore, monochorionic twins cannot be readily and safely reduced, so the adverse perinatal statistics of elective single-embryo transfer are a major setback for good outcomes. Although elective single-embryo transfer is appropriate for some, we believe that for many couples, the transfer of 2 embryos is generally a more rational approach.

Twin pregnancy reduction is not an 'all or nothing' problem: a response to Räsänen

In his paper, 'Twin pregnancy, fetal reduction and the 'all or nothing problem', Räsänen sets out to apply Horton's 'all or nothing' problem to the ethics of multifetal pregnancy reduction from a twin to a singleton pregnancy (2-to-1 MFPR). Horton's problem involves the following scenario: imagine that two children are about to be crushed by a collapsing building. An observer would have three options: do nothing, save one child by allowing their arms to be crushed, or save both by allowing their arms to be crushed. Horton offers two intuitively plausible claims: (1) it is morally permissible not to save either child and (2) it is morally impermissible to save only one of the children, which taken together lead to the problematic conclusion that (3) if an observer does not save both children, then it is better to save neither than save only one. Räsänen applies this problem to the case of 2-to-1 MFPR, arguing ultimately that, in cases where there is no medical reason to reduce, the woman ought to bring both fetuses to term. We will argue that Räsänen does not provide adequate support for the claim, crucial to his argument, that aborting only one of the fetuses in a twin pregnancy is wrong, so the 'all or nothing' problem does not arise in this context. Furthermore, we argue that the scenario Räsänen presents is highly unrealistic because of the clinical realities of 2-to-1 MFPR, making his argument of limited use for real-life decision making in this area.

Twin pregnancy, fetal reduction and the 'all or nothing problem'

Fetal reduction is the practice of reducing the number of fetuses in a multiple pregnancy, such as quadruplets, to a twin or singleton pregnancy. Use of assisted reproductive technologies increases the likelihood of multiple pregnancies, and many fetal reductions are done after in vitro fertilisation and embryo transfer, either because of social or health-related reasons. In this paper, I apply Joe Horton's all or nothing problem to the ethics of fetal reduction in the case of a twin pregnancy. I argue that in the case of a twin pregnancy, there are two intuitively plausible claims: (1) abortion is morally permissible, and (2) it is morally wrong to abort just one of the fetuses. But since we should choose morally permissible acts rather than impermissible ones, the two claims lead to another highly implausible claim: the woman ought to abort both fetuses rather than only one. Yet, this does not seem right. A plausible moral theory cannot advocate such a pro-death view. Or can it? I suggest ways to solve this problem and draw implications for each solution.

Fetal reduction from twin to singleton gestation: A meta-analysis

OBJECTIVE

To evaluate outcomes of fetal reduction in twin pregnancy.

SEARCH STRATEGY

PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and Google Scholar were searched from 1980 through December 2020.

SELECTION CRITERIA

Prospective or retrospective studies of pregnant women with twin gestations who had a transabdominal reduction of twin to singleton pregnancy with a comparison group of ongoing twin gestations.

DATA COLLECTION AND ANALYSIS

Outcomes were meta-analyzed only if reported in at least three studies.

MAIN RESULTS

Six studies with a pooled sample of 2867 women with a twin pregnancy of whom 624 underwent 2-to-1 reduction and 2243 did not. In the fetal reduction group, the odds of preterm birth before 34 and 37 weeks of pregnancy were lower by 36% (odds ratio [OR] 0.64, 95% confidence interval [CI] 0.48-0.86, P < 0.003) and 77% (OR 0.23, 95% CI 0.12-0.44, P < 0.001), respectively, than in the control group, and the odds of hypertensive disorders and cesarean delivery were lower by 75% (OR 0.25, 95% CI 0.15-0.43, P < 0.001) and 65% (OR 0.35, 95% CI 0.20-0.62, P < 0.001), respectively.

CONCLUSION

Twin reduction to singleton pregnancy decreased the possibility of preterm birth, hypertensive disorders in pregnancy and cesarean delivery. Sufficiently powered prospective studies are needed to support these findings.

Elective Fetal Reduction in Dichorionic Diamniotic Twin Pregnancies on Parental Request: A Single-Centre Experience

OBJECTIVES

Our study aimed to examine a subset of electively reduced twins and compare their outcomes with those of expectantly managed twins, along with a cohort of singleton pregnancies. The secondary aim was to ascertain the procedure-related miscarriage risks.

METHODS

A retrospective cohort analysis was performed at Apollo Centre for Fetal Medicine, New Delhi, comparing pregnancy outcomes in dichorionic diamniotic twin pregnancies which were reduced to singletons (group 1) with that of women with dichorionic twins managed expectantly (group 0) and women with a singleton pregnancy (group 2). Comparison of continuous and categorical variables was conducted using standard statistical tests.

RESULTS

We analysed 35 twins which were reduced to singletons, 421 expectantly managed dichorionic twins and 1915 women with a singleton pregnancy. In the reduction group, the rate of procedure related pregnancy loss<24 weeks was lower, compared to the expectantly managed twins, although the difference was not statistically significant (5.71% [2/35] vs. 7.13% [30/421]; p = 1.000). The median gestational age at delivery was significantly higher in reduced twins compared to expectantly managed twin pregnancies (38.0 vs. 35.4 weeks respectively, p < 0.001) with a higher mean birth weight at delivery, both of which were comparable to that among the singleton pregnancies (38.3 weeks). The rates of preterm birth <32 weeks and <34 weeks in the expectantly managed twins were significantly higher at 19.8% (66/334) and 25.7% (86/334) compared to the reduced twins, all of whom delivered beyond 34 weeks. The rates of preterm births <32 weeks, <34 weeks, and the late preterm births in the reduced twins were comparable to those in the singleton cohort.

CONCLUSIONS

The obstetric and perinatal outcomes after reduction of a dichorionic twin are better than an expectantly managed twin without an associated increase in pregnancy loss rates. Fetal reduction of dichorionic twin to a singleton appears to be a safe procedure in expert hands.

Bibliometric analysis of research hotspots and development trends in selective fetal reduction

AIM

To evaluate the theme trends and knowledge structure of multifetal pregnancy reduction (MPR)-related literature by using bibliometric analysis.

METHODS

Published scientific papers regarding MPR were retrieved from the PubMed database. Data extraction and statistics were conducted using Bibliographic Item Co-Occurrence Matrix Builder (BICOMB). Furthermore, gCLUTO software was used in the study for bi-clustering analysis and strategic diagram analysis.

RESULTS

According to the search strategy, 906 total papers were included. Among all the extracted MeSH terms, 41 high frequency ones were identified and hotspots were clustered into four categories. In the strategic diagram, research on intrauterine treatment of MPR was most well developed. In contrast, statistical data on the sequelae of fetal reduction surgery and applications of MPR in assisted reproductive technologies were relatively immature.

CONCLUSION

The analysis of common terms among the high-frequency network terms in multiparous pregnancy reduction can help researchers and clinicians understand the hotspots, key topics, and issues to be discovered on MPR. Research on intrauterine treatment of MPR was most well developed.

Optimal timing of fetal reduction from twins to singleton: earlier the better or later the better?

OBJECTIVES

To determine the rate of pregnancy complications and adverse obstetric and neonatal outcomes of twin pregnancies that were reduced to singleton at an early compared with a later gestational age.

METHODS

This was a historical cohort study of dichorionic diamniotic twin pregnancies that underwent fetal reduction to singletons in a single tertiary referral center between January 2005 and February 2017. The study population was divided into two groups according to gestational age at fetal reduction: those performed at 11-14 weeks' gestation, mainly at the patient's request or as a result of a complicated medical or obstetric history; and selective reductions performed at 15-23 weeks for structural or genetic anomalies. The main outcome measures compared between pregnancies that underwent early reduction and those that underwent late reduction included rates of pregnancy complications, pregnancy loss, preterm delivery and adverse neonatal outcome.

RESULTS

In total, 248 dichorionic diamniotic twin pregnancies were included, of which 172 underwent early reduction and 76 underwent late reduction. Although gestational age at delivery was not significantly different between the late- and early-reduction groups (38 weeks, (interquartile range (IQR), 36-40 weeks) vs 39 weeks (IQR, 38-40 weeks); P = 0.2), the rates of preterm delivery < 37 weeks (28.0% vs 14.0%; P = 0.01), < 34 weeks (12.0% vs 1.8%; P = 0.002) and < 32 weeks (8.0% vs 1.8%; P = 0.026) were significantly higher in pregnancies that underwent late reduction. Regression analysis revealed that late reduction of twins was an independent risk factor for preterm delivery, after adjustment for maternal age, parity, body mass index and the location of the reduced sac. Rates of early complications linked to the reduction procedure itself, such as infection, vaginal bleeding and leakage of fluids, were comparable between the groups (7.0% for early reduction vs 9.2% for late reduction; P = 0.53). There was no significant difference in the rate of pregnancy loss before 24 weeks (0.6% for early reduction vs 1.3% for late reduction; P = 0.52), and no cases of intrauterine fetal death at or after 24 weeks were documented. There was no significant difference in the prevalence of gestational diabetes mellitus, hypertensive disorders of pregnancy, preterm prelabor rupture of membranes or small-for-gestational age. The rates of respiratory distress syndrome (6.7% vs 0%; P = 0.002), need for mechanical ventilation (6.7% vs 0.6%; P = 0.01) and composite neonatal morbidity (defined as one or more of respiratory distress syndrome, sepsis, necrotizing enterocolitis, intraventricular hemorrhage, need for respiratory support or neonatal death) (10.7% vs 2.9%; P = 0.025) were higher in the late- than in the early-reduction group. Other neonatal outcomes were comparable between the groups.

CONCLUSIONS

Compared with late first-trimester reduction of twins, second-trimester reduction is associated with an increased rate of prematurity and adverse neonatal outcome, without increasing the rate of procedure-related complications. Technological advances in sonographic diagnosis and more frequent use of chorionic villus sampling have enabled earlier detection of fetal anatomic and chromosomal abnormalities. Therefore, efforts should be made to complete early fetal assessment to allow reduction during the first trimester. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Transabdominal fetal reduction: a report of 124 cases

To prevent fetal loss, preterm delivery, and perinatal morbidity of multifetal pregnancies (MPs), fetal reduction (FR) is offered to some patients. We retrospectively analysed the data of 124 MPs that underwent transabdominal FR to twin (n = 63) and singleton (n = 61) pregnancies at a mean gestational age of 12 + 6 weeks between December 2006 and January 2018. FR was performed transabdominally with the injection of potassium chloride into the intracardiac or intrathoracic space of the fetus or fetuses after ultrasound screening for nuchal translucency and anatomical defects. The initial number of embryos were 48 twins, 63 triplets, 11 quadruplets, and 2 quintuplets. The procedure-related pregnancy loss rate was 0.8% (1/124), the overall pregnancy loss rate was 2.4% (3/124), the fetal loss rate was 1.6% (2/124), and the neonatal death rate was 0.8% (1/124). The baby take-home rates were 96% for twin pregnancies and 96.7% for singletons. This study shows that transabdominal FR is an effective and safe procedure with a pregnancy loss rate of 2.4%.Impact statementWhat is already known on this subject? The incidence of multifetal pregnancies has increased over the years. Because multifetal pregnancies increase perinatal morbidity and mortality due to prematurity, fetal reduction is offed to some patients.What the results of this study add? The results of this study add to the growing body of research on fetal reduction. The study showed that transabdominal fetal reduction is a safe procedure with a pregnancy loss rate of 2.4%.What the implications are of these findings for clinical practice and/or further research? The results of this study can be used in counselling couples with multifetal pregnancies who are considering fetal reduction. Further research is needed to confirm the current findings.

Pregnancy outcome following fetal reduction from dichorionic twins to singleton gestation

BACKGROUND

There are still some controversies regarding the risks and benefits of fetal reduction from twins to singletons. We aimed to evaluate if fetal reduction from twins to singleton improves pregnancy outcome.

METHODS

Retrospective analysis of all dichorionic-diamniotic twin pregnancies, who underwent fetal reduction. Pregnancy outcome was compared to ongoing, non-reduced, dichorionic-diamniotic gestations. Primary outcome was preterm birth prior to 37 gestational weeks. Secondary outcomes included: preterm birth prior to 34 gestational weeks, gestational age at delivery, birthweight, small for gestational age, hypertensive disorders, gestational diabetes and stillbirth.

RESULTS

Ninety-eight reduced pregnancies were compared with 222 ongoing twins. Preterm birth < 37 gestational weeks (39.6% vs. 57.6%, p < 0.001) was significantly lower in the reduced group compared to the ongoing twins' group. A multivariate analysis, controlling for parity and mode of conception, demonstrated that fetal reduction independently and significantly reduced the risk for prematurity (aOR 0.495, 95% CI -0.299-0.819). Subgroup analysis, similarly adjusted demonstrated lower rates of preterm delivery in those undergoing elective reduction (aOR = 0.206, 95% CI 0.065-0.651), reduction due to fetal anomalies (aOR = 0.522, 95% CI 0.295-0.926) and 1st trimester reduction (aOR = 0.297, 95% Cl 0.131-0.674) all compared to ongoing twins. A Kaplan-Meier survival curve showed a significant proportion of non-delivered women at each gestational week in the reduced group compared to non-reduced twins, after 29 gestational weeks.

CONCLUSIONS

Fetal reduction from twins to singleton reduces the risk of preterm birth < 37 gestational weeks, but not for more severe maternal and perinatal complications.

Safety and Efficacy of Higher Order Multifetal Pregnancy Reduction: A Single-Center Retrospective Study

Objective  This research was aimed to study the safety and efficacy of higher order multifetal pregnancy reduction (MFPR). Study Design  This was a retrospective study of patients from an academic maternity center between 2005 and 2015. We evaluated outcomes of 131 consecutive patients who underwent higher order MFPR (quadruplets and greater). MFPR was performed at 11 to 18 weeks of gestation in all cases. In total, 122 of 131 cases of higher order multiple pregnancy were reduced to twins. We discuss the perinatal outcomes of patients who underwent higher order MFPR, followed by a comparative analysis between the 122 cases of MFPR that were reduced to twins and 101 cases of nonreduced twin pregnancies. Results  The study included 104 sets of quadruplets, 20 sets of quintuplets, 5 sets of sextuplets, 1 set of septuplets, and 1 set of octuplets. The perinatal outcomes of the 131 cases were as follows: pregnancy loss, preterm deliveries at 28 to 33 (+ 6/7 ) weeks, and preterm deliveries at 34 to 36 (+ 6/7 ) weeks occurred in 23.66, 9, and 37% of cases, respectively. The mean time of delivery was 36.56 ± 1.77 weeks, and mean birth weight was 2,409.90 ± 458.16 g, respectively. A total of 122 cases that were reduced to twins were compared with nonreduced twins. The pregnancy loss rate for reduced twins was significantly higher than that for nonreduced twins. The preterm labor rate, mean delivery week, mean birth weight, birth-weight discordance, incidence of gestational diabetes mellitus, and pregnancy-induced hypertension were not significantly different between the groups ( p  > 0.05). Conclusion  Perinatal outcomes were significantly improved by reducing the number of fetuses in higher order multifetal pregnancies. This study involved a large, diverse sample population, and the results can be used as a reference while conducting prenatal counseling.

Negotiating risk and choice in multifetal pregnancies

Today, across all aspects of societal living, risk assessment is an ever-present exercise. Pervasiveness of technology in the everyday life has caused the world of 'risk' to change tremendously, and this is particularly true for childbearing females. The social construction of pregnancy and childbirth as, arguably, medical events that necessitate medical intervention - ever more so for multifetal pregnancies - makes it almost impossible to avoid the notions of risk that surround the events. Drawing on semi-structured interviews with 41 mothers of twins or triplets, we investigate how understandings of risk, combined with the ideology of good motherhood and information provided by physicians impact perceptions of fetal reduction or termination. We have discussed and theorized empirical findings within the framework of risk, discourses of the responsibilization of females, and the potential 'sacred child' in a context where selective reduction becomes a potentiality.

Comparing pregnancy outcomes and loss rates in elective twin pregnancy reduction with ongoing twin gestations in a large contemporary cohort

BACKGROUND

As compared with singleton gestations, twin pregnancies are associated with a significantly higher risk of preterm birth and maternal complications as well as fetal and neonatal morbidity and mortality. Multifetal pregnancy reduction is a technique developed in the 1980s to reduce the fetal number in higher-order multiple pregnancies to reduce the risk of adverse pregnancy outcomes, most importantly preterm birth.

OBJECTIVE

The objective of the study was to compare pregnancy outcomes and loss rates in elective twin pregnancy reduction to ongoing twin gestations in a large contemporary cohort.

STUDY DESIGN

This was a retrospective review of dichorionic diamniotic twin gestations that underwent first-trimester ultrasound at our institution from January 2008 to September 2016. Planned elective 2-to-1 multifetal pregnancy reductions at less than 15 weeks' gestation were compared with ongoing dichorionic diamniotic twin gestations. Data were collected via chart review. Demographics between 2-to-1 reduced singletons and ongoing twins were assessed using a Student t test or a Wilcoxon rank-sum test, as appropriate, for continuous variables and χ² or Fisher exact tests, as appropriate, for categorical variables. Univariable and multivariable logistic regressions were used to compare pregnancy outcomes between ongoing twins and reduced singletons adjusting for maternal age, body mass index, race, in vitro fertilization, use of chorionic villus sampling, prior term birth, and prior preterm birth.

RESULTS

Of 1070 dichorionic diamniotic twin pregnancies identified, completed follow-up data were available and analyzed for 855 patients (79.9%). Among those, 250 (29.2%) were 2-to-1 singletons and 605 (70.8%) were ongoing twins. Reduced singleton patients were slightly older, more likely white, and had lower body mass index. They were also more likely to have undergone in vitro fertilization (63.6% vs 48.8%), had chorionic villus sampling (92% vs 37.5%), and had prior term births (54% vs 35.7%). Compared with 2-to-1 singletons, the adjusted odds of having preterm delivery at 37 weeks for ongoing twins were 5.62 times (95% confidence interval, 3.67-8.61; P < .001) and 2.22 times (95% confidence interval, 1.20-4.11; P < .001) at 34 weeks. While intrauterine growth restriction, placental abruption, and gestational diabetes were not significant, ongoing twins were more likely to have a cesarean delivery (odds ratio, 5.53, 95% confidence interval, 3.60-8.49; P < .001) and preeclampsia (odds ratio, 3.33, 95% confidence interval, 1.60-6.96; P < .001) after adjusting for maternal characteristics. There were also significant differences between groups for preterm premature rupture of membranes and low birthweight at less than the fifth and 10th percentiles. Total pregnancy loss (at 24 and 20 weeks) was similar between singleton and ongoing twins (4% vs 2.5%, P = .23, and 3.6% vs 1.7%, P = .09 for respective weeks). There were no significant differences in the rate of unintended pregnancy loss (2.4% vs 2.3%; P = .94) and the rate of intrauterine fetal death greater than 24 weeks (1.2% vs 0.7%; P = .43) in reduced singleton versus ongoing twin group, respectively.

CONCLUSION

In our study, patients who elected to reduce to a singleton pregnancy had a higher gestational age of delivery and lower rates of preterm birth and pregnancy complications without an increased risk of pregnancy loss.

Is it worth reducing twins to singletons after IVF-ET? A retrospective cohort study using propensity score matching

INTRODUCTION

Many studies have shown that multifetal reduction of high-order multiple pregnancies results in improved pregnancy outcomes. However, whether conducting elective fetal reduction from dichorionic twins after in vitro fertilization (IVF) is worthwhile remains controversial. This study aimed to determine whether elective fetal reduction of dichorionic twins after IVF and embryo transfer (IVF-ET) is associated with increased take-home baby rate.

MATERIAL AND METHODS

This was a retrospective cohort study of 3600 dichorionic twin pregnancies after IVF-ET. The reduced group included 71 women with transvaginal elective fetal reduction between 7 and 8 weeks of gestation. The control group (n = 3529) comprised women who were managed expectantly. Propensity score matching was conducted before pregnancy outcomes were compared.

RESULTS

The take-home baby rate was significantly lower in the reduced group (83.1% vs 92.8%, P = 0.004). The total miscarriage rate was significantly higher in the reduced group (12.7% vs 6.2%, P = 0.04). Although preterm delivery rate was lower in the reduced group (P < 0.001), over 90% were over 32 weeks, whereas the proportions were equal in the reduced group.

CONCLUSIONS

In dichorionic twin pregnancies after IVF-ET, elective fetal reduction to singleton significantly decreased the chance of taking home live babies.

Ethical Considerations in Multiple Pregnancy: Preterm Delivery in the Setting of Discordant Fetal Anomaly

Planning for the preterm birth of a fetus with known anomalies can raise complex ethical issues. This is particularly true of multiple pregnancies, where the interests of each fetus and of the expectant parent(s) can conflict. In these complex situations, parental wishes and values can also conflict with the recommendations of treating clinicians. In this article, we consider the case of a dichorionic twin pregnancy complicated by the diagnosis of vein of Galen aneurysmal malformation (VGAM) in one of the twins at 28 weeks' gestation. Subsequent deterioration of the affected twin prompted the parents to request preterm delivery to prevent the imminent in-utero demise of the affected twin. However, given the associated risks of prematurity, complying with the parents' request may have disadvantaged the health and wellbeing of the unaffected twin. This article canvases the complex ethical issues raised when parents request preterm delivery of a multiple pregnancy complicated by a fetal anomaly in one twin, and the various ethical tools and frameworks that clinicians can draw on to guide their decision-making in such cases.

Transabdominal amnioinfusion in the correction of oligohydramnios following twin-to-singleton reduction – A report of two cases

Background:

On rare occasions, elective iatrogenic reduction of a dichorionic twin is performed due to maternal request and in order to improve the perinatal outcome.

Materials and methods:

Nine twin-to-singleton reductions were identified retrospectively at the Feto-maternal Unit, University of Szeged, Hungary, between December 1997 and June 2015. A post-procedure, routine weekly sonographic scan revealed severe oligohydramnios in two out of the nine cases (22.2%) and amnioinfusion was performed in the mid-trimester to prolong gestation. The fetus survived in one case (11.1%) and the pregnancy continued until preterm birth.

Conclusion:

A repeated sonographic follow-up for an early diagnosis of oligohydramnios is feasible to avoid miscarriage after artificial embryo reduction.

Multi-fetal pregnancy reduction (MFPR) to twins or singleton - medical justification and ethical slippery slope

Multi-fetal pregnancy reduction (MFPR) is an ethically acceptable procedure aimed to increase survival and well-being of the remaining fetuses from high-order multiple gestations. In most cases we offer the procedure to triplets or quadruplets and opt to preserve twins; lately, the option to maintain a single fetus was suggested. We examined the outcomes of 140 pregnancies that underwent MFPR in our center and were followed to delivery - 105 were reduced to twins and 35 to singletons. The rate of procedure-related pregnancy loss was identical (2.9%). Leaving only one fetus was associated with a higher gestational age at delivery (35.4±2.4 weeks vs. 37.7±2.1 weeks, P<0.0001), with heavier neonates (2222 g vs. 3017 g, P<0.0001) and with a reduction in the cesarean section (CS) rate (76% in twins vs. 51.4% in singletons, P=0.02). Six pregnancies reduced to twins (5.8%) ended before 32 weeks as compared to one pregnancy reduced to a singleton. We conclude that reduction of triplets to singletons is medically and ethically acceptable, after thorough counseling of patients. However, considering the pregnancy loss risk of MFPR and the relatively good outcome of twin gestations, reduction of twins to singletons is ethically acceptable only in extraordinary maternal or fetal conditions.

Reducing the number of fetuses in a pregnancy: providers' and patients' views of challenges

STUDY QUESTION

How do patients and providers perceive and make decisions about possible reductions of multi-fetal pregnancies?

SUMMARY ANSWER

Physicians may be transferring additional embryos, assuming that patients will later undergo reduction if need be; but decisions to reduce pregnancies are difficult for patients, who may agree to undergo the procedure in advance and later renege.

WHAT IS ALREADY KNOWN

Implanting more than one embryo increases the likelihood that at least one embryo will successfully lead to a child but also that the patient may end up with twins or higher-order multiple births.

STUDY DESIGN, SIZE, DURATION

In-depth interviews of ~1 h each were conducted with 37 ART providers and patients (17 physicians, 10 other health providers and 10 patients) and systematically analyzed.

PARTICIPANTS/MATERIALS, SETTING, METHOD

The telephone interviews explored the participants' views and decisions regarding pregnancy reduction. The answers were analyzed systematically.

MAIN RESULTS AND THE ROLE OF CHANCE

Providers may be transferring additional embryos, thinking that doing so will increase the likelihood of a 'take home baby' and that the patients could undergo reductions, if need be, to avoid the risks and complications of twins or multiple births. Yet patients often appear to have difficulty confronting the prospect of fetal reduction and/or renege on prior agreements to undergo the procedure. Providers should thus be wary and exceedingly careful about these situations.

LIMITATIONS, REASONS FOR CAUTION

The sample size was sufficient for qualitative research designed to elucidate the issues and themes that emerge, but not for statistically analyzing how various groups may differ (e.g. physicians versus patients). Future studies should investigate these issues with larger samples.

WIDER IMPLICATIONS OF THE FINDINGS

These data, the first to examine how IVF providers and patients view and approach decisions regarding the reduction of fetuses, suggest several complications and dilemmas. This information has critical implications for future practice, guidelines, research and education of providers, patients, insurers, policymakers and others.

STUDY FUNDING/COMPETING INTERESTS

Funding was provided by grant #UL1 RR024156 from the National Center for Research Resources, the Greenwall Foundation and the John Simon Guggenheim Memorial Foundation. There are no conflicts of interest to declare.

Screening and Testing in Multiples

The choice of screening or invasive procedure in twin pregnancies is a personal choice of whether the patient wishes to take a small risk of having a baby with a serious disorder versus a small risk of having a complication because she wishes to avoid that. How to interpret such risks has profound effects on the perceived value of techniques, either leading to a decision to screening or going directly to chorionic villus sampling. There are profound issues surrounding the data and the interpretation of the data. No single short review can exhaustively examine all of the issues.

Outcomes in twin pregnancies reduced to singleton pregnancies compared with ongoing twin pregnancies

OBJECTIVE

Multifetal pregnancy reduction has been shown to improve outcomes in triplet and higher-order multiple pregnancies. The data for fetal reduction of twin pregnancies are limited. The purpose of this study was to compare adverse pregnancy outcomes in ongoing twin pregnancies compared with twin pregnancies reduced to singletons.

STUDY DESIGN

This was a retrospective cohort study comparing dichorionic diamniotic twin pregnancies with dichorionic diamniotic twin pregnancies reduced to singleton gestations between 11 and 24 weeks' gestation in a single maternal-fetal medicine practice over a 9 year period. Adverse pregnancy outcomes after 24 weeks were compared, with a value of P < .05 used for significance.

RESULTS

Five hundred one ongoing twin pregnancies and 63 twin pregnancies reduced to singletons were included. Patients with reductions to singletons had a significantly lower risk of preterm delivery before 37 weeks' gestation (10% vs 43%; P < .001) but no difference in the risk of preterm delivery before 34 weeks' or 28 weeks' gestation. Patients with reductions to singletons also had a lower risk of infant birthweight less than the 10% (23% vs 49%; P < .001) but no difference in the risk of infant birthweight less than the 5%. There was no difference in the risk of fetal demise after 24 weeks' gestation.

CONCLUSION

Fetal reduction of twin pregnancies decreases the risk of late preterm birth and birthweight less than the 10% but not the risks of more severe complications such as early preterm birth or birthweight less than the 5%.

Pregnancy outcome after fetal reduction in women with a dichorionic twin pregnancy

STUDY QUESTION

What are the pregnancy outcomes for women with a twin pregnancy that is reduced to a singleton pregnancy?

SUMMARY ANSWER

Fetal reduction of a twin pregnancy significantly improves gestational age at birth and neonatal birthweight, however at an increased risk of pregnancy loss and preterm delivery.

WHAT IS KNOWN ALREADY

Women with a multiple pregnancy are at increased risk for preterm delivery. Fetal reduction can be considered in these women.

STUDY DESIGN, SIZE, AND DURATION

Retrospective cohort study of 118 women with a twin pregnancy reduced to a singleton pregnancy between 2000 and 2010.

PARTICIPANTS/MATERIALS, SETTING, AND METHODS

We compared the outcome of pregnancy in consecutive women with a dichorionic twin pregnancy that was reduced to a singleton pregnancy to that of women with a dichorionic twin pregnancy that was managed expectantly and women with a primary singleton pregnancy. Reductions were performed between 10-23(6/7) weeks' gestation by intracardiac or intrathoracic injection of potassium chloride, mostly for congenital anomalies. We compared median gestational age, pregnancy loss <24 weeks, preterm delivery <32 weeks, neonatal birthweight and perinatal deaths.

MAIN RESULTS AND THE ROLE OF CHANCE

We studied 118 women with a twin pregnancy that was reduced to a singleton, 818 women with an ongoing dichorionic twin pregnancy and 611 women with a primary singleton pregnancy. Loss of the entire pregnancy <24 weeks and preterm delivery occurred significantly more in the reduction group compared with the ongoing twin group (11.9 versus 3.1% <24 weeks, P< 0.001 and 18.6 versus 11.5% <32 weeks, respectively, P < 0.001). In the reduction group, the percentage of women without any surviving child was significantly higher compared with the ongoing twin and primary singleton group (14.4, 3.4 and 0.7%, respectively, P < 0.001). Median gestational age was 38.9 weeks (interquartile range (IQR) 34.7-40.3) for reduced pregnancies, 37.1 weeks (IQR 35.3-38.1) for ongoing twin pregnancies and 40.1 (IQR 39.1-40.9) for primary singletons (P < 0.001 for all comparisons).

LIMITATIONS, REASONS FOR CAUTION

The main limitations of the study were its retrospective character, and the fact that indications for reduction were heterogeneous.

WIDER IMPLICATIONS OF THE FINDINGS

In women with a dichorionic twin pregnancy fetal reduction increases median gestational age only at considerable risk of complete early pregnancy loss.

STUDY FUNDING/COMPETING INTERESTS

The study was not funded. None of the authors has conflicts of interest.

Selective Reduction: "A Soft Cover for Hard Choices" or Another Name for Abortion?

Selective reduction and abortion both involve the termination of fetal life, but they are classified by different designations to underscore the notion that they are regarded as fundamentally different medical procedures: the two are performed using distinct techniques by different types of physicians, upon women under very different circumstances, in order to further dramatically different objectives. Hence, the two procedures appear to call for a distinct moral calculus, and they have traditionally evoked contradictory reactions from society. This essay posits that despite their different appellations, selective reduction and abortion are essentially equivalent.

Perinatal outcome after fetal reduction from twin to singleton: to reduce or not to reduce?

OBJECTIVE

To determine whether reduction of twin gestation to singleton pregnancy is associated with improved perinatal outcome.

DESIGN

A retrospective cohort study.

SETTING

Single tertiary care medical center.

PATIENT(S)

A cohort of 63 singleton pregnancies after reduction from dichorionic-diamniotic twins gestation and 62 dichorionic-diamniotic nonreduced twins.

INTERVENTION(S)

Fetal reduction between 11 and 14 weeks of gestation.

MAIN OUTCOME MEASURE(S)

Obstetric outcome.

RESULT(S)

The rates of preterm delivery at <34 weeks (1.6% in pregnancies after reduction vs. 11.7% in nonreduced twins) and at <37 weeks of gestation (9.5% vs. 56.7%) were significantly lower in patients whose pregnancies were reduced to singletons. The rates of miscarriage of one twin (0% vs. 4.8%) and early pregnancy loss before 24 weeks of gestation as well as the rates of gestational diabetes (11.1% vs. 10%), hypertensive diseases of pregnancy (6.3% vs. 15%), and intrauterine growth restriction (0% vs. 3.3%) were similar in both groups.

CONCLUSION(S)

Fetal reduction of twins to singleton is associated with a lower risk of prematurity and superior perinatal outcome compared with nonreduced twins. Therefore, the option of fetal reduction should be considered in certain cases of twin pregnancies, where the risk for adverse outcome seems exceptionally high.

Current principles and practice of ethics and law in perinatal medicine

One of the most controversial discussion topics in modern bioethics, science or philosophy is represented by the beginning of the individual human life. It is ethically, medically and scientifically correct that the human conception product to be born, so to gain personality and individuality, to be treated as a patient since the intrauterine life. Intrauterine foetal interventions, performed in various therapeutic purposes are still in the experimental stage even in centres with rich experience in perinatal medicine. Progresses truly outstanding are present especially in the prenatal diagnostic methods. Non invasive prenatal testing represents without a doubt a great progress in prenatal diagnosis, but from this point of view, the role of practitioners in the field of perinatal medicine, on counselling and addressing the indication of this test becomes essential. Beyond cultural, national, social or related differences, in perinatal medicine practice is particularly important to respect and permanently reassess the ethical codes. Our paper is targeting to spotlight the essential principles and practice of ethics and law in perinatal medicine nowadays on one hand, and to bring an update review on a controversial topic on the other hand.

Multiple pregnancies following assisted reproductive technologies--a happy consequence or double trouble?

The association between assisted reproduction technologies (ART) and multiple pregnancy is well-established, with a multiple birth rate of 24% in ART pregnancies. Multiple pregnancy is associated with significantly increased maternal and perinatal morbidity and mortality, as well as increased costs to the National Health Service. Evidence relating to the obstetric outcomes of ART twins versus naturally conceived twins is discussed in this review. Methods to reduce the risk of multiple births including elective single embryo transfer and multifetal pregnancy reduction are also discussed.

Paternity balancing

BACKGROUND

Gestational carriers and egg donors have been used by 'traditional' and now increasingly, gay couples. Three gay male couples, all using egg donors and gestational carriers with semen from both partners, had triplets. All desired reductions to twins for the standard medical indications, but requested, if reasonably possible, to have twins with one fathered by each partner.

METHODS

Following our usual clinical protocol, we performed chorionic villus sampling at 12 weeks on all fetuses obtaining FISH and karyotype. For paternity analysis, 14 polymorphic molecular markers on villi were compared to DNA samples from the two men to include or exclude each.

RESULTS

Standard assessments were all normal. Paternity testing showed that one partner fathered two of the triplets, and the other one. In all cases, one of the 'twins' was reduced with good clinical outcomes ensuing.

CONCLUSIONS

Paternity balancing increases options for satisfying family planning desires of gay male couples. We believe it comparable to gender preferences in reductions, i.e. it can be considered but only completely subservient to any clinical criteria. Paternity balancing raises similar ethical issues as reduction with gender preferences, but may increase patient autonomy and mainstream acceptance of stable, gay families.

Evolution of gender options in multiple pregnancy management

OBJECTIVE

Fetal reduction (FR) in multiples dramatically improves outcomes. We prioritize FR decisions for health and historically declined to factor gender. As male preferences apparently diminished, our bioethicist encouraged a re-evaluation.

METHODS

Three hundred ninety-six patients reducing triplets or twins were categorized as 3➔2, 3➔1, and 2➔1, Major (M) anomaly or minor (m) anomaly, same gender (SG), and those for whom gender preference (GP) was possible. Higher order and non chorionic villus sampling were excluded. FR decisions were prioritized by M anomaly, Suspicious, or m anomaly. If neither, we considered GP.

RESULTS

Of 319, 214 (67%) had either M/m or SG. Of those, 3➔2 with gender option: 71/79 chose male and female or had no preferences, one chose male/male, and seven chose female/female. We reduced monochorionic twins in 33/35 3➔1 cases. Of 20 with GP choice, 10 chose male and 10 chose female. Of 162 2➔1, 54 had M or m, 50 were SG, but of the 44 M/F twins, 20 chose male and 24 chose female.

CONCLUSIONS

There has been a cultural shift mostly preferring one of each or having no preference. When reducing to one, >50% prefer a girl. In addition to identifying abnormalities, chorionic villus sampling before FR expands patient autonomy.

Intracranial KCl injection--an alternative method for multifetal pregnancy reduction in the early second trimester

OBJECTIVE

This study aimed to assess the effectiveness and feasibility of transabdominal intracranial KCl injection as an alternative to intrathoracic KCl injection for multifetal pregnancy reduction (MFPR) in the early second trimester.

METHODS

In this study, 40 cases who underwent fetal reduction between 12 and 18 weeks of gestation at the Reproductive Medical Center of Peking University Third Hospital from January 2006 to December 2011 were divided into two groups: group A (16 cases of intracranial injection) and group B (24 cases of intrathoracic injection). The groups were compared for clinical procedures and outcomes.

RESULTS

The two groups were similar in terms of patient age, gestation, as well as starting and finishing fetal numbers. Group A needed significantly fewer punctures for each fetus than group B did (1.1 ± 0.2 vs. 1.4 ± 0.6), but both groups received similar doses of KCl (2.6 ± 0.8 ml vs. 2.6 ± 1.2 ml per fetus). All cases succeeded in the first procedure, with no heartbeat recovery. The two groups had similar miscarriage rates and gestational ages at delivery.

CONCLUSION

MFPR by intracranial KCl injection was as effective as, but an easier procedure than intrathoracic KCl injection between 12 and 18 weeks of gestation.

Health policy, patient-centred care and clinical ethics

RATIONALE, AIMS AND OBJECTIVES

Patient-centred care has been a central part of US and UK health policy for over a decade, but, despite its importance, the policy literature often fails to provide an adequate theoretical justification for why and how we should value it. This omission is problematic because it renders the status, content and appropriate evaluation of patient-centredness unclear. In this paper we aim to examine two different accounts of patient-centred care.

METHOD

We draw upon methods of conceptual and ethical analysis.

RESULTS

We argue that neither of the two accounts of patient-centred care identified appropriately grounds patient-centredness because neither of them takes into account the inherently moral nature of terms such as 'respect' and 'dignity', terms that are central to discussions of patient-centred care.

CONCLUSIONS

We suggest that clinical ethics can help to provide a theoretical justification for patient-centred care, and that clinical ethical practices can further patient-centred initiatives through ethics consultation, education and policy development and review.

Selective reduction in twins and multiple pregnancies

The number of multiple pregnancies has increased, mainly due to the uncontrolled use of the assisted conception techniques. Multifetal pregnancy reduction (MFPR) has been used to reduce the risks associated with these high-risk pregnancies. It is performed in the first trimester of pregnancy by transabdominal injection of potassium chloride into the fetal heart. The risk of miscarriage seems to be associated with the final number of fetuses. A review of the literature suggests that MFPR results in better pregnancy outcome, regardless of the initial number of fetuses. The reduction to a lower number of fetuses reduces fetal losses, prematurity, infant mortality and morbidity.

Discordance of first-trimester crown-rump length is a predictor of adverse outcomes in structurally normal euploid dichorionic twins

OBJECTIVE

The purpose of this study was to determine the association between discordant crown-rump length (CRL) measurements in structurally normal euploid dichorionic twins and adverse pregnancy outcomes.

METHODS

This retrospective cohort study included women with dichorionic twins who underwent chorionic villus sampling and delivered in our facility from January 2000 to September 2007. Only pregnancies with viable twin fetuses and normal karyotypes were included. The association between CRL discordance, defined as a CRL discrepancy of 9% or greater, and adverse pregnancy outcomes was evaluated.

RESULTS

Seventy-eight women met inclusion criteria and included 24 discordant twins (group 1) and 54 concordant twins (group 2). Maternal ages were similar: mean ± SD, 38.2 ± 3.1 years in group 1 versus 39.2 ± 3.9 years in group 2 (P = not significant). The median gestational ages at delivery were 35.6 ± 3.1 weeks in group 1 and 37.3 ± 2.0 weeks in group 2 (P < .01). At least 1 major complication occurred in 19 women (79%) in group 1 and 25 (46%) in group 2 (P = .01). Group 1 had significantly more major complications overall (P = .0008). Preterm premature rupture of membranes occurred in 10 women (42%) in group 1 and 6 (11%) in group 2 (P = .005). Delivery before 37 weeks' gestation occurred in 19 of 24 women (79%) in group 1 and 24 of 54 (44%) in group 2 (P = .006). There was a significant difference for younger gestational age at delivery in the discordant group (P < .01).

CONCLUSIONS

Our data suggest that there is an increased risk of adverse pregnancy outcomes in chromosomally normal dichorionic twins with first-trimester discordant CRL measurements. These results may be clinically useful for counseling, management, and antenatal surveillance.

Intra-uterine exposure to dual fetal programming sequences among surviving co-twins

OBJECTIVE

The dynamics of fetal programming following in utero demise of a co-twin are poorly understood.

METHODS

The authors examined fetal programming using a unique application of the change-point analysis method, and identified two types of fetal programming that occurred when a viable twin sibling died in utero, while the co-twin survived.

RESULTS

In one type, the initial twin fetal programming trajectory was maintained while in a subset of surviving co-twins a "switch" from a twin to a singleton fetal program (dual fetal programming exposure) was observed. The results suggest that the timing in utero of conversion from a twin to a singleton programming pattern occurred slightly earlier among opposite-sex than in same-sex surviving co-twins.

CONCLUSION

For the conversion from a twin to a singleton program to happen, the surviving co-twin must have attained a "critical mass" when the twin sibling died. Whereas, for same-sex surviving co-twins the critical mass for conversion was the 80th percentile of gestational-age specific birth weight, opposite-sex surviving co-twins converted at a lower critical mass (70th percentile). These novel findings warrant further study to confirm the new hithertofore unknown phenomenon of dual fetal programming sequence, and to determine the implications in terms of subsequent morbidity or mortality during infancy, childhood and adult life.

Epidemic of plurality and contributions of assisted reproductive technology therein

A commentary on contributions of ART to the pandemic of multiple gestations is presented and mechanistic aspects therein are explored.

Strategies to reduce multiple pregnancies due to ovulation stimulation

OBJECTIVE

To review factors associated with high-order multiple births (HOMB) due to ovulation induction (OI) and the efficacy of strategies to reduce their occurrence.

DESIGN

Retrospective analysis of published studies of OI with intrauterine insemination (IUI) where patient and cycle characteristics were fully documented.

RESULT(S)

High-order multiple pregnancies (HOMP) were positively related to use of high doses of gonadotropin, number of 7-10 mm preovulatory follicles, and E(2), and inversely related to age and number of treatment cycles. Strategies successful in reducing HOMP include: use of clomiphene (CC) before gonadotropins, minimal gonadotropin doses, cancellation for more than three follicles >10-15 mm, and aspiration of excess follicles. Depending on the strategy used, 5%-20% of cycles may be canceled but HOMP rates can be less than 2% and pregnancy rates can average 10%-20% per cycle. Pregnancy rates per patient need not be reduced if low doses are continued for 4-6 cycles.

CONCLUSION(S)

High-order multiple pregnancies due to OI can be reduced to 2% or less by less aggressive stimulation without reducing overall chances of pregnancy for most patients.

Evolving trends in 2000 cases of multifetal pregnancy reduction: a single-center experience

OBJECTIVE

The purpose of this study was to examine changes in multifetal pregnancy reduction (MPR) procedures in 2000 cases and to evaluate evolving trends within the last 1000 MPRs.

STUDY DESIGN

Two thousand patients who underwent MPR were identified. Data were collected from a computerized database. Comparisons were made between the first 1000 patients (group 1) and the second 1000 patients (group 2). In addition, changing trends within group 2 were also analyzed. Differences in proportions were evaluated by chi-square test and Fisher's exact test, as appropriate.

RESULTS

There was a significant difference in the starting and finishing number of fetuses and a significant increase in the use of chorionic villus sampling before MPR in group 2 vs group 1 (43.7% vs 1.5%; P < .0001). The incidence of monochorionicity was significantly higher in group 2 (5.7%), compared with group 1 (2.1%; P < .001).

CONCLUSION

Recent trends in MPR demonstrates significant increases in overall reductions to a singleton fetus, the use of chorionic villus sampling, and the presence of monochorionicity.