Multifetal pregnancy reduction: a review of the world results for the period 1993-1996

Perinatal outcomes in multifetal pregnancy following fetal reduction

BACKGROUND

There is currently insufficient evidence regarding the prognosis of multifetal pregnancy following elective fetal reduction to twin or singleton pregnancy. We compared perinatal outcomes in pregnancies with and without fetal reduction.

METHODS

We used data on all stillbirths and live births in British Columbia, Canada, from 2009 to 2013. We compared outcomes of multifetal pregnancies with fetal reduction (to twin or singleton pregnancy) with outcomes of pregnancies without fetal reduction. The primary outcome was a composite of serious neonatal morbidity or perinatal death. Other outcomes studied included preterm birth, low birth weight and small-for-gestational-age live birth.

RESULTS

The rate of serious neonatal morbidity or perinatal death did not differ significantly between pregnancies reduced to twins and unreduced triplet pregnancies (adjusted rate ratio 0.50, 95% confidence interval [CI] 0.24-1.07) or between pregnancies reduced to singletons and unreduced twin pregnancies (adjusted rate ratio 1.57, 95% CI 0.74-3.33). The rate was significantly lower in the fetal reduction group reduced to twins versus unreduced triplet pregnancies when we restricted the analysis to pregnancies conceived following the use of assisted reproduction technologies (adjusted rate ratio 0.35, 95% CI 0.18-0.67). The rates of preterm birth, very preterm birth, low birth weight and very low birth weight were significantly lower among pregnancies reduced to twins than among unreduced triplet pregnancies. Compared with unreduced twin pregnancies, pregnancies reduced to singletons had lower rates of preterm birth and low birth weight.

INTERPRETATION

Fetal reduction to twins and singletons was not associated with a decreased risk of serious neonatal morbidity or perinatal death. However, such fetal reduction was associated with substantial improvements in several other perinatal outcomes, such as preterm birth and low birth weight. Clinicians discussing the risks associated with multifetal pregnancy should counsel parents on the potential risks and benefits of fetal reduction.

Outcomes of Triplets reduced to Twins versus non-reduced Triplet Pregnancies

INTRODUCTION

This study examined the outcomes of triplet pregnancies selectively reduced to twin pregnancies, compared with non-reduced triplet pregnancies using a standardized approach.

MATERIAL AND METHODS

This study is an observational retrospective study of all women who presented to the Fetal Diagnostic Center between 1999-2009, had triplet pregnancies in the first trimester, received prenatal care and delivered at Abington Memorial Hospital. Data analysis was performed with SPPS version 15 for Windows using analysis of variance and Fisher's Exact test.

RESULTS

132 triplet pregnancies were identified. In the reduced group (n = 30) compared to the non-reduced triplet group (n = 102) average gestational age of delivery was longer 34.6 weeks versus 31.2 weeks gestation (P = <0.0005) and days in hospital were less 9.0 versus 26.7 days (P = .001). There was a significantly lower incidence of gestational diabetes and preterm labor in reduced pregnancies. Rate of loss, defined as delivery less than 24 weeks, were similar [3.3% versus 4.9%].

DISCUSSION

Women electing to reduce a triplet pregnancy to twins have higher gestational ages at delivery, lower rates of gestational diabetes and preterm labor, and spent fewer days in hospital than non-reduced triplet pregnancies.

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.

Application of legal principles and medical ethics: multifetal pregnancy and fetal reduction

In the management of complex medical cases such as a multifetal pregnancy, knowledge of the ethical and legal implications is important, alongside having competent medical skills. This article reviews these principles and applies them to scenarios of multifetal pregnancy and fetal reduction. Such a discussion is not solely theoretical, but is also relevant to clinical practice. The importance of topics such as bioethical principles and informed consent are also herein addressed.

Retain singleton or twins? Multifetal pregnancy reduction strategies in triplet pregnancies with monochorionic twins

OBJECTIVE

To assess the effectiveness and feasibility of retaining a singleton or twins for multifetal pregnancy reduction (MFPR) in triplet pregnancy with monochorionic twins.

STUDY DESIGN

This retrospective study was conducted from January 2006 to September 2011 at a university reproductive medical center. Multifetal pregnant patients (n=35) with dichorionic triplets underwent MFPR in the first trimester to reduce one or both monochorionic twins. These cases were divided into two groups: Group A (9 MFPR cases to reduce one monochorionic twin) and Group B (26 MFPR for both monochorionic twins). Control A (for Group A) included another 18 cases of trichorionic triplet reduction to twins; Control B (for Group B) included 35 cases of trichorionic triplet reduction to singletons. MFPR was performed during the same period for all groups. Pregnancy outcomes were compared between groups.

RESULTS

Patients were 28-39 years old; the average gestation for fetal reduction was 6-8 weeks. The early abortion rate was lower in Group A than Group B (0 versus 11.5%, p=0.339), but the late abortion rate was significantly higher in Group A. (33.3% versus 0, p=0.000). Groups A and B did not differ significantly in premature labor rate, term birth rate, gestation at delivery and take-home baby rate. The rate of very low and low birth weight was significantly higher in Group A than Group B (50% versus 0, p=0.001), and the average birth weight was significantly lower in Group A (2391.7±318.5 versus 3119.6±523.9, p=0.001). Group A had significantly more low birth-weight newborns than Control A (50% versus 13.3%, p<0.05 [0.024]). Group B (retained singleton) had similar pregnancy outcomes and neonatal conditions as Control B.

CONCLUSIONS

Retaining a singleton is always the best choice when deciding about using MFPR to improve pregnancy outcomes. For patients having a triplet pregnancy with monochorionic twins and strongly desiring to keep twins, MFPR in one monochorionic twin was feasible by aspirating embryonic parts early in gestation (6-8 weeks) with no drug injection. Pregnancy outcomes are similar with twin reduction in trichorionic triplet pregnancy.

Multi-Fetal Pregnancy Reduction Does Not Influence Perinatal Results in Twin Pregnancies

The objective of this study was to compare perinatal results in multifetal pregnancies where the reduction to twins was performed with non-reduced twin pregnancies. Perinatal results in 99 sets of twins after transabdominal multifetal pregnancy reduction of triple and higher-order multiple pregnancies performed in a single center were compared with a control group consisting of 151 twin pregnancies conceived in the same time period after infertility treatment, which were not a result of reduction. The main outcome measures were length of pregnancies, weight of the newborns, percentage of miscarriages and the mode of the delivery were analyzed. No significant difference could be found at a 5% level of significance regarding the average duration of pregnancy or average weight of the twins. Fisher test on 5% significance level did not ascertain any significant difference in the probability of miscarriage between the group with reduction (5.26%) and the group without reduction (12.84%). At a 5% level of statistical significance, no significant difference in probability of perinatal death of the fetus or delivery of a stillborn fetus was found. The percentage of cesarean sections did not differ significantly in both groups. The analysis of both groups demonstrated that reduction of multifetal pregnancies to twins may not influence perinatal results in comparison to twin pregnancies where reduction was not performed.

Multifetal pregnancy reduction in pregnancies with a monochorionic component

We conducted a retrospective, cross-sectional study to evaluate the efficacy, safety, and effect of first-trimester multifetal pregnancy reduction on procedure-related complications and obstetrical outcome in multiple pregnancies with a monochorionic component. Although procedure-related complications were relatively common, the obstetrical outcome was favorable in most cases when the monochorionic twin component was reduced.

Ethics and assisted reproduction

In vitro fertilization and assisted reproductive technology have made great progress during the last 20 years. Genetic material donation, human embryo cryopreservation, selective embryo reduction, preimplantation genetic diagnosis and surrogacy are currently practiced in many countries. On the other hand, embryo research is practiced only in a small number of nations, whereas human cloning has thus far been universally condemned. The rapid evolution and progress of all these techniques of assisted reproduction has revealed certain ethical issues that have to be addressed.

A historical perspective of the clinical evolution of the assisted reproductive technologies

The practice of assisted reproduction technology today is the result of the dedicated patient care, observation, research, and experimentation undertaken by previous generations of physicians. The building blocks of progress have been assembled over past decades, by scientists whose primary objective has been to push forward the frontiers of knowledge, in order to offer more effective methods of infertility treatment. And fortunately that process continues today. Amongst the many scientific developments that have led to the modern practice in assisted reproductive technology, a small number stand out as having had a unique importance. This historical review redraws the path through which in vitro fertilization went from an experimental to an accepted infertility treatment.

Aggressive perinatal care for high-order multiple gestations: Does good perinatal outcome justify aggressive assisted reproductive techniques?

OBJECTIVE

The purpose of this study was to determine the factors that must be considered for appropriate counseling of patients with high-order multiple gestations.

STUDY DESIGN

A retrospective chart review was carried out from all high-order multiple gestations that were managed by a single perinatology group from February 1993-June 1998. Twin pregnancies that did not result from fetal reduction procedures were used as a control group.

RESULTS

Clinical outcome data were analyzed from 9 quadruplet, 25 triplet, 19 reduced twin, and 24 nonreduced twin pregnancies. Women with quadruplet pregnancies were admitted more frequently at an early gestational age, the infants were delivered earlier, and the maternal and neonatal hospital days were longer than for triplet and reduced and nonreduced twin gestations. Triplet pregnancies had an earlier gestational age at delivery (32.3 vs 34.2 weeks), a higher incidence of preterm labor (87% vs 68%), and a higher percentage of neonatal intensive care unit admissions (94% vs 59%) than reduced twin gestations. Reduced twins were hospitalized longer (16.4 vs 9.8 days), were delivered earlier (34.2 vs 36.2 weeks), had a higher incidence of preterm labor (68% vs 29%), and had a greater percentage of neonatal intensive care unit admissions (59% vs 21%), a greater percentage of birth weight <1500 g, and a greater frequency of respiratory distress syndrome (16% vs 2%) than nonreduced twins. There was no difference in neonatal survival and neurologic morbidity when all groups were compared.

CONCLUSION

Although early delivery and prolonged (maternal and neonatal) hospitalization were common with quadruplets and triplets, maternal and neonatal outcomes were excellent. The decision for reduction from triplets to twins may not necessarily change pregnancy outcome but should still be discussed as an option for the parents. Continued efforts need to be made to reduce the overall number of iatrogenic high-order multiple gestations.

Should multifetal pregnancy reduction be used for prevention of preterm deliveries in triplet or higher order multiple pregnancies?

This article reviews the arguments for the use of multifetal pregnancy reduction (MFPR) for the prevention of preterm deliveries in triplet and higher order multiple pregnancies and evaluates its effectiveness based on data from published studies. The arguments in favour of pregnancy reduction are based on the substantial mortality and morbidity associated with these pregnancies. Triplets and higher order multiples have increased rates of preterm delivery and intrauterine growth retardation, both of which are independent risk factors for death and handicap. Even controlling for gestational age, rates of mortality and handicap are higher for multiples than for singletons. Moreover, the family's risk of losing a child or having a handicapped child is greater because there are more infants at risk. MFPR effectively lowers these risk by reducing the frequency of preterm delivery. However, its effectiveness may be limited. In some studies, the proportion of preterm deliveries in reduced pregnancies remains above levels found in spontaneous twin or singleton pregnancies and MFPR does not appear to reduce the prevalence of low birth weight. Furthermore, the procedure itself has unwanted side effects: it increases the risk of miscarriage, premature rupture of the membranes and causes adverse psychological effects such as grief or depression for many patients. The authors note that a majority of the higher order multiple pregnancies result from a medical intervention in the first place, either through IVF techniques or the use of ovulation stimulation drugs. Although MFPR is an effective measure for reducing the substantial morbidity and mortality associated with higher order multiple pregnancies, preventive methods, such as limiting to 2 the number of embryos transferred for IVF and better control of the use of ovulation induction drugs, remain more effective and less intrusive.

Infertility: from a personal to a public health problem

The inability to conceive a child is most often viewed as a private matter, but public health perspectives and skills can contribute greatly to our knowledge about infertility, and the development of effective and rational public policy for prevention, access to health care, and regulation of new technologies. We offer a primer of public health aspects of infertility in an effort to encourage the broad spectrum of public health professionals to become more knowledgeable about these topics and join in the national debate about preventive strategies, cost-benefit assessment, resource allocation, and ethics.