Selective reduction

Fetal reduction of triplet pregnancy: one or two?

OBJECTIVE

To review outcomes following reductions in trichorionic triplet pregnancies at our institution.

METHOD

Retrospective analysis of the outcome of trichorionic triamniotic triplets reduced to singletons (group I, n = 44) or twins (group II, n = 136) at 10 and 12 weeks of gestation.

RESULTS

Reduction to one or two was based on parent's preference, hence unrelated to any specific obstetrical or maternal issue. Early fetal loss rate (e.g. <24 weeks) was 9.1% in group I versus 5.1% in group II (p = 0.83). In group I, the take-home baby rate was 86.4% versus 91.9% in group II (p = 0.8). In group I, 17.5% of the women gave birth between 33 and 36(+6) weeks of gestation versus 40.6% in group II (p = 0.026). Delivery beyond 37 weeks was 72.5% in group I and 46.9% in group II (p = 0.01). Intrauterine growth restriction rate was 27.0% in group I versus 45.0% in group II (p = 0.049).

CONCLUSION

Reduction to one rather than two fetuses led to significantly higher term delivery rate without significant differences in fetal loss rate or take-home baby rate.

Relative contribution of ovarian stimulation versus in vitro fertilization and intracytoplasmic sperm injection to multifetal pregnancies requiring reduction to twins

The proportion of twins resulting from multifetal pregnancy reduction of higher-order multiples is increased in pregnancies resulting from hormone stimulation when compared with twins following in vitro fertilization/intracytoplasmic sperm injection treatment. These reduced twin pregnancies may carry a higher perinatal risk compared with other twin pregnancies, which should be taken into account when assessing the perinatal outcome of twin pregnancies after assisted reproduction.

[Multiple pregnancies after ART: problems and possible solutions]

Multiple pregnancies following an assisted reproduction technique (ART) should be seen as a complication, and for that reason they should be avoided. In contrast to singleton pregnancies following ART, the multiple pregnancies are associated with a higher prenatal, neonatal and maternal risk; furthermore this results in a financial burden for the health care system. This paper gives an overview of the latest literature and different attempts of European countries, trying to reduce the multiple pregnancy rate. An efficient reduction is only possible by single-embryo transfers. There should be strict and cross-national regulation for the choice of women who should have a transfer of more than one embryo.

ART: iatrogenic multiple pregnancy?

Assisted reproductive technologies (ART) are now widely accepted as effective treatment for most causes of infertility. With improving success rates, attention has turned to the problem of multiple pregnancies, which are associated with a poor perinatal outcome, maternal complications and significant financial consequences. The challenge is to reduce multigestational pregnancies while maintaining good treatment outcomes. Methods to prevent multiple pregnancy include restrictive use of ART in couples with a good chance of spontaneous pregnancy, cautious use of gonadotrophins, and increased use of natural-cycle intra-uterine insemination and elective single embryo transfer in in-vitro fertilization and intracytoplasmic sperm injection. The aim of this article is to review the contribution of fertility treatment to multiple pregnancies and strategies for reducing multiples in ART.

Risks of miscarriage and early preterm birth in trichorionic triplet pregnancies with embryo reduction versus expectant management: new data and systematic review

BACKGROUND

Triplet pregnancies are associated with a high risk of miscarriage and early preterm birth. It is uncertain if the outcome is improved by embryo reduction (ER).

METHODS

We examined trichorionic triplet pregnancies with three live fetuses at 10-14 weeks of gestation that were managed expectantly or by ER. The two groups were compared for the rates of miscarriage, defined as pregnancy loss before 24 weeks, and preterm delivery prior to 32 weeks. In addition, systematic searches were performed to identify studies comparing outcomes in expectant management versus ER in triplet pregnancies.

RESULTS

We combined data from 365 pregnancies managed in our centre with those of five previous studies. In total there were 893 pregnancies. In the ER group (n=482) compared to the expectantly managed group (n=411), the rate of miscarriage was higher [8.1 versus 4.4%; relative risk (RR)=1.83, 95% confidence interval (CI)=1.08-3.16, P=0.036] and the rate of early preterm delivery was lower (10.4 versus 26.7%, RR=0.37, 95% CI=0.27-0.51, P<0.0001). It was calculated that seven (95% CI=5-9) reductions needed to be performed to prevent one early preterm delivery, while the number of reductions that would cause one miscarriage was 26 (95% CI=14-193).

CONCLUSIONS

In trichorionic triplets, ER to twins is associated with an increase in the risk of subsequent miscarriage and decrease in risk of early preterm birth.

IVF results: optimize not maximize

The desire to improve in vitro fertilization (IVF) results has led clinicians to replace more than 1 embryo in the uterus. As a result, multiple births have increased over the last 2 decades to epidemic proportions, exposing the field of assisted conception to justified criticism. This review aims to ensure that physicians involved in the field of fertility treatment are aware of the risks and complications related to multiple pregnancies, and to explore possible strategies such as blastocyst culture, preimplantation genetic screening, and embryo cryopreservation, which can help to control and reverse the tide of multiple pregnancies without reducing the good success rate that modern IVF treatment enjoys. A brief overview of the respective UK legislative system is also presented.

Targeted first-trimester prenatal diagnosis before fetal reduction in triplet gestations and subsequent outcome

OBJECTIVE

To assess the feasibility of targeted first-trimester ultrasound evaluation in triplet gestations and to report the outcome in reduced and expectantly managed triplets.

METHODS

This was a retrospective analysis of 127 triplets at 11-14 weeks with targeted ultrasound examination including nuchal translucency (NT) screening.

RESULTS

One or more abnormal findings were observed in 33 of 381 fetuses (8.7%), including increased NT (n = 18), malformations (n = 4), aneuploidy (n = 3), relative intrauterine growth restriction (n = 2) or spontaneous demise (n = 13). Of 63 patients (49%) who chose reduction, selective termination due to abnormal findings was performed in 13 fetuses. The rates of complete abortion <24 weeks were 9.8% and 3.2% for those with expectant management and fetal reduction, respectively. Expectantly managed triplets delivered significantly earlier (31.1 +/- 3.8 vs. 35.6 +/- 3.3 weeks) (P < 0.01) with a lower mean birth weight (1483 +/- 552 g vs. 2305 +/- 557 g) (P < 0.01) and a lower number of liveborn fetuses (85.6% vs. 97.4%) (P < 0.01) than those reduced.

CONCLUSION

Targeted first-trimester ultrasound is feasible and reliable in triplet gestations and should be an integral part of the counseling process. It results in more accurate selection for those who consider fetal reduction. Our data further support fetal reduction as a valuable strategy to improve perinatal outcome in triplet pregnancies.

Fetal gender and sonographic assessment of crown-rump length: implications for multifetal pregnancy reduction

OBJECTIVES

Fetal size is a common criterion for the selection of an individual fetus to be reduced during multifetal pregnancy reduction. We investigated whether a difference in crown-rump length (CRL) exists between male and female fetuses at 9-13 weeks' gestation.

METHODS

A total of 883 singleton pregnancies was evaluated at the time of chorionic villus sampling. The mean gestational age at the time of intervention was 10.9 weeks. Pregnancies were dated by certain last menstrual period (LMP). Pregnancies with uncertain dating by LMP or with a sonographic difference of gestational age > 1 week compared with LMP were excluded, as were all cases with chromosomal abnormalities. CRL differences between male and female fetuses were compared using Student's t-test.

RESULTS

A total of 417 female and 466 male fetuses fulfilled our study criteria. Their gestational ages ranged between 9.3 and 13.9 weeks. We found no significant difference in size between the male and female fetuses.

CONCLUSION

Using the CRL to guide multifetal pregnancy reduction should not result in a clinically significant selection of either gender.

Feasibility of nuchal translucency in triplet pregnancies

OBJECTIVE

To assess the feasibility of nuchal translucency in triplets compared with singletons.

METHODS

Nuchal translucency thickness as part of routine first-trimester screening in the general population was compared between 3128 singleton pregnancies and 51 triplets (153 fetuses). Crown-rump length was also noted. The 5th, 50th, and 95th percentiles were determined and compared between the 2 groups, and regression curves of nuchal translucency measurements plotted against crown-rump length were drawn.

RESULTS

The mean nuchal translucency thickness was 1.23 mm for singletons and triplets. The 5th and 95th percentiles were also the same between the 2 studied groups. The regression curves of 5th, 50th, and 95th percentiles of nuchal translucency plotted against crown-rump length of triplets and singletons overlapped.

CONCLUSIONS

Nuchal translucency values and distribution are the same in triplets and singletons, validating the utility of the cutoff values.