Effects of fetal number and multifetal reduction on length of in vitro fertilization pregnancies

Spontaneous reduction before 12 weeks' gestation and selective reduction similarly extend time to delivery in in vitro fertilization of trichorionic-triamniotic triplets

OBJECTIVE

To determine the prevalence and the relative benefits conferred by selective and spontaneous reduction of one or more fetuses in trichorionic triamniotic triplet pregnancies on time to delivery.

DESIGN

Retrospective cohort study.

SETTING

Academic medical center.

PATIENT(S)

IVF patients with trichorionic triamniotic triplets between January 1998 and December 2007.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Gestational length at time of delivery.

RESULT(S)

Selective reduction to twins was used in 87 of the 153 (56.9%) triplet pregnancies that did not spontaneously reduce prior to <12 weeks, and was associated with longer gestation (13.9 days) with a fourfold greater likelihood of delivery at ≥ 34 weeks' gestation (odds ratio [OR], 4.3; 95% confidence interval [CI] = 2.2-8.6), compared with pregnancies not undergoing selective reduction. Compared with ongoing triplets, spontaneous reduction at <12 weeks' gestation (28 cases) was associated with longer gestation (13.7 days) and significantly greater likelihood delivering at or after 34 weeks' gestation (OR, 3.7; 95% CI, 1.4-9.9).

CONCLUSION(S)

Selective reduction of one fetus was used in 56.9% of patients in this population. Early spontaneous reduction (<12 weeks) and selective reduction to twins each conferred similar benefits by extending time to delivery and increasing the likelihood of delivery at or after 34 weeks' gestation.

Maternal physiology and complications of multiple pregnancy

Approximately 1% to 3% of all pregnancies in the United States are multiple gestations. The vast majority (97-98%) are twin pregnancies. Multiple pregnancies constitute significant risk to both mother and fetuses. Antepartum complications-including preterm labor, preterm premature rupture of the membranes, intrauterine growth restriction, intrauterine fetal demise, gestational diabetes, and preeclampsia-develop in over 80% of multiple pregnancies as compared with approximately 25% of singleton gestations. This article reviews in detail the maternal physiologic adaptations required to support a multiple pregnancy and the maternal complications that develop when these systems fail or are overwhelmed.

A two- versus three-embryo transfer: the oocyte donation model

OBJECTIVE

To compare implantation and pregnancy rates in oocyte recipients undergoing a two-embryo versus three-embryo transfer, 3 days after retrieval.

DESIGN

Retrospective comparative analysis.

SETTING

University-based in vitro fertilization center.

PATIENT(S)

All oocyte recipients undergoing embryo transfer from January 1, 1997 through August 31, 1999.

INTERVENTION(S)

Recipients received two or three embryos.

MAIN OUTCOME MEASURE(S)

Implantation, and clinical and multiple pregnancy rates.

RESULT(S)

Seventy-three recipients underwent a two-embryo transfer, and 376 had three embryos replaced. The numbers of oocytes retrieved (12.7 +/- 0.89 vs. 13.1 +/- 0.36) and embryos obtained (8.05 +/- 0.65 vs. 8.77 +/- 0.27) did not differ between the two-embryo and three-embryo transfer groups, nor did the proportion of patients with embryo cryopreservation (54.3% vs. 42.6%, respectively). There was no significant difference in pregnancy or implantation rates when comparing those patients with a two-embryo transfer to those with a three-embryo transfer. Significantly, 13.8% of the pregnancies in the three-embryo transfer group were triplet.

CONCLUSION(S)

Reducing the number of embryos transferred in an oocyte donation cycle can lower the incidence of triplet pregnancies without significantly lowering the overall pregnancy rate.

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.

Prenatal care and multiple pregnancy

Prenatal care of multiple pregnancy presents a variety of nursing challenges. Specialized care, beginning in early pregnancy, can have a significant impact on the outcome for mothers and neonates. Dramatically increasing roles for advanced technology in the care of multifetal pregnancies must be balanced with families' needs for education and support.