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

Non-selective fetal reduction is malpractice

Non-selective multifetal pregnancy reduction is carried out to reduce healthy higher order multiple fetuses to one or two fetuses. No studies exist to show any benefit of this practice and a Cochrane review, as well as investigators in the field, have not found any justification for such practice. From a medical point of view, this non evidence-based practice is not following good clinical practice. Any practice that transfers more than one or two embryos, for instance due to commercial interests, should be abandoned by the international medical community because multifetal pregnancies can, to a large extent, be avoided by transferring only one or a maximum of two fertilized eggs by in vitro fertilization. Further, ovarian stimulating programs should strictly adhere to protocols aiming at mono-ovulation.

How and why are triplets disadvantaged compared to twins?

The current epidemic of triplets, a result of the widespread use of assisted reproduction, started less than two decades ago. Its full impact has been appreciated only recently. Triplets are disadvantaged from every perinatal perspective compared to twins--preterm birth, low birth weight, morbidity and mortality--because the human uterus probably is better equipped to carry twins than triplets. Although modern neonatal care has improved survival rates of preterm as well as low-birth-weight triplets, other complications remain and are of great clinical importance. The alternative to carrying triplets--multifetal pregnancy reduction--is associated with improved outcomes, as expected from comparing twin to higher-order multiples. However, the improved outcomes of triplets in recent years might call for second thoughts about the frequent recommendation of multifetal pregnancy reduction of triplets to twins.

Preterm birth, stillbirth and infant mortality among triplet births in Canada, 1985-96

Recent increases in the frequency of multiple births and simultaneous increases in preterm birth among multiple births have focused attention on such births. However, most previous studies have examined twins rather than higher-order multiples. We carried out a study to examine rates and trends in preterm birth and in gestational age-specific fetal and infant mortality among triplet births in Canada. We used data from the stillbirth, live birth and mortality files of Statistics Canada for the years 1985-97. All births in Canada (excluding those occurring in Ontario and Newfoundland) were included in the study, with two periods (1985-90 vs. 1991-96) being contrasted for assessing temporal change. Changes were estimated using relative risks, 95 confidence intervals [CI] and two-tailed P-values. The rate of preterm birth among triplet live births increased by 6 (95 CI 3, 9) from 90.4 in 1985-90 to 96.0 in 1991-96. Stillbirth rates among triplets did not change significantly and were 30.3 per 1000 total births in 1985-90 and 33.8 per 1000 total births in 1991-96. Infant mortality among triplets declined from 112.7 per 1000 live births in 1985-90 to 73.8 per 1000 live births in 1991-96. In spite of temporal reductions in infant mortality, triplet births continue to be associated with very high rates of preterm birth and fetal and infant mortality. Fetal mortality among triplets has not changed over the last ten years.

Morbidity and mortality of preterm twins and higher-order multiple births

OBJECTIVE

To determine if preterm infants of higher-order multiple (HOM) gestations have a significantly worse outcome during hospital stay when compared with preterm twins.

STUDY DESIGN

Retrospective cohort analysis.

METHODS

Perinatal outcome variables including gestational age (GA), birthweight, prenatal steroid use, cesarean section delivery rate, Apgar scores, and growth retardation were analyzed for 106 preterm HOM births (triplets and quadruplets) versus 328 preterm twins admitted to a single tertiary level neonatal intensive care unit. A comparison of the mortality and major neonatal morbidities such as respiratory distress syndrome, patent ductus arteriosus, intraventricular hemorrhage, necrotizing enterocolitis, bronchopulmonary dysplasia, and retinopathy of prematurity was made for these two groups. In addition, the duration of respiratory support including surfactant therapy, nasal continuous positive airway pressure, and mechanical ventilation, as well as the length of hospitalization, was analyzed.

RESULTS

There were no significant differences in major morbidities between the infants of HOM and twin births of similar GA. There was no statistically significant difference in mortality, but the data showed a trend for lesser mortality in HOM. There was a highly significant increase in antenatal steroid use as well as the use of cesarean section for delivery in the HOM when compared with twin gestations. The infants of HOM gestations were of significantly lower birthweight than the twins and had a longer hospitalization.

CONCLUSION

Although premature infants of HOM had lower birthweight and needed a longer hospital stay, their mortality and morbidity at hospital discharge were not worse than that for preterm twins.

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.

Assisted reproductive technology (ART) in humans: facts and uncertainties

Since the first in vitro fertilization (IVF) in human, the number of patients using Assisted Reproductive Technologies (ART) has increased tremendously. ART technologies have increased in number and their spectrum has also widened. The first IVF babies are now more than 20 years old. All the retrospective analyses have demonstrated that the obstetrical and pediatrical impact has not really affected single births. The main problems observed occur with multiple pregnancies, including high costs for the couples and for society. The decrease in the number of embryos transferred has improved the situation and moreover does not impair the final results. IntraCytoplasmic Sperm Injection (ICSI) is a more debatable and questionable technique with a real negative genetic impact. The main problem is chromosome abnormalities more specifically related to the sex chromosomes. The question of a systematic genetic work-up on the patients entering ICSI programs is discussed. No negative impact of cryopreservation has been demonstrated even though some controversy arises from time to time. Pre-implantation Genetic Diagnosis (PGD) is now a interesting tool for patients carrying genetic defects. Blastocyst biopsy now has a future role in reproductive medicine. Gender selection through sperm sorting is also now a reality. As with the other developing bio-technologies related to reproduction, there are ethical questions. The decisions concerning these technologies do not belong solely to scientists but are rather a matter for society to decide.