Do assisted-reproduction twin pregnancies require additional antenatal care?

Abstract

Iatrogenic twinning has become the main side-effect assisted reproduction treatment. We have evaluated the evidence for additional care that assisted-reproduction twins may require compared with spontaneous twins. Misacarriages are increased in women with tubal problems and after specific treatments. Assisted-reproduction twin pregnancies complicated by a vanishing twin after 8 weeks have an increased risk of preterm delivery and of low and very low birthweight compared with singleton assisted-reproduction pregnancies. Monozygotic twin pregnancies occur at a higher rate after assisted reproduction treatment and are associated with a higher risk of perinatal complications. The incidence of placenta praevia and vasa praevia is increased in assisted-reproduction twin pregnancies. Large cohort studies do not indicate a higher rate of fetal congenital malformations in assisted-reproduction twins. Overall, assisted-reproduction twins in healthy women <45 years of age are not associated with a notable increase in antenatal complication rates and thus do not require additional antenatal care compared with spontaneous twins. The risks of maternal and fetal morbidity and mortality associated with assisted-reproduction twins is only increased in women with a pre-existing medical condition such as hypertensive disorders and diabetes and most of these risks can be avoided with single-embryo transfer. Following the birth of the first IVF baby, rumours started to spread in both the medical literature and the media about the long-term health effects for children born following assisted reproduction treatment. However, after more than 30 years, the most common complications associated with IVF treatment remain indirect and technical such as the failure of treatment and ovarian hyperstimulation. Iatrogenic twinning has become the main side-effect of assisted reproduction treatment and the increasing number of twin pregnancies, in particular in older women, has generated numerous debates on the need for additional healthcare provision. In this review, we have evaluated the evidence for additional care that assisted-conception twin pregnancies may require compared with spontaneous twin pregnancies. Twin pregnancies are obviously at higher risk of perinatal complications than singletons due to a natural increase in the incidence of fetal anomalies, antenatal disorders and obstetric and neonatal complications associated with the development of two fetuses instead of one. Overall, our review indicates that some antenatal complications are more frequent in assisted-conception twin pregnancies than in spontaneous twin pregnancies but their prevalence is low and thus their impact on the morbidity and mortality of an individual assisted-conception twin pregnancy is limited. Assisted reproduction treatment has become available to older women with pre-existing maternal medical conditions such as chronic hypertension and diabetes. The increased obstetrical risks in this population must be considered prior to attempts at assisted conception, and the transfer of more than one embryo should be avoided in women with a pre-existing maternal medical condition.