The effect of ICSI, maternal age, and embryonic stage on early clinical loss rate of twin versus singleton pregnancies

ObjectivesTo compare early loss rates between twin and singleton pregnancies following ART.Study designFirst-trimester sonography counted the number of embryos with positive heartbeat in women undergoing IVF/ICSI and transfer of one to three embryos. The number of lost pregnancies was calculated from a second-trimester sonogram. Loss rates of the entire pregnancy were related to maternal age <38 or ≥38 years, IVF or ICSI, and cleavage or blastocyst stage embryo transfers (in ICSI cases).ResultsPatients underwent IVF with (n = 672) and without (n = 189) ICSI. The overall odds of miscarrying the entire singleton pregnancy were 2.6 times that of a twin gestation (95% CI 1.5, 4.5). The disadvantage for singletons compared to twins seems more apparent in pregnancy after ICSI in the subgroup of patients <38 years (OR 2.9, 95% CI 1.5, 5.8). In this subgroup, the disadvantage conferred to singletons appeared only among days 2–3 embryo transfers (OR 3.0, 95% CI 1.3, 7.2).ConclusionA significantly lower early spontaneous loss rate of twin pregnancies seems related to ICSI followed by cleavage stage embryo transfer in patients <38 years.