Outcomes of singleton versus twin pregnancies in the fifth and sixth decades

Pregnancies in the fifth and sixth decades of life have been increasing, but current data are limited regarding the outcomes of twin compared with singleton pregnancies in this age group and to twin pregnancies at younger age.

To compare obstetrical and neonatal outcomes of IVF conceived pregnancies, in twin gestations of women who were ≥45 years old at delivery to singletons at similar age and twin gestations at the age of <35 years, and to assess if the complications are mainly influenced by the very advanced maternal age or by the multifetal pregnancy.

A retrospective cohort study from a single tertiary medical center of women aged ≥45 at delivery between March 2011 and January 2018 and women aged <35 at delivery with twin pregnancies that conceived by IVF. Exclusion criteria were spontaneous pregnancies or pregnancies after ovulation induction, monochorionic twin pregnancies, higher order multiple gestations, or women that underwent fetal reduction. Pregnancy, delivery, postpartum and neonatal outcomes were compared between singleton and twin pregnancies. Multivariate logistic regression was used to evaluate the association between twin pregnancies and adverse outcomes.

Out of 67,355 deliveries, 612 were of women ≥45 years old, of whom 492 women conceived via IVF (395 singleton and 97 twin pregnancies). Of those, 60 women were ≥50 years old, 49 of them carried singleton and 11 carried twin pregnancies. Baseline characteristics were similar between groups. Women at the fifth and sixth decades with twins had significantly higher rates of preeclampsia (32.0% vs. 10.9%, p < 0.001), gestational diabetes mellitus (35.4% vs. 23.8%, p = 0.020), preterm deliveries <32 weeks of gestation (8.2% vs. 1.3%, p = 0.001), and fetal growth restriction (18.6% vs. 7.6%, p = 0.001) compared with singleton pregnancies at similar maternal age. After multivariate analysis adjusting for confounders, the odds ratio for the composite of preeclampsia, gestational hypertension, intrauterine fetal growth restriction, and placental abruption was 3.19 for twin compared with singleton pregnancies and 1.73 for gestational diabetes mellitus. Pregnancy complications among older women with twins were also significantly higher when compared with younger women with twins (<35 years old). Women in the fifth and sixth decades with twins had higher rates of cesarean deliveries (91.8% vs. 56.4%, p<0.001), gestational hypertension, preeclampsia, and gestational diabetes mellitus (10.3% vs. 4.2%., p=0.016; 32.0% vs. 6.2%, p<0.001; 35.1% vs. 8.1%, p<0.001, respectively) than the younger group carrying twins.

Twin pregnancies in the fifth and sixth decades carry significantly higher complications rate compared with singleton pregnancies at the same age and twin pregnancies at younger age.