Twin versus singleton pregnancy in women ≥ 45 years of age: comparison of maternal and neonatal outcomes.

The aim of the study is to compare the effect of very advanced maternal age (≥45 years) on maternal and neonatal outcomes of twin and singleton pregnancies. This retrospective cohort study included women ≥ 45 years of age who gave birth to twins. Each was randomly matched to two women ≥ 45 years of age who gave birth to singletons within 7 days of the study subject. Data on maternal age, gravidity, parity, background medical information, body mass index at conception, number of fetuses, mode of conception (either spontaneous or assisted reproductive technology [ART]), mode of delivery, and gestational age at delivery were extracted from a real-time computerized database. The data of 75 twin pregnancies of women aged ≥ 45 years were compared with those of 150 singleton pregnancies matched for maternal age. There were significantly more cases of hypertensive complications among the twin pregnancies compared to the singleton pregnancies (41.33 versus 14.00%, respectively, OR = 3.33, 95% CI = 2.26-8.30,  = .000) and more cases of preeclamptic toxemia (29.33 versus 12.00%, respectively, OR = 3.04, 95% CI = 1.51-6.13,  = .001). The duration of twin pregnancies was much shorter compared to singleton pregnancies, with a higher incidence of deliveries prior to 37 weeks' gestation (56.00 versus 8.00%, respectively, OR = 14.64, 95% CI = 6.94-30.85,  = .000), and deliveries prior to 34 weeks' gestation (22.67 versus 2.00%, respectively, OR = 14.36, 95% CI = 4.06-50.86,  = .000). More infants of twin pregnancies had a low birth weight (68.00 versus 10.00%, respectively, OR = 19.13, 95% CI = 10.14-36.06,  = .000), and many had a very low birth weight (10.67 versus 0.67%, respectively, OR = 17.79, 95% CI = 2.33-135.97,  = .000). The infants of twin pregnancies also included more cases of intubation (10.00 versus 0.00%, respectively,  = .000), more cases of hypoglycemia (12.67 versus 5.33%, respectively, OR = 2.57, 95% CI = 1.09-6.08,  = .026), and were admitted much more often to the neonatal intensive care unit (36.00 versus 8.00%, respectively, OR = 6.47,  = .00, CI = 3.29-12.74). Women ≥ 45 years of age with twin pregnancies and their neonates sustain more severe adverse outcome compared to matched pairs of singleton pregnancies. It is recommended that a single embryo transfer should be offered in preference to multiple embryos when those women are undergoing ART.