Perinatal Outcomes of Singleton, Twin and Triplet Gestations after Oocyte Donation: A Retrospective, Population-Based Cohort Analysis.

Background/objectives: Although high live birth rates are associated with oocyte donation (OD), these pregnancies are associated with increased obstetric and perinatal risks. This study evaluated maternal and neonatal risks after OD compared to in vitro fertilization (IVF) with autologous oocytes, and to spontaneous pregnancies (SPs), among singletons, twins and triplets.

Methods: A retrospective, large, population-based cohort study was conducted based on electronic data from Maccabi Healthcare Services. A total of 469,134 pregnancies were grouped according to the mode of conception. The main outcome measures were preterm birth (PTB), small for gestational age (SGA) and pregnancy-induced hypertension (PIH). The data were analyzed separately for singletons, twins and triplets.

Results: The mean maternal age was older in the OD group compared with the IVF and SP groups (singletons: 39.7 ± 4.1 vs. 34.5 ± 4.8 and 31.7 ± 5.3 years; twins: 39 ± 4.6 vs. 32.6 ± 4.4 and 31.2 ± 5.1 years; and triplets: 35.6 ± 2.5 vs. 32 ± 3.9 and 29.7 ± 5 years). The mean gestational age was younger among the OD group compared to the SP group (singletons: 37.5 ± 3 vs. 39 ± 2 = 0.001, and twins: 35 ± 3 vs. 36 ± 2.5 = 0.001). Higher rates of PTB < 37, PTB < 34 and PTB < 28 weeks were found among OD singletons. Multivariable logistic regressions for PTB < 37 weeks and SGA in singletons demonstrated that OD and IVF are significant risk factors (OR = 4.1, 95%CI = 3.3-5.2; OR = 4.3, 95%CI = 4.1-4.6; OR = 1.9, 95%CI = 1.3-2.6; OR = 2.2, 95%CI = 2-2.4, respectively). Significantly higher rates of PIH were demonstrated among the OD vs. IVF and SP groups in singleton (4.3% vs. 1.7% and 0.7%) and in twin pregnancies (7.5% vs. 4.3% and 3.4%).

Conclusions: OD pregnancies are at increased risk for PTB, SGA and PIH.