Obstetric and maternal outcomes of IVF and oocyte donation pregnancies among women ages 40–45—a large cohort study

Purpose: To analyze the perinatal and maternal outcomes of women ranging in age from 40 to 45 years who gave birth after in vitro fertilization or oocyte donation, compared to spontaneous conception. Methods: This retrospective cohort study used electronic data from a national healthcare service from 2000 through 2019. Three groups were compared: spontaneous pregnancy (SC), in vitro fertilization (IVF) utilizing autologous oocytes, and pregnancies resulting from oocyte donation (OD). The primary study outcomes were preterm labor (PTL) before 37 weeks of gestation, and infants classified as small for gestational age (SGA). Results: The cohort included 26,379 SC, 2237 IVF pregnancies, and 300 OD pregnancies for women ages 40–45 years at delivery. Women with OD or IVF had a higher incidence of PTL < 37 weeks compared to women with SC (19.7% vs. 18% vs. 6.9%, p = 0.001), PTL < 34 (7% vs. 4.5% vs. 1.4%, p = 0.001), PTL < 32 (3.7 vs. 2.1 vs. 0.6, p = 0.001). A multivariable logistic regression for PTL < 37 weeks demonstrated that age (OR = 1.18) and hypertensive diseases (OR = 3.4) were statistically significant factors. The OD group had a lower rate of SGA compared to SC (1% vs. 4.3%, p = 0.001), while the IVF group had a higher rate of SGA compared to SC (9.1% vs. 4.3%, p = 0.001). Hypertensive diseases in pregnancy were significantly higher among the OD group and the IVF group compared to SP pregnancies (3.3% vs. 1%, p = 0.002; 2.3% vs. 1%, p = 0.001, respectively). Conclusions: Women ages 40–45 undergoing IVF or OD have a greater risk of PTL, possibly due to higher rates of hypertensive disorders of pregnancy.