Background: The aim of the study is to compare the obstetric outcome between single pregnancies obtained by medically-assisted procreation using oocyte donors (MAP-E) versus homologous gametes (MAP-O) and single spontaneous conception pregnancies (SC).
Methods: This is a retrospective case-control study on pregnancy outcome of consecutive singleton live birth pregnancies from MAP-E between January 2011 and August 2017 referred to Careggi University Hospital, Florence. The control group includes singleton pregnancies from MAP-O and pregnancies from spontaneous conceptions in the same period. The pregnancy outcomes considered were: postpartum hemorrhage (PPH), cesarean section (CS), gestational diabetes mellitus (GDM), hypertensive disorders including preeclampsia (HDP), preterm birth ≤34 weeks (PTB), and small-for-gestational-age (SGA) fetuses.
Results: The study group included 290 MAP-E pregnancies that were compared with 290 MAP-O and 870 singleton spontaneous conception pregnancies. The three groups did not show significant differences in maternal traits except for mean age (43.4±2.9 vs. 37.7±2.4 vs. 33.6±5.5, P<0.001), including a higher percentage of patients over 45 years (41.3% vs. 5% vs. 0.8%, P<0.001) and higher incidence of obesity (7.2% vs. 1.7%, P=0.02) in MAP-E than in MAP-O. The risk of HDP is increased in singleton pregnancies by oocyte donation with a significantly increased risk if compared to MAP-O (12% vs. 1%, P<0.001, OR=12.6). The risk of PPH in singleton pregnancies from oocyte donation is higher than in MAP-O (22% vs. 9% P<0.0001, OR=2.87). When we considered severe PPH (blood loss >1000 mL) the risk for MAP-E was higher if compared to MAP-O (OR=2.1, P=0.2) and mostly to SC (OR=14, P<0.005). Compared to SC, MAP-E pregnancies showed increased OR for all the outcomes: CS (78% vs. 30.8%, P<0.001, OR=7.91); GDM (26.1% vs. 10.8%, P<0.001, OR=2.92); HDP (12% vs. 2.2%, P<0.001, OR=5.99); PPH (22% vs. 8.5%, P<0.0001, OR=3.0); SGA (16% vs. 11%, P<0.05, OR=1.16); PTB ≤34 weeks (9.4% vs. 1%, P<0.001, OR=7.94).
Conclusions: Most women who undergo MAP-E are in advanced age, representing a high-risk population for obstetric complications, like HPD and PPH, which stands as the main worldwide cause of maternal mortality.