Obstetric and perinatal outcomes of singleton pregnancy from donated frozen versus fresh oocytes

To evaluate whether oocyte cryopreservation affects obstetric and perinatal outcomes, 350 donor oocyte recipients with live-born singletons were divided into three groups: frozen embryo transfer (FET) with fresh oocytes (n = 101), fresh embryo transfer (ET) with frozen oocytes (n = 190), FET with frozen oocytes (n = 59). Gestational age differed significantly (P = 0.025), with the FET with frozen oocytes group showing longer gestational age than FET with fresh oocytes group (276 days vs. 272 days, P = 0.04). Other outcomes were comparable among groups. Subgroup analysis of FET pregnancies revealed no significant differences between frozen and fresh oocyte groups in gestational age (B 1.38, P = 0.749), birth weight (B -0.11, P = 0.530), premature birth rates (6.8% vs. 11.9%, P = 0.746), low birth weight (LBW) (5.1% vs. 12.9%, P = 0.865), macrosomia (5.1% vs. 4.0%, P = 0.976), small for gestational age (SGA) (6.8% vs. 11.9%, P = 0.599), large for gestational age (LGA) (22.0% vs. 18.8%, P = 0.943), gestational diabetes mellitus (GDM) (10.2% vs. 11.9%, P = 0.343), hypertensive disorders of pregnancy (HDP) (8.5% vs. 17.8%, P = 0.143) or placental abnormalities (8.5% vs. 19.8%, P = 0.133). The study confirmed oocyte cryopreservation did not affect birth weight or obstetrical complications in donor oocyte recipients.