P-778 Same mother-different Oocyte: Comparison of obstetric and perinatal outcomes between pregnancies achieved through oocyte donation versus those achieved through spontaneous conception for the same mother
Authors: Miller N , Shalev H , Hershko Klement A , Wiser A 
Published: June 2023

Abstract

Study question
Is there a difference in obstetrical and perinatal outcomes between pregnancies achieved through oocyte donation versus those achieved through spontaneous conception for the same mother

Summary answer
OD pregnancies show higher incidences of preterm labor and pregnancy-induced hypertension, and lower incidences of small for gestational age, compared to spontaneous pregnancies

What is known already
Oocyte donation (OD) is an integral part of modern assisted reproductive care and has been used for over three decades. OD pregnancies have an increased rate of hypertension, cesarean section, and preterm labor. Yet most of these complications are attributed to the mothers going through OD, not to the biological effect of different oocyte sources (autologous Vs. donation).

Study design, size, duration
This study is a retrospective cohort study that utilizes electronic data from Maccabi Healthcare Services. This 2.5-million-patient integrated care organization represents 25% of the pregnant population in the country. The data used in this study were collected from 2000 through 2018.

Participants/materials, setting, methods
The study included mothers who experienced both a spontaneous conception (SP) pregnancy and later an oocyte donation (OD) pregnancy. The study compared obstetric and perinatal outcomes, including the incidence of preterm labor (PTL) and small for gestational age (SGA). Mother's obstetric outcomes such as pregnancy induced hypertension (PIH), gestational diabetes, malpresentation, and postpartum hemorrhage were also analyzed. A paired t-test was performed to compare each outcome for the same mother

Main results and the role of chance
The cohort included 194 mothers who had a first spontaneous pregnancy and a second pregnancy with oocyte donation.
The mean age of the mother during her OD pregnancy was statistically older than the OD pregnancy (mean difference 2.2 years, p = 0.0028). No difference was found between pregnancies regarding the BMI (p = 0.216). A trend toward a higher prevalence of PIH was found in the OD pregnancy compared to the SP (mean difference 2.5, p = 0.058). No difference was found between pregnancies regarding gestational diabetes (p = 0.7), malpresentation (p = 1), retained placenta (p = 0.318), and Cesarean section (p = 0.565).
Perinatal outcomes show a higher prevalence of premature labor before the 34th week and 32nd week in the OD pregnancies compared to SC pregnancies (mean difference 3.6, p = 0.034 and mean difference 3, p = 0.33 respectively). No difference was found between pregnancies regarding labor before the 37th week (p = 1). A statistically lower prevalence of SGA was found in the OD pregnancy compared to the SP (p = 0.0057).

Limitations, reasons for caution
Due to its retrospective character, some information is lacking. Information regarding indications leading to OD/AO are missing which might have elaborated our findings

Wider implications of the findings
OD pregnancies should be considered high-risk, primarily due to the increased risk of PTL and PIH. Adequate recommendations should be considered, including cervical length surveillance, frequent blood pressure measurements, and perhaps prophylactic low-dose aspirin to reduce the risk of preeclampsia.

Trial registration number
0046-18-BBL