Donated-embryo pregnancies are associated with increased risk of hypertensive disorders even for young recipients: a retrospective matched-cohort study.

Objective: To determine whether pregnancies with donated embryos are at a higher risk of complications than the pregnancies from autologous frozen-thawed embryo transfer (FET).

Design: Anonymous, multicenter, comparative, observational, retrospective, matched-cohort study.

Setting: Six French assisted reproductive technique centers from 2003 to 2018.

Patient(s): Seventy-three singleton pregnancies with donated embryos (exposed) and 136 singleton pregnancies after autologous FET (nonexposed) were matched at 7-8 weeks of gestation (pregnancy date, parity, and women's age) (2:1 ratio, respectively). In accordance with French practices, all women were <44 years old and donated embryos were discarded frozen embryos from other couples.

Intervention(s): Not applicable.

Main Outcome Measure(s): Percentages of hypertensive disorders of pregnancy (HDPs) with donated embryos versus autologous FET.

Result(s): Groups were comparable (mean age: 34.5 years) and HDPs (24.6% vs. 11.9%) were significantly more frequent among the donated-embryo pregnancies, mostly in its severe forms (17.5% vs. 4.6%). In contrast, their respective isolated hypertension frequencies were comparable (7.0% vs. 7.3%). Multivariate analysis retained increased severe HDP risk with donated embryos (odds ratio 2.08 [95% confidence interval: 1.08-4.02]). No significant effect of endometrial preparation was observed. C-sections were more frequent for donated-embryo pregnancies (47.3% vs. 29.2%). Newborns from embryo donation or autologous FET were comparable for prematurity, birth weight and length, Apgar score, small for gestational age, large for gestational age, neonatal malformations, and sex ratio.

Conclusion(s): Even for young women, the risk of severe HDP was 4 times higher for donated-embryo pregnancies than for autologous-FET pregnancies. The HDP risk must be acknowledged to inform donated-embryo recipients and provide careful pregnancy monitoring.