P–765 Embryo donation pregnancies are at high risk even in young recipients
Authors: Peigné M , Mouzon J D , Kiehl A , Fraissinet A , Maget V , Saïas-Magnan J , Mathieu-D’Argent E , Gervereau O , Letur H 
Published: August 2021

Abstract

Study question
Are pregnancies after embryo donation (ED) at higher risk of complications than those issued from autologous frozen-thawed embryo transfer (FET)?

Summary answer
Even in young women, the risk of pregnancy induced hypertension (PIH) is four time higher in pregnancies after ED versus controls.

What is known already
After oocyte donation, a higher risk of PIH is well described. It is more controversial after sperm donation. The risk origin remains uncertain, even though an immunological explanation seems most likely. In ED, the fetus being fully allogeneic to his parents may be less well-tolerated. Very few data are reported about pregnancies after ED. The same allogenic model exists in surrogacies, but pregnancy complications are not well described in the literature.

Study design, size, duration
This anonymous, multicenter, comparative observational retrospective cohort study included all singleton ED pregnancies diagnosed at 7–8 weeks, from January 2003 to December 2018, in six French ART centers. For each, two controls were matched among autologous FET pregnancies. 209 pregnancies were included: 73 ED and 136 controls. Multiple pregnancies were excluded because of their increased associated obstetrical risks.

Participants/materials, setting, methods
Controls were matched according to pregnancy date, parity and women’s age. The first two singleton pregnancies after each index case meeting the selection criteria were retained. Each center coordinator collected information on infertility, pregnancy pathologies, outcomes and newborns. Statistical methods included univariate and multivariate analyses. According to French practice, all women were under 44 y/o. The main outcome was the percentage of PIH for ED versus controls.

Main results and the role of chance
ED was indicated for genetic disease in 17 cases (23.3%), double total infertility in 28 cases (38.3%), and double partial/total infertility in 35 cases (47.9%). Groups were comparable in age (mean age: 34.5 ± 8.6 versus 34.5 ± 4.5; p = 0.68), BMI, except for parity (more nulliparity in ED group: 90.4% vs 79.4%; p = 0.04). Pregnancy outcomes were similar for ED and control groups, the percentages of deliveries being 80.8% and 83.8%, respectively (p = 0.58). PIH occurred significantly more frequently among ED than control pregnancies (24.6% versus 11.9%; P = 0.04), with the difference mainly observed for severe forms: preeclampsia and HELLP (17.5% vs 4.6%; p = 0.01). No eclampsia was reported. In contrast, isolated hypertension frequency was comparable (7.0% vs. 7.3%, p = 0.94). Regarding labor and delivery mode, in ED group C-section was more frequent (47.3% vs 29.2%; p = 0.03). In neonatal data, no difference was found between ED and control group for prematurity, weight and height at birth, Apgar score, Small for gestational age, Large for gestational age and sex ratio. Seven neonatal malformations were recorded in ED group and 3 in the control group (NS).

Limitations, reasons for caution
Retrospective study in a relatively long period when different endometrial preparation for frozen-thawed embryo transfer and embryo cryopreservation method were used. Relatively limited number of ED because of low practice in France. No analysis of embryo stage at transfer (cleaved embryo or blastocyst).
Wider implications of the findings: The PIH risk must be acknowledged to inform couples and provide careful pregnancy monitoring. A special care for gestational carrier should also be done since the allogenic situation is the same than in ED recipients.

Trial registration number
Not applicable