Women who act as pregnancy surrogates appear to have a higher risk of health complications than those who carry their own babies, researchers have found. The use of surrogates, or “gestational carriers”, has boomed in recent years, with figures for England and Wales revealing that the number of parental orders, which transfer legal parentage from the surrogate, rose from 117 in 2011 to 413 in 2020. A study based on data from Canada suggests surrogates are more likely to experience complications including severe postpartum haemorrhage and severe pre-eclampsia than women who conceived naturally or with IVF. Babies were more likely to be born prematurely to surrogates, although they were no more likely to have severe neonatal complications. Experts say the findings highlight the need for improved prenatal care for surrogates, and the creation of strict criteria and regulations for women who wish to undertake such a role. Dr Maria Velez, the first author of the research, from McGill University in Canada, said it was important to counsel the intended parents and the gestational carriers about potential complications. “Those complications are important for [gestational carriers],” she said. “But they also have an impact for the intended parents, [and] for the physician who is taking care of this patient.” Writing in the journal Annals of Internal Medicine, Velez and colleagues report how they used the Better Outcomes Registry & Network (Born) database to explore the occurrence of complications among 863,017 singleton births in Ontario that took place from 2012 to 2021. Of these births, the team report 806 were babies born to surrogates – typically involving the receipt of an embryo from the intended parents – 846,124 were a result of unassisted conception and 16,087 involved IVF. The team found that the rate of severe maternal health complications was 7.8% for surrogates, 2.3% among the unassisted conception group and 4.3% for pregnancies involving IVF. While the researchers found surrogates were more likely to have certain characteristics, including having given birth before, living in a lower-income area, being obese and having high blood pressure, such factors do not appear to fully explain the results. Indeed, after taking into account factors including age, level of income, number of previous births, obesity, smoking and high blood pressure, the team found that the risk of severe postpartum haemorrhage was 2.9 times higher for surrogates compared with women who became pregnant without assistance, while the risk of giving birth before 37 weeks was 1.79 times higher. Such risks were also higher, albeit to a lesser degree, for surrogates when compared with women for who had undergone IVF. “It might be that there are other mechanisms, including maybe an immunological mechanism, that could be involved in this higher risk [for gestational carriers],” Velez said. Jackie Leach Scully, a professor of bioethics at the University of New South Wales, who was not involved in the study, noted that the research had limitations, including that it included only a small group of surrogates, and that such women may have had healthy babies previously with no health issues during pregnancy. “Nevertheless, what this paper does highlight is that we actually know relatively little about the particular risks of harm to the woman who acts as surrogate, or the baby, in surrogacy,” she said, adding that while a surrogate should ideally be healthy and at low risk of complications, that did not always happen in practice. “This raises some ethical questions, first of all about the potential exploitation of women who act as gestational carriers and who effectively bear the risks of pregnancy on behalf of someone else,” she said. “Second, the scarcity of accurate data on the risks and outcomes of surrogate pregnancies must really make us ask how seriously the health of women, as opposed to the health of the foetus or baby, is taken. The neglect of women’s health in the history of medicine is well recognised, and may be exacerbated in the situation of surrogacy, where the gestational carrier’s role is socially obscured.”