Similar obstetric outcomes for gestational surrogacy, pregnancies using fertility treatments

Key takeaways:

• Obstetric outcomes were similar for surrogacy and non-surrogacy using fertility treatments.
• Hypertensive disorders of pregnancy rates for surrogacy and assisted pregnancies were higher vs. general pregnancies.

Obstetric outcomes for gestational carriers were similar to non-surrogate pregnancies using fertility treatments, with both groups having higher odds for hypertensive disorders of pregnancy vs. general pregnancies, data show.

“Gestational carriers may experience the potential risks associated with pregnancy and delivery, such as hypertensive disorders of pregnancy, gestational diabetes or cesarean delivery due to the high rate of multiple gestations, which is an iatrogenic complication of assisted reproductive technology,” Shinya Matsuzaki, MD, PhD, of the department of gynecology at Osaka International Cancer Institute, Japan, and colleagues wrote in JAMA Network Open. “Assisted reproductive technology for gestational carriers may be associated with increased rate of placenta previa, placenta accreta spectrum and placental abruption.”

Matsuzaki and colleagues conducted a comprehensive systematic search of several databases and identified six studies published from 2011 to 2023 that examined obstetric characteristics and outcomes in gestational carrier pregnancies of 24 or more weeks’ gestation. Of the six studies, one compared obstetric outcomes between gestational carrier pregnancies and general pregnancies; all studies compared outcomes between gestational carrier pregnancies and non-gestational carrier pregnancies that used assisted reproductive technology. Researchers evaluated maternal characteristics and obstetric outcomes associated with pregnancies with vs. without gestational carriers.

Primary outcomes were obstetric characteristics, hypertensive disorders of pregnancy, preterm birth and low birth weight. Secondary outcomes were severe maternal morbidity and mortality associated with gestational carrier pregnancies.

Overall, the six studies included 28,300 gestational carrier pregnancies and 1,270,662 non-gestational carrier pregnancies. Gestational carrier pregnancies accounted for 3.8% of assisted reproductive technology (ART) pregnancies and 0.1% of all pregnancies.

Compared with nongestational carrier ART pregnancies, gestational carrier pregnancies had a higher likelihood of conceiving by frozen embryo transfer (OR = 2.84; 95% CI, 1.56-5.15). Rates of single embryo transfer were similar between pregnancies with vs. without gestational carriers (OR = 1.18; 95% CI, 0.94-1.48).

Nulliparity was observed among 1.7% of gestational carrier pregnancies. In addition, gestational carrier vs. nongestational carrier ART pregnancies had a higher likelihood of having multifetal pregnancies (OR = 1.18; 95% CI, 1.02-1.35).

Researchers observed lower odds of cesarean delivery (adjusted OR = 0.42; 95% CI, 0.27-0.65) and similar rates of hypertensive disorders of pregnancy (aOR = 0.86; 95% CI, 0.45-1.64), preterm birth (aOR = 0.82; 95% CI, 0.68-1) and low birth weight (aOR = 0.79; 95% CI, 0.5-1.26) for gestational carrier pregnancies and nongestational carrier ART pregnancies. Gestational carrier pregnancies also had higher odds of hypertensive disorders of pregnancy vs. nongestational carrier and non-ART pregnancies (aOR = 1.44; 95% CI, 1.13-1.84).

“Gestational surrogacy involves carrying a pregnancy that is the result of either the intended parent’s or parents’ gametes, or donor gametes,” the researchers wrote. “Theoretically, immune reactions to foreign antigens in gestational surrogacy may be comparable with responses observed in people after receiving oocyte donations, which increases the risk of hypertensive disorders of pregnancy compared with autologous ART.”

Gestational carrier pregnancies had similar risk for cesarean delivery as nongestational carrier and non-ART, or general, pregnancies (aOR = 1.06; 95% CI, 0.9-1.25).

Both severe maternal morbidity and maternal mortality were rare for gestational carrier pregnancies.

“There is a need for further research to comprehensively understand obstetric outcomes in gestational carrier pregnancies and better understand the associated risk profile,” the researchers wrote.