Gestational carrier (GC) pregnancies have improved outcomes, but increased risks compared to general pregnancies, according to a recent study published in JAMA Network Open.1
Takeaways
- Gestational carrier pregnancies show improved outcomes compared to general pregnancies, with notable findings in reduced risks for certain complications.
- Despite some improved outcomes, gestational carrier pregnancies are associated with higher risks of complications such as hypertensive disorders of pregnancy and gestational diabetes.
- The study found that gestational carrier pregnancies have comparable outcomes to non-gestational carrier assisted reproductive technology pregnancies, particularly in terms of preterm birth and low birth weight.
- Additional research is necessary to thoroughly compare gestational carrier pregnancies to non-ART general pregnancies to better understand the full spectrum of risks and outcomes.
- The study involved a systematic review and meta-analysis of 6 retrospective studies, including 28,300 gestational carrier pregnancies and over 1.2 million non-gestational carrier pregnancies.
Surrogacy refers to when an individual carries a fetus in utero and delivers a newborn in place of the offspring’s intended parents. Unlike gestational surrogacy, traditional surrogacy involves the use of the surrogate’s gametes. In gestational surrogacy, an embryo from donated gametes or the intended parents is implanted into a GC’s uterus.
Gestational surrogacy is usually employed to overcome medical, ethical, biological, or psychosocial barriers to pregnancy. However, the risks of complications such as gestational diabetes (GD), hypertensive disorders of pregnancy (HDP), and cesarean delivery (CD) may be increased in GCs.
In a review evaluating surrogate pregnancies, the prevalence of multiple pregnancies ranged from 2.6% to 75%, preterm birth (PTB) from 0% to 11.5%, and low birthweight (LBW) from 0% to 11.1%.2 No major psychological differences were observed in GC-pregnancy offspring vs non-GC pregnancy offspring after 10 years.
To evaluate maternal characteristics and obstetric outcomes associated with GC pregnancies, investigators conducted a systematic review and meta-analysis.1 The PubMed, Web of Science, and the Cochrane Central Register of Controlled Trials were searched for literature posted before October 31, 2023.
Two investigators performed title, abstract, and full-text screening, with key words relating to surrogate mothers and pregnancy outcomes. Eligibility criteria included pregnancy outcomes in gestational surrogacy, comparing outcomes between gestational surrogacy and nonsurrogacy, and at least 24 weeks’ gestation.
Exclusion criteria included insufficient outcome information, unavailable data about the number of surrogacies, non-English language study, and certain article types. Two investigators performed data extraction, recording the study year, location, first author’s name, number of cases, and relevant outcomes.
Participant groups included GC pregnancies, non-GC assisted reproductive technology (ART) pregnancies, and non-GC non-ART pregnancies. Maternal characteristics and obstetrics outcomes were the primary outcomes and encompassed GD, HDP, PTB, LBW, fetal growth restriction, placenta previa, placental abruption, and intrauterine fetal death.
Secondary outcomes included severe maternal morbidity (SMM), the rate of CD, and postpartum hemorrhage. SMM included maternal death, intensive care unit admission, and hemolysis, elevated liver enzymes, and low platelets syndrome.
There were 6 retrospective studies including 28,300 GC pregnancies and 1,270,662 non-GC pregnancies included in the analysis. Five studies were from the United States while 1 was from the United Kingdom. All studies compared outcomes from GC pregnancies to those from non-GC ART pregnancies, with 1 including general pregnancies.
Patients with GC pregnancies had a lower median maternal age vs those with non-GC ART pregnancies, at 31 vs 38 years, respectively. GC pregnancies were also associated with reduced nulliparity and a significantly increased prevalence of multiple gestation.
HDP risks were compared in 1 study, which found that GC pregnancies had increased HDP rates vs general pregnancies, with an adjusted odds ratio (aOR) of 1.44. When comparing GC pregnancies to non-GC ART pregnancies, the aOR was 0.86.
PTB was evaluated in 4 studies. Comparable risks were reported between GC and non-GC ART pregnancies, with an aOR of 0.82. When comparing LBW, the OR across 4 studies was 0.80. However, the aOR across 2 studies of 0.79 was not statistically significant.
CD risk was evaluated in a US nationwide study, which found a similar risk when comparing GC to general pregnancies but a lower risk when comparing GC to non-GC art pregnancies. The aORS for these comparisons were 1.06 and 0.42, respectively.
One study evaluated SMM risk, reporting an aOR of 1.03 for composite risk between GC pregnancies and general pregnancies. This indicated similar risks of SMM between groups.
These results indicated comparable obstetrics outcomes between GC pregnancies and non-GC ART pregnancies. However, investigators noted the need for additional research comparing GC pregnancies to non-GC non-ART pregnancies.
Reference
- Matsuzaki S, Masjedi AD, Matsuzaki S, et al. Obstetric characteristics and outcomes of gestational carrier pregnancies: A systematic review and meta-analysis. JAMA Netw Open. 2024;7(7):e2422634. doi:10.1001/jamanetworkopen.2024.22634
- Söderström-Anttila V, Wennerholm UB, Loft A, et al. Surrogacy: outcomes for surrogate mothers, children and the resulting families-a systematic review. Hum Reprod Update. 2016;22(2):260-76. doi:10.1093/humupd/dmv046.
