Women who conceived babies using in vitro fertilization or assisted reproductive technology (ART) were two to three times as likely as women who did not use ART to suffer serious health complications during delivery, according to a new study led by School of Public Health researchers.
The study in the journal Obstetrics & Gynecology used Massachusetts birth and hospitalization data from 2004 to 2010 to compare health outcomes during delivery for women who had conceived using ART with those of women who were fertile or sub-fertile and did not use ART.
Researchers found that the overall prevalence of severe maternal morbidity—defined as potentially life-threatening conditions, largely indicated by the need for blood transfusions during delivery—was 3.14 percent among mothers who used ART, compared to 1.09 percent among fertile women and 1.44 percent among sub-fertile women.
The analysis, led by Candice Belanoff, clinical assistant professor of community health sciences, said further study is needed to understand why women who had ART might have elevated risks of morbidity. The study controlled for age, education, race, ethnicity, and other factors that might affect mothers’ health outcomes.
Belanoff said that while the profile of the ART patient population tends to reflect greater social advantage and factors protective against severe maternal morbidity, ART previously has been associated with some known risk factors at delivery, including placenta accrete, plural births, and cesarean delivery
“Women who use ART to conceive are more likely to have underlying health and fertility problems that necessitated the use of ART, but we need more research to understand what factors are putting them more at risk during delivery,” she said.
She emphasized that severe maternal morbidities are rare across the board, and that, “even with this elevation in risk, the overall known maternal risk associated with ART is still quite low.”
In adjusted analyses, women with ART who delivered by C-section had 1.75 times higher odds of health complications during delivery compared with sub-fertile women who had C-sections, the study found. Women with ART who delivered vaginally had 1.97 times higher odds of serious complications than sub-fertile women, and 2.27 times higher odds than fertile women.
Among twin births, the only significant difference for ART mothers was in cesarean births. Cesarean ART deliveries had significantly greater severe maternal morbidity, compared to cesarean deliveries by fertile mothers, the study says.
The study notes that the rate of pregnancy-related deaths in the US rose from 7.2 per 100,000 in 1987, to 17.8 in 2011. The rate of severe maternal morbidity more than doubled between 2001 and 2011, from 78.6 per 10,000 delivery hospitalizations, to 162.8.
During the same period, the proportion of babies born as a result of ART increased from 0.9 percent to 1.5 percent.
The new study is the latest component of the larger Massachusetts Outcomes Study of Assisted Reproductive Technology, which links ART treatment records to birth certificates and maternal and infant hospitalization records in Massachusetts from 2004 through 2010. Researchers are trying to determine whether ART procedures put mothers or their children at increased risk of adverse health outcomes.
Besides Belanoff, SPH co-authors include Eugene Declercq, professor of community health sciences; Thien Nguyen, project manager in community health sciences; and Daksha Gopal, senior statistical programmer in community health sciences. Other researchers are from the Massachusetts Department of Public Health, Massachusetts General Hospital, Harvard Medical School, Michigan State University, and the Geisel School of Medicine at Dartmouth.