“Advancing maternal age — specifically being age 35 and older — increases the risk of having or developing conditions, such as chronic high blood pressure, that increase the risk of pregnancy complications,” said study author Dr. Pensée Wu, senior lecturer and honorary consultant obstetrician and subspecialist in maternal fetal medicine at Keele University School of Medicine in Staffordshire, UK, in a statement.
The study, published Tuesday in the Journal of the American Heart Association, compared more than 106,000 deliveries in which the baby was conceived with assisted reproductive technology to more than 34 million births conceived without such aid.
Women who used infertility treatments had more preexisting health conditions, such as high blood pressure and diabetes, and were more likely to be obese when they started treatment, the study found.
Women using assisted reproductive technology to get pregnant had a 2.5 times higher risk of acute kidney failure and a 65% higher risk for an irregular heartbeat. They also had a 57% higher risk of placental abruption, when the placenta separates from the inner wall of the uterus before birth. The women were also 38% more likely to need a cesarean delivery, and 26% more likely to have the baby born prematurely.
A limitation of the study was that it did not compare different fertility treatments, which is an “important distinction,” said Chicago reproductive endocrinology and infertility specialist Dr. Sigal Klipstein, via email. She was not involved in the study.
“A woman requiring a short course of fertility pills in order to conceive and a woman requiring multiple cycles of IVF (in vitro fertilization) were all lumped together in this study,” said Klipstein, a liaison member of the American College of Obstetricians and Gynecologists’ Committee on Ethics.
“There may be significant differences between groups based on type of fertility treatment, length of treatment, and time between treatment and conception,” she said.
There were increased risks for women who underwent fertility treatments even when they had no preexisting symptoms of heart disease, the study also found.
“We were surprised that assisted reproductive technology was independently associated with these complications, as opposed to being associated with only the existence of pre-existing health conditions or only among older women undergoing infertility treatment,” Wu said.
That finding did not surprise Klipstein. “It is often the underlying infertility, and not the fertility treatment, that is associated with worse outcomes.”
She pointed to PCOS, or polycystic ovary syndrome, a common hormonal disorder in women. It’s a leading cause of infertility and also comes with an increased lifetime risk of cardiovascular disease. Women with PCOS are seven times more likely to suffer a heart attack, she said.
“According to the current study, 1 in 5 women enter pregnancy with a history of cardiovascular risk factors,” Klipstein said, which can raise health risks for the woman as she carries and delivers her child.
In her view, Klipstein said the main message of the study is the need for women to address any risk factors for heart disease prior to getting pregnant if that is possible. Women can focus on losing weight, lowering high blood pressure and getting their cholesterol under control, she said.
“The take home message is that physicians should counsel all women with preexisting cardiovascular risk factors who might become pregnant about pregnancy related risks, whether or not they have a history of infertility,” she added.