Jan. 27, 2011 -- Maternal deaths resulting from in vitro fertilization (IVF) are relatively rare, but they do occur, British doctors warn in an editorial in the journal BMJ.
In the U.S. there were more than 140,000 IVF cycles in 2008, according to the Society for Assisted Reproductive Technology (SART). During IVF, an egg and sperm are fertilized outside of the body in a laboratory and then implanted in the woman’s uterus. Fertility drugs are often used to stimulate a woman’s ovaries to produce eggs.
One leading U.S. fertility doctor says he is not aware of any deaths in the U.S. related to IVF pregnancies.
In the new report, Susan Bewley, an obstetrician at Kings College in London, and colleagues cite a study in the Netherlands that shows that the rate of pregnant women dying during IVF pregnancies is higher than during pregnancies in the general population. Specifically, there were 42 deaths per 100,000 IVF pregnancies, compared with six deaths seen among 100,000 pregnancies in the general population.
Ovarian hyperstimulation syndrome can occur as a result of fertility drugs used to stimulate the development of eggs in a woman's ovaries. If the ovaries are overstimulated they can become enlarged and symptoms such as abdominal pain, nausea, and vomiting can occur. In severe cases fluid may accumulate around the lungs or heart.
The authors call for tracking of IVF-associated risks including ovarian hyperstimulation syndrome to better understand risks associated with IVF. “More stringent attention to stimulation regimens, preconceptual care, and pregnancy management is needed so that maternal death and severe morbidity do not worsen further,” they write.
U.S. fertility doctors point out that the reasons women undergo IVF may account for the increased risk of death seen in the studies.
“It is very tenuous to say these were caused by IVF,” says Jamie Grifo, MD, PhD, program director of New York University Fertility Center in New York City.
Underlying health issues in women who turn to IVF to get pregnant may affect their risk profile, he says. These women may have had previous uterine surgery or are predisposed to high blood pressure or diabetes. Women who undergo IVF are also usually older than their counterparts who conceive without such assistance. Advancing maternal age is associated with riskier pregnancies.
“The population of people who need IVF may add special contributing factors to the risk of death during their pregnancy,” he says. Multiple pregnancies are more likely as a result of IVF, which also increases risks to moms and babies.
The new findings may not apply to the U.S. due to differences in obstetrical care, he says.
“We manage risks better [here], and do reductions more in multiple pregnancies,” Grifo says. The best way to protect the mother’s health and that of the baby regardless of how the pregnancy occurred is good prenatal care.
“If there are things about the pregnancy that increases their risk, women should be cared for by high-risk obstetricians who know how to manage complications and take them seriously,” he says.
“I have never heard of anyone dying from IVF in the U.S.,” says SART President R. Stan Williams, MD, the chairman of obstetrics and gynecology at University of Florida in Gainesville.
In the new report, “they are comparing apples to oranges when they compare pregnancy in the general population to IVF pregnancies,” he says.
“The first major difference is the ages,” he says. "The majority of people getting IVF are in their mid-30s, and the majority of women in the general population who get pregnant are in their 20s.”
The underlying disease process that caused fertility problems in the first place is also a factor.
That said, every procedure does have some inherent risks, including IVF.
“There are risks with IVF, I don’t deny it,” he says. “The risks are rare but they are real and need to be taken into account when thinking about using IVF to have a baby.”
Many couples may downplay or even ignore the risks due to their desire to have children, he says.
“It is the physician’s responsibility to make sure they are not driven only by the goal of establishing a pregnancy and that they really understand any and all risks that they are taking,” says Gerald Scholl, MD, associate chief of human reproduction at North Shore University Hospital in Manhasset, N.Y.
He says that the risk of maternal mortality among IVF pregnancies is “really extremely low.”
These women are screened extensively before IVF to make sure they are appropriate candidates.”If women have any underlying diseases or conditions that could worsen during pregnancy, they are counseled not to start IVF,” he says.