There’s no question that conceiving a baby using assisted reproductive technologies can be a complex and difficult process.
Now, a new study suggests the pregnancy that results may have complications as well, including an increased risk of preeclampsia — a dangerous form of high blood pressure that can potentially claim a mother’s life.
Reporting in the March issue of the Journal of the American College of Obstetricians and Gynecologists, a group of Denver researchers say women pregnant with two or more babies conceived via fertility treatments are more than twice as likely to develop preeclampsia, compared to women who conceive their multiple pregnancies naturally.
Not all researchers think there’s a definitive link between preeclampsia and assisted reproductive technologies such as in vitro fertilization (IVF) or gamete intra fallopian tube transfer (GIFT), and say other health factors might be to blame.
However, lead author Dr. Anne Lynch says, “We were extremely careful in this study to define all the criteria as precisely as we could, not only the parameters that define preeclampsia, but also in gathering information about any factors that could influence study results, such as a woman’s age, a previous history of preeclampsia, if this was her first birth, even her race.”
“Even after we factored out all the possible details that could influence our finding, the results still remained,” she adds.
The study also looked at women who used the fertility drugs clomiphene citrate and HMG without using IVF or GIFT. The researchers report they did not find a statistically significant spike in the number of women who experienced preeclampsia. That finding may owe to the small study size, Lynch concedes.
“We suspect that in a larger group of women, those who use fertility drugs alone may also be at greater risk for preeclampsia, but we can’t say for sure right now,” says Lynch.
Lynch adds she can’t say if preeclampsia is caused by any fertility treatments, or is the result of some other factor.
That thought also occurred to Dr. Jaime Grifo, director of the division of reproductive endocrinology at New York University Medical Center.
“It’s definitely an interesting and important study. However, it does not show any definite correlation between the IVF procedure itself and preeclampsia. And there are many variables that could account for this result,” says Grifo, who is also president of the Society for Assisted Reproductive Technology.
The risk for preeclampsia could be the result of the original cause of the infertility, he says.
“Whatever is keeping these women from getting pregnant naturally may also play a role in increasing their risk of preeclampsia,” Grifo says.
Other factors that could be at work, says Lynch, would be undiagnosed health problems, such as insulin resistance or even heart disease.
“But the problems could also be related to donor eggs, donor sperm, ovulation induction — any or all of these factors alone, or in combination, may initiate preeclampsia in fertility patients,” Lynch says.
The study involved 528 women selected from a population of nearly 30,000 women who delivered babies at Kaiser Permanente health-care facilities from 1994 to 2000. The group consisted of 330 women who conceived a multiple pregnancy naturally, as well as 198 who used assisted reproductive technologies that resulted in a multiple pregnancy. This second group included 68 women who used a combination of fertility drugs and IVF, and one who used fertility drugs and GIFT.
An additional 121 women used fertility drugs alone to help them conceive, 38 using the medication HMG and 91 using the drug clomiphene. Both drugs encourage egg production.
The study relied on patient interviews and medical charts to determine which women had experienced preeclampsia. It also took into account specific factors that could influence the rate of this condition, including age, history of preeclampsia, first pregnancy and the birth order — triplets and quadruplets as opposed to twins. The researchers also factored in race because black women are at greatest risk of preeclampsia.
The result: 94 women had developed preeclampsia, with 70 cases considered mild and 24 classified as severe. After adjusting for factors that could affect outcome, the authors found women who had a multiple-birth pregnancy using IVF or GIFT were slightly more than twice as likely to experience preeclampsia than women who conceived their multiples naturally.
While the researchers also documented a slight increase in preeclampsia among women who used fertility drugs alone, the difference was thought to be statically insignificant at this time.
“The findings are important, but the results should not frighten women away from having IVF,” says Grifo. “If anything, it should underscore the need for women who conceive with assisted reproductive technologies to seek the care of a high-risk pregnancy expert and to make certain they are monitored more carefully throughout their pregnancy.”
If preeclampsia should develop, Grifo says, there are treatments that help.
Studies show preeclampsia and eclampsia (a more severe form of this condition) are the third-leading cause of maternal death in the United States, and account for up to 15 percent of all hospital admissions of pregnant women for reasons other than delivery.
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