New research reveals that egg-donated pregnancies increase the risk of hypertension or high blood pressure threefold.

Researchers examined data gathered from seven in vitro fertilization (IVF) centers in France. The team matched each singleton egg donation pregnancy recorded during weeks seven to eight from 2005 to 2011 to two control routine IVF ones. A total of 580 pregnancies with 217 egg donations and 363 controls reported during the time frame.

The team then compared the risk of hypertension in women and found that women who received egg donations had threefold chances of developing high blood pressure. The prevalence rate for hypertension increased from 5.3 percent to 17.8 percent for these women. Their risk for pre-eclampsia, which is hypertension during the later trimesters of pregnancy, increased from 2.8 percent to 11.2 percent.

"A few other studies have shown results suggesting an increased risk of pregnancy-induced hypertension in egg donation patients," said Dr. Hélène Letur of the Institut Mutualiste Montsouris in Paris.

He added that most of those studied had small samples and did not adequately control for several important confounders, such women's age, multiple pregnancy, and infertility history. "Our aim was to find out whether pregnancies from egg donation are genuinely associated with a higher risk of hypertension and pre-eclampsia than those from treatments using the patient's own eggs. This has growing importance because of the increasing number of egg donations."

The team said the study's findings confirm previous studies with a large sample and matched control group. "We would have to conclude from the results that egg donation itself is a risk factor for pregnancy-induced hypertension and pre-eclampsia," said Dr. Letur.

The findings were presented at the 30th Annual Meeting of the European Society of Human Reproduction and Embryology held in Munich, Germany.