Taking multivitamins around the time of conception dramatically reduces a woman's risk of preeclampsia, a complication during pregnancy that can be lethal to a woman and her fetus, researchers at the University of Pittsburgh report.
Women who took multivitamins at least once a week three months before the start of pregnancy and three months after were 45% less likely to develop preeclampsia compared with women who did not take supplements, the study found.
Previous preeclampsia studies have largely focused on vitamin use after the first trimester of pregnancy and have found little benefit.
The new study, which is scheduled to be published in the September issue of the American Journal of Epidemiology, underscores the oft-repeated message from doctors that women thinking of getting pregnant should be vigilant about their health.
"While we don't know what causes preeclampsia, we do know that maintaining ideal body weight, regular exercise and good nutritional habits are going to at least stack the deck in your favor," said Dr. John T. Repke, chairman of Penn State University's department of obstetrics and gynecology, who was not involved in the research.
Preeclampsia is a condition in which blood vessels in the womb constrict, cutting off blood and oxygen to the fetus. It occurs in late pregnancy and causes increased blood pressure in the mother.
It kills about 76,000 women and fetuses a year worldwide. In the United States, it occurs in about 8% of pregnancies and accounts for 15% of premature births.
Currently, the only effective treatment for preeclampsia is to induce labor, said lead author Lisa M. Bodnar, a nutritionist and epidemiologist at the University of Pittsburgh.
Bodnar and colleagues theorized that improving the mother's nutrition early on could improve the development of the placenta and the network of blood vessels connecting the mother to the fetus.
The group monitored 1,835 women from 1997 to 2001. Overall, 4% of the women developed preeclampsia.
Slightly fewer than half of the women reported taking multivitamins, which included vitamins A, C, D and E, folic acid, calcium, iron, zinc, selenium and copper.
Women who took the multivitamins and maintained a normal body weight experienced the biggest reduction -- about 72% -- in their risk of developing preeclampsia.
Overweight women, however, saw virtually no reduction in their risk, Bodnar said.
She said obesity possibly caused some metabolic changes that could not be overcome by improved nutrition.