For the first time a study has been launched that will gauge how exactly common medications affect pregnancy.

The FDA and a consortium of HMOs have launched a huge set of studies to find out how medications affect women during pregnancy.

"These data will guide regulatory policy and influence medical practice," Webmd quoted the FDA Commissioner Dr. Margaret Hamburg, as saying in a news release.

While many women do take some kind of medicine during pregnancy, but very few drugs are tested in pregnant women.

But now, the Medication Exposure in Pregnancy Risk Evaluation Program (MEPREP) has been launched.

The program is a collaboration between the FDA, Kaiser Permanente, Vanderbilt University (using Tennessee Medicaid data), and a consortium of HMOs called the HMO Research Network Center for Education and Research in Therapeutics (managed by Harvard University).

The study will analyze health care data on about 1 million U.S. births from 2001 to 2007.

The idea is to gather information on all medications prescribed for pregnant women and to look for health effects and birth outcomes.

"Results of these studies will provide valuable information for patients and physicians when making decisions about medication during pregnancy," said Dr. Gerald Dal Pan.

Until the data become available, women and their doctors will have to make their own decisions on whether a drug provides enough of a benefit to pregnant women to override concerns about possible risk.