In a study to be published Monday in The Journal of Obstetrics and Gynecology, researchers say it may be advisable for pregnant women to reduce or even eliminate their caffeine consumption, The New York Times reported Sunday.

Obstetricians often advise patients to limit caffeine intake the newspaper said, but there has been conflicting information on the subject in past studies.

Pregnant women who consume 200 milligrams or more of caffeine daily -- about what you'd find in 10 ounces of coffee or 25 ounces of tea -- may double the risk of miscarriage, the report said.

Dr. De-Kun Li, the lead author of the study and a reproductive and perinatal epidemiologist at the Kaiser Permanente Division of Research in Oakland, Calif., told the Times women should at least try to go without caffeine for the first three or four months of pregnancy.

"If, for whatever reason, they really can't do it, think of cutting to one cup or switching to decaf," Dr. Li said.

Representatives for the American College of Obstetricians and Gynecologists and the American Society for Reproductive Medicine told the newspaper their organizations do not have official positions on caffeine.