A new study from the National Institutes of Health (NIH) indicates that women who use opioids while trying to conceive have a 29 percent lower chance of becoming pregnant.

Those who used opioids early in the pregnancy were more than twice as likely to have a miscarriage than those who did not use opioids.

The study analyzed data from 1,228 women ages 18 to 40, with a history of one or two pregnancy losses. Among the women who became pregnant, those who used opioids around the time of conception were 1.5 times as likely to have a miscarriage as women who had not.

For the women who used opioids in the first four weeks of pregnancy, their chance of miscarriage more than doubled. If they used opioids in the first four through eight weeks of pregnancy, they were 2.5 times more likely to miscarry.

"Our findings indicate that women who are pregnant or planning a pregnancy should, along with their physicians, consider the potential effects opioids may have on their ability to conceive or sustain a pregnancy," said study author Kerry Flannagan, Ph.D., with NIH's National Institute of Child Health and Human Development.