Although most research has focused on opioid dependency, non-habitual and periodic opioid use can also have negative consequences, especially for pregnant women. A study by the National Institutes of Health revealed that opioid use can lower the chances of getting pregnant in women who are trying to conceive. Published in the journal Epidemiology, the study also found that opioid use in early pregnancy is associated with a greater chance of miscarriage. 
The research team focused on aspirin, which is often prescribed at low doses to prevent pregnancy loss. The data was taken from Effects of Aspirin in Gestation and Reproduction (EAGeR) trial. The participants had a history of one or more pregnancy losses. Their ages ranged from 18 to 40 years. Women who did not get pregnant were followed in six-monthly cycles. Those who became pregnant were followed throughout their pregnancy. Their urine samples were used analyzed for prescription opioids.
Of the 1,228 participants, 18 percent used opioids while trying to get pregnant. 5 percent used opioids in early pregnancy. None of them tested positive for opioid dependency. The team found that opioid use before conception chances of pregnancy by 29 percent when compared to women who were not on opioids. When used around conception, women were 1.5 percent more likely to suffer a miscarriage. Use in the first four weeks increased the risks by twice as much. When used from week four to eight, the risk further increased to 2.5 times.
Given the high risk factors, the authors asked for additional research on the effect of opioids on fertility and pregnancy. They stressed that these risk factors must be considered by physicians and women who are pregnant or trying to conceive before they are prescribed.