The debate over whether or not antidepressants cause birth defects has gone on for years, with a range of findings. Now, a new study published in health journal The BMJ offers a more definitive answer—simply put: Some do and some don’t, NPR reports.

For the study, researchers analyzed data on more than 38,000 women who gave birth between 1997 and 2009. Scientists checked the number of babies born with birth defects, then asked those babies’ mothers whether they took any antidepressants in the month before they conceived or during the first three months they were pregnant.

Researchers found that among the women who took antidepressants, 40 percent used Zoloft (sertraline), a commonly used antidepressant. Other antidepressants used were Celexa (citalopram), Lexapro (escitalopram), Prozac (fluoxetine) and Paxil (paroxetine).

Findings showed no association between Zoloft, Celexa or Lexapro and birth defects when taken in early pregnancy. But researchers found that women who took either Prozac or Paxil early in their pregnancy raised the relative risk of them having babies with birth defects by two to three and a half times. These birth defects included heart issues, problems with infants’ abdominal walls, and missing brain and skull defects.

Still, researchers stressed the report showed just a small risk that Prozac or Paxil might be associated with birth defects. “If you’re planning to get pregnant, it really is important to talk with your health care provider to see if there are options and if you could choose a safer option among antidepressants,” suggested Jennita Reefhuis, PhD, an epidemiologist at the Centers for Disease Control and Prevention and the study’s lead author.

In addition, health experts also warned that expecting mothers should not just stop taking their mental health meds all together without consulting their doctors first.

For more information on how stress can affect the health of both mother and child, click here.