In every pregnancy, a woman starts out with a 3-5% chance of having a baby with a birth defect. This is called her background risk. This sheet talks about whether exposure to MDMA may increase the risk for birth defects over that background risk. This information should not take the place of medical care and advice from your health care professional.

What is MDMA?


MDMA is short for 3,4 methylenedioxymethamphetamine. This is a man-made drug that causes people who use it to experience psychedelic and hallucinogenic effects, meaning they see or hear things that are not really there. Common or street names for MDMA are Molly, ecstasy, E, X, XTC and Mandy. MDMA can be swallowed as a pill or capsule, or snorted/inhaled as a powder.

Will MDMA use during pregnancy cause birth defects?

It is unclear if MDMA use during pregnancy increases the risk for birth defects. There is very little published data on MDMA use during pregnancy. One small study in humans reported an increase in heart defects and/or club foot (when the foot is twisted). As with other illicit drugs, MDMA may come in a form that is mixed with several other drugs such as cocaine or caffeine. This means that it is hard to know for sure whether it’s the MDMA or something else that is added. Since the effects of MDMA on a baby during pregnancy are unknown, the healthiest choice is to avoid MDMA during pregnancy.

I used MDMA later during pregnancy. How will this affect the baby?

Studies are very limited. One study that followed a small group of children exposed one month prior to pregnancy and in the first and second trimester suggested that babies exposed to MDMA might be delayed in their development up to two years of age. The women also reported exposure to alcohol as well as other recreational drugs. Additional studies are needed.

I have already used MDMA during my pregnancy. What can I do to find out if the baby has a birth defect?

If you have used MDMA in pregnancy, talk with your healthcare provider. They can offer you a detailed ultrasound to screen for birth defects.

After the baby is born, is it safe to use MDMA while I breastfeed?

Studies have found MDMA in the breast milk of mothers who used this drug. Amphetamine drugs (like MDMA) are concentrated in the breast milk, meaning they are at a higher concentration than in the blood. The effect of MDMA in breast milk on an infant is not known. The use of MDMA in breastfeeding is strongly discouraged. However, if MDMA has already been taken, it has been recommended to not breastfeed for 48 hours. During this time breast milk should be expressed and discarded.

What if the father of the baby uses MDMA?

Some animal studies have found MDMA can damage the DNA in sperm. However, no decrease in the ability to father a pregnancy was seen. At this time there is no evidence that paternal use of MDMA increases the risk for birth defects or other problems. For more information about paternal exposures, please see please see the MotherToBaby fact sheet on Paternal Exposures and Pregnancy at https://mothertobaby.org/fact-sheets/paternal-exposures-pregnancy/pdf/.

Selected References:

  • Barenys M. 2009. Chronic exposure to MDMA (ecstasy) increases DNA damage in sperm and alters testes histopathology in male rats. Toxicol Lett. 191:40-46.
  • Committee on Drugs, American Academy of Pediatrics. 2001. The transfer of drugs and other chemicals into human milk. Pediatrics. 108:776-89.
  • Fríguls B, et al. 2010. A comprehensive review of assay methods to determine drugs in breast milk and the safety of breastfeeding when taking drugs. Anal Bioanal Chem. 397:1157–1179.
  • McElhatton P, et al.1999. Congenital anomalies after prenatal ecstasy exposure. Lancet. 354:1441-2.
  • Parrott A, et al. 2014. MDMA and heightened cortisol: a neurohormonal perspective on the pregnancy outcomes of mothers used ‘Ecstasy’ during pregnancy. Hum Psychopharmacol. Jan;29(1):1-7.
  • Plessinger M, 1998. Prenatal exposure to amphetamines. Risks and adverse outcomes in pregnancy. Obstet Gynecol Clin North Am. 25:119-38.
  • Singer LT, et al. 2012. Neurobehavioral outcomes of infants exposed to MDMA (Ecstasy) and other recreational drugs during pregnancy. Neurotoxicol Teratol. 34(3):303-10.
  • Singer L, et al. 2012. One-year outcomes of prenatal exposure to MDMA and other recreational drugs. Pediatrics. Sep; 130(3): 407–413.
  • Singer LT, et al. 2015. Developmental outcomes of 3,4-methylenedioxymethamphetamine (ecstasy)-exposed infants in the UK Hum Psychopharmacol 30(4): 290-294.
  • Singer LT, et al. 2016. Motor delays in MDMA (ecstasy) exposed infants persist to 2 years. Neurotoxicol Teratol 54: 22-28.