Drugs can affect an unborn child. It is safer not to use any drugs during pregnancy unless under medical supervision. Psychoactive drugs cross the placenta (the barrier between the mother's and the baby's blood) so a baby is exposed to the same chemicals as the mother. These chemicals can affect the growth and development of the baby and cause miscarriage, premature birth and birth defects.

It is recommended that women check with their doctor (or other health professional) if they are using or planning to use drugs including prescribed and over-the-counter medicines, while pregnant or breastfeeding.