Drug use and abuse in pregnancy

Taking drugs for pleasure is not a good idea when you’re pregnant. Here's why...


For obvious reasons, the research available for the direct impact of drug use in pregnancy is patchy. What evidence there is suggests that most illegal drugs are, unsurprisingly, potentially damaging to your developing baby. Studies have shown the use of many illicit drugs to be associated with an increased risk of developmental problems and abnormalities, premature birth and even miscarriage and stillbirth.



What little evidence there is relating to marijuana use during pregnancy is conflicting, and most studies face difficulties separating out the effects of marijuana from the effects of other drugs frequently taken in association with it, such as alcohol and tobacco. At least one study in the US has linked heavy marijuana use in pregnancy with unusual newborn behaviour.

There’s no evidence linking the use of marijuana by in pregnancy with birth defects and abnormalities. However, there’s been much speculation about the potential impact of marijuana use during pregnancy on your child’s subsequent development, particularly the affect it may have on your child’s academic performance, ability to concentrate and susceptibility to depression and other mental illness.

Tobacco use in pregnancy has proven health risks for your developing baby, so mixing marijuana with tobacco for smoking purposes poses a definite health risk to your baby. Also bear in mind that marijuana is often mixed with other chemicals without the users’ knowledge, and these chemicals may carry proven health risks to your unborn baby.


Studies have associated cocaine use in pregnancy with a broad range of health problems for your developing baby. Cocaine can cross the placenta to your baby and may affect foetal development, possibly causing brain damage and even death. Cocaine potentially restricts the flow of blood to your baby, and so could limit the nutrients your baby receives.

As cocaine suppresses appetite, it means it’s quite likely for your nutrition to suffer, affecting the healthy development of your baby.

Cocaine use has been linked to a higher incidence of miscarriage in early pregnancy, to stillbirth in late pregnancy and to premature birth and low birth weight. Babies born to regular cocaine users are twice as likely to be born prematurely. These babies are consequently exposed to the broad health risks associated with low birth weight and premature birth.


Heroin taken in pregnancy readily crosses the placenta to your baby and may seriously affect healthy development. Heroin is associated with an increased risk of various pregnancy complications such as poor foetal growth, low birth weight, prematurity and premature breaking of the waters, and stillbirth.

After birth, babies of heroin users display withdrawal symptoms such as fever, trembling, irritability and excessive crying, diarrhoea and vomiting. As with cocaine, heroin use has been linked with an increased risk of SIDS (Sudden Infant Death Syndrome).

If you are a heroin user it’s important that you don’t try to stop taking the drug yourself during pregnancy: you’ll need the help of your doctor to come off the drug safely, without putting your baby at risk.

Amphetamines (such as ecstasy), ketamines, LSD and PCP

As the wide-scale use of amphetamines as recreational drugs is a relatively recent phenomenon, there have been even fewer studies into the potential impact on pregnancy. What little evidence there is suggests that use of the drugs is linked to poor foetal growth, premature delivery, low birth weight and placental problems.


The impact of ketamines, LSD and PCP is also under-researched, but use of these potent drugs is a serious health risk at any time and is certainly best avoided during pregnancy.

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