Speed (amphetamines) can affect a baby’s development in the womb, and has been linked with bleeding, miscarriage and early labour. It may increase the heart rate of both mother and baby and restrict the amount of oxygen that baby gets. If used regularly, this could have harmful consequences for the baby. However, a one-off event such as you experienced is very unlikely to put your baby at risk. Make sure that you attend your antenatal appointments regularly and if you do have any remaining concerns, your GP or midwife would be likely to be able to answer these for you.