The effect a drug has on a fetus depends upon many factors, including the nature of the drug, the amount taken by the mother, the stage of the pregnancy at which it is taken, and the duration of use. The baby is in the greatest danger during the first three months (referred to as the first trimester) when your babies’ major organs are developing. Some drugs, however, can harm the foetus even when taken much later in pregnancy.
The ability of cannabis preparations (i.e. marijuana, hashish, hashish oil, and tetrahydrocannbinol or THC) to cause birth defects has been studied in many animal species, but information about the effects in human pregnancy is, as yet, scanty.
In animals, THC (the main ingredient in cannabis which produces the effects on mood and perception) crosses the placenta and enters the foetal circulation. Although very high doses must be given to produce visible abnormalities, lower doses can produce subtle changes in the behaviour and development of an animal offspring. Also, cannabis smoke – which besides THC contains, among other things, carbon monoxide has been shown to increase the risk of death in the animal fetus and newborn.
The drug caffeine is present in foods and beverages, including chocolate bars, colas, coffee, and tea as well as in several drug preparations.
Recently, concern has increased that caffeine taken in large quantities by pregnant women may harm the fetus. Therefore, most physicians agree that caffeine intake should be decreased during pregnancy; if you can’t cut down on your coffee or tea intake, make sure you are drinking decaffeinated.
Babies of tobacco smokers weigh less at birth and weight differences appear to be directly related to the number of cigarettes per day that the woman smokes. Also, the more the woman smokes, the greater the risk of miscarriage, premature delivery, and stillbirth. Mothers who smoke also have a significantly higher risk of infant death syndrome (Cot Death) than non-smoking mothers.
Only in recent years have adverse effects of alcohol on the fetus been widely recognized. It is now generally felt that even two drinks a day can have an undesirable effect, and the risk of alcohol related problems increases remarkably at higher consumption levels. Alcohol appears to be associated with risk throughout pregnancy , it is, therefore, wise for an expectant Mothers to avoid alcohol intake.