Medicinal uses for cannabis: Menstrual cramps, morning sickness and labour pain

One of the biggest medical uses of cannabis in the 19th century was for the treatment of menstrual cramps and reduction of labour pain. Queen Victoria was prescribed cannabis for this reason by her physician J.R. Reynolds. Yet there is nothing mentioned in 20th century medical literature. Possibly we have a such a fear of the unborn child being harmed by its mother's drug taking that any research on this subject would leave the researcher open to attack. However studies in populations that use cannabis socially (Costa Rica and Jamaica) have shown that there is no negative effect on the unborn child.

The studies that do show a negative effect need to be checked to make sure that it is not some other factor such as poverty that causes the effect. Also, most studies concentrate on people that take cannabis by smoking it. One must be careful to seperate the effects of smoking from those intrinsic to cannabis. As well as the various tars and other by-products of smoking, smoking leads the user to inhale more carbon monoxide than they would otherwise. This reduces the ability of blood to transport the necessary oxygen to the fetus. As a result of these issues, several studies regarding cannabis have produced a result showing similar effects to those of tobacco smokers.

Despite the controversy, many women have experimented with cannabis, and have found that it does control menstrual cramps, makes labour quicker and less painful and relieves the nausea (morning sickness) associated with pregnancy. If severe nausea is reducing the mother's food intake, then the child may be harmed by not taking cannabis.

Scientific evidence

Very little scientific research has been done on the subject of treating menstrual cramps, morning sickness and labour pain with cannabis. The analgesic and anti-emetic effects of cannabis discussed elsewhere show at least a potential in solving some of the problems women experience as a result of these problems. The evidence in this section will therefore dwell on the issue of the safety of taking cannabis whilst pregnant. This should not be taken to indicate that other research on this matter is important, it simply has not been done yet. If cannabis is found to have any negative effect on unborn babies then it is a case of deciding whether or not it outweighs any benefits it may bring. In addition, the following research is only relevant to those patients who are pregnant. Evidently women suffering menstrual problems whilst not pregnant need not consider the effects on unborn children!

Cornelious et al (1995) reviewed existing studies on the subject of taking cannabis whilst pregnant and found that several of the results were inconsistent. They did find suggestions that the gestation period was shorter in cannabis-smoking mothers, but only in those in their adolescence. Studies by Fried (1982) and Hingson et al (1982) showed that women who smoked cannabis regularly whilst pregnant tended to have babies of a lower weight than those who did not. As mentioned above however, how much of this is actually due to cannabis compared to the effects caused by general smoking is unknown.

Zuckerman et al (1989) performed a similar study and found that offspring from mothers who smoked cannabis whilst pregnant weighed on average 3.4 ounces less than the control group's babies. However there was no difference in the gestation period, nor in the amount of congenital abnormalities.

Ammenheuser et al (1998) found that mothers who smoked cannabis during pregnancy produced babies with higher mutation rates than those of non-smokers. This is a very similar finding to their 1994 study on mutations in tobacco-smoking mothers, so yet again it is hard to distinguish the effects of cannabis from the effects of general smoking.

One of the few studies not involving the smoking of cannabis, but rather focusing on its traditional preparation in tea form was done by Dreher et al (1994). There were no differences in neurobehaviour assessments made between babies birthed by cannabis ingesting mothers and non-cannabis ingesting mothers.

Fried (1995) carried out a relatively long-term experiment which measured the cognitive ability of children born to mothers who smoked cannabis during pregnancy compared to a control group of mothers who did not. The population was split into those born to mothers who smoked heavily, moderately and not at all during pregnancy. There were found to be no differences in 'intelligence' (tested in terms of measures such as language development, reading ability, visual and perceptual tests). Initially some small deficits were noticed among children born to cannabis smoking mothers, but by the time the child was 5 years old the deficits had vanished. On the other hand, another study by Fried et al (1998) found that children of mothers who smoked cannabis during pregnancy who were between 9 and 12 years old had reduced ability in terms of 'executive functioning' - involving concepts such as planning and anticipation.

The World Health Organisation found no evidence that cannabis causes any chromosomal or genetic damage. Likewise, the NHS National Teratology Information Service finds no evidence 'to suggest either an increase in the overall malformation rate or any specific pattern of malformations [following marijuana use in pregnancy]'.