NSAIDs increase miscarriage risk
New research shows that taking non-steroidal anti-inflammatory drugs (NSAIDs) or aspirin during pregnancy increases risk of miscarriage.
Therefore, it might be prudent for women who are planning to become
pregnant to avoid using these drugs, according to researchers at the
Kaiser Foundation Research Institute in California.
The researchers examined whether prenatal use of painkillers is associated
with miscarriage in 1,055 women at 20 weeks gestation. They found that
using NSAIDs during pregnancy increased risk of miscarriage by 80 per
cent. The risk was highest when NSAIDs were taken around the time of
conception (hazard ratio, 5.6) or for longer than a week (hazard ratio,
8.1).
A similar association was found for aspirin. However, use of paracetamol
during pregnancy was not associated with increased risk of miscarriage
regardless of when it was used or for how long.
The reason for this difference is that paracetamol has a different pharmacological
effect, the researchers suggest. All three inhibit the production of
prostaglandin. However, NSAIDs and aspirin do this in most of the body’s
organs whereas paracetamol only has this effect in the central nervous
system.
They comment that animal studies have shown that prostaglandins are needed
for successful implantation of an embryo into the uterus wall. So inhibition
of prostaglandin synthesis could lead to abnormal implantation and subsequent
miscarriage. Another possible effect of prostaglandin suppression in
pregnancy is through an adverse effect on placental perfusion and circulation.
Current guidance in the BNF states that most manufacturers advise that
NSAIDs should be avoided in pregnancy.
Although the researchers say that their findings will need to be confirmed,
they comment: “If NSAID use during pregnancy, especially around
conception, is associated with miscarriage it will have wide clinical
implications because many women are likely to be prescribed NSAIDs during
the periconceptional period.” They add that women planning to become
pregnant should be aware of the risk and avoid using NSAIDs around conception
(BMJ 2003;327:368). |
