Pill may increase asthma risk
20 January 2009

The oral contraceptive pill could increase the risk of asthma, according to a study.

Norwegian researcher Ferenc Macsali and team sent postal questionnaires to women in Denmark, Estonia, Iceland, Norway, and Sweden from 1999 to 2001.

After excluding pregnant women, women using hormone replacement therapy and women under 45 years old, the final study population included 5,791 women aged 25-44 years. Out of these women, 17% (around one in six) used the oral contraceptive pill.

The researchers found that women taking the pill had an increased risk of asthma and asthma symptoms including wheeze and shortness of breath. They also had an increased risk of hay fever. However, this association was only seen in women who were a normal bodyweight or were over-weight, and not in women considered to be underweight.
 
Mascali commented: ‘These findings add to the literature suggesting that sex steroid hormones may be of importance for respiratory health, and that sex hormones may interact with metabolic status in effect on the airways.’

They also emphasised: ‘This cross-sectional postal survey was not designed to investigate side effects of drugs, and the results should be interpreted with great caution.’

Dr Elaine Vickers, Research Relations Manager at Asthma UK, said: ‘The evidence linking the contraceptive pill to asthma risk is still contradictory; therefore we aren’t advising women to change their behaviour in response to this research.

‘However, this is an important study which raises questions over the possibility of asthma as a side effect of taking the contraceptive pill. We recommend that further studies into oral contraceptives should include an investigation into the impact they have on a woman’s respiratory health.’