Benefits outweigh risks for inhaled steroids in pregnancy
It is always a worry when a woman taking regular medication becomes pregnant. Usually the risks to the pregnancy of continuing treatment have not been well defined. The GP has to balance the risk of stopping treatment against the uncertainty of continuing, and frame appropriate advice for the woman. Inhaled steroids, considered by Lucie Blais and colleagues in this paper, are a good example.
We already know that stopping treatment in asthma is associated with increased risk of exacerbations and reduction in asthma control. We know too that oral corticosteroids carry increased risk to the fetus in pregnancy. What, then, do we tell women with asthma who are pregnant and taking inhaled steroids?
The results of this paper are reassuring. A total of 4,561 pregnancies were identified in women with asthma in Quebec who delivered between 1990 and 2000. Data were obtained from provincial databases and clinical records were examined. The objective was to compare the outcomes of women taking inhaled steroids at different doses during the first trimester with those of women who were not on treatment.
Large numbers were needed to deal with confounding variables, which included previous obstetric status, socioeconomic group, other chronic illness and maternal lifestyle habits.
I suspect that the fact that this paper was published such a long time after the study period reflects the time spent on data collection and analysis.
The results indicate that women with asthma had a higher incidence of fetal malformation (9.2%) and major malformation (6.1%). These figures seem very high and may reflect the predominantly deprived socioeconomic group studied.
Forty per cent of the women used inhaled steroids during the first trimester; these were stratified into ‘low' (<500µg beclometasone-CFC equivalent daily), ‘medium' (500-1000µg), and ‘high' (>1000µg) doses based on repeat prescription data. Results show a reduced risk of fetal malformation in the ‘low' and ‘medium' groups and an equal risk in the ‘high' group when compared with controls not on treatment. Patients on treatment tended to be of higher socioeconomic status and better controlled from the asthma point of view.
The key message seems to be that using inhaled steroids in pregnancy is safe and improves fetal outcome when compared with ‘no preventer' treatment in women with asthma.
Blais L, Beauchesne M-F, Rey É, et al. Use of inhaled corticosteroids during the first trimester of pregnancy and the risk of congenital malformations among women with asthma. Thorax 2007;62:320-8Reviewer
Dr Peter Saul
GP, Wrexham and hospital practitioner in paediatrics (asthma and allergy)