January 9, 2017

expert reaction to a review of the association between heartburn medication in pregnancy and risk of childhood asthma

A review of studies, published in the Journal of Allergy and Clinical Immunology, reported a possible association between mothers taking heartburn medication during pregnancy and the risk of their children developing childhood asthma.

Prof. Jean Golding, Emeritus Professor of Paediatric and Perinatal Epidemiology, University of Bristol, said:

“This research has considered 8 different studies linking the use of two types of medication for heartburn in pregnancy in order to determine whether they were associated with the risk of the offspring developing asthma. Each study compared the risk of asthma for children of women taking these drugs with that for children of pregnant women who did not take these drugs and showed that these medications were associated with an increased risk of asthma. However, it may be that the heartburn itself may be the most important association rather than the drugs used to treat it. In order to test this, the appropriate comparison should be with offspring of women who have heartburn but do not use medication to treat the condition. This study has not addressed this important possibility, and therefore cannot claim to have demonstrated a causal connection.”

Prof. Seif Shaheen, Clinical Professor of Respiratory Epidemiology, Queen Mary University of London (QMUL), said:

“A number of epidemiological studies have suggested that taking antacid medicines in pregnancy is linked to an increased risk of asthma in the offspring. This latest research summarises the evidence in a comprehensive way, but does not shed further light on whether this association is likely to be causal or not. The authors rightly acknowledge this, and point out that the association may be explained by confounding factors (other background factors which are linked to both antacid use and asthma risk) which have not been adequately controlled for in the studies included in their review. For example, the majority of studies did not control for obesity in pregnancy – a third factor which is linked both to worse heartburn (and a need to take antacids) and to risk of asthma in the offspring, thus producing an association between antacids and asthma which is not causal.

“Also, whilst it has been mooted that antacids may cause asthma by promoting the development of allergy, the majority of studies have not reported associations with allergic diseases other than asthma to support this hypothesis.  Advice to pregnant women does not need to change on the back of these latest data, which should be interpreted with caution. For now we should assume that the link is not causal and pregnant women should be reassured.”

Dr Martin Ward Platt of the Royal College of Paediatrics and Child Health (RCPCH) & Consultant Paediatrician in Neonatal Medicine at the Royal Victoria Infirmary, Newcastle upon Tyne, said:

“This new work brings together several studies, which in combination point to a strong association between the use of acid-suppressant medicines in pregnancy and subsequent asthma and allergic disease in the offspring.  It is possible and plausible that there is a causal connection but this study cannot prove it – there may easily be other unmeasured factors that give rise to the apparent link.  The issue is important to mothers and children and needs to be resolved with a large randomised trial.”

* ‘Acid-suppressive medications during pregnancy and risk of asthma and allergy in children: a systematic review and meta-analysis’ by Devine et al. will be published in Journal of Allergy and Clinical Immunology at 12:00 UK time on Monday 9th January, which is also when the embargo will lift. 

Declared interests

Prof. Jean Golding: No conflicts of interest.

Prof. Seif Shaheen: “I have no conflicts of interest to declare.”

Dr Martin Ward-Platt: Is Senior Editor for the journal Archives of Disease in Childhood. No other conflicts of interest.