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Long term effects of antenatal betamethasone on lung function: 30 year follow up of a randomised controlled trial
S R Dalziel1, H H Rea, N K Walker
1Clinical Trials Research Unit, The University of Auckland, Auckland, New Zealand.
Insights
Antenatal betamethasone exposure did not affect adult lung function or asthma prevalence at age 30. This study followed individuals from a large randomized trial, assessing lung function and asthma symptoms in adulthood.
Area of Science:
- Obstetrics and Gynecology
- Neonatal Medicine
- Pulmonology
- Epidemiology
Background:
- Antenatal betamethasone is standard for preventing neonatal respiratory distress syndrome in preterm infants.
- Long-term effects of antenatal betamethasone on adult lung function are not well understood.
Purpose of the Study:
- To investigate the long-term impact of antenatal betamethasone exposure on adult lung function and asthma prevalence.
Main Methods:
- Followed 534 individuals at age 30 from a landmark randomized controlled trial of antenatal betamethasone.
- Assessed lung function using portable spirometry.
- Evaluated asthma symptoms via the European Community Respiratory Health Survey questionnaire.
Main Results:
- No significant difference in current asthma prevalence between betamethasone-exposed (20%) and placebo-exposed (19%) groups (RR 0.98, p=0.89).
- No differences in lung function parameters, including forced vital capacity and forced expiratory volume in 1 second, between groups.
Conclusions:
- A single course of antenatal betamethasone does not alter lung function at age 30.
- Antenatal betamethasone exposure does not increase the prevalence of wheeze or asthma in adulthood.
Background:
Antenatal betamethasone is routinely used for the prevention of neonatal respiratory distress syndrome in preterm infants. However, little is known of the long term effects of exposure to antenatal betamethasone on lung function in adulthood.
Methods:
Five hundred and thirty four 30 year olds whose mothers had participated in the first and largest randomised controlled trial of antenatal betamethasone were followed. Lung function was assessed by portable spirometric testing. The prevalence of asthma symptoms was assessed using the European Community Respiratory Health Survey questionnaire.
Results:
Fifty (20%) betamethasone exposed and 53 (19%) placebo exposed participants met the criteria for current asthma (relative risk 0.98 (95% CI 0.74 to 1.30), p = 0.89). 181 betamethasone exposed and 202 placebo exposed participants had acceptable spirometric data. There were no differences in lung function between betamethasone and placebo exposed groups (mean (SD) forced vital capacity in the betamethasone and placebo groups 105.9 (12.0) v 106.6 (12.6)% predicted, difference = -0.7 (95% CI -3.2 to 1.8), p = 0.59; mean (SD) forced expiratory volume in 1 second in the betamethasone and placebo groups 98.9 (13.4) v 98.5 (13.6)% predicted, difference = 0.3 (95% CI -2.4 to 3.1, p = 0.80)).
Conclusions:
Antenatal exposure to a single course of betamethasone does not alter lung function or the prevalence of wheeze and asthma at age 30.
