Women with asthma who suffer asthma exacerbation while pregnant are at increased risk for complications during pregnancy and delivery, and their infants are at increased risk for respiratory problems, according to data from a longitudinal study of 58,524 women with asthma.
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“Asthma exacerbation during pregnancy has been found to be associated with adverse perinatal and pregnancy outcomes such as low birth weight, small for gestational age, preterm delivery, congenital malformation, preeclampsia, and perinatal mortality,” but previous studies have been small and limited to comparisons of asthmatic and nonasthmatic women, wrote Kawsari Abdullah, PhD, of Children’s Hospital of Eastern Ontario, Ottawa, and colleagues.
To determine the impact of asthma exacerbation on maternal and fetal outcomes, the researchers analyzed data from the Ontario Asthma Surveillance Information System to identify women with asthma who had at least one pregnancy resulting in a live or still birth between 2006 and 2012.
Overall, significantly more women with exacerbated asthma had preeclampsia or pregnancy-induced hypertension, compared with asthmatic women who had no exacerbations, at 5% vs. 4% and 7% vs. 5%, respectively (P less than .001), according to the study published in the European Respiratory Journal.
Adverse perinatal outcomes were significantly more likely among babies of mothers with exacerbated asthma, compared with those who had no exacerbations, including low birth weight (7% vs. 5%), small for gestational age (3% vs. 2%), preterm birth (8% vs. 7%), and congenital malformation (6% vs. 5%). All P values were less than .001, except for small for gestational age, which was P = .008.
In addition, significantly more babies of asthmatic women with exacerbated asthma during pregnancy had respiratory problems including asthma and pneumonia, compared with those of asthmatic women who had no exacerbations during pregnancy, at 38% vs. 31% and 24% vs. 22% (P less than .001 for both). The researchers found no significant interactions between maternal age and smoking and asthma exacerbations.
The findings were limited by several factors, including the lack of a validated algorithm for asthma exacerbation, which the researchers defined as five or more visits to a general practice clinician for asthma during pregnancy. Other limitations included the lack of categorizing asthma exacerbation by severity, and the inability to include the potential effects of asthma medication on maternal and fetal outcomes, Dr. Abdullah and colleagues noted.
However, the results were strengthened by the large sample size and ability to follow babies from birth until 5 years of age, they said.
“Targeting women with asthma during pregnancy and ensuring appropriate asthma management and postpartum follow-up may help to reduce the risk of pregnancy complications, adverse perinatal outcomes, and early childhood respiratory disorders,” they concluded.
Dr. Iris Krishna
This study is important because asthma is a common, potentially serious medical condition that complicates approximately 4%-8% of pregnancies, and one in three women with asthma experience an exacerbation during pregnancy, Iris Krishna, MD, a specialist in maternal/fetal medicine at Emory University, Atlanta, said in an interview.
“This study is unique in that it uses population-level data to assess the association between an asthma exacerbation during pregnancy and adverse perinatal outcomes,” Dr. Krishna said. “After adjusting for confounders, and consistent with previous studies, study findings suggest an increased risk for women with asthma who have an asthma exacerbation during pregnancy for preeclampsia [odds ratio, 1.3; P less than .001], pregnancy-induced hypertension [OR, 1.17; P less than .05], low-birth-weight infant [OR, 1.14; P less than .05], preterm birth [OR, 1.14; P less than .05], and congenital malformations [OR, 1.21; P less than .001].”
Dr. Krishna also noted the impact on early childhood outcomes. “In this study, children born to women who had an asthma exacerbation during pregnancy had a 23% higher risk of developing asthma before 5 years of age, which is consistent with previous studies. [The] investigators also reported a 12% higher risk of having pneumonia during the first 5 years of life for children born to women who had an asthma exacerbation during pregnancy.”
“Previous studies have suggested children born to mothers with uncontrolled asthma have an increased risk for respiratory infections, but this study is the first to report an association with pneumonia,” she said. This increased risk for childhood respiratory disorders warrants further study.
Consequently, “Women with asthma during pregnancy should have appropriate management to ensure good control to optimize pregnancy outcome,” Dr. Krishna emphasized. “Women who experience asthma exacerbations in pregnancy are at increased risk for preeclampsia, [pregnancy-induced hypertension], low birth weight, and preterm delivery and may require closer monitoring.”
The study was supported by the Institute for Clinical Evaluative Sciences. The researchers and Dr. Krishna had no financial conflicts to disclose.
SOURCE: Abdullah K et al. Eur Respir J. 2019 Nov 26. doi: 10.1183/13993003.01335-2019.