Background. Asthma is a serious chronic condition which affects up to 8% of pregnant women in the United States. While severe or poorly controlled asthma might significantly complicate pregnancy and harm both mother and fetus, adequate asthma therapy in pregnancy is challenging to accomplish due to safety concerns for the fetus.
Objective. This dissertation aimed to evaluate: (1) the effect of maternal asthma control on adverse perinatal outcomes; (2) the effect of fetal sex on maternal asthma control in pregnancy; and (3) the safety of asthma controller mediations, leukotriene receptor antagonists (LTRA), in pregnancy.
Methods. Subjects were participants of the Organization of Teratology Information Specialists Asthma Medications in Pregnancy Study. Information about maternal medication use, asthma control, demographic and lifestyle characteristics, pregnancy complications, and perinatal outcomes was prospectively collected from 1,165 pregnant women.
Results. The incidence of preterm delivery was significantly higher among women with inadequate asthma symptom control (OR=1.93; 95% CI: 1.10; 3.40) and women requiring hospitalization(s) for asthma exacerbations during pregnancy (OR=2.29; 95% CI: 1.06; 4.94) independent of other risk factors.
Asthmatic pregnant women carrying a girl had more hospitalizations for asthma during pregnancy and a tendency of having more unscheduled asthma clinic visits compared with women carrying a boy. Fetal sex did not influence the association between maternal asthma control and fetal growth.
The birth prevalence of major structural anomalies in children born to LTRA users was significantly higher compared with non-asthmatic controls (p=0.007), but not different from the asthmatic comparison group (p=0.524). Furthermore, the birth defects in the LTRA group did not represent a consistent pattern. Use of LTRAs was not associated with large risks of other adverse perinatal outcomes.
Conclusions. This study demonstrates a substantial risk posed by poorly controlled maternal asthma on preterm delivery. Pregnant asthmatic women carrying a girl might be more susceptible to asthma exacerbations, particularly early in pregnancy; however, all women with asthma should be carefully monitored for pregnancy-associated changes in asthma symptoms. LTRAs do not appear to be a major human teratogen; however, results should be interpreted with caution due to the relatively small number of women taking LTRAs.