Asthma is a common chronic airway disorder characterized by periods of reversible airflow obstruction known as asthma attacks. One in 12 people (about 25 million, or 8% of the U.S. population) had asthma in 2009. It is estimated that the number of people with asthma will grow by more than 100 million by 2025.1 In 2008, asthma hospitalizations were 1.5 times higher among female than male patients.2
During an asthma attack, airways become swollen and inflamed. The muscles around the airways contract, causing breathing (bronchial) tubes to narrow, which may produce symptoms of cough, wheezing , difficult breathing, and a reduced delivery of oxygen to the mother. A severe asthma attack can become a life-threatening emergency. When the bronchi constrict, they become unable to deliver oxygen which leads to hypoxia (an insufficient amount of oxygen at the level of the body's cells), which can cause death. This is particularly hazardous for a fetus, which depends on the mother for its oxygen. Therefore, asthma should be well controlled in pregnant women.
A recent study has suggested that 30% of women with asthma stop their medication therapy when they become pregnant.3 This can lead to poor control and even worsening of symptoms, and dramatically increase the risk of maternal and neonatal complications. In this recent study, the researchers collected information from a large pregnancy database. This cohort study included 25,709 pregnancies. Data was collected over a study period of 1 year before pregnancy until 6 months after birth, and the data was analyzed from pregnant women who received at least 1 prescription for an asthma medication during the study period. They concluded that the average use of asthma medications did not change during pregnancies from 1994-2003. However, during the 2004-2009 period, there was a significant decrease in use of asthma medications during the first months of pregnancy.
Another study, evaluated the complications of uncontrolled asthma on pregnancy.4 Pregnant women with uncontrolled asthma have a higher risk of preeclampsia, gestational diabetes, and placental disorders (abruption and placenta previa). Women with uncontrolled asthma have a higher risk of preterm birth, breech presentation of fetus, hemorrhage, pulmonary embolism and maternal ICU admission. Similarly, they are less likely to have spontaneous labor and vaginal delivery. Therefore, uncontrolled asthma is more dangerous to the mother, and the fetus, when compared to the minimal complications of the drugs used to control asthma during pregnancy.
Further, another meta-analysis included 182 pregnant women with asthma.5 Women with exacerbations during pregnancy were 2.5 times more likely to deliver a low birth weight baby than women without asthma at mean gestation of 38 weeks.
Therefore, it is quite clear that uncontrolled asthma is far more dangerous to the mother and the fetus as compared to the complications of drugs of asthma used in pregnancy.
Sonia Shoukat M.D.
Thomas W. Hale Ph.D.
1) World Health Organization. Global surveillance, prevention and control of chronic respiratory diseases: a comprehensive approach, 2007.
2) National Hospital Discharge Survey, Mortality Component of the National Vital Statistics System, National Center for Health Statistics, CDC, 2011.
3) Zetstra-van der Woude PA, Vroegop JS, Bos HJ, de Jong-van den Berg LT. A population analysis of prescriptions for asthma medications during pregnancy. J Allergy Clin Immunol. 2012 Oct 11. pii: S0091-6749(12)01390-5. doi: 10.1016/j.jaci.2012.08.027.
4) Mendola P, Laughon SK, Männistö TI, Leishear K, Reddy UM, Chen Z, Zhang J.Obstetric complications among US women with asthma.Am J Obstet Gynecol. 2012 Nov 15. pii: S0002-9378(12)02062-5. doi: 10.1016/j.ajog.2012.11.007.
5) Jana N, Vasishta K, Saha SC, Khunnu B. Effects of bronchial asthma on the course of pregnancy, labour and perinatal outcome. J Obstet Gynaecol 1995;21:227–32.