- Asthma is the most common chronic respiratory disorders during pregnancy.
- It affects 5%-8% pregnant women in United States.
- Among the women suffering from asthma,almost one third experience exacerbation during second trimester of pregnancy.
- Some women experience the symptoms of asthma first time during pregnancy.
- It has been observed that,about one third of asthmatic women discontinue their asthma controller medications and reliever medications, during pregnancy fearing its adverse effects on fetus.
It has been observed that, there happens no chanage in FEV1,no admissible change in FEV1/FVC and a slight increase in FVC ,during normal pregnancy.There should be a cause of concern in case of any deviation seen in these observed parameters.
In normal pregnancy,there happens a change in cardiac output,stroke volume and heart rate.Women already diagnosed asthma may experience exacerbation due to these changes.Some women especially those who are genetically predisposed to develop asthma may experience the symptoms of asthma first time due to these changes during pregnancy.The enlarged gravid uterus my compress the inferior vena cava during third trimester of pregnancy,thereby decreasing cardiac output.This mechanical change along with some hormonal changes may exacerbate asthma and nonallergic rhinitis.
There is a strong correlation of asthma with obstetric and non obstetric comorbidities.Among obstetric ,the important ones are,preeclamsia,placenta previa,abruptio placenta eand obstetrical hemorrhage. There is higher rates of caesarean delivery in women with asthma.Among non obstetric comorbidities are increased rates of gestational Diabetes,increased rates of pulmonary embolism and increased frequency of respiratory infections including influenza.
Asthma exacerbation causes adverse effects on fetuses which includes,prematurity,low birth weight,fetal deaths(still birth) and some congenital anomalies in the form of cleft lip and cleft palate.Low birth weight has been seen more commonly in female while prematurity and still births have been seen more commonly in male fetuses.Children born to mothers having asthma have more chance of developing asthma.
Variuos research studies show that a good control of asthma symptoms and reducing or avoiding asthma exacerbation results in better outcome for mother and babies. There is a growing evidence in literatures that suggest that, inhalational corticosteroids(ICS) and beta-2 agonists(SABA), both are safe to be used during pregnancy for asthma management.Among ICS, the most studied is budesonide.ICS use during pregnancy improves FEV1 and reduces exacerbations.
The safety of biologicals in the form of IgE inhibitor(omalizumab) and anti IL-5(meplozumab and reslizumab),have not been established.However ,the woman already on these medications before becoming pregnant has not been seen to experience any adverse outcome.
Treating comorbidities is an important part to control asthma. If there is coexisting allergic or nonallergic rhinitis,it should be treated with intranasal sterioids.Coexisting GER should be treated with PPI . If there is coexisting anxiety and depression ,these should be addressed properly.
We should not forget to avoid allergen exposure in the form of house dust mite,animal danders,cockroaches,pollen and indoor molds. According to NAEP ,allergen impermeable bed coverings should be used,bed sheets should be washed weekly with water at or above 130 degree F,and humidity should be kept below 50%.
Good control of asthma by non pharmacologic and whenever needed pharmcologic measures gives better outcome for mothers and babies
REFERENCES:
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3.Global Initiative for Asthma. Global strategy for asthma management and prevention, 2017. www.ginasthma.org Accessed October 3, 2017.
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