Asthma and Pregnancy: Respiratory Tract Changes

What's Going On In My Lungs?

Asthma Pregnancy
Will My Asthma Worsen In Pregnancy?. Getty- Digital Vison

When asthma and pregnancy occur together, many patients wonder what will happen to their asthma, especially as their pregnancy progresses.

Is Wheezing Worse During Pregnancy?

Asthma symptoms will improve in a third, worsen in a third, and stay the same in the last third. If you are a more severe asthmatic before getting pregnant you are more likely to develop problems with wheezing during pregnancy.

Pregnant With Asthma: Structural Changes In The Respiratory Tract

Pregnancy leads to changes in the upper airways that may lead to congestion and runny nose. The changes can also lead to a benign, non-cancerous tumor growth (known by several names including pregnancy tumor, pregnancy granuloma, or telangiectatic polyp) that may not only make the previously mentioned symptoms worse, but also lead to epistaxis or a bleeding nose. The bleeding is managed similarly to other adults with a bleeding nose.

While you might expect there to be changes in the diaphragm (the large muscle that separates the chest and abdomen) and thorax or chest due to a growing baby, the changes actually occur in early pregnancy before your baby significantly increases in size. The diaphragm rises higher and the diameter of the chest increases in the first trimester. You may notice that you are more barrel chested than pre-pregnancy.

Pregnant With Asthma: Functional Changes In The Respiratory Tract

When pregnant with asthma there are also functional changes that occur in the respiratory tract. These changes are related to how fast you breathe or changes in parameters such as FEV1.

Progesterone, one of the hormones that significantly increases during pregnancy is a respiratory stimulant.

While you do not necessarily breathe faster, you do take in larger volumes of air per breath. This alone can lead to a complaint of dyspnea or shortness of breath. As many as 70% 0f women may experience shortness of breath in pregnancy and your doctor will want to rule out a number of cardiac and pulmonary causes.

Overall, asthma and pregnancy do not impact your spirometry. While FEV1 does not change in pregnancy there are a number of other objective assessments that do change. Few studies have assessed hyperresponsiveness because bronchoprovocation challenge testing is not recommended in pregnancy, but limited data seems to indicate the airways are less hyperresponsive when pregnant with asthma.

Sources

  1. Toppozada H, Michaels L, Toppozada M, El-Ghazzawi I, Talaat M, Elwany S. The human respiratory nasal mucosa in pregnancy. An electron microscopic and histochemical study.. J Laryngol Otol.1982;96(7):613.
    Accessed on September 7, 2015.
  2. Gilroy RJ, Mangura BT, Lavietes MH. Rib cage and abdominal volume displacements during breathing in pregnancy.. Am Rev Respir Dis. 1988;137(3):668. Accessed on September 7, 2015.
  1. Stenius-Aarniala B, Piiril├ĄP, Teramo K. Asthma and pregnancy: a prospective study of 198 pregnancies.. Thorax. 1988;43(1):12. Accessed on September 7, 2015.

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