How can pregnancy affect breathing in all women?
Interestingly, about 70 percent of women notice shortness of breath during pregnancy. Although one might expect that as the baby grows, in most of those women, it actually starts early in pregnancy. The exact causes aren't known, but it's felt to be related to extra breathing induced by hormones, presumably to provide the extra oxygen that the baby needs. As a result, the woman is breathing deeper during pregnancy and, for many women, it seems to translate into a feeling of shortness of breath. That can, of course, sometimes be confusing in people with asthma. But while any woman can experience shortness of breath during pregnancy, a cough, wheezing or chest tightness is associated with asthma.
Can pregnancy ever trigger asthma for the first time?
It does appear that some women develop asthma for the first time during pregnancy. In some of the women who appear to have asthma for the first time, if you go into some detail in the medical history, you find that they probably had some previous asthma, it just was very mild or very intermittent, so it wasn't noticed until now because the pregnancy seemed to make it worse.
Also, about a third of people with asthma may get worse during pregnancy and anywhere from a quarter to a third may find their asthma gets better during pregnancy. These changes that occur during pregnancy revert most of the time after delivery, or at least within the three months postpartum. So it does appear that it was really the pregnancy that did it.
