Asthma symptoms may become worse during pregnancy. There are things to be aware of if you have asthma and are pregnant. Asthma symptoms may become worse during pregnancy for one-third of pregnant women. These symptoms may be most severe between 29 and 36 weeks of pregnancy. If your asthma is not under control, the health of your baby as well your own health may be affected. Read more on what you can do to control your asthma during pregnancy.