As some of you know, one of my sons is an obstetrician/ gynecologist so from time to time you have seen some articles directed to women and especially pregnant women. Some of the topics have dealt with topics such as smoking, sleep disorders and the effect of air quality on the developing fetus. Yet I have never, to my knowledge, taken on the simple complaint of shortness of breath in pregnancy.
Shortness of breath is actually a normal occurrence in pregnancy and results from several physiologic changes that occur during pregnancy. One significant change is an increase in blood volume of the mother and a concurrent increase in the cardiac output or amount of blood pumped by the heart in a certain time period. The increase in breathing which occurs causes the mother’s blood to be slightly alkaline. This change in blood chemistry is thought to be helpful to the fetus in eliminating waste.
The increase in the depth and rate of breathing begins early in pregnancy and continues throughout the first and second trimester but usually remains stable but elevated during the third trimester. The early onset of shortness of breath in the first trimester is not thought to be related to changes in uterine size but rather to increase levels of progesterone, a hormone that is elevates during pregnancy.
There are, however, abnormal causes of shortness of breath during pregnancy. Women should discuss their symptoms with their obstetrician if there is any doubt!