Like heartburn, indigestion and constipation, shortness of breath is yet another delightful symptom that most women experience at some stage of their pregnancy. It is a common and harmless sign, occurring from normal body changes at the time .
Although you may be gasping for air after climbing up the stairs or walking from the car to your door, be assured that this is not bothering your baby in any way as the placenta is supplying him with enough oxygen .
Although it may come pretty early during the first trimester in some women, the feeling of breathlessness is not considered an early pregnancy symptom as it can occur anytime during gestation.
There may be different factors responsible for making it hard to breath in the three trimesters.
The increasing hormone levels, especially progesterone, induce the brain in the first or early second trimester, so you can take frequent deeper breaths to get enough oxygen for you and your growing baby . So, you take in considerably higher amounts of air with each breath, making you feel out of breath all the time . Additionally, the pregnancy hormones contribute to the breathing difficulty by causing the respiratory tract capillaries to swell while relaxing the lung and bronchial tube muscles .
During the later part of your second trimester, the growing uterus starts putting pressure on the diaphragm, leading to breathing problems, often accompanied by chest pain and heartburn . It is more common in twin pregnancies and women carrying the baby high .
By the later part of your third trimester, the growing uterus starts pushing all the other organs (including the lungs) away to make space for itself . The diaphragm moves up almost 4cm from its normal position , providing less space for the lungs to expand during inhalation, leading to rib pain and breathing problems .
After weeks 35-36, your baby starts to drop down into the pelvis (engage) to get into the birth position. So, your breathlessness is likely to ease slightly as there is less pressure on the lungs and ribcage . However, the baby does not engage until the end of term in case of a second or subsequent pregnancy .
Following delivery, the breathlessness goes away on its own as the progesterone levels go down to normal, relieving the pressure on your lungs.