Heartburn or acidity during pregnancy is very common, and while it can happen any time during pregnancy, it is most common during the third trimester.
Many women complain of this problem during pregnancy and many women suffer from heartburn for the first time in their lives when they get pregnant. The situation will resolve itself after the baby is born and the reasons for this are as follows:
This is due to the fact that the baby is so big and takes up such a lot of space in the abdominal cavity at this time that the stomach is rather constricted causing the bile to rise.
The other reason why this happens is that during this time the levels of the progesterone hormone are high in the body. This causes the valve separating the stomach from the food pipe to relax and hence the contents of the stomach tend to flow back up from the stomach and give that disagreeable burning sensation that seems to spread out all over the chest area.
The progesterone hormone also causes the process of digestion itself to slow down, which can also cause heartburn and various other problems such as constipation etc during pregnancy.