Heartburn during pregnancy.
Heartburn is common during pregnancy, affecting 22% of women in the first trimester, 39% in the second and 72% in the third¹. This is because during pregnancy your body produces the hormone, progesterone, which slows down digestion and causes the muscular valve between the oesophagus and the stomach to relax, increasing the risk of gastro-oesophageal reflux.

As a result stomach acid is more likely to leak into the oesophagus and cause a burning pain in your chest and throat. Also, as your baby grows, the pressure on your stomach increases and this can force stomach acid into the oesophagus, again causing gastro-oesophageal reflux.

1 Source: Marrero JM, Goggin PM, de Caestecker JS, Pearce JM, Maxwell JD. Determinants of pregnancy heartburn. Br J Obstet Gynaecol 1992;99: 731-4