During pregnancy, significant changes occur in most systems of the body. Hormone levels change, weight gain is expected and the centre of gravity of the body shifts to accommodate the weight gain. This can cause strain.

Nausea and vomiting in early pregnancy is common. Sometimes it is the earliest signs of pregnancy. This is due to the rising level of female hormones. There will be increased levels of estrogen and progesterone produced by the ovaries and subsequently by the placenta. Other changes include frequency of micturation, constipation and breast enlargement.

In the middle or second trimester, weight gain and upwards enlargement of the uterus puts pressure on the gastro-intestinal tract. This gets worse in the third trimester, and indigestion and heartburn is most likely.

The weight gain is concentrated mostly in the abdominal area and more likely to cause reflux than a non-pregnant woman with equivalent weight gain. It is more likely in the apple rather than the pear shape. Apple shape is more prone to reflux and GERD.

It is not surprising that a twin or triplet pregnancy will increase the frequency and severity of heartburn.

Near term and in multiple pregnancies the fundus of the uterus sits in the upper abdomen (epigastrium). This can derange the complex mechanism that is the lower esophageal sphincter. It also slows down gastric emptying and encourages the formation of hiatus hernia.

High levels of the two hormones can affect contractility of the esophagus. This will affect the ability to rid food from the esophagus into the stomach and clear refluxed food from the esophagus. At this stage, however, there is likely to be increased salivation. This is helpful.

Women who are more prone to acid reflux in pregnancy are ones who had reflux in previous pregnancies, women who had reflux whether mild or severe before falling pregnant, and women over 35.

Dr. Phil Hariram,