Q: I seem to have a problem with constipation when my period is approaching though it goes away once I start menstruating.

I have hard stools and sometimes I don't move my bowels for several days. When that happens, I usually take a laxative which solves the problem for two or three days. I have also tried to eat more bananas and salad and drink fruit juice but it doesn't always work. Do I still need to increase my fibre intake?

A: During the menstrual cycle, the body goes through certain hormonal changes. There is a surge of progesterone just before the onset of menstruation and the progesterone level falls when the menstrual flow starts.

Progesterone causes delayed gastrointestinal transit time, meaning that it slows down the gut and hence aggravates constipation. With the fall in progesterone, there is an increase in bowel activity, which is why your constipation goes away with the start of the menses.

Constipation can be due to various causes. One of the key causes to exclude would be that of colorectal cancer. Other causes could be hypothyroidism (hormonal imbalance), electrolyte imbalance, certain medications, slow colonic transit (a slow-moving colon) or pelvic outlet obstruction (incoordination of muscles involved in defaecation).

Simple measures to try to help the constipation can include increasing fluid intake, increasing fibre intake and exercising. Should the constipation still persist, it would be better to see a doctor to help you sort out this problem.

Dr Aileen Seah

This article was first published in Mind Your Body, The Straits Times on Sep 25, 2008.