If your period poop feels different from other times of the month, you’re not imagining it. It’s not uncommon to have loose stools or to visit the toilet more often during those few days.
This is due to hormonal changes in your body. In fact, hormones influence your bowel habits throughout your menstrual cycle.
Assistant Professor Jill Lee, who is both an obstetrician and gynaecologist and urogynaecologist at KK Women’s and Children’s Hospital (KKH), explained that hormones like oestrogen and progesterone affect bowel movements.
In the first half of your menstrual cycle, oestrogen levels rise. After ovulation, progesterone rises and both hormones remain elevated before falling if pregnancy does not occur.
The interplay between oestrogen and progesterone across your menstrual cycle can contribute to alternating constipation and looser stools, because of the impact they have on the digestive process and your intestines.
“Following ovulation, rising progesterone levels slow down digestion, which can cause constipation,” said Asst Prof Lee, a senior consultant at KKH’s Department of Urogynaecology. “Just before your period, oestrogen and progesterone levels drop sharply and this makes your intestine muscles contract more quickly, causing faster bowel movements.”
During your period, there is also an increase in hormone-like compounds known as prostaglandins.
Dr June Tan Sheren, consultant family physician at Tucker Medical, said these compounds have many functions in the body, including mediating inflammation, blood flow, pain and uterine contractions during menstruation and labour.
“Elevated prostaglandins during menstruation not only stimulate uterine contractions but also increase gastrointestinal movement, leading to loose and more frequent stooling in many women during their periods,” she told CNA Women.