Half of pregnant women will suffer from constipation at some time during their pregnancy, according to a report published in the journal Obstetrics & Gynecology Thursday.

Though constipation is believed to occur frequently in pregnancy, there has been little research to determine its actual prevalence, said Dr. Catherine S. Bradley of the University of Iowa Hospitals & Clinics in Iowa City.

Bradley and her colleagues investigated and followed 103 healthy women beginning in their first trimester of pregnancy.

Researchers found that 24 percent of participants reported constipation during their first trimester, 26 percent had constipation during the second trimester and 16 percent during the third trimester.

Moreover, 24 percent had constipation during the first 3 months after they gave birth, according to the report.

Breast-feeding and other postpartum factors could affect women's bowel function after pregnancy, the researchers suggested.

Women who take iron supplements are 3.5 times more likely to have constipation as those who don't, while women who had been treated for constipation in the past have three times the risk of constipation during pregnancy, said the report.

"Given our findings, we suggest that pregnant women who report a history of constipation at their initial obstetric visit or those who require iron supplementation be screened and counseled about constipation treatment options during pregnancy," the researchers conclude.

(Agencies via Xinhua December 20, 2007)