The inhibitory effect of ferrous fumarate (FeF) on bowel movements was studied using cross-over technique under the double blind method in pregnancies of twelve to thirty-two weeks of gestation. The subjects had more than 5 defecation days in a 2-week medication-free observation period.
Daily oral doses of four tablets of either FeF (300 mg) or placebo were given for two weeks, and then crossed over for another two weeks.
The number of subjects was 116 in total, of which 70 cases were in the preceding placebo group and 46 cases were in the preceding FeF group. Drop out cases were significantly more in the preceding FeF group because the patients easily noticed the discoloration of feces when the medication was crossed from FeF to placebo.
In respect of the bowel movements the number of days with defecation and frequency of defecation during each 14-day period were determined. During the preceding control period no significant difference was observed by the groupcomparison analysis between the two groups.
A sign test revealed that the number of days and frequency decreased significantly in the FeF administration period in both groups.
The cross-over analysis between FeF and placebo revealed a significant decrement in the number of days and frequency by FeF administration, but no other significant effect was found in the analysis.