Pregnancy-related constipation. 
Constipation is a common complaint in pregnancy.  Its symptoms may include infrequent defecation, hard or scybalous stool, or excessive straining.  An extensive evaluation is usually unnecessary for women who present with constipation for the first time during pregnancy.  Most patients respond to dietary measures or simple laxatives.  Few laxatives have been evaluated in clinical trials for use in pregnancy.  Evidence supports treatment with fiber supplements and senna.  The use of a pharmacologic agent for treatment of constipation during pregnancy must be weighed against possible adverse effects.  Most laxatives carry a pregnancy category B or C classification.  First-line therapy includes increasing fiber intake through diet or supplements.  Osmotic laxatives may be beneficial for some patients.  The short-term use of osmotic or stimulant laxatives is generally reserved for patients who fail to respond to dietary changes or bulking agents.