Medical Encyclopedia

Medical Encyclopedia

First trimester of pregnancy

First trimester of pregnancy

The first trimester of pregnancy is the first three months after conception. Signs of early pregnancy are missed menstrual periods, fatigue, breast enlargement, abdominal distention, and nausea. During this period of time all organ development takes place so the fetus is most susceptible to damage from toxins, drugs, and infections.

Update Date: 11/9/2007

Updated by: Peter Chen, M.D., Department of Obstetrics and Gynecology, University of Pennsylvania Medical Center, Philadelphia, PA. Review provided by VeriMed Healthcare Network.

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