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third trimester of pregnancy

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Alternative Names
late prenatal period

Definition

Pregnancy is the term given to the series of events for a childbearing woman from the time of conception until the birth of the child.

Measured from the start of a woman's last normal menstrual period (LMP), pregnancy usually lasts about 40 weeks or roughly 9 calendar months. The third trimester of pregnancy generally spans weeks 28 through 40, though healthy babies may be born a few weeks sooner or later.

Although most women undergo many of the same physical changes during this time, no two pregnancies are alike.

What is the information for this topic?

During the third trimester, continuing growth and development in mother and baby cause many changes to occur. Women may notice:

As the body readies for birth, a woman's cervix begins to thin out and open. During the third trimester, certain discomforts and mood changes may occur:

In the unborn child:

At 40 weeks, the baby is considered full term. It is about 20 inches long and weighs 6 to 9 pounds. The most common health risks and concerns in the third trimester of pregnancy are:

During the third trimester of pregnancy, monitoring is more frequent. In the seventh and eighth months, it may include:

Any worrisome symptoms or concerns should be reported to the healthcare professional.

After the 32nd week, the healthcare professional may suggest monitoring every two weeks. Monitoring occurs weekly after about the 36th week, as the ninth month begins. It may include all of the above as well as examination of the cervix and discussion about the signs and symptoms of labor.


Author:Dr. Karen Wolfe, MBBS, MA
Date Written:04/30/00
Medical Review:Adam Myers, MD
Date Written:10/3/2006
Reviewer:Reginald Finger, MD
Date Reviewed:11/29/2006
Contributors
Potential conflict of interest information for reviewers available on request