Pregnancy Guide

Time Frame

Pregnancy is divided into three trimesters. The first trimester is accompanied by a rapid surge of hormones that create changes in the body to make it ready for the baby. The second trimester often sees a number of physical changes in the pregnant women, including rapid growth of the abdomen. The third trimester sees the growth of a fetus that is almost ready to be born but that needs more time for lung and brain development.

There are about nine months of growth during pregnancy, but the baby will not grow at the same rate throughout the pregnancy. The initial growth of the embryo is extremely rapid compared to the rate of growth during later stages of pregnancy. The need for pregnancy hormones during the first trimester is often what causes the nausea that many women experience at this time. As many as 80% of pregnant women feel the nausea known as morning sickness during this trimester.

The second trimester is marked by an increase of energy for many women. Morning sickness fades away for most women during this time and their appetites return. During the second trimester, food cravings often begin and the abdomen begins to get the round shape that gives away the pregnancy. It is also during this trimester that the mother first feels the baby move. Most babies are active during this trimester because they have plenty of room to maneuver in the womb.

During the third trimester, the baby puts on weight rapidly as it builds the fat it will need just after birth. By the end of a typical 40-week pregnancy, the baby will be gaining about 1 ounce of fat per day. In the days after birth, babies often lose weight as they adjust to drinking milk and begin having bowel movements. The baby will move less in the womb during the third trimester because its larger size makes it less able to twist and turn. During this trimester the baby should move into a head-down position to get ready for birth.

During the first trimester, pregnant women will typically need to undergo a general physical exam and have the heartbeat of the fetus assessed. Some doctors do an ultrasound in the ninth or tenth week to make sure that the fetus is in the proper position and that it is growing normally. During the second trimester, there are generally several blood tests done to check for birth defects as well as high blood pressure, anemia and gestational diabetes in the mother. A second ultrasound may be done during this time to assess the baby's organs and rate of growth. During the third trimester, mothers typically must go to weekly appointments to have their blood pressure and the baby's heart rate monitored for abnormalities.