Second Trimester

The second trimester is often called the planning trimester. For most women, the fatigue and nausea from the first trimester ease, and she has a good amount of energy, and has not grown enough to be uncomfortable. This allows them to shop, start on the nursery, and get many things done that will be harder to do as she continues to grow. This trimester is also full of excitement. During the beginning to middle of this trimester is when the mother experiences quickening, which is feeling those first movements of the growing baby. Click for a week-by-week view of fetal development, or learn more about pregnancy at 15 weeks, 16 weeks, 17 weeks, 18 weeks, 19 weeks, 20 weeks, 21 weeks, 22 weeks, 23 weeks, 24 weeks, 25 weeks, 26 weeks or 27 weeks.

Baby's Development

Fourth Month: At the beginning of this month, the baby is about 4 inches long and weighs just over an ounce. The baby's face continues to develop and buds are forming that will be the outer ear. The tail has disappeared and the head is about half of the baby's size. The baby is continuing to move and this is the month where many women start to feel the baby. It begins as a slight sensation that often feels like bubbling or flutters. By the end of this month, the baby is about 8 to 10 inches long and will weigh about six ounces.

Fifth Month: This month is one of tremendous growth. The internal organs continue to mature. The baby is growing muscle and fat is being stored under the baby's skin. Body hair is starting to grow. The baby is much more active now and wakes and sleeps at regular intervals. The baby can hear your heart beating and a muffled version of the sounds outside of your uterus. By the end of this month, the baby is about 10-12 inches long and weighs about a pound.

Sixth Month: The baby's skin is covered with lanugo, a fine, soft hair, and vernix, a waxy substance that protects the baby's skin. The baby's brain is continuing to develop. Baby girls will develop eggs in their ovaries during this month. During this month, the baby has developed fingerprints, which are unique to him or her. The baby is almost fully formed, but because the lungs are not well developed and the baby is very small, it takes very specialized care for the baby to survive outside the uterus if it is born this early. By the end of the sixth month, the baby is around 11 to 14 inches long and weighs about 1 to 1 1/2 pounds.

Mother's Body

Pregnancy Symptoms: For most women, the main discomforts of the first trimester lessen as she enters the second trimester. Most women experience more energy and less nausea, but other discomforts are increasing. In the second trimester, women typically experience skin changes, forgetfulness, swelling, clumsiness, backaches, nosebleeds, constipation, heartburn, and hemorrhoids.

Emotional changes: It's normal for a woman in the second trimester to be somewhat forgetful and have trouble concentrating. For many women, their emotions start to stabilize during the second trimester. As she starts to show and then starts to feel the baby move, the pregnancy becomes more real and exciting. As her energy increases, she is able to make use of this excitement to begin to prepare for the coming arrival.

Physical changes: This is the time when many women begin to "feel" pregnant. Regular clothes begin to not fit very well, and the switch is made to maternity clothes. As the baby grows, and the mother starts to show, it starts to become obvious to the world that she is pregnant. For most women the second trimester is a very exciting time. She is starting to feel pregnant, but is not yet so big as to be uncomfortable.

Weight Gain: Weight gain in the second trimester should be about a pound a week. Women who are underweight or overweight before pregnancy should consult with their healthcare provider to stay within a recommended weight gain specific for their situation.

Doctor's Visits

When to see your provider: Prenatal appointments in the second trimester should continue to occur every 4 to 6 weeks, unless complications arise.

Second trimester prenatal appointments: At each visit your provider will monitor blood pressure, uterine size, urine sampling for protein and glucose, fetal heart rate, and weight gain. At around 20 weeks, fundal height measurement begins to monitor the baby's size, growth rate, and position. This is a measurement from the pubic bone to the top of the uterus.

Several tests can be done during this time. An alpha-fetoprotein test (around 16-18 weeks), as well as an amniocentesis (15-18 weeks) can be done to rule out neural tube defects, down syndrome, and other chromosomal defects. At around 24-28 weeks, most doctors routinely perform a glucose tolerance test to test for gestational diabetes. During the second trimester an ultrasound can determine the baby's sex.

Problems to Watch Out For

Late Miscarriage: Since most miscarriages happen in the first trimester, the chances for a miscarriage decrease after 12 weeks. However, miscarriages do sometimes still occur between 12 and 20 weeks. In most cases, a miscarriage during this time is caused by an incompetent cervix. This occurs when the cervix dilates prematurely and cannot hold the weight of the baby.

Premature labor: Premature labor occurs when a woman has contractions accompanied by bloody discharge, anywhere between the twentieth and the thirty-seventh week. Symptoms of premature labor are menstrual-like cramps, with possible diarrhea, nausea or indigestion, lower back pain, and all the other symptoms of labor. This is an emergency situation and can be treated with medications that postpone the labor. In the worst-case scenario, the baby is delivered prematurely and treated in a neonatal intensive care unit.

Reprinted with permission from American Pregnancy Association.