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.
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.
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.