Your Baby Today

Pregnancy

SECOND TRIMESTER DOCTOR VISITS

By Julianne Deveraux

Step right up
Throughout your second trimester, you'll continue to visit your doctor once a month -- as long as your pregnancy is progressing normally. Each appointment probably will begin with you stepping on the scale.

Monitoring your weight gain
During your fourth, fifth, and sixth months, you should be gaining one-half to three-quarters of a pound a week. By tracking your weight, your doctor can estimate your baby's growth and watch for signs of preeclampsia. Doctors stress that you should try hard to stay within a 25- to 35-pound weight gain. Straying too far from this guideline can lead to problems.

By gaining too much weight:

You put extra stress on your heart, which already is working overtime to pump your increased blood volume.
You put additional stress on your joints, which pregnancy hormones have loosened and made lax.
You increase your risk of developing preeclampsia, a serious condition that can be life-threatening.
You'll be more likely to develop aches in your lower back.
You may make labor and delivery more difficult because your baby will be big.

Second-trimester tests

Urinalysis This test, performed at each doctor's visit, measures the protein and sugar in your urine. It will detect excess protein, which can be a warning sign of preeclampsia. Urinalysis also may be used to detect the presence of drugs or bladder infection.
Triple marker test This blood screening usually is performed between the fifteenth and eighteenth weeks of pregnancy. Part of the test measures a specific protein, alpha-fetoprotein or AFP, in your blood. If the AFP levels are high it may identify a neural tube defect; if AFP levels are low (combined with abnormalities found in two other tests) this may identify Down Syndrome.
Rhesus (Rh)-antibody-level test (a blood test) for rhesus negative women. Most people have a specific protein in their blood called the Rh factor. Those who don't are Rh-negative. If a woman tests Rh-negative, the father of the child also must be tested for his Rh factor because problems arise when an Rh-negative woman conceives a baby with an Rh-positive man. The tests are done about halfway through the pregnancy, or at once if the woman has a bleeding problem.

An Rh-positive baby's blood factor, also called an antigen, can stimulate an intense immune response in his mother. The problem isn't so great with a first pregnancy, where the mother's body hasn't yet built a strong immune defense against her child's blood. But a second pregnancy can be tragic. The mother's antibodies can cross the placenta and terminate the pregnancy. Fortunately, a substance called Rh-immune globulin, injected into the mother, can protect the baby.
Ultrasound This test uses high-frequency sound waves to visualize the unborn baby. It's been used for more than 25 years, and it appears to be safe for both the mother and fetus.

Some of today's obstetricians even have the capability of performing ultrasound tests right in their offices. The doctor will coat your abdomen with mineral oil or gel to minimize the loss of ultrasound waves where the transducer meets the skin. Then she will move the transducer gently and smoothly over your stomach, allowing the sound waves to pass through into your abdominal cavity. The waves will bounce back to the transducer, forming an image that's displayed as a picture on a monitor. With a vaginal ultrasound, the transducer is placed in the vagina to let the doctor see the early pregnancy sac and detect any abnormalities.

An ultrasound examination can detect a pregnancy as early as six weeks after your last menstrual period and show the baby's movements at approximately 12 weeks of gestational age.
Extra test for older moms-to-be: Amniocentesis This test of the fluid that surrounds your baby detects chromosomal and other genetic disorders, such as Down syndrome, hemophilia, and sickle-cell anemia. It usually is performed on women over 35 when they're 15 to 16 weeks pregnant, and on women who have an abnormal triple-screen result. The procedure is done by inserting a long, thin needle through the abdominal wall to remove a sample of amniotic fluid. This fluid then is genetically studied in the laboratory.