Medical visits during the second trimester focus primarily on tracking the development of the fetus, establishing an accurate due date and monitoring your general health. Your doctor will check your blood pressure and weight, and will discuss any symptoms that you may be experiencing. He or she will also measure the size of your uterus to help determine your baby’s true age.
Special tests may be suggested for you during this stage of pregnancy.
1. Ultrasound exam This is the safest form of imaging during pregnancy. High-frequency sound waves create images of the fetus that you can see on a monitor. The images are high quality and often show the baby in motion. Many doctors feel that at least one ultrasound should be performed during each pregnancy to make sure that you and your baby are progressing well. Ultrasounds are used to
• record fetal heartbeats and breathing movements
• measure fetal growth
• determine if you are carrying more than one fetus
• find the location of the placenta
• date the pregnancy through fetal measurements
• assess the amount of amniotic fluid
Ultrasound scanning may also be used during the first trimester to confirm evidence of pregnancy and fetal growth. Later in your pregnancy, it may be used to monitor the baby’s health or to identify conditions that may cause problems during the pregnancy or delivery.
2. Alpha-fetoprotein test Alpha-fetoprotein (AFP) is a substance normally produced by a growing fetus. Between 15 and 18 weeks you may be tested to determine the level of this substance in your blood. A sample of your blood is studied at a laboratory to detect the presence of abnormalities that may cause birth defects such as spina bifida or Down’s syndrome.
3. Amniocentesis This test involves collecting and analyzing a small sample of the fluid that fills the amniotic sac surrounding the fetus. The amniotic fluid contains skin cells and other genetic material from your developing fetus, so it provides a great deal of valuable information about the health of your baby. The test begins with an ultrasound to locate the position of the baby. Guided by the ultrasound images, a long, thin needle is passed into the uterus to remove a fluid sample. The sample is sent to a laboratory, where it is studied to determine if the fetus has normal chromosomes. Amniocentesis is recommended for women at increased risk for having a baby with a birth defect, especially women who are over 35 years old or who have a family history of birth defects. Amniocentesis is also used to find out if your baby’s lungs are mature enough for an early delivery or to follow up on an AFP test that is positive for abnormalities. The procedure is usually performed between 16 and 18 weeks, when there is enough amniotic fluid for an effective sample. There is a 1 in 200 chance of miscarriage after an amniocentesis.
4. Glucose tolerance testing This is a test for gestational diabetes. Even if you did not have diabetes before you became pregnant, you may be at risk of developing the disorder during your pregnancy. Changes in hormones and metabolism during pregnancy sometimes affect the ability of your body to produce or use the hormone insulin. This hormone imbalance creates problems for the health of your baby. To test for gestational diabetes, you will be asked to drink a glucose solution. An hour later, your blood will be tested for abnormal levels of blood glucose. If this test is positive, a follow-up test will be necessary to confirm the diagnosis of gestational diabetes.
5. Rh factor testing The Rhesus (Rh) factor is a type of protein that is sometimes present in your blood. If you have it, you are Rh-positive; if you don’t, you are Rh-negative. If you and your baby have incompatible Rh factors, your body will produce antibodies that will cause damage or death to your fetus. A sample of your blood will be tested at a laboratory to determine your Rh factor.
6. Hemoglobin testing By measuring your hemoglobin levels, your doctor can determine if you have anemia, which is usually caused by an iron deficiency in your blood. Most pregnant women do not absorb enough iron from their food to meet the demands of pregnancy. The condition can be improved with dietary changes and iron supplements.
The Third Trimester
The third trimester is a time of conflicting emotions. You will be excited at the prospect of your baby’s upcoming birth, yet worried about your baby’s health and safety during these crucial last weeks. You’ll probably be very tired of being pregnant, yet fear the pain and uncertainty of giving birth. For most women, the final three months of pregnancy is a time of decision-making, planning and great anticipation. This stage lasts from the 28th week of pregnancy until the delivery of your baby.