| During the second trimester, you and your spouse | | | | Maternal serum screening test |
| should continue to see your doctor for prenatal care. | | | | This blood test can be called by many different |
| Most pregnant women have monthly office visits | | | | names including multiple marker screening test, triple |
| with their doctor or midwife until the end of this | | | | test, quad screen, and others. This test is usually |
| trimester. | | | | given between 15 and 20 weeks of pregnancy. It |
| During the second trimester your doctor can use an | | | | checks for birth defects such as Down syndrome, |
| ultrasound to see if the baby is developing in a | | | | trisomy 18, or open neural tube defects. Doctors |
| healthy way and to find out your baby's sex. You will | | | | take a sample of your blood. They check the blood |
| also be offered screening tests to look for genetic | | | | for 3 chemicals: alpha-fetoprotein (AFP) (made by the |
| birth defects. | | | | liver of the fetus), and two pregnancy hormones: |
| According to the U.S. Department of Health & Human | | | | estriol and human chorionic gonadotropin (hCG). |
| Services, birth defects result from problems with a | | | | Sometimes, doctors test for a fourth substance in |
| baby's genes, inherited factors that are passed down | | | | the blood called inhibin-A. Testing for inhibin-A may |
| from the mother and the father at conception. | | | | improve the ability to detect fetuses with a high risk |
| Genetic birth defects sometimes occur in people with | | | | of Down syndrome. |
| no family history of that disorder. Women over the | | | | According to the U.S. Department of Health & Human |
| age of 35 have the greatest chances of having a | | | | Services, higher levels of AFP are linked with open |
| baby with birth defects. Some of the diagnostic and | | | | neural tube defects. In women age 35 and over, this |
| screening tests the doctor might suggest in the | | | | test finds about 80% of fetuses with Down |
| second trimester include: | | | | syndrome, trisomy 18, or an open neural tube defect. |
| Amniocentesis | | | | In this age group, there is a false positive rate |
| According to the U.S. Department of Health & Human | | | | (having a positive result without actually having a |
| Services, this test is performed in pregnancies of at | | | | fetus with one of these health problems) of 22%. In |
| least 16 weeks. It involves your doctor inserting a | | | | women under age 35, this test finds about 65% of |
| thin needle through your spouse's abdomen, into her | | | | fetuses with Down syndrome, and there is a false |
| uterus, and into the amniotic sac to take out a small | | | | positive rate of about 5%. |
| amount of amniotic fluid for testing. The cells from | | | | Targeted ultrasound |
| the fluid are grown in a lab to look for problems with | | | | The best time to get a targeted ultrasound is |
| chromosomes. The fluid also can be tested for AFP. | | | | between 18 and 20 weeks of pregnancy. Most major |
| About 1 in 200 women have a miscarriage as a result | | | | problems with the way the baby is formed can be |
| of this test. | | | | seen at this time. Some physical defects such as |
| Chorionic villus sampling (CVS) | | | | clubbed feet and heart defects may not be seen. |
| This test is performed between 10 and 12 weeks of | | | | According to the U.S. Department of Health & Human |
| pregnancy. The doctor inserts a needle through your | | | | Services, your doctor can also use ultrasound on |
| partner's abdomen or inserts a catheter through her | | | | your pregnant wife to see if your baby has any |
| cervix in order to reach the placenta. He then takes a | | | | neural tube defects, such as spina bifida. In most |
| sample of cells from the placenta. These cells are | | | | cases, if you want to find out the sex of your baby, |
| used in a lab to look for problems with chromosomes. | | | | you can ask your doctor during this test. This is not |
| This test cannot find out whether your baby has | | | | the most accurate test for Down syndrome. Only 1 |
| open neural tube defects. About 1 in 200 women | | | | in 3 babies with Down syndrome have an abnormal |
| have a miscarriage as a result of this test. | | | | second trimester ultrasound. |