Prenatal Screening Tests | Tests during the second trimester of pregnancy
Ultrasound: Also known as ultrasound or sonogram, this diagnostic test through images can be made at any time during pregnancy, but often is offered at 20 weeks. The reasons for having an ultrasound or ultrasound are several: to measure the size of the fetus to predict your date of birth, diagnose a multiple pregnancy, placenta previa investigate complications and other malformations, view their bodies, to detect the sex and know their features. There are now three-dimensional ultrasound which let you see your baby in more detail.
Evidence of alpha-fetoprotein in maternal serum (MSAFP) and multiple marker test: You can do one of two tests and the objective is to detect the possibility of defects in the baby’s spine or existence (or not) of Down syndrome when the doctor recommends. The alpha-fetoprotein test measures the presence of this substance (in the amniotic fluid, fetal blood and breast) produced by the fetus during its development.
When blood is drawn for this test is also used to analyze the levels of estriol (a hormone produced by the liver of the fetus and placenta) and hCG (human chorionic gonadotropin levels or pregnancy hormone) is called the triple test. And if you add the analysis of so-called inhibin-A (a hormone produced by the placenta), then this test is known as the quad screen. The precision with which it is detected Down Syndrome is 70% of cases for the triple and 80% of cases for the quad. The trial of alpha-fetoprotein (AFP in Spanish, or MSAFP) detects the existence of the neural tube in 80% of cases.
Amniocentesis: Generally, this test is done between 15 and 18 weeks of gestation and is optional. Tends have done if you have more than 35 years, while you’re at higher risk that your baby develops any genetic disorder. It is also recommended when testing alpha-fetoprotein or multiple marker showed suspicious results. Amniocentesis involves inserting a needle into the abdomen to extract amniotic fluid, which is the one that contains cells from the sac surrounding the baby. A variant is the chorionic villus sampling, in which what are the cells are removed from the placenta and can be done in the first half.
Glucose Test: The test to measure your risk of developing gestational diabetes during pregnancy, which causes your baby overweight, complicated deliveries and other problems for your health and your baby. It is usually between 24 and 28 weeks of pregnancy. To test for glucose, you have to take a special liquid (sweet) and then wait an hour for you to have blood drawn. If your results are high, we repeated the test: you have to take a fasting glucose solution and you must draw blood every hour for 2 or 3 hours.