Trimester Prenatal Screening Tests

First trimester screening combines a fetal ultrasound with blood tests from the mother. This process can help assess the risk of the fetus having certain chromosomal abnormalities. Additionally, there is a non-invasive prenatal testing (NIPT) option that can detect these abnormalities as early as 9 weeks into pregnancy.

For the second trimester, prenatal screening typically involves several blood tests known as multiple markers. These tests provide crucial information regarding the risk of genetic conditions or birth defects in your baby.

First Trimester Prenatal Screening Tests

First trimester screening includes both a fetal ultrasound and maternal blood tests to determine the likelihood of the fetus having certain birth defects. These tests can be done alone or in combination with others.

The components of first trimester screening are:

• Ultrasound for Fetal Nuchal Translucency: This examines the back of the baby’s neck for any increased fluid or thickening.
• Ultrasound for Fetal Nasal Bone Determination: This checks for the nasal bone, which may not be visible in some babies with chromosome abnormalities, like Down Syndrome. This is performed between 11 and 13 weeks of pregnancy.
• Maternal Serum (Blood) Tests: These tests measure two important substances in the blood of all pregnant women:
• Pregnancy-associated Plasma Protein A (PAPP-A): A protein produced by the placenta in early pregnancy. Abnormal levels may indicate a higher risk for chromosomal issues.
• Human Chorionic Gonadotropin (hCG): A hormone produced by the placenta early in pregnancy. Abnormal levels can suggest an increased risk of chromosomal abnormalities.

Using both nuchal translucency screening and maternal blood tests together increases the chances of identifying potential issues like Down Syndrome (trisomy 21) and trisomy 18. If any results from these tests seem abnormal, genetic counseling is highly recommended.

Second Trimester Prenatal Screening Tests

Second trimester screening usually involves taking a blood sample between 15 and 20 weeks of your pregnancy, with the ideal timing being 16 to 18 weeks.

• AFP Screening: This blood test measures the level of alpha-fetoprotein (AFP) during pregnancy.
• Estriol: A hormone produced by the placenta. It can be measured in maternal blood or urine to help assess fetal health.
• Inhibin and Human Chorionic Gonadotropin: Both are hormones produced by the placenta.

When you undergo both first and second trimester screenings, the combined results improve the ability to detect any abnormalities compared to relying on a single screening alone.

If you need any help, feel free to consult with our doctors.