What tests are required at 20 weeks of pregnancy?

At 20 weeks’ gestation—approximately five months into pregnancy—you are approaching the midpoint of your pregnancy and entering a critical window for comprehensive prenatal assessment. This visit typically coincides with the detailed anatomy ultrasound, also known as the mid-pregnancy or anomaly scan, which is ideally performed between 18 and 22 weeks’ gestation. During this ultrasound, a trained sonographer or maternal-fetal medicine specialist evaluates fetal anatomy in detail—including the brain, heart, spine, kidneys, limbs, face, and placental position—to screen for structural congenital anomalies.

In addition to the anatomy scan, your obstetric provider will routinely assess maternal vital signs (blood pressure, weight, fundal height), check for signs of gestational hypertension or preeclampsia, and evaluate fetal growth and movement. You may also undergo routine laboratory testing if not already completed, such as screening for gestational diabetes (typically between 24–28 weeks, but risk assessment begins now), repeat hemoglobin/hematocrit to monitor for iron-deficiency anemia, and assessment of Rh status and antibody screening if Rh-negative. Group B Streptococcus (GBS) screening occurs later (35–37 weeks), so it is not indicated at this stage.

This visit is also an excellent opportunity to discuss pregnancy-related symptoms—such as back pain, leg cramps, or heartburn—and receive evidence-based guidance on nutrition, physical activity, warning signs requiring urgent evaluation (e.g., vaginal bleeding, persistent headache, visual changes, decreased fetal movement), and preparation for labor and delivery. If you have not yet chosen a birth setting or developed a birth plan, your provider can support those discussions as well.

It’s important to note that individualized care may vary depending on your medical history, risk factors (e.g., prior preterm birth, chronic hypertension, diabetes), or findings from earlier prenatal visits. Always follow your provider’s recommendations for additional or specialized testing, such as genetic counseling or referral to maternal-fetal medicine, if indicated.