Mayo Clinic Health Library

Prenatal care: 2nd trimester visits

Updated: 11-10-2018

The goal of prenatal care is to ensure that you and your baby remain healthy during your entire pregnancy. Ideally, prenatal care starts as soon as you think you're pregnant. Your health care provider might schedule prenatal care appointments about every four weeks throughout the second trimester.

Here's what to expect at your second trimester prenatal appointments.

Review the basics

Your health care provider will check your blood pressure and weight at every visit. Share any concerns you have. Then it's time for your baby to take center stage. Your health care provider might:

  • Track your baby's growth. By measuring the distance from the pubic bone to the top of your uterus (fundal height), your health care provider can gauge your baby's growth. After 20 weeks of pregnancy, this measurement in centimeters often matches the number of weeks you've been pregnant, plus or minus 2 centimeters.
  • Listen to your baby's heartbeat. At second trimester visits, you might hear your baby's heartbeat using a Doppler instrument. The Doppler instrument detects motion and conveys it as sound.
  • Assess fetal movement. Tell your health care provider when you begin noticing flutters or kicks. Keep in mind that mothers notice these movements at different times, and movement at this time in pregnancy is typically unpredictable. You'll likely notice flutters for the first time around 18 to 20 weeks of pregnancy.

Also, talk to your health care provider about any vaccinations you might need.

Consider prenatal testing

During the second trimester, you might be offered various prenatal screenings or tests:

  • Genetic tests. Blood tests might be offered to screen for genetic or chromosomal conditions, such as spina bifida or Down syndrome. If your results are abnormal or worrisome, your doctor will recommend a diagnostic test, typically an amniocentesis. During amniocentesis, a sample of the fluid that surrounds and protects a baby during pregnancy is removed from the uterus for testing.
  • Fetal ultrasound. Fetal ultrasound is an imaging technique that uses high-frequency sound waves to produce images of a baby in the uterus. A detailed ultrasound can help your health care provider evaluate fetal anatomy. Fetal ultrasound also might give you an opportunity to find out the baby's sex.
  • Blood tests. Blood tests might be offered between week 24 to 28 of pregnancy to check your blood count and iron levels and screen for diabetes that can develop during pregnancy (gestational diabetes). If you have rhesus (Rh) negative blood — an inherited trait that refers to a specific protein found on the surface of red blood cells — you might need a blood test to check for Rh antibodies. These antibodies can develop if your baby has Rh positive blood and your Rh negative blood mixes with your baby's blood. Without treatment, the antibodies could cross the placenta and attack the baby's red blood cells — particularly in a subsequent pregnancy with a baby who has Rh positive blood.

Keep your health care provider informed

The second trimester often brings a renewed sense of well-being. Morning sickness typically begins to ease. You begin to feel the baby move. Your belly becomes more noticeable. There's a lot happening.

Tell your health care provider what's on your mind, even if it seems silly or unimportant. Nothing is too trivial when it comes to your health — or your baby's health.