The goal of prenatal care is to help you and your baby stay healthy during your pregnancy. At best, prenatal care starts as soon as you think you're pregnant. You might have prenatal care visits about every four weeks through the second trimester.

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

Your healthcare team checks your blood pressure and weight at each visit. These visits focus on:

• Your baby's growth. Your baby's growth is tracked by measuring from your pubic bone to the top of your uterus. This is called the fundal height. After 20 weeks of pregnancy, this number in centimeters often matches the number of weeks you've been pregnant, plus or minus 2 to 3 centimeters.
• Your baby's heartbeat. At second trimester visits, you might hear your baby's heartbeat using a Doppler device. The Doppler device turns the motion of your baby's heart into sound.
• Your baby's movement. You might start to feel flutters or kicks around 18 to 22 weeks of pregnancy. Tell your healthcare professional when they start. Keep in mind that not all pregnant people feel these movements at the same time in their pregnancies.

At your visits, ask about any worries or questions you have. Also, talk to your healthcare team about vaccinations you need.

During the second trimester, your healthcare team may offer you prenatal tests. These might include:

• Genetic tests. Blood tests can screen for conditions caused by genes or chromosomes. These include tests for spina bifida and Down syndrome. If your results cause concern, your healthcare team likely will suggest a diagnostic test, most often chorionic villus sampling or amniocentesis.

  During chorionic villus sampling, a sample of the placenta is taken for testing of the baby's chromosomes or genes. During amniocentesis, a sample of the fluid surrounding the baby is removed from the uterus for testing.

• Fetal ultrasound. Fetal ultrasound is an imaging test that uses sound waves to make images of a baby in the uterus. An ultrasound can give useful information about the baby. Fetal ultrasound also might tell you the baby's sex if you want to know.

• Blood tests. Blood tests between weeks 24 and 28 of pregnancy can check your blood count and iron levels. And they can screen for diabetes that can start during pregnancy, called gestational diabetes.

  Blood tests also check for your Rh status and Rh antibodies. Rh factor is a trait passed through families, also called an inherited trait. Rh factor is a protein found on red blood cells. If your blood is Rh negative, you need a blood test to check for Rh antibodies.

  You might have these antibodies if your baby has Rh positive blood and your Rh negative blood mixes with your baby's blood. Without treatment, the antibodies could attack the baby's red blood cells.

The second trimester often brings a renewed sense of well-being. You might have more energy and feel more like being active. For many pregnant people, morning sickness begins to ease during the second trimester. You begin to feel the baby move. And you can see your belly's growth. There's a lot going on.

Tell your healthcare team what's on your mind, even if it seems silly or not important. Nothing is too small when it comes to your health or your baby's health.

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 concerning, 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 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.

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.