Trimester means "3 months." A normal pregnancy lasts around 10 months and has 3 trimesters.

The word prenatal means before birth. The first trimester starts when your baby is conceived. It continues through week 14 of your pregnancy. Your health care provider may talk about your pregnancy in weeks, rather than in months or trimesters.

Pregnancy care - first trimester

You should schedule your first prenatal visit soon after you learn that you are pregnant. Your doctor or midwife will:

• Draw your blood
• Perform a full pelvic exam
• Do a Pap smear and cultures to look for infections or problems

Your doctor or midwife will listen for your baby's heartbeat, but may not be able to hear it. Most often, the heartbeat cannot be heard or seen on ultrasound until at least 6 to 7 weeks.

During this first visit, your doctor or midwife will ask you questions about:

• Your overall health
• Any health problems you have
• Past pregnancies
• Medicines, herbs, or vitamins you take
• Whether or not you exercise
• Whether you smoke, use tobacco, drink alcohol or take drugs
• Whether you or your partner have genetic disorders or health problems that run in your family

You will have many visits to talk about a birthing plan. You can also discuss it with your doctor or midwife at your first visit.

The first visit will also be a good time to talk about:

• Eating healthy, exercising, getting adequate sleep, and making lifestyle changes while you are pregnant
• Common symptoms during pregnancy such as fatigue, heartburn, and varicose veins
• How to manage morning sickness
• What to do about vaginal bleeding during early pregnancy
• What to expect at each visit

You will also be given prenatal vitamins with iron if you are not already taking them.

In your first trimester, you will have a prenatal visit every month. The visits may be quick, but they are still important. It is OK to bring your partner or labor coach with you.

During your visits, your doctor or midwife will:

• Weigh you.
• Check your blood pressure.
• Check for fetal heart sounds.
• Take a urine sample to test for sugar or protein in your urine. If either of these is found, it could mean that you have gestational diabetes or high blood pressure caused by pregnancy.

At the end of each visit, your doctor or midwife will tell you what changes to expect before your next visit. Tell your doctor or midwife if you have any problems or concerns. It is OK to talk about them even if you do not feel that they are important or related to your pregnancy.

At your first visit, your doctor or midwife will draw blood for a group of tests known as the prenatal panel. These tests are done to find problems or infections early in the pregnancy.

This panel of tests includes, but is not limited to:

• A complete blood count (CBC)
• Blood typing (including Rh screen)
• Rubella viral antigen screen (this shows how immune you are to the disease Rubella)
• Hepatitis panel (this shows if you are positive for hepatitis A, B, or C)
• Syphilis test
• HIV test (this test shows if you are positive for the virus that causes AIDS)
• Cystic fibrosis screen (this test shows if you are a carrier for cystic fibrosis)
• A urine analysis and culture

An ultrasound is a simple, painless procedure. A wand that uses sound waves will be placed on your belly. The sound waves will let your doctor or midwife see the baby.

You should have an ultrasound done in the first trimester to get an idea of your due date. The first trimester ultrasound will usually be a vaginal ultrasound.

All women are offered genetic testing to screen for birth defects and genetic problems, such as Down syndrome or brain and spinal column defects.

• If your doctor or midwife thinks that you need any of these tests, talk about which ones will be best for you.
• Be sure to ask what the results could mean for you and your baby.
• A genetic counselor can help you understand your risks and test results.
• There are many options now for genetic testing. Some of these tests carry some risks to your baby, while others do not.

Women who may be at higher risk for these genetic problems include:

• Women who have had a fetus with genetic problems in earlier pregnancies
• Women, age 35 years or older
• Women with a strong family history of inherited birth defects

In one test, your doctor or midwife can use an ultrasound to measure the back of the baby's neck. This is called nuchal translucency.

• A blood test is also done.
• Together, these 2 measures will tell if the baby is at risk for having Down syndrome.
• If a test called a quadruple screen is done in the second trimester, the results of both tests are more accurate than doing either test alone. This is called integrated screening. If the test is positive, an amniocentesis or cell-free DNA test may be recommended.

Another test, called chorionic villus sampling (CVS), can detect Down syndrome and other genetic disorders as early as 10 weeks into a pregnancy.

A newer test, called cell free DNA testing, looks for small pieces of your baby's genes in a sample of blood from the mother. This test is newer, but offers a lot of promise for accuracy without risks of miscarriage. It may reduce the need for an amniocentesis, and so is safer for the baby.

There are other tests that may be done in the second trimester.

Contact your doctor or midwife if:

• You have a significant amount of nausea and vomiting.
• You have bleeding or cramping.
• You have increased discharge or a discharge with odor.
• You have a fever, chills, or pain when passing urine.
• You have any questions or concerns about your health or your pregnancy.

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Hobel CJ, Williams J. Antepartum care. In: Hacker N, Gambone JC, Hobel CJ, eds. Hacker & Moore's Essentials of Obstetrics and Gynecology. 6th ed. Philadelphia, PA: Elsevier; 2016:chap 7.

Ormandy J. Antenatal and postnatal care. In: Magowan B, ed. Clinical Obstetrics and Gynaecology. 5th ed. Philadelphia, PA: Elsevier; 2023:chap 23.

Smith RP. Routine prenatal care: first trimester. In: Smith RP, ed. Netter's Obstetrics and Gynecology. 4th ed. Philadelphia, PA: Elsevier; 2024:chap 207.

Williams DE, Pridjian G. Obstetrics. In: Rakel RE, Rakel DP, eds. Textbook of Family Medicine. 9th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 20.