What to expect each trimester

Prenatal care is an important part of a healthy pregnancy. Here's what to expect during the first few prenatal appointments. You will receive a copy of the Mayo Clinic Guide to a Healthy Pregnancy book at an early prenatal appointment. Be sure to consult this often to learn about healthy pregnancy.

The first visit
As soon as you think you're pregnant, schedule your first prenatal appointment. Set aside ample time for the visit, as you and your health care provider will have plenty to discuss. You may want to include your partner in the appointment, as well.

Medical history
Your health care provider will ask many questions, including details about:

• Your menstrual cycle and gynecological history.
• Past pregnancies.
• Your personal and family medical history.
• Medication use, including prescription and over-the-counter medications or supplements.
• Your lifestyle, including your use of tobacco, alcohol and caffeine.

Be sure to mention even sensitive issues, such as domestic abuse, abortion or past drug use. Remember, the information you share will help your health care provider take the best care of you — and your baby. If there's any part of your medical history that you don't want to share with your partner or other loved ones, mention it to your health care provider privately.

Due date
Few women give birth on their due dates. Still, establishing your due date — or estimated date of delivery — is important. An accurate due date allows your health care provider to monitor your baby's growth and the progress of your pregnancy, as well as schedule certain tests or procedures at the most appropriate time.

To estimate your due date, your health care provider will use the date your last period started, add seven days and count back three months. The due date will be about 40 weeks from the first day of your last period. Your provider may use a fetal ultrasound to help confirm the date.

Physical exam
At this exam, your provider will:

• Check your weight and height, and use this information to calculate your body mass index (BMI). He or she will use your BMI to determine the recommended weight gain you need for a healthy pregnancy.
• Measure your blood pressure, heart rate and breathing rate, and perform a complete physical exam. He or she will check for any undiagnosed medical conditions.
• Examine your vagina and the opening to your uterus (cervix). Changes in the cervix and in the size of your uterus can help confirm the stage of your pregnancy. You might need a Pap test to screen for cervical cancer, as well, depending on how long it's been since your last screening.

Lab tests
At your first prenatal visit, blood tests might be performed to:

• Check your blood type. This includes your rhesus, or Rh, status. Rh factor is an inherited trait that refers to a specific protein found on the surface of red blood cells. Your pregnancy needs special care if you're Rh negative and your baby's father is Rh positive.
• Measure your hemoglobin. Hemoglobin is an iron-rich protein found in red blood cells that allows the cells to carry oxygen from your lungs to other parts of your body, and carry carbon dioxide from other parts of your body to your lungs so that it can be exhaled. Low hemoglobin is a sign of anemia — a lack of healthy red blood cells.
• Check immunity to certain infections. This typically includes rubella and chickenpox, or varicella, unless proof of vaccination or natural immunity is documented in your medical history.
• Detect exposure to other infections. Your health care provider might suggest blood tests to detect various other infections, such as hepatitis B, syphilis, gonorrhea or chlamydia, and HIV, the virus that causes AIDS. A urine sample will be tested for signs of infection.

Screening tests for fetal abnormalities
Prenatal tests can provide valuable information about your baby's health. Your provider might offer ultrasound, blood tests or other screening tests to detect fetal abnormalities.

Lifestyle issues
Your provider will discuss the importance of proper nutrition and prenatal vitamins. Your first prenatal visit is a good time to discuss exercise, sex during pregnancy and other lifestyle issues. You also may discuss your work environment and the use of medications during pregnancy. If you smoke, ask your health care provider for suggestions to help you quit.

Normal discomforts of pregnancy
You might notice many changes in your body early in your pregnancy. Your breasts might be tender and swollen. Nausea with or without vomiting, called "morning sickness," also is common. Talk to your health care provider if your morning sickness is severe.

Other first trimester visits
Subsequent prenatal visits — often scheduled about every four weeks during the first trimester — will probably be shorter than the first visit. Your health care provider will check your weight and blood pressure, and you'll discuss any concerns.

Near the end of the first trimester — by about nine to 12 weeks of pregnancy — you might be able to hear your baby's heartbeat with a small device (fetal Doppler) that bounces sound waves off your baby's heart.

Remember, your provider is there to support you throughout your pregnancy. Your prenatal appointments are an ideal time to discuss any questions or concerns, including things that might be uncomfortable or embarrassing.

During the second trimester, prenatal care includes routine lab tests and measurements of your baby's growth. You might consider prenatal testing, too.

Prenatal care seeks to ensure that you and your baby remain healthy during your entire pregnancy. Prenatal care should start as soon as you think you're pregnant. Your health care provider will ask you to 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 might have.

Then it's time for your baby to take center stage. Your provider will:

• Track your baby's growth. By measuring the distance from the pubic bone to the top of your uterus, your health care provider can gauge your baby's growth. This measurement in centimeters often equals the number of weeks of your pregnancy to date.
• Listen to your baby's heartbeat. At second trimester visits, you might listen to your baby's heartbeat using a Doppler instrument. The Doppler instrument detects motion and conveys it as sound, which allows you to "hear" the baby's heartbeat.
• Assess fetal movement. Tell your health care provider when you begin noticing flutters or kicks. This usually happens by about 20 weeks — or perhaps earlier if you've been pregnant before.

Possible prenatal testing

During the second trimester, you might be offered prenatal screenings or tests based on various health factors. See the Mayo Clinic Guide to a Healthy Pregnancy book for more information on possible testing.

• Genetic tests
  Blood tests might be offered to screen for genetic or chromosomal conditions, such as spina bifida or Down syndrome.
• 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 will be offered to check your blood count and iron levels, screen for a type of diabetes that can develop during pregnancy (gestational diabetes), and check for some infections. 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 an Rh-positive baby.
• Urine tests
  A urine sample might be tested for the presence of protein or signs of infection.
• Diagnostic tests
  If the results of a blood test or ultrasound are worrisome, or your history suggests high risk, your health care provider might recommend a more invasive diagnostic test, such as amniocentesis. During amniocentesis, a sample of amniotic fluid — the fluid that surrounds and protects a baby during pregnancy — is removed from the uterus for testing.

Keep your health care provider informed

The second trimester often brings a renewed sense of well-being. Morning sickness typically begins to dissipate. 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.

During the third trimester, prenatal care might include vaginal exams to check the baby's position.

Prenatal care is an important part of a healthy pregnancy, especially as your due date approaches. Your health care provider will ask you to schedule prenatal care appointments during your third trimester about every two or four weeks, depending on your health and obstetrical history. Starting at 36 weeks you'll need weekly checkups until you deliver.

Ongoing monitoring
Your health care provider will continue to monitor your blood pressure and weight gain, as well as your baby's heartbeat and movements. A urine sample also may be tested for the presence of protein or infection. As always, share any symptoms of concern.

Your health care provider will ask you to track of how often you feel the baby move daily and alert your health care team if the baby stops moving as much as usual.

Test for group B Streptococcus
Expect to be screened for group B Streptococcus during the third trimester. This is a common bacterium often carried in the intestines or lower genital tract that's usually harmless in adults. But babies who become infected with group B Streptococcus from exposure during vaginal delivery can become seriously ill.

To screen for group B Streptococcus, your health care provider will swab your lower vagina and anal area. The sample will be sent to a lab for testing.

If the sample tests positive for group B Streptococcus — or you previously gave birth to a baby who developed group B Streptococcus disease — you'll be given IV antibiotics during labor. The antibiotics will protect your baby from the bacterium.

Check the baby's position
Near the end of pregnancy, your health care provider will estimate the baby's weight and check to see if your baby is positioned headfirst in the uterus. You also may have an ultrasound to confirm the baby's position and determine the level of amniotic fluid around the baby.

If your baby is positioned rump-first (frank breech) or feet-first (complete breech), it's possible that he or she could still turn headfirst before you give birth. However, your health care provider might try to turn the baby to improve the chances of a vaginal birth. To do so, your health care provider will apply pressure to your abdomen (external cephalic version). If your baby remains in a breech position, you might need a cesarean section delivery.

Detect cervical changes
As your due date approaches, your health care provider might perform a pelvic exam to detect cervical changes. As your body prepares for birth, your cervix will begin to soften, open (dilate) and thin (efface). Progress is typically expressed in centimeters and percentages. For example, your cervix might be 3 centimeters dilated and 30% effaced. When you're ready to push your baby out, your cervix will be 10 centimeters dilated and 100% effaced.

Keep asking questions
You will likely have plenty of questions as your due date approaches. Is it OK to have sex? How will I know when I'm in labor? What's the best way to manage the pain? Should I create a birth plan? Ask away. Feeling prepared can calm your nerves before delivery.

Also, be sure to discuss symptoms that should cause you to call your health care provider, such as vaginal bleeding or fluid leaking from the vagina, as well as when and how to contact your health care provider once labor begins.