Pregnancy Stages | Baylor Scott & White Health

Understanding each stage of your pregnancy

While a full-term pregnancy lasts 40 weeks, there are many milestones along the way. Pregnancy is divided into three stages, known as trimesters. Week by week, each stage takes your baby one step closer to delivery. The obstetrician-gynecologists (OBGYNs) at Baylor Scott & White provide comprehensive, compassionate maternity care for every trimester of your pregnancy.

Pregnant woman sitting next to her partner, placing a hand on her belly while they both look at an

First trimester: Weeks 1 to 12

At your first routine maternal health checkup, your OBGYN will confirm whether you are pregnant and establish your due date. Your OBGYN will provide education to help you make healthy choices for your pregnancy. People with a typical pregnancy will see their OBGYN monthly during the first trimester.

Providers typically measure pregnancy in weeks, starting from the first day of your last menstrual period. Over the first 12 weeks, you release an egg, which is fertilized by sperm and implants in your uterus. The fertilized egg, a single cell, divides many times until it forms an embryo and then, at about 10 weeks, a fetus with facial features and a detectable heartbeat. By week 12, your fetus is about 3 inches long and weighs about an ounce.

Early signs and symptoms

During early pregnancy, you may experience symptoms including:

Changes in your bathroom habits, such as constipation or needing to go more often
Exhaustion
Food cravings or aversions
Headaches
Heartburn, nausea or vomiting
Mood swings
Tender or swollen breasts
Weight changes (either losing or gaining weight)

No single sign means you are pregnant. However, if you experience several symptoms together or have missed a period, you may want to take a pregnancy test or come to your OBGYN’s office for testing. If a home pregnancy test confirms pregnancy, make an appointment with your OBGYN right away to get your pregnancy off to a healthy start.

Second trimester: Weeks 13 to 28

In the second trimester, you will continue to visit your OBGYN each month unless you need extra care. Your OBGYN will provide other tests you may need to keep you and your baby healthy. For instance, a diabetes test may influence their guidance for nutritious eating throughout pregnancy. Your OBGYN may also recommend that you receive certain vaccinations.

During this second stage of pregnancy, your baby develops rapidly. By week 28, your baby is about a foot long and may weigh up to 1.5 pounds. Their bones begin to harden, make blood cells, and move.

Growth and development

You and your baby are both growing during the second trimester. Your baby’s skeleton and organs continue to develop. They have sleep and wake cycles. At around week 22, many people can feel their baby moving.

Your body will also continue to change. Your belly expands as your uterus grows to accommodate your baby. Your blood volume increases, as does the amount of blood your heart pumps, known as your cardiac output. In other words, your body is working hard.

Third trimester: Weeks 29 to 40

Generally, checkups occur every two 2-3 weeks from week 28 through week 36, then weekly until your baby arrives. During these visits, your OBGYN will continue to monitor your baby’s health. They’ll discuss your birth plans with you and may offer resources such as childbirth and parenting classes, lactation consultation, and other services for you and your baby.

During the third trimester of pregnancy, your baby finishes growing and even begins to add fat. A full-term infant generally arrives between 39 and 40 weeks. Full-term babies may weigh between 6 and 9 pounds and be around 19 to 21 inches long.

Final development stages

During the third trimester, your baby prepares for birth. Their lungs and other organs finish developing, and their bones continue to harden. They may turn their head down in preparation for childbirth.

Your body also changes as you gain more weight and experience the baby settling lower into your pelvis or “dropping.” You may begin to feel heaviness in your breasts and even leak a few drops of colostrum, a watery, milk-like substance.

Fourth trimester: After baby arrives

Many people describe the 12 weeks after birth as the fourth trimester of pregnancy. During this postpartum phase, your body continues to change as you recover from childbirth and many of the physical changes of pregnancy reverse.

Postpartum visits will occur, at minimum, within three weeks after birth and again at six weeks. Your OBGYN will check that you’re healing physically and monitor your mental well-being. Your OBGYN will also provide contraceptive guidance if you want it. If you experienced high blood pressure or gestational diabetes when you were pregnant, your OBGYN may perform a risk assessment and help you coordinate care for these conditions.

Moms who deliver at BSWH have access to Virtual Postpartum Care for comprehensive support during those first six months after delivery. You can speak directly to a Nurse Care Advocate for personalized guidance and access specialists for lactation support and pelvic floor therapy – all through convenient virtual services.

Healthcare after delivery

Your baby will have their first visit with a pediatrician during their first week of life. You should also keep in touch with your OBGYN to discuss concerns about your health and attend postpartum checkups as scheduled to help ensure a good recovery.

You may experience pain from tearing during a vaginal birth or from a cesarean section. Some women develop hemorrhoids after delivery, as well. Call your OBGYN if your pain does not go away in a few weeks.

Also, watch for symptoms of high blood pressure or postpartum preeclampsia, which could include:

Bad headaches
Blurry vision, sensitivity to light, temporary vision loss or other vision changes
Pain under your ribs, usually on the right side
Nausea and vomiting
Shortness of breath
Urinating less than you normally do

Our pregnancy services

Routine testing is a big part of prenatal care. Your OBGYN will determine which tests you need based on your health history and the results of your prenatal care visits.

Alpha-fetoprotein (AFP) test

An AFP test is performed around 18 weeks into your pregnancy. This test measures AFP levels, a protein found in the baby's liver. The results of this test can tell if the baby has any genetic disorders or birth defects that affect the brain and spine, known as neural tube defects, including spina bifida.

Amniocentesis

An amniocentesis tests your amniotic fluid, the liquid that surrounds and protects your growing baby in the womb. Performed between weeks 15 and 20, amniocentesis looks for signs of Down syndrome or open neural tube defects, such as spina bifida. This type of test is rare.

Ultrasounds

Ultrasounds are noninvasive tests that use sound waves to project an image. You may receive an ultrasound to check for a heartbeat during your first visit. Your baby is tiny at this stage, but ultrasounds at subsequent checkups help determine how quickly your baby grows, if there are multiples (such as twins) and the baby’s sex.

Noninvasive prenatal testing (NIPT)

NIPT is a blood test that typically happens around 11 weeks into the pregnancy. It analyzes the baby's DNA to screen for abnormalities or genetic defects, such as Down syndrome. This test was developed to replace chorionic villus sampling.

Glucose (blood sugar) screening

Glucose screenings can tell your doctor if you have or are at risk for gestational diabetes. The test is typically performed between 24 and 28 weeks unless urine samples show high blood sugar levels before then.

Rh factor

This blood test tells your doctor if you and your partner have Rh factor, a protein in red blood cells. If one of you does and one does not, you are considered Rh incompatible. In some cases, Rh incompatibility can increase certain risks, and the tests will help your OBGYN guide treatment decisions during pregnancy.

Find a location near you

You can find comprehensive pregnancy care at Baylor Scott & White locations throughout North and Central Texas.

Baylor Scott & White All Saints Medical Center - Fort Worth

1400 8th Ave , Fort Worth, TX, 76104