Pregnancy is the time when a developing baby grows inside your uterus, or womb. It starts with conception, when a sperm penetrates and fertilizes an egg. The fertilized egg then travels through the fallopian tube, implants in the uterine wall, and starts to grow.

The resulting embryo is a cluster of cells that form the fetus and the placenta. The placenta is a temporary organ that provides nutrients and oxygen to the growing fetus. It also removes waste products.

Pregnancy is divided into 3 roughly equal phases, called trimesters. They estimate your due date by counting the weeks from your last menstrual period. A typical pregnancy lasts about 40 weeks from the first day of your last period. The fourth phase or trimester is the 3 months after the birth of your baby.

Here are some of the changes you may experience.

First trimester

You’ll likely feel more tired than usual as your body works to nurture the growing fetus. You may have morning sickness, a common term for the nausea and vomiting caused by pregnancy hormones that can happen at any time of the day (not just the morning).

Once the embryo is more than 8 weeks old, doctors call it a fetus.

Heartburn, constipation, breast tenderness, and the need to urinate frequently are common pregnancy symptoms during the first trimester. You may also have mood swings caused by fluctuating hormones.

Second trimester

You may have a burst of energy during the second trimester as your hormones balance out. You’ll gain weight more rapidly, and your breasts will get bigger. Your hands and feet may swell, and you might notice aches and pains in your belly as the ligaments stretch.

Around the middle of the second trimester (week 20 or so), you’ll start to feel the baby move, or “quicken."

Third trimester

After week 28, you may begin to feel more tired again. The baby often drops to a lower position in your belly as you get ready for labor and delivery. You may feel more intense abdominal pain, backache, breast tenderness, and heartburn.

Many women have frequent Braxton Hicks contractions during the third trimester. This tightening of the uterus helps prepare your body for labor. But they're not as strong as actual labor contractions.

It may be difficult to find a comfortable position for sleeping as your due date gets closer. Your emotions may feel more intense toward the end of pregnancy. Many women get a “nesting” instinct in the last trimester—a desire to get things ready for the baby.

Pregnancies that make it to the third trimester end with giving birth—either labor and delivery or surgical delivery by cesarean section.

Fourth trimester

The fourth trimester is the first three months after your baby is born. During this time, both you and your baby are adjusting to life outside the womb. For your baby, everything is new—sounds, lights, and sensations they haven’t experienced before. For you, it’s a time of healing, learning, and big emotional changes.

Your body is still recovering from pregnancy and birth. Hormones are shifting, sleep is often limited, and caring for a newborn can feel overwhelming at times. The uterus slowly returns to its normal size, bleeding can last for several weeks, and feeding routines—breast or bottle—begin to take shape.

Emotional ups and downs are common during the fourth trimester. You may feel joy and closeness one moment and exhaustion or sadness the next. “Baby blues” are normal, and some people experience postpartum depression or anxiety. These conditions are common and treatable, and help is available.

This stage is also about finding your footing as a parent and building a new family rhythm. It’s okay to ask for help, rest when you can, and give yourself time to adjust. Eating well, staying hydrated, moving gently when ready, and leaning on loved ones can all support recovery. The fourth trimester is a time of transition—not perfection—for both you and your baby.

Most pregnancies go according to plan, but sometimes an unexpected problem comes up. At Carilion, we have the expert staff to care for you and your baby, should any complications occur during your pregnancy.

• Pregnancy loss: Loss before 20 weeks is a miscarriage. After, it’s a stillbirth.
• Preeclampsia: Pregnancy-related high blood pressure.
• Gestational diabetes: Pregnancy-related high blood sugar.
• Preterm labor: When labor begins before 37 weeks of pregnancy.
• Placenta previa: When the placenta covers the opening of the cervix.
• Placental abruption: When the placenta separates from the uterine wall.
• Hyperemesis gravidarum: Extreme nausea and vomiting.
• Gestational hypertension: Pregnancy related high blood sugar.

When choosing someone to care for you during pregnancy, it’s important to find a trusted professional who listens to your concerns. During your pregnancy, your care may be provided by an OB/GYN, midwife, or nurse practitioner. If specialized care is needed, a maternal-fetal medicine specialist may also be part of your care team. No matter who is involved in your care, you’ll receive compassionate, professional support throughout your pregnancy.

Here are some ways we care for you during pregnancy.

Prenatal visits

You’ll have monthly visits with your care team. In your third trimester, you’ll be seen every 2 weeks, and every week during the last month of pregnancy.

We’ll run tests to make sure you and your baby are doing well. These might include blood and urine tests, ultrasounds, and other tests as needed.

Prenatal screenings

If you have a risk of having a baby with a specific genetic condition, you may choose to have prenatal screening. We have two perinatal genetic counselors on staff, the only ones in the region. They can meet with you to determine your chances of having a baby with a specific condition.

Childbirth classes

We offer virtual childbirth classes to help you and your partner prepare for labor and delivery. You can also take a virtual tour of our labor and delivery rooms.