20 Weeks Pregnant: The Anatomy Scan Week

Congratulations—you’re 20 weeks pregnant and officially halfway through your pregnancy! This is a major milestone that many parents celebrate. Your baby is now about the size of a banana and is developing rapidly. This is typically the week of the anatomy scan, a comprehensive ultrasound that gives you a detailed look at your baby’s development—and, if you choose, reveals whether you’re having a boy or a girl. Your baby is active, your bump is unmistakable, and the second half of your pregnancy journey begins now.

Baby Development at 20 Weeks

Your baby is now approximately 6.5 inches long from crown to rump (about 10 inches from head to toe)—about the size of a banana—and weighs about 10.5 ounces. From this point forward, baby length is typically measured from head to heel rather than crown to rump.

Your baby’s skin is thickening and developing layers. The epidermis (outer layer) is forming four layers that will eventually include the protective outer layer. The vernix caseosa coating continues to protect the skin from the amniotic fluid.

Your baby’s digestive system is producing meconium—the dark, sticky substance that will be your baby’s first bowel movement after birth. Meconium is made up of amniotic fluid, digestive secretions, and skin cells that your baby has swallowed.

Your baby is swallowing more amniotic fluid, which helps develop the digestive system and provides practice for feeding after birth. The taste buds are well-developed, and your baby can taste the flavors of your meals through the amniotic fluid—research suggests this early flavor exposure may influence food preferences later in life.

If your baby is female, the uterus is fully formed and the ovaries contain about 7 million primitive eggs (a number that will decrease to about 2 million by birth). If male, the testes have begun descending from the abdomen.

Your Body This Week

At 20 weeks, your uterus has reached your belly button. From this point, your healthcare provider will begin measuring fundal height at each appointment—the distance from the top of the uterus to the pubic bone. This measurement (in centimeters) roughly corresponds to your weeks of pregnancy.

Your bump is prominent, and you’ve likely gained 10-15 pounds. Weight gain should continue at about 1 pound per week through the rest of pregnancy. See our pregnancy weight gain guide for healthy weight gain targets.

The top of your uterus is now at your belly button, which means your internal organs are being pushed upward and outward. This can cause shortness of breath (as the diaphragm has less room to expand) and heartburn (as the stomach is compressed). Both symptoms tend to intensify as pregnancy progresses.

Your body is producing about 50% more blood than before pregnancy. This increased blood volume supports your baby’s growth but can cause visible veins, mild swelling, and occasional heart palpitations.

Common Symptoms at 20 Weeks

Regular Baby Movement: Most women are feeling distinct kicks and movement by week 20. Your baby may be most active at night or when you’re resting. Start paying attention to movement patterns—this awareness will be valuable in the third trimester.

Heartburn and Indigestion: As your uterus pushes your stomach upward, acid reflux becomes more common. Eat smaller, more frequent meals, avoid spicy and fatty foods, don’t lie down immediately after eating, and talk to your doctor about safe antacids.

Leg Cramps: Painful cramps, especially at night, continue to be common. Stretching your calves before bed, staying hydrated, and maintaining adequate calcium and magnesium intake can help.

Swelling: Mild swelling in your feet, ankles, and hands is normal. It’s caused by increased fluid retention and blood volume. Elevate your feet when possible, and avoid standing for long periods. Sudden or severe swelling should be reported to your doctor.

Skin Changes: Stretch marks may be appearing, and the linea nigra may be more prominent. Some women develop a “pregnancy mask” (melasma)—darkening of the skin on the face. Use sunscreen to minimize these changes.

What to Do This Week

Have your anatomy scan. This is typically the most comprehensive ultrasound of your pregnancy. The sonographer will examine your baby’s brain, heart, kidneys, spine, limbs, and other structures. The scan also checks your placenta position, amniotic fluid levels, and cervical length. This is usually when you can learn your baby’s sex.

Celebrate the halfway mark! Take a bump photo, write in your pregnancy journal, or do something special to mark this milestone. You’re halfway to meeting your baby.

Begin thinking about the third trimester. The second half of pregnancy moves quickly. Start considering baby names, nursery setup, birth preferences, and postpartum planning. Our birth plan template can help you think through your options.

Continue exercising. Regular physical activity remains important. Pregnancy-safe exercises support healthy weight gain, reduce discomfort, improve mood, and prepare your body for labor.

Consider signing up for childbirth classes if you haven’t already. Classes covering labor, delivery, pain management, newborn care, and breastfeeding are typically attended during the third trimester but can fill up quickly.

Nutrition Spotlight: Balanced Second-Trimester Eating

At the halfway point, it’s a good time to review your overall nutrition. During the second trimester, you need about 340 extra calories daily (increasing to 450 in the third trimester). Quality matters more than quantity.

Key nutrients to prioritize: protein (70-100g daily for baby’s growth), iron (27mg to support blood volume), calcium (1,000mg for bone development), DHA (200-300mg for brain development), and fiber (25-30g for digestive health).

Meal planning tip: Each meal should include a protein source, a complex carbohydrate, a healthy fat, and fruits or vegetables. Snacks should be nutrient-dense—think Greek yogurt with berries, apple slices with nut butter, or trail mix with nuts and dried fruit.

Stay hydrated with at least 8-10 glasses of water daily. Proper hydration supports amniotic fluid production, nutrient transport, and helps prevent constipation and preterm contractions. For a complete nutrition overview, visit our pregnancy nutrition guide.

When to Call Your Doctor

Contact your healthcare provider if you experience:

• Vaginal bleeding
• Leaking fluid from the vagina
• Severe abdominal pain or cramping
• Regular contractions (more than 4-6 per hour before 37 weeks)
• Severe or sudden swelling of face, hands, or feet
• Severe headaches with visual changes
• Decreased fetal movement after previously feeling regular movement
• Fever over 100.4°F

See our when to call your doctor guide for complete information.

Frequently Asked Questions