17 Weeks Pregnant: Your Baby Is Getting Bigger

At 17 weeks pregnant, your baby is about the size of a pear and is becoming increasingly active. You may be starting to feel those first magical flutters of movement, especially if this isn’t your first pregnancy. Your body is adjusting beautifully to the second trimester, and you’re likely enjoying renewed energy and a growing connection with your baby. This week brings exciting developmental milestones as your baby’s body fat begins to form and their skeleton continues to strengthen.

Baby Development at 17 Weeks

Your baby is now approximately 5.1 inches long from crown to rump—about the size of a pear—and weighs about 5 ounces. Your baby is growing rapidly and developing important body systems.

A major development this week: body fat is beginning to form. Called brown fat or adipose tissue, this fat layer will eventually help regulate your baby’s body temperature after birth. Right now, your baby is still very lean, but fat accumulation will accelerate throughout the rest of pregnancy.

Your baby’s skeleton is transitioning from soft cartilage to bone. This ossification process requires significant amounts of calcium, which is why your calcium intake is so important. The umbilical cord is growing stronger and thicker to accommodate increased blood flow.

Your baby’s sweat glands are developing, and the fingerprints are fully unique. Your baby can now make sucking and swallowing motions, practicing skills needed for feeding. The placenta is fully functioning and continues to grow, providing oxygen and nutrients while removing waste products.

Your Body This Week

At 17 weeks, your uterus is about 2 inches below your belly button. Your pregnancy bump is unmistakable now, and you may have fully transitioned to maternity clothes. Most women have gained about 5-10 pounds by this point.

Your center of gravity is continuing to shift as your bump grows, which can affect your balance and posture. You may notice yourself leaning back slightly to compensate for the weight in front—a posture that can contribute to lower back strain.

Increased blood flow may be causing your hands and feet to feel warm. Some women experience carpal tunnel syndrome symptoms during pregnancy due to fluid retention and swelling compressing the nerves in the wrists.

Your heart is now pumping about 40-50% more blood than before pregnancy. This extra cardiovascular workload is normal but can cause occasional breathlessness during physical activity.

Common Symptoms at 17 Weeks

Baby Movement (Quickening): Many second-time mothers begin feeling movement between weeks 16-18. First-time mothers may need to wait until weeks 18-22. The first movements feel like gentle flutters or bubbles. See our baby movement guide.

Increased Appetite: Your body needs fuel to support your growing baby. You need about 300 extra calories daily during the second trimester. Choose nutrient-dense foods that provide vitamins, minerals, and sustained energy.

Vivid Dreams: Many pregnant women report more vivid, emotional, or strange dreams during pregnancy. Hormonal changes, anxiety about parenthood, and disrupted sleep patterns all contribute.

Stretch Marks: As your skin stretches to accommodate your growing belly and breasts, pink, red, or purple stretch marks may appear. Genetics play the biggest role in whether you develop stretch marks, but keeping skin well-moisturized may help with itching.

Heartburn: As your uterus grows and progesterone relaxes the esophageal sphincter, heartburn becomes increasingly common. Eating smaller meals, avoiding trigger foods, and not lying down immediately after eating can help.

What to Do This Week

Start tracking baby movements. Once you begin feeling movement, pay attention to patterns. While formal kick counts aren’t usually recommended until the third trimester, becoming familiar with your baby’s activity helps you recognize changes later.

Consider your birth plan preferences. Now is a good time to start thinking about your birth preferences. Where do you want to deliver? What pain management options interest you? Who do you want in the delivery room? Our birth plan template can help you organize your thoughts.

Keep exercising. Regular, moderate exercise supports healthy pregnancy outcomes. See our exercise guide for safe second-trimester activities. Swimming is particularly beneficial—the buoyancy reduces stress on joints and back.

Take photos. Document your growing bump with weekly photos. These become wonderful keepsakes and help you appreciate the amazing transformation your body is undergoing.

Nutrition Spotlight: Healthy Fats

As your baby begins developing body fat this week, healthy dietary fats become even more important. Essential fatty acids support your baby’s brain development, eye development, and nervous system formation.

Omega-3 fatty acids (especially DHA) are critical for brain development. Sources include fatty fish (salmon, sardines—limit to 2-3 servings per week), walnuts, flaxseeds, and chia seeds.

Monounsaturated fats from avocados, olive oil, and nuts support heart health and help absorb fat-soluble vitamins (A, D, E, K).

Avoid trans fats (found in processed and fried foods) and limit saturated fats. Focus on getting 20-35% of your daily calories from healthy fat sources. For more nutrition guidance, visit our pregnancy nutrition guide.

When to Call Your Doctor

Contact your healthcare provider if you experience:

• Vaginal bleeding
• Severe abdominal pain or cramping
• Fever over 100.4°F
• Sudden swelling of face, hands, or feet
• Severe or persistent headaches with visual changes
• Leaking fluid from the vagina
• Decreased fetal movement (if you’ve been feeling regular movement)

See our when to call your doctor guide.

Frequently Asked Questions