17 Weeks Pregnant
second trimester · Month 5
23 Weeks to Go!
Baby is as long as a turnip
Key Takeaways
- Sweat glands developing; baby practices breathing motions
- Fat begins forming under skin
- Heart rate responds to activity — 120-160 bpm
17 Weeks Pregnant
Baby’s Development
Your baby is now about 13 centimeters long — around the size of a turnip or pear — and weighs roughly 140 grams [1]. The sweat glands are developing, and fat (specifically brown adipose tissue) is beginning to form under the skin, which will be essential for regulating your baby’s temperature after birth. The umbilical cord is now fully formed, with two arteries carrying oxygen-poor blood from your baby to the placenta and one vein bringing oxygen-rich blood back, all cushioned by Wharton’s jelly. Your baby’s heart rate ranges from 120 to 160 beats per minute and shifts with activity. They’re even practicing breathing motions, drawing amniotic fluid in and out, while the skeleton transforms from cartilage to bone. A protective white, waxy coating called vernix is now covering the skin. Movement is very active — kicks, punches, rolls, and hiccups [2].
Pregnancy Symptoms
Your second-trimester “honeymoon” continues, with energy running high and your libido often strong. You may still be dealing with round ligament pain, a backache, worsening heartburn, constipation, bloating, leg cramps, nasal congestion, headaches, and occasional nosebleeds. For many, the kicks are now distinct enough to tell apart from gas. You might also notice skin changes — the linea nigra darkening, melasma, and stretch marks (which 50 to 90% of pregnant people develop, and which depend more on genetics than any lotion). Heartburn can worsen as your uterus presses against your stomach [2].
Body Changes
Your uterus is about halfway between your pubic bone and your navel, and a weight gain of 7 to 12 pounds by week 17 is typical. Your bump is clearly visible now. You might notice visible blue veins, varicose veins, or small red dots called spider angiomas. Your breasts may be up 1 to 1.5 cup sizes, and colostrum (your first milk) may begin to leak. Your posture is shifting as the curve in your lower back increases, and your center of gravity is moving forward [2].
Tips for Week 17
- Stay active — aim for 30 minutes of moderate exercise most days, whether walking, swimming, prenatal yoga, or a stationary bike. ACOG advises avoiding the supine position (lying flat on your back) after the first trimester.
- Address back pain — strengthen your core with pelvic tilts and glute bridges, wear supportive shoes, use a pregnancy pillow for sleep, and consider a prenatal massage.
- Build kick-counting awareness — it’s not formal yet, but start noticing patterns. Most moms report 10 or more movements in two hours when their baby is active.
- Research childbirth classes — options range from hospital-based classes (4 to 6 weeks, free or inexpensive) to Bradley Method (12 weeks, around $300), HypnoBirthing (5 weeks, around $300), or a one-day Lamaze intensive. Aim to book by 20 to 24 weeks.
Things To Do (Checklist)
- Continue 30 min moderate exercise most days
- Buy pregnancy pillow (U-shape or C-shape) for sleep
- Research and book childbirth class (20-24 weeks ideal)
- Notice kick patterns; journal times
- Consider prenatal massage (your area: $80-150/session)
Frequently Asked Questions
Q: I’m having vivid dreams. Normal? A: Yes. Hormonal shifts, sleep disruption, and emotional processing often combine to produce vivid dreams. Common themes include water, animals, birth, or a missing child — and they’re not predictive [2].
Q: Is lower back pain normal? A: It’s very common. The relaxin hormone loosens your joints, your posture shifts, and weight gain adds strain. Prevention comes from core strengthening, supportive shoes, a pregnancy pillow, and avoiding heavy lifting. Mention it to your OB if it becomes severe [1].
Q: When can I find out the sex? A: It’s often visible on the anatomy scan, between 18 and 22 weeks. Some providers also offer early sex determination through NIPT from 10 weeks on, with about 99% accuracy [1].
For Dads
- Start a hospital bag list — you’re not packing yet, but draft one now. Think comfortable clothes, a phone charger, snacks, a change of clothes, toiletries, and a going-home outfit for the baby. Make it a project.
- Take a hospital tour — most hospitals offer free tours. Look into Washington, Eden, or UCSF Benioff, and book for around 24 to 28 weeks since spots fill up.
- Begin researching infant care classes — look for “Daddy Boot Camp,” “New Dads,” or “Caring for Your Newborn.” Your local Dad’s Group or church community may have options too.
- Read The Expectant Father, Chapters 11-12 — they cover the deepening second trimester, those “real” feelings, and the body changes of pregnancy.
- Pray for skeletal and fat development — your baby’s bones are hardening and the brown fat is building, preparing for temperature regulation after birth.
Sources
- ACOG — How Your Fetus Grows During Pregnancy
- Mayo Clinic — 17 Weeks Pregnant
- What to Expect When You’re Expecting — Heidi Murkoff (Chapters 11-12: Second Trimester)
Sources
- guideline ACOG — How Your Fetus Grows During Pregnancy
- medical Mayo Clinic — 17 Weeks Pregnant
- book What to Expect When You're Expecting — Heidi Murkoff
Your Checklist
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Action Plan Items for Week 17
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