Week 17: Growing Stronger
Your baby's skeleton is transforming from soft cartilage to bone. Fat stores are beginning to develop under the skin, and sweat glands are forming.
Medically reviewed by Samantha L. Fox, RN, BSN, MSN
Nursing Informaticist · United States Navy Nurse Corps · Last reviewed
Your baby is the size of a...
🍐 Pear!
👶 Baby Development
- ✓Cartilage is hardening into bone throughout the skeleton
- ✓Fat begins accumulating under the skin
- ✓Sweat glands are developing
- ✓Umbilical cord is growing thicker and stronger
- ✓Baby can move all joints
- ✓Unique fingerprints are fully formed
💊 Common Symptoms
- •Growing belly and shifting center of gravity
- •Increased appetite — eating for two!
- •Sciatic nerve pain may develop
- •Stretch marks may begin appearing
- •Increased vaginal discharge
- •Feeling baby movements (if not already)
🩺Clinical Context — From a Nurse's View
Sciatica — sharp pain shooting from the low back down one leg — is common starting now as the growing uterus presses on the lumbar nerve roots and the relaxin hormone loosens pelvic ligaments. Stretching, prenatal yoga, a maternity support belt, and side-sleeping with a pillow between your knees all help. Acetaminophen is safe for breakthrough pain; ibuprofen and other NSAIDs are best avoided in pregnancy after the first trimester (and especially after 20 weeks per FDA 2020). Stretch marks (striae gravidarum) are partly genetic — if your mother got them, you probably will too — and no cream has been proven to prevent them, though hydrating the skin is reasonable. Fundal height is now palpable below the navel. The anatomy scan is coming up — write down questions about it now while you're thinking of them.
Written by Samantha L. Fox, RN, BSN, MSN — Emergency Department nurse, US Navy Nurse Corps officer.
🚨 When to Call (or Go to the ER)
- !Vaginal bleeding — call
- !Severe headache, especially with visual changes — call
- !Sharp persistent abdominal pain — call
- !Decreased fetal movement after you've felt regular movement — call
✅ Normal — Even If It Feels Worrying
- ✓Sciatic-type pain on one side
- ✓Stretch marks beginning to appear
- ✓Larger appetite
- ✓Increased clear discharge
✅ To-Do This Week
- Start using stretch mark prevention cream or oil
- Invest in supportive shoes (your center of gravity is changing)
- Begin researching parenting philosophies and books
- Set up a college savings account (529 plan)
- Practice good posture to reduce back pain
- Take a prenatal class with your partner
🩺 Questions for Your Doctor
- ?Is sciatic pain normal and how can I manage it?
- ?Are stretch marks preventable?
- ?How is the baby's bone development?
- ?Should I be concerned about round ligament pain?
- ?Is my fundal height measurement normal?
- ?When should I start thinking about a birth plan?
📚 References
- [1]ACOG Committee Opinion No. 762: Prepregnancy Counseling. Obstet Gynecol. 2019;133(1):e78-e89.
- [2]ACOG Committee Opinion No. 804: Physical Activity and Exercise During Pregnancy and the Postpartum Period. Obstet Gynecol. 2020;135(4):e178-e188.
Editorial review: Samantha L. Fox, RN, BSN, MSN. Last reviewed: see footer.
Your baby is the size of a...