Week 15: Sensing Light
Even though baby's eyes are still fused shut, they can sense light! If you shine a flashlight on your belly, baby might move away from it.
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...
🍎 Apple!
👶 Baby Development
- ✓Baby can sense light through closed eyelids
- ✓Legs are now longer than the arms
- ✓Baby is practicing breathing movements with amniotic fluid
- ✓Taste buds are forming
- ✓Ears are nearly in their final position
- ✓Skeleton is developing with cartilage turning to bone
💊 Common Symptoms
- •Possible nosebleeds due to increased blood flow
- •Swollen gums (pregnancy gingivitis)
- •Increased appetite
- •Lower back pain beginning
- •Skin may appear more radiant
- •Occasional headaches
🩺Clinical Context — From a Nurse's View
Week 15 is when many providers offer the maternal serum quad screen if you didn't do NIPT — it screens for trisomies 21 and 18 plus open neural tube defects. AFP (alpha-fetoprotein) is the neural tube component; an elevated AFP can indicate spina bifida or anencephaly and warrants a detailed anatomy scan. NIPT does not screen for neural tube defects, so even if you did NIPT, an isolated MSAFP is sometimes added. Pregnancy gingivitis (red, swollen, bleeding gums when brushing) is real and is driven by progesterone-mediated changes in your gum tissue, not by poor hygiene. Keep brushing — gentler if needed — and floss; severe periodontitis has weak associations with preterm birth. Get a dental cleaning if you haven't this year (it's safe). Nosebleeds are also common from increased blood volume and nasal congestion; a humidifier helps.
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 one-sided pain — call
- !New or worsening severe headache — call
- !Fever with pelvic pain or burning urination — call
✅ Normal — Even If It Feels Worrying
- ✓Bleeding gums with brushing
- ✓Nosebleeds
- ✓Mild lower back ache as posture shifts
- ✓Spotting after sex (cervix is more vascular now)
✅ To-Do This Week
- Research cord blood banking options
- Start shopping for a car seat (safety is priority #1)
- Begin thinking about the nursery design
- Stay active — prenatal yoga is great now
- Eat omega-3 rich foods for baby's brain development
- Stay up to date on dental appointments
🩺 Questions for Your Doctor
- ?Are nosebleeds common in pregnancy?
- ?When should I start looking into cord blood banking?
- ?Is my weight gain on track?
- ?Should I be concerned about headaches?
- ?Are there exercises to help with back pain?
- ?What's the plan for the mid-pregnancy ultrasound?
📚 References
- [1]ACOG Practice Bulletin No. 175: Ultrasound in Pregnancy. Obstet Gynecol. 2016;128(6):e241-e256.
- [2]ACOG Committee Opinion No. 762: Prepregnancy Counseling. Obstet Gynecol. 2019;133(1):e78-e89.
Editorial review: Samantha L. Fox, RN, BSN, MSN. Last reviewed: see footer.
Your baby is the size of a...