Second Trimester
Week 15: Baby can sense light through the uterus — they respond to bright light.
Here's everything happening with your baby and your body this week.
Your baby is the size of a
Apple
Length
4.0 in
Weight
117 g
Week
15 / 40
💡 Expert tip
The quad screen/AFP blood test is offered at 15–20 weeks. It screens for spina bifida and chromosomal conditions.
🌱 Baby's development this week
- Can sense light — will move away from bright sources
- Bones getting stronger and showing on ultrasound
- Taste buds maturing
- Baby may suck thumb
Science fact
Light sensitivity in the womb: at 15 weeks, if a bright light is shone at the abdomen, the baby will turn away. The fetus can detect light through the uterine wall.
🤰 Your symptoms this week
Visible bump for many women from 15 weeks (earlier for second pregnancies)
Pregnancy glow
increased blood flow to skin creates luminosity
Nose bleeds
increased blood volume and mucosal swelling; harmless
Elevate feet when sitting, stay hydrated, reduce sodium. Sudden severe swelling: call your provider.
💛 Changes in your body
- Pregnancy glow
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💙 Mental health this week
Body image changes accelerate. Many women struggle with the
🥗 Nutrition focus
- AFP/quad screen timing: avoid vitamin A supplements before this test (can affect results)
- Calcium needs increase — dairy, fortified plant milk, sardines with bones
- Vitamin B complex supports nervous system and reduces pregnancy fatigue
📅 Appointment / test
Quad screen / AFP blood test: offered at 15–20 weeks, screens for neural tube defects and chromosomal conditions.
✅ This week's checklist
Schedule quad screen if you want it (15–20 week window)
Consider a babymoon trip before the third trimester
Start researching baby gear — waitlists for nursery furniture exist
Track your pregnancy week by week
Interactive guide · 40 weeks · Fruit size visualizations · Personalized tips
Open Week 15 in Interactive Guide → →