Pregnancy Calculator — Week 31: Baby Size, Symptoms & Due Date
You are in week 31 of a standard singleton pregnancy. Below is a complete evidence-based snapshot — baby's growth, your body, nutrition, exercise, red flags and a doctor visit checklist for this exact week.
Pregnancy Calculator
Enter the first day of your last menstrual period (LMP). EDD = LMP + 280 days.
How to Use This Calculator
1. Enter the LMP date
Use the labelled fields and units that match your situation.
2. Calculate instantly
The result, visual comparison, and working update as values change.
3. Discuss the estimate with your clinician
Check assumptions, then copy, print, or share the calculation.
Practical Examples & Use Cases
| Starting date | Method | Calculation | Planning use |
|---|---|---|---|
| 1 Jan | LMP | +280 days | Estimated due date |
| Known clinical date | Ultrasound | Clinician dating | Confirm or revise estimate |
Baby at week 31
This week: All five senses functional. Fetus urinates ~500 ml/day into amniotic fluid.
Mother's body — what changes
In week 31 you may notice: Fundus 11 cm above navel. Heartburn worsens. Difficulty sleeping.
Nutrition & supplements
Add ~450 kcal/day. Increase iron and DHA — brain growth peaks now. Split meals into 5–6 small portions to control heartburn and stable glucose.
Safe exercise
Reduce intensity but keep moving. Pelvic floor + squats prepare for labour. Avoid contact sports, ski, horse-riding and hot yoga.
Doctor visit checklist — week 31
- ✓Attend antenatal / breastfeeding classes
- ✓Blood pressure + weight + urine dipstick at every visit
- ✓Fetal heart tones from week 10–12 (Doppler)
Warning signs — call your provider immediately
- ⚠Heavy bleeding (soaking a pad in an hour)
- ⚠Severe abdominal pain that does not ease
- ⚠Fever above 38°C / 100.4°F
- ⚠Regular contractions before 37 weeks (preterm labour)
- ⚠Reduced fetal movement — fewer than 10 kicks in 2 hours
- ⚠Sudden swelling of face/hands + severe headache (preeclampsia)
- ⚠Bright red bleeding (placental abruption or previa)
Week 31 — Frequently asked questions
Content aligned with ACOG, NHS UK and Mayo Clinic. Reviewed by Dr. Maria Rehman, MD (OB/GYN). This page is educational and does not replace personal medical advice — call your obstetrician for any concern.
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