IVF Pregnancy Calculator — Week 37 (Day 3 & Day 5 Transfer)
You are 37 weeks pregnant after IVF (gestational age counted from egg retrieval + 14 days for day-5 transfer, +12 days for day-3 transfer). Below is what your embryologist and REI clinic expect at this exact stage.
IVF Pregnancy Calculator
Enter your egg retrieval date and select day-3 or day-5 transfer. EDD = retrieval + 266 days.
Baby at week 37
At 37 weeks gestational after IVF transfer: Early term. Full-term brain and lung development continues. Grasping reflex strong.
Mother's body — what changes
Post-IVF at week 37, clinical picture: Membranes may rupture (waters break). Contractions may start.
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. Post-IVF continue progesterone support and prenatal vitamin exactly as your REI prescribed. Do not add herbal supplements without clearance — many interact with luteal support.
Safe exercise
Reduce intensity but keep moving. Pelvic floor + squats prepare for labour. Avoid contact sports, ski, horse-riding and hot yoga. After IVF avoid high-impact activity until confirmed viability at 8-week scan. Then follow standard trimester guidance.
Doctor visit checklist — week 37
- ✓Confirm hospital bag ready and birth plan finalised
- ✓Progesterone support review — continue until placenta takeover (week 10–12)
- ✓Beta-hCG doubling every 48–72 hours until viability scan
- ✓First IVF viability ultrasound at 6–7 weeks gestational
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 37 — Frequently asked questions
How accurate is the IVF Pregnancy Calculator at week 37?
The calculator uses standard gestational-age arithmetic (LMP + 280 days for standard; egg retrieval + 266 days for IVF day-5). Ultrasound crown-rump length between weeks 8–13 is more accurate (±5 days) than LMP — adjust EDD accordingly if the scan differs by more than 7 days.
What size is my baby at week 37?
Approximately the size of a Swiss chard — length 48.6 cm and weight 2860 g. These are median values from ASRM, SART and ESHRE references.
Which symptoms are normal in week 37?
Membranes may rupture (waters break). Contractions may start. Every pregnancy is different — call your provider if anything on the warning-signs list appears.
Should I have an ultrasound at week 37?
Confirm hospital bag ready and birth plan finalised. Routine scan windows are: dating (10–13w), anatomy (18–22w), growth (28–32w).
How much weight should I gain by week 37?
Approximately 12.8 kg cumulative if you started at a normal BMI (IOM guideline). Underweight mothers gain more; overweight mothers less.
Day 3 vs Day 5 transfer at week 37 — what's the difference?
Day-5 blastocyst transfer adds 5 days to embryo age; Day-3 transfer adds 3 days. Gestational age = transfer date + (14 − transfer day) days + weeks since transfer. Both converge on the same due date; the difference matters only in the first 2 weeks.
Should I continue progesterone at week 37?
Most REI clinics wean progesterone by week 12. Follow your clinic's exact taper — abrupt stop before placental takeover risks miscarriage.
Content aligned with ASRM, SART and ESHRE. 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.