Pregnancy Calculator — Week 20: Baby Size, Symptoms & Due Date
You are in week 20 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.
Baby at week 20
This week: Halfway point. Fetus swallows amniotic fluid — practices digestion. Sex confirmed on anatomy scan.
Mother's body — what changes
In week 20 you may notice: Fundus reaches the navel. Weight gain 4–6 kg by now is expected in singleton pregnancy.
Nutrition & supplements
Add ~340 kcal/day above pre-pregnancy baseline. Prioritise iron (27 mg/day), calcium (1000 mg), omega-3 DHA (200–300 mg) and 71 g protein. Continue prenatal vitamin.
Safe exercise
Continue 150 min/week. Avoid supine (flat-on-back) exercises after week 20 — they compress the vena cava. Swimming and prenatal Pilates are ideal now.
Doctor visit checklist — week 20
- ✓Anatomy scan completed — save images and report
- ✓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
- ⚠Sudden gush of fluid (early rupture of membranes)
- ⚠Absent fetal movement for 12+ hours after 24 weeks
- ⚠Severe headache + visual disturbance (preeclampsia)
Week 20 — Frequently asked questions
How accurate is the Pregnancy Calculator at week 20?
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 20?
Approximately the size of a banana — length 25.6 cm and weight 300 g. These are median values from ACOG, NHS UK and Mayo Clinic references.
Which symptoms are normal in week 20?
Fundus reaches the navel. Weight gain 4–6 kg by now is expected in singleton pregnancy. Every pregnancy is different — call your provider if anything on the warning-signs list appears.
Should I have an ultrasound at week 20?
Anatomy scan completed — save images and report. Routine scan windows are: dating (10–13w), anatomy (18–22w), growth (28–32w).
How much weight should I gain by week 20?
Approximately 5.1 kg cumulative if you started at a normal BMI (IOM guideline). Underweight mothers gain more; overweight mothers less.
What is my EDD if today is week 20?
Your estimated due date is 20 weeks from today. Calculator adds (280 − 7 × 20) days to today's date.
Can I travel during week 20?
Second trimester (weeks 14–27) is the safest travel window. Wear compression stockings for flights over 4 hours.
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.