Pregnancy Calculator — Week 27: Baby Size, Symptoms & Due Date
You are in week 27 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 27
This week: Regular sleep/wake cycles. Brain tissue and neurons develop rapidly. Lungs produce surfactant.
Mother's body — what changes
In week 27 you may notice: Third trimester begins. Breathlessness as diaphragm compresses. Fatigue returns.
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 27
- ✓Antenatal visits move to every 2 weeks
- ✓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 27 — Frequently asked questions
How accurate is the Pregnancy Calculator at week 27?
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 27?
Approximately the size of a cauliflower — length 36.6 cm and weight 875 g. These are median values from ACOG, NHS UK and Mayo Clinic references.
Which symptoms are normal in week 27?
Third trimester begins. Breathlessness as diaphragm compresses. Fatigue returns. Every pregnancy is different — call your provider if anything on the warning-signs list appears.
Should I have an ultrasound at week 27?
Antenatal visits move to every 2 weeks. Routine scan windows are: dating (10–13w), anatomy (18–22w), growth (28–32w).
How much weight should I gain by week 27?
Approximately 8.3 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 27?
Your estimated due date is 13 weeks from today. Calculator adds (280 − 7 × 27) days to today's date.
Can I travel during week 27?
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.