Week 27 of Pregnancy
Learn about your baby's development and what to expect at 27 weeks pregnant.
Baby's Size This Week
Baby Development at Week 27
- ● At week 27, your baby is approximately 36.6 cm and weighs around 875g — the last week of the second trimester.
- ● The lungs are producing surfactant and developing the branching airway structures needed to sustain breathing after birth.
- ● Your baby has distinct sleep and wake cycles averaging 12–14 hours of sleep per day, and movements are strong and frequent when awake.
- ● The eyes are now fully open and can respond to light; the retina continues developing its light-sensitive layers.
- ● Rapid brain growth continues — the brain is now forming surface folds (gyri and sulci) that dramatically increase its cognitive capacity.
- ● Your baby can now hiccup — you may feel rhythmic, repetitive movements in your abdomen, which are completely normal and harmless.
Your Body at Week 27
- ● At week 27, your growing belly may cause backaches and difficulty finding a comfortable sleeping position — a wedge pillow under the abdomen can provide relief.
- ● Braxton Hicks contractions (mild, irregular practice contractions) may be more noticeable at the end of the second trimester.
- ● Heartburn and indigestion are common as the growing uterus puts pressure on the stomach — avoid lying down immediately after eating.
- ● Restless leg syndrome (an uncomfortable urge to move the legs, particularly at night) affects up to 25% of pregnant women and may worsen in the third trimester.
- ● Fatigue often returns in the late second trimester as carrying the extra weight becomes more demanding on your body.
- ● Your skin may feel itchy, particularly over the abdomen, as it stretches — moisturize regularly and contact your provider if itching is severe or widespread.
Week 27 Checklist
- ☐ Schedule your glucose challenge test immediately if not yet completed — the window for screening is weeks 24–28.
- ☐ Register for a childbirth education class (Lamaze, Bradley method, or hospital-based), as classes typically begin in the third trimester.
- ☐ Attend all scheduled prenatal appointments and follow recommended screenings.
- ☐ Begin researching pediatricians: ask for referrals, check insurance coverage, and schedule a meet-and-greet visit.
- ☐ Start or continue daily iron-rich and calcium-rich foods to prevent pregnancy anemia and support fetal bone development.
- ☐ Focus on adequate omega-3 intake (DHA) to support the rapid brain growth occurring over the next several weeks.
Frequently Asked Questions
What should I expect at 27 weeks pregnant?
At 27 weeks pregnant, you are in the final week of your second trimester. Your baby is about the size of a Head of cauliflower (36.6 cm) and is developing open eyes, brain folds, and a reliable sleep-wake cycle. Common symptoms include heartburn, backache, Braxton Hicks contractions, restless legs, and fatigue. Always consult your healthcare provider for personalized guidance.
How big is my baby at 27 weeks?
At week 27, your baby is approximately 36.6 cm in length and weighs around 875g — roughly the size of a Head of cauliflower. These measurements are averages based on WHO fetal growth charts; individual babies vary naturally in size.
Why does my baby hiccup in the womb?
Fetal hiccups are caused by the diaphragm contracting and then relaxing as your baby practices breathing movements using amniotic fluid. They are completely normal and are actually a reassuring sign of neurological development. You will feel them as rhythmic, repetitive jolts — different from the rolling kicks of general movement.
What is restless leg syndrome in pregnancy and how is it treated?
Restless leg syndrome (RLS) causes an uncomfortable urge to move the legs, typically at night. In pregnancy, it may be linked to low iron or folate levels, dopamine pathway changes, and poor circulation. Treatment includes iron supplementation if levels are low, gentle stretching before bed, avoiding caffeine, and maintaining regular physical activity. Speak with your provider before taking any medications.
What should I know about entering the third trimester next week?
Starting at week 28, you enter the third trimester — the final stretch before birth. Prenatal visits will increase in frequency (every 2 weeks from 28–36 weeks, then weekly). You will be monitored more closely for signs of preeclampsia, gestational diabetes complications, and preterm labor. Starting daily kick counts, taking the Tdap vaccine (weeks 27–36), and preparing your hospital bag are key third-trimester priorities.
Track Your Exact Pregnancy Week
Use our free Pregnancy Week Tracker to find out exactly how far along you are based on your last menstrual period or due date.
Track My Pregnancy →Sources
- ACOG
- WHO Fetal Growth Charts
- Mayo Clinic
Medical disclaimer: This content is for informational purposes only and is not intended as medical advice. Always consult a qualified healthcare provider for guidance specific to your pregnancy.