Week 31 of Pregnancy
Your baby is about the size of a coconut
Your Baby This Week
Development milestones for week 31
At 31 weeks pregnant, your baby measures about 16 inches and weighs around 3.3 pounds. The major development this week centers on the brain and nervous system, which are maturing rapidly. Your baby can now process information from all five senses - they can see light filtering through your belly, hear your voice and heartbeat, taste the amniotic fluid, and feel when you press on your bump. The bones are hardening through a process called ossification, though the skull bones remain soft and flexible to allow for easier passage through the birth canal. Your baby's movements are becoming more coordinated and purposeful. Many moms describe feeling their babies respond to their partner's voice or to music at this stage. The digestive system is also practicing by processing amniotic fluid, which helps develop the intestines.
Your Body This Week
Changes you may experience
Welcome to the world of lightning crotch - that sudden, sharp, shooting pain in your pelvis that catches you completely off guard. It affects up to half of pregnant women and feels like an electric shock through your vagina or groin. It happens when your baby presses on or kicks nerves in your cervical area. While startling and uncomfortable, it typically lasts only 15 to 60 seconds and is not a sign of labor. Sciatic nerve pain may also be ramping up as your baby and uterus put pressure on the nerve that runs from your lower back down your legs. Frequent urination is intensifying too - about 40% of pregnant women deal with some bladder control issues, especially in the third trimester when the baby is heaviest. Your sleep is likely becoming increasingly fragmented between bathroom trips, discomfort, and an active baby.
Tips & Advice for Week 31
Practical guidance from real moms
For lightning crotch relief, a pregnancy support band worn low on your abdomen can help lift the baby off your pelvis. Move slowly when standing up or changing positions, and try prenatal yoga poses that open your hips. For sciatic pain, lie on the side that does not hurt, use a body pillow for support, and consider prenatal massage or chiropractic care. Swimming provides relief because the water supports your baby's weight. Kegel exercises are important now - strengthening your pelvic floor helps with bladder control during pregnancy and aids recovery after birth. Practice by tightening the muscles you would use to stop urinating, holding for a few seconds, then releasing. This is also a good time to take a hospital tour if you have not already. Seeing the labor and delivery unit can help reduce anxiety about the big day.
Medical Guidance for Week 31
What to discuss with your healthcare provider
Appointments continue every two weeks. Your provider will check that your baby is growing appropriately and monitor for signs of gestational diabetes complications or preeclampsia. Discuss what to expect during labor and delivery at your birth location. If you are planning a vaginal birth after cesarean (VBAC), now is the time to finalize that plan with your care team.
Disclaimer: For educational purposes only. Consult your healthcare provider for personalized medical advice.