Day 167 of 280, second trimester
You are 23 weeks and 6 days
The lungs are the last organs to work fully, but they're developing rapidly now.
113 days until your due date
Your baby's lungs are starting to mature as the barrier between the blood and what will become the air sacs gradually thins. The thinner it is, the more easily oxygen and carbon dioxide pass into and out of the blood.
The lungs stay full of fluid throughout pregnancy, and when your baby practices breathing, the fluid moves out into the amniotic fluid.
At 23 weeks, cells lining the smallest branches of the lungs start producing surfactant, a substance that greatly helps the lungs work. It keeps the tiny air sacs open as a newborn breathes in and out, so gases can keep passing across. Without it, the air sacs would collapse after each breath, making breathing much harder work. The surfactant-producing cells aren't fully working yet.
Explainer
Music for two
There's no harm in playing music to your baby now. If it helps you relax, it benefits you both.
Ask a Doctor
Is it true that playing music to my unborn baby helps her development?
Some research suggests playing music to an unborn baby leads to a shorter labor, an easier birth, and a newborn who cries less, is more relaxed, and is healthier overall. So far there's no significant evidence that it makes babies more intelligent or develop faster.
The jury is still out, but many pregnant women say their babies move in time to music. It makes sense that as you relax to gentle music or feel energized by livelier tunes, your baby responds too. Many moms also say music played often during pregnancy seems familiar and soothing to their newborns.
So whether your baby is simply sharing your good mood or responding to the rhythm, playing music is a good idea.
Appointments and key dates around now
- Whooping cough vaccineUsually around 20 weeks, best before 32 weeks
Read the full 23 weeks pregnant guide
This is general information based on NHS guidance, not medical advice, and every pregnancy is different. Talk to your midwife or GP about anything that worries you. If your baby's movements slow down or change, or you have bleeding, severe pain or leaking fluid, call your maternity unit straight away. In an emergency, call 999.