Day 249 of 280, third trimester
You are 35 weeks and 4 days
The lungs don't become fully functional until these final weeks, but important development is happening now.
31 days until your due date
Imagine the lung as a tree. The windpipe, or trachea, is the trunk. It forms several branches, the bronchi, which divide again and again like twigs to produce the most delicate structures, the alveoli, which are the leaves. Gas exchange will take place in the alveoli.
The alveoli began developing at 24 weeks and keep increasing in number throughout pregnancy. They contain cells that produce surfactant to keep them open, and these cells now become fully functional.
Good to know
Prescribed bedrest
Toward the end of pregnancy, there are some situations in which you may be admitted to hospital for bedrest:
- If you're having contractions but your waters haven't broken.
- If you develop preeclampsia; measures will be taken to lower your blood pressure.
- If you have a placental abruption, where the placenta separates from the uterus.
Focus on
Your body: Getting strong
Keeping up muscle strength, stretching, and gentle exercise right up to the birth helps your posture, minimizing backache, reducing stress on your skeleton, and leaving you more energized and relaxed. As long as you feel good and follow safe exercise guidelines, you can carry on with your activities.
Above all, use common sense and listen to your body. If you're in pain, feel exhausted, or have dizzy spells, stop exercising and see your doctor straight away. Carrying all that extra weight is tiring, so adjust your activities, perhaps lowering the intensity and exercising for less time, but if you feel good, don't stop entirely. Avoid any exercises that involve lying on your back at this stage.
Explainer
Monitoring in hospital
If there's any concern about your health or your baby's toward the end of pregnancy, you may be closely monitored in hospital, with a fetal monitor checking your baby's heartbeat.
Appointments and key dates around now
- RSV vaccineFrom 28 weeks
Read the full 35 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.