Third trimester
30 weeks pregnant
The fetus is around the size of a cabbage. Bone marrow has taken over red blood cell production completely, and amniotic fluid is starting to decrease as the fetus takes up more room.
Size of
cabbage
Length
40 cm
Weight
1320 g
Your baby at 30 weeks
Bone marrow now produces all red blood cells, a role previously shared with the liver and spleen.
Lanugo begins to disappear as fat insulates the body instead. The brain develops the characteristic grooves and folds that increase its surface area.
The fetus can distinguish between light and dark, and may turn toward a bright light held against the abdomen.
How you may be feeling
The uterus is high and space is limited, making breathlessness and heartburn more pronounced. Sleep is usually difficult.
Many people notice mood shifts in the third trimester — a combination of physical discomfort, poor sleep, and the approach of something genuinely significant.
Common symptoms around week 30
- Breathlessness
- Heartburn
- Difficulty sleeping
- Mood changes
- Braxton Hicks becoming more frequent
Appointments and tests around now
Appointments continue every two weeks. The baby’s position is checked, though plenty of babies are still not head-down at this stage and have time to turn.
What is normal, and what varies
A baby not yet head-down at 30 weeks is common and usually irrelevant. Most turn by 36 weeks, and there are options if they do not.
Worth doing this week
Talk about how you are feeling
Antenatal anxiety and low mood are common and treatable. Mentioning it at an appointment is a normal thing to do, not an imposition.
Do not worry about position yet
There is plenty of time for a baby to turn. Position starts to matter clinically around 36 weeks.
Finish the practical preparations
Car seat, bag, contact numbers. Energy tends to decline from here, so earlier is easier.
Looking ahead
Next week the fetus continues gaining weight quickly and its senses sharpen further.
Nearby weeks
Not sure which week you are in? The week tracker works it out from the first day of your last period, and the due date calculator gives you an estimated due date.