MIA
How pregnancy weeks are counted
Pregnancy is counted from the first day of your last period, not from the day you conceived. That is why you are already “four weeks pregnant” when a test first turns positive. A full-term pregnancy is around 40 weeks, and anywhere from 37 to 42 weeks is normal.
Your due date is a best guess. Only about one baby in twenty arrives on the exact day. Your dating scan, usually between weeks 10 and 14, gives the most reliable date.
The first trimester: weeks 1 to 13
Your baby’s heart, brain and spine begin to form in these weeks. By week 12 your baby is fully formed and about the size of a plum, though still very small.
For many people this is the hardest stretch. Tiredness, nausea, sore breasts and big feelings are common, even though nobody can see your bump yet. Rest when you can and keep meals small and simple.
The second trimester: weeks 14 to 27
Energy often comes back and nausea fades. Your bump starts to show, and somewhere between weeks 16 and 24 you will likely feel the first flutters of movement.
The anomaly scan, offered at 18 to 21 weeks, checks how your baby is growing. This is also a good time to start thinking about where you want to give birth and to book antenatal classes.
The third trimester: weeks 28 to 40
Your baby grows quickly, puts on fat and usually turns head down. You may feel heavier, more breathless and more tired again. Sleeping on your side from week 28 is advised.
From now on, get to know your baby’s usual pattern of movements. Pack your bag around week 36, finish your birth plan and talk with your midwife about the signs of labour.
Your check-ups
In the UK, a first pregnancy usually has around ten antenatal appointments, and later pregnancies around seven. Your midwife checks your blood pressure, urine and the growth of your bump, and talks you through tests and choices.
Bring your questions. Writing them down between visits helps. No question is too small.
First trimester
Third trimester