Your baby’s development in trimester 1

Here’s what you need to know about your baby’s development in your first trimester

Trimester 1: Your baby’s development

From your baby’s conception, here’s what you can expect your baby to go through in trimester 1 of your pregnancy

Baby development trimester 1 474

From the moment your baby is conceived, their development begins, here’s what you can expect your baby to go through in trimester 1.

Week 1-4: The sperm and egg joined at the moment of conception and first formed a single cell, which forms a ball of cells called a blastocyst. The blastocyst implants in your womb and begins to produce pregnancy hormones, which tell your body not to have a period.

Week 5: Your baby’s heart has started to form and will soon beat for the first time.

Week 6: All your baby’s vital organs – their heart, kidneys and liver – are in place, but of course they’ve still got a lot of developing to do.

Week 7: With its little arm and leg ‘buds’ your baby starts making uncoordinated movements this week. Although you won’t feel these until your second trimester.

Week 8: Your baby’s fingers, toes and the bones of their little face are forming.

Week 9: Baby even has eye lids now and ears are developing too, but they won’t begin to hear for 6 weeks or so yet.

Week 10: Your baby has already graduated from an embryo to a fetus and is floating in a protective liquid called amniotic fluid.

Week 11: Baby’s skeleton and nerves are now formed. Their blood is circulating and all their organ systems are functioning too.

Week 12: Genitals develop around this time but your scan won’t give you a reliable answer yet. You might be able to find out at your anomaly scan at around 20 weeks.

Your baby’s development in trimester 1