Your First Trimester: Baby’s Early Growth
The first trimester is a time of deep transformation as your body adapts to nurture your growing baby. You’ll likely notice several physical changes, some subtle, others more pronounced, as your pregnancy progresses.
Foetal Development
Weeks 1-4: After fertilisation, the tiny embryo begins to form and travels to implant in the wall of your uterus. The cells are dividing quickly, laying the foundation for all the major organs. By week 4, your baby is about the size of a poppy seed, just 2mm long!
Weeks 5-8: This is a key time for brain development. The neural tube (which becomes the brain and spinal cord) starts to form, and the baby’s heart begins to beat. Basic features like the eyes, arms, and legs also begin to take shape. By week 8, your baby is about the size of a raspberry, measuring around 16mm.
Weeks 9-13: Your baby is now called a foetus. Fingers and toes are forming, and features like eyelids and ears are becoming more defined. By the end of this phase, all major organs are in place and ready to grow and mature in the coming months. At week 12, your baby is about the size of a plum, measuring 5.4cm from head to bottom.
The first 12 weeks of pregnancy are a very important time for your baby's development. During this stage, major organs and body systems are starting to form. Because of this, the baby is more sensitive to things that could be harmful, like alcohol, tobacco, certain medications, infections, radiation, and other toxins. These can affect how the baby grows.
That’s why it’s so important to take extra care of your health early in pregnancy. By paying attention to what you’re exposed to, you can help create the safest and healthiest environment for your baby right from the start.