First trimester: weeks 1–13

The first trimester on Cloverlatch — every week page, in order.

• Week 1Week 1 is counted from the first day of the last menstrual perio…
• Week 2Ovulation typically happens near the end of this week; fertiliza…
• Week 3The fertilized egg divides as it travels toward the uterus, beco…
• Week 4Implantation usually completes this week. The embryo is about th…
• Week 5The neural tube — which becomes the brain and spinal cord — is f…
• Week 6The heart begins to beat in a regular rhythm, and small buds tha…
• Week 7The brain is growing rapidly, arms and legs lengthen, and the em…
• Week 8Fingers and toes are forming, the embryo is moving (though it ca…
• Week 9All essential organs have begun to form. The embryo is transitio…
• Week 10Now officially a fetus. Vital organs are formed and beginning to…
• Week 11Genitals begin to develop, tooth buds and hair follicles form, a…
• Week 12Reflexes begin — the fetus can curl its toes and make sucking mo…
• Week 13The fetus can put a thumb in its mouth, vocal cords are forming,…

Educational information only — not medical advice. Every pregnancy and every baby develops on their own timeline. If you have any concern, talk to your obstetric provider or your baby's pediatrician.