Pregnancy is measured in 40 weeks, counted from the first day of your last menstrual period. Across those roughly 280 days your baby grows from a microscopic cluster of cells into a fully formed newborn. This week-by-week guide walks you through what's happening to your baby — and to you — at every stage.
The three trimesters
Pregnancy is grouped into three trimesters, each with its own milestones:
- First trimester (weeks 1–13): the foundation. Major organs, the neural tube, the heart and early facial features all form. The heartbeat typically begins around week 6.
- Second trimester (weeks 14–27): the "golden" trimester. Nausea usually eases, you may feel the first kicks, and the 20-week anomaly scan checks your baby's anatomy.
- Third trimester (weeks 28–40): rapid weight gain and lung maturity as your baby prepares for birth.
Baby size, week by week
One of the most loved ways to track growth is comparing your baby to a fruit or vegetable. Around week 8 your baby is the size of a raspberry; by week 20 you're halfway there at the size of a banana; and by week 40 your baby is roughly the size of a small pumpkin, weighing about 3.5 kg on average.
What changes for you
Your body adapts dramatically: increased blood volume, a growing uterus, shifting posture and evolving nutritional needs. Iron, calcium, folate and omega-3 (DHA) all become more important as pregnancy progresses.
Track your journey
Following your pregnancy week by week helps you know what to expect, spot what's normal, and celebrate each milestone. Journey280 shows your exact week and day, your baby's size, weekly nutrition and your due-date countdown — all in one place.
This article is informational and not a substitute for medical advice. Always confirm concerns with your midwife or doctor.