reference
Pregnancy Week-by-Week Chart
Pregnancy week chart with trimester milestones.
Gestational weeks run from LMP, with full term at 40 weeks. This chart highlights major milestones — individual pregnancies vary.
Gestational week milestones (approximate)
| Weeks | Trimester | Key Milestones |
|---|---|---|
| 1–4 | First | Implantation; missed period around week 4 |
| 5–8 | First | Heartbeat detectable (~week 6); organ formation begins |
| 9–12 | First | End of embryonic period; reduced miscarriage risk after week 12 |
| 13–16 | Second | Gender may be visible on ultrasound; energy often improves |
| 17–20 | Second | Quickening (first movements); anatomy scan (~week 20) |
| 21–27 | Second | Viability improves; glucose screening (~week 24–28) |
| 28–32 | Third | Eyes open; rapid brain development |
| 33–36 | Third | Lungs mature; weekly monitoring may begin |
| 37–40 | Third | Full term at 37 weeks; due date at 40 weeks |
Frequently asked questions
How do I use this Pregnancy reference?
Find your category or range in the table, then use the linked calculator to compute an exact value for your inputs.
Try the calculator
Pregnancy Calculator