Week 5
The embryo is a few millimetres, with the start of a heart tube. Sore breasts or unusual tiredness can appear — or not.
Length and weight
Length0.2 cm
Weight0 g
Early weeks are crown to rump; later weeks are head to heel. The bar is not a ruler. It is a rough comparison with the average at week 40.
Approximate
Ask your midwife or doctor before you change medicine, herbs, or a birth plan.
Related
The first trimester
Weeks are counted from the last period, and the early body is allowed to feel strange without owing anyone a glow.
Sizes and dates are averages. Feeding and sleep notes follow widely published public-health guidance, including World Health Organization infant-feeding advice and back-to-sleep recommendations. They are not a protocol for your hospital.