Week 23
Hearing is developing. A voice outside can reach the uterus as a muffled rhythm, not as words. Viability, with intensive care, begins to be discussed around now — that is a hospital conversation, not a home one.
Length and weight
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 second trimester
Movement becomes a language, and the anatomy scan is a look — not a verdict you have to pass.
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.