Weeks pregnant
About 2 mm
The brain and spinal cord are beginning to form.
Weeks pregnant
About 13–16 mm
Developing organs, limb structures and cardiac activity.
Weeks pregnant
Continuing to mature
Organs, limbs, bones and muscles are in place and developing.
Weeks pregnant
A changing clinical stage
Nervous-system development and viability are individual clinical questions.
Language with care
Accurate terms do not need to become weapons.
Pregnancy dating starts from the first day of the last menstrual period, about two weeks before fertilisation in a typical cycle. “Embryo” is used early and “fetus” later; “baby” may express relationship. A clinician can explain development in your pregnancy.
Your baby’s development
Every week brings new growth.
Your baby is not standing still. Their body, organs and nervous system are developing continuously. You can ask a qualified clinician to show you what is happening at your stage of pregnancy.
See baby development month by month ↗Weeks 5–8
A tiny body is taking shape
The brain and spinal cord begin forming, arm and leg buds appear, and major organs continue developing.
From week 11
Growth continues quickly
The fetal stage begins and your baby’s body and organs keep growing, maturing and becoming more coordinated.
As pregnancy continues
Your baby keeps responding
Movement, reflexes and nervous-system development unfold over time. Each scan or appointment can help you understand more.
A careful note about pain
Earlier pain cannot simply be ruled out.
Scientists disagree about when an unborn baby may first experience pain. A peer-reviewed 2020 paper argues that an immediate, unreflective pain experience may be possible earlier than traditional cortical measures suggest, while acknowledging that the precise timing remains uncertain.
Held With Hope takes a precautionary, life-affirming approach: uncertainty is a reason for gentleness and care, not a reason to dismiss developing life.
The second link is an advocacy research resource. Neither link replaces personalised advice from a qualified clinician.