4 weeks pregnant

Your baby

Your baby is developing inside a fluid-filled amniotic sac. A small yolk sac provides nourishment while the tissues that will form the placenta develop. At this early stage, the embryo is tiny; the poppy-seed illustration is only a comparison, not a way to assess how your own pregnancy is progressing.

Your body

A missed period may be the first change you notice. Breast tenderness, tiredness or no obvious symptoms are all possible. Pregnancy weeks are usually counted from the first day of your last period, rather than the day of conception. If your cycles are irregular or you do not know that date, tell your care team so they can help establish your dates.

This week

Getting started with prenatal care

After a positive home test, contact a prenatal care provider to arrange your first visit. Make a list of your medicines, vitamins, allergies, health conditions and previous pregnancies. Include questions about food, activity and anything you use for symptoms. Ask about a prenatal vitamin and folic acid, and check before starting or stopping a medicine. You do not need to have every answer ready: the first conversation is a chance to work out what information and support you need.