Pregnancy at Weeks 1 to 4

In weeks 1 and 2, many people are not technically pregnant yet by conception timing. The count is still useful because it gives your GP, midwife, obstetrician, hospital, and ultrasound reports a shared way to estimate gestation and your likely due date.

Around conception, an egg is fertilised and begins dividing as it travels toward the uterus. Over the next several days, those early cells keep multiplying. By the end of week 4, Pregnancy Birth and Baby describes the embryo as implanted in the uterus, called a blastocyst, and about 0.2 mm wide.

Most people will not notice obvious body changes in the first few weeks. The missed period at the end of week 4 is often the first clue. Some people also notice breast tenderness, tiredness, mild cramping, bloating, mood changes, food aversions, or needing to wee more often, while others feel nothing different yet.

A home pregnancy test works by detecting hCG, the pregnancy hormone. Testing too early can be confusing, so follow the packet instructions and repeat the test if your period does not arrive. If you have a positive test, book a GP or maternity appointment rather than waiting for stronger symptoms.

Folate is worth acting on before the pregnancy feels real. Pregnancy Birth and Baby says neural tube defects can happen in the first weeks of pregnancy, when the brain and spinal cord are forming. If you have not already been taking folic acid, start as soon as you know you are pregnant and ask your doctor what dose is right for you.