5 weeks pregnant

5 weeks is about 1.2 months of gestation, counted from the first day of your last period. You are in the first trimester.

Around 2 mm long and < 1 g, roughly the size of a sesame seed. These are averages; individual babies vary.

Trimester 1 · about 1 month · baby is about the size of a sesame seed.

Baby at 5 weeksa sesame seed2 mm · < 1 g

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Your baby this week

The neural tube, which becomes the brain and spinal cord, is forming. A simple heart tube begins to beat.

Tiredness, sore breasts and needing to pee more are common.

Care this week: Book your first prenatal appointment.

How many months is 5 weeks pregnant?

5 weeks is about 1.2 months of gestation, counted from the first day of your last period. You are in the first trimester.

How big is a baby at 5 weeks?

Around 2 mm long and < 1 g, roughly the size of a sesame seed. These are averages; individual babies vary.

Not sure which week you're in? The pregnancy calculator works it out from your last period or due date.