Your baby measures 0.05 in (0.13 cm) from crown to rump and weighs 0.004 oz (0.11 g).

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Pregnancy Facts - Week 4

Your baby's development in week 4 of pregnancy

Week 3 was an exciting week for your baby what with the beginning of existence and all. Things have literally settled down this week with the blastocyst embedding itself into the thick lining of your uterus.


Inside the blastocyst is an embryo that consists of the actual cells that have been tasked to become your baby.

It is from the wall of your uterus that the blastocyst will receive all the nourishment it needs to continue growing, sucking blood through the lining of the uterus.

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Although the blastocyst has made itself comfortable in the womb, unlike a freeloading friend living on your couch and eating your fridge empty, the embryo is making itself useful by spending all its energy dividing and multiplying its cells to literally become somebody one day.


It might be a bit of a letdown, but not much really goes on in the fourth week of pregnancy. It's best that you keep popping prenatal vitamins daily as your baby will benefit from everything that you eat during this time. Yes, even ice cream.

How big is your baby in week 4 of pregnancy

This week, your baby is about 0.05 inches (0.13 centimeters) big and weighs about 0.004 ounces (0.11 grams).

My baby 0.05 in (0.13 cm) from crown to rump and weighs 0.004 oz (0.11 g)