Here I will go through week by week with your pregnancy.
Here is your fourth week.
Baby size: <.1 in (Poppyseed)
Baby weight: <.04 oz
This is the first week you may be able to get a positive test result on a home pregnancy test, but for the most accurate results you need to wait a week until your body is producing enough hormone’s to be detected.
A lot of that extra blood is heading straight for your breasts, resulting in tiredness and the tendency for your nipples to show … through your down jacket. (Another early pregnancy sign: Your cervix is softening and changing color. But if this is something you’re able to notice on your own, we don’t want to know about it.)
What you are thinking:
“Instant messages. Instant coffee … Why the heck hasn’t anyone invented an instant pregnancy test?”
Your microscopic embryo is already hard at work this week creating the placenta, umbilical cord and the basics of his or her body.
The embryo is now made of three layers that will transform into the different parts of your baby’s body. The endoderm, or inner layer, will become your baby’s intestines, liver and lungs. The middle layer, or mesoderm, will become your baby’s heart, sex organs, muscles, bones, and kidneys, and the ectoderm, or outermost layer, will develop into your baby’s hair, skin, eyes, and nervous system. Believe it or not, your baby is already starting to look like a tiny little being (not necessarily a human being) complete with a head, a mouth opening and a primitive brain and heart.