Your baby moves through different stages, starting as a blastocyst, then maturing into an embryo, and then a fetus. Around the five week mark, your baby’s heart will begin to beat, at 27 weeks they’ll have regular sleep and wake cycles, and at 39 weeks your baby is physically developed.
What You’re Seeing: In this 3D image of the developing embryo, you can see a big change since previous week of the first trimester. The baby-to-be curves inward, with the umbilical cord in the middle. The head appears at the upper right side of the image.
The American Pregnancy Association also has some of the best sources for current pregnancy diagrams as well as prenatal advice and other tips for pregnant women. Contact the association directly to see if they’ll send you literature. The association’s website also has a variety of diagrams and charts easily accessible at your convenience.