Fetal Development by Month

Although every baby develops differently, this guide will give you an idea of how your baby is growing and developing throughout your pregnancy.

First Month
Second Month
Third Month
Fourth Month
Fifth Month
Sixth Month
Seventh Month
Eighth Month
Ninth Month

First Month

The blastocyst, as the fertilized egg is called at this stage, completed its journey from your fallopian tube where it was fertilized to your uterus in the first week and has since settled into your nutrient-rich endometrial lining and been dividing and growing feverishly. By the end of this month it has grown to about 1/4 of an inch long, and along with its extended tailbone that makes it look like a tadpole, it already has a head and mouth, eyes (partially covered by eyelid folds), buds that will become arms and legs, the beginning of lungs and a digestive tract, and a heart that will begin to beat at the end of this month. In the meantime, an early version of the placenta, the chorionic villi, and the umbilical cord - which delivers nourishment and oxygen to the baby - are already on the job.

Your little blastocyst is now 10,000 times larger than it was when fertilized!

You have missed your first period and hormones are surging through your body, preparing you for the coming months. You may also notice your breasts are swollen and tender.

See What Happens Next Month