Fetal Development

Fetal Development answers your questions about the changes that take place in the womb during pregnancy. Learn about each of the three trimesters and the developmental milestones that occur in each.

Featured
Guide to Being Three Weeks Pregnant

If you're trying for a baby, this is your big moment. Conception typically occurs during week three, which means you are not just technically pregnant, you're actually pregnant. At last, a microscopic ball of cells to call your own.


What Do Babies See Before Birth?

Very little is known about what or how fetuses see. This study shows their vision capabilities are more advanced than previously thought.

Fetal Lambs in 'Biobags' Show Promise for Artificial Human Wombs

A new device tested on fetal lambs could change care for human preemies, immersing them in a "biobag" with lab-made amniotic fluid, keeping them underwater for weeks.

Survival Rate Improving for Extremely Preterm Babies

New analysis also shows that preemies born between 22 and 24 weeks of pregnancy are less likely to develop health issues.

10 Must-have Tests During Pregnancy

To make sure your little bundle of joy arrives healthy, it's a good plan to have regular monitoring tests during your pregnancy. See what's in store for the next nine months.

Guide to Being 39 Weeks Pregnant

Thirty-nine weeks down, only one or two more to go! Here's what's going on with you and baby during these final days of pregnancy.

Guide to Being 40 Weeks Pregnant

You're having a baby any day now! We'll take you through the final preparation for the long-awaited event.

Guide to Being 41 Weeks Pregnant

At 41 weeks pregnant, it's very possible your due date has come and gone. Read on for why your little bundle of joy could just not be ready to make an appearance.

Guide to Being 42 Weeks Pregnant

So, your due date came and went, and you're still lugging around that passenger. How can someone so little be so stubborn?

Guide to Being 42+ Weeks Pregnant

Well, it's official: You're overdue, post-term, post-date or just plain sick of this miracle happening inside you. So what's taking that (not so) little one so long?

Guide to Being 37 Weeks Pregnant

That baby is technically ready to go, and it could happen any minute now. So what are you experiencing at 37 weeks, and what's happening in that enormous belly of yours?