Pregnancy Calendar Week 5

Week 5

What's Happening to My Body?

The countdown continues: Five weeks down, 35 to go. Your baby is now 3 weeks old, and even though the cells are multiplying, he sure doesn't look human yet. How could he, really? He's barely a millimeter long!

The cells are beginning to divide into three separate layers that will develop into different body parts. The inner layer (endoderm) will become the respiratory and digestive systems; the middle layer (mesoderm) forms bones, most muscles, cartilage, sex organs, kidneys and the circulatory system; and the outer layer (ectoderm) will develop into skin, hair and the nervous system.

Right now, your baby looks like a tube with a cleft at each end; the slight swelling at one end will develop into the brain. The central nervous system, heart, skeleton and muscles are in the earliest stages of development. The somites have appeared; these are tight groups of cells that appear as bumps along the middle of the embryo. They will become vertebrae, ribs and some muscles. Blood vessels appear in the yolk sac and embryo, and a primitive cardiovascular system emerges.

Is your head spinning yet? Could be the science lesson -- or it could be the earliest preggers symptoms creeping in. Then again, it's probably the science lesson.

By now, you've missed your period, which is always a shock to the body and mind, even if you haven't noticed any other signs of pregnancy. Maybe you haven't noticed them because you're asleep -- fatigue is common in early pregnancy. Your mood may shift erratically from cranky to cracked. To top it off, you have to pee all the time, and even a slight whiff of certain smells may turn your stomach. Who named that feeling morning sickness? Well, it isn't just about mornings anymore...

All of this, and the whole idea of becoming a parent, might be freaking you out a bit. If so, you're right on schedule.