Week 3

Baby:

Congratulations! If your egg and your partner's sperm have joined successfully, your embryo is really there, although it's very small -- about the size of the head of a pin. It doesn't look like a fetus or baby; it's just a group of about 100 cells multiplying and growing rapidly. The outer layer of cells will become the placenta, and the inner layer will become the embryo.

Mother:

You won't notice any changes. It's too soon. Remember, you haven't even missed your period yet.

Dad:

She's officially pregnant. You've succeeded in your most important duty--you fertilized that egg! One of your little stallions made it to the finish line.

Congratulations! But don't celebrate just yet young father, your work is far from over. Besides, you don't even know she's pregnant yet! But that is coming right up...

Do's and Don'ts

Do be sure you get enough folic acid to prevent neural tube defects in the embryo. Folic acid needs to bepresent at the moment when an embryo's cells curve over oneanother to create the neural tube, between the 25th and 28th dayafter conception -- often before a woman knows she's expecting. While it's possible to get enough folic acid from diet alone, experts advise that every woman of childbearing agetake a daily supplement of 400 micrograms.

Exercise

Backaches are common during pregnancy, but if you strengthen your abdominal muscles now, you may be able to minimize them as your uterus expands. Doctors don't advise lying on your back after the first trimester, so talk to a trainer about learning pregnancy-safe exercises that work your core.

Tips for this week:

Home pregnancy tests are about as reliable as a urine test or blood test done in the doctor's office and can give you more immediate results than waiting for a doctor's visit. To ensure accuracy, make sure you've read the directions carefully and that all equipment being used is clean.

Week 4

Baby:

Your baby is still very small, only about 0.014 inches to 0.04 inches in length. The embryo, probably in about its second week of development, has multiplied to about 150 cells. Your baby is being nourished by secretions from the uterine lining. Layers of cells already are specialized according to functions. The outer layer will become the nervous system, skin and hair; the inner layer will be the breathing and digestive organs; and the middle layer will become the skeleton, bones, cartilage, muscles, circulatory system, kidneys and sex organs.

Mother:

You're probably expecting your period this week, and if it doesn't occur it might be one of the first signs that you're pregnant. You may also notice light spotting as the embryo implants itself in your uterus. You might not feel any different yet, but the amniotic cavity, which will be filled with fluid, and the placenta, which will bring oxygen and nutrients to nourish your baby, are forming in your uterus.

Dad:

Perhaps by now you know she's pregnant. Or perhaps you don't. It's good to be prepared either way, as your diet, daily routine, and all around lifestyle are soon to be changed forever. Start living as a pregnant couple (read: eat healthy, be active, etc.) and this whole journey will be made a lot easier.

Do's and Don'ts

Do stop smoking as soon as you suspect you are pregnant. When a pregnant woman smokes, it reduces the flow of oxygen to her baby, which can cause him to grow more slowly and gain less weight in the womb. Smoking during pregnancy has also been linked to miscarriage and preterm labor.

Exercise

The days when pregnancy was considered a delicate condition in which you take to your bed are over. Now exercise is considered both safe and smart. Studies indicate that women in good physical shape have easier labors, a reduced risk of cesarean section, and a faster recovery.

Tips for this week

Try to eat healthfully, which means choosing a variety of foods from the recommended food groups and drinking at least six to eight 8-ounce glasses of water a day. But you don't really need to "eat for two." You need only an extra 300 calories per day during pregnancy. And don't worry if your food intake drops a little in the beginning because of morning sickness. If you've been eating right already, your baby will get what it needs.