Your Pregnancy: Week 4

Your Baby
The uterus has formed a lush bed of tissue, and the production of estrogen and progesterone increases as the uterus decides to hold onto its precious cargo -- the cluster of cells that nests inside. Some of these cells become attached to the uterine wall and form the placenta, while others become the embryo. Implantation triggers the production of human chorionic gonadotropin (hCG), the hormone that turns your pregnancy test positive and your whole world upside down.

Your Body
This is very likely the week you experience your first missed period or see only some slight spotting, called implantation bleeding. You won't experience any visible signs of pregnancy, but your body is changing in amazing ways and you will feel exhausted. Your breasts become harder and more tender. If you don't know you are pregnant, you may unwittingly attribute this to PMS. In fact, you may attribute all of your pregnancy symptoms[MDASH]bloating, cramping, backache, mood swings[MDASH]to the period that is expected but will not arrive.

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.

Health
When you phone your doctor to make your first appointment, ask about taking a folate supplement if you haven't already started. Don't wait until you can get in for a visit. Weeks 5 through 10 are critical to neural development -- and so is the B vitamin folate, otherwise known as folic acid.

Mom to Mom

Make time to put romance back in your relationship, before life gets a whole lot busier. "My husband and I make a date once a week for lunch. My favorite part is when I see him waiting for me in the lobby -- it feels like we're dating again!" - Nancy Carr, Baltimore, MD

Shopping

Get ready for nine months of the most serious shopping you'll ever do. To save on layette costs, sign up at a warehouse club, such as Costco or Sam's Club. They sell brand-name baby clothes at low prices.

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.

Relationships
Even if you've planned and anticipated pregnancy for some time, you and your partner may feel sudden self-doubt when you suspect that the pregnancy is real ("Will we be good parents? Can we afford it?"). Remind each other that conflicting emotions surrounding pregnancy are normal--and that you needn't feel grateful and glowing all the time.

Siblings
Are you incubating a creative type? If you already have a few children, you might be. When it comes to birth order, the youngest sibling is often creative, since he has so much time to himself. And he often has fewer responsibilities than his siblings because others always lend him a hand. The youngest are often fun-loving, affectionate, and outgoing.

Twins
While twins remain a common bonus of fertility treatments, higher-order multiples more likely will be a rare gift from Mother Nature. That's because the latest in-vitro technology allows doctors to better target the fertilized eggs with the best chance of viability, and they needn't implant multiple eggs to up the odds.