Welcome To Week 13:

Your Baby: M Is For Muscles, N Is For Nerves, O Is For Organs:

Weighing approximately 0.5 to 0.7 ounces and measuring 3 inches (almost 8 cm) long, the fetus has plenty of room to grow inside your uterus. Initially, the eyes on the fetus are on the sides, but in this week they move to the front and appear closer together (to begin the makings of the face). Likewise in this week, the ears move to the proper position on the sides of the head.

Your Body: Second Trimester Tales:

For some women, this week begins what is sometimes referred to as the "golden period," when the risk of miscarriage has decreased -- though not disappeared entirely -- and you can feel comfortable sharing your extraordinary news. With that, the fatigue, nausea, and other first-trimester side effects may disappear, your sleeping should improve, and you might even enjoy a surge of energy. In general, you might feel more like the "old" you.

Around this time, you will also notice a few baby-related changes. Being pregnant will probably feel more real to you. Sometime around week 10 to 12, your doctor may have listened to the baby's heartbeat using Doppler ultrasound, and, in another few weeks, you will probably start feeling little flurries inside. Those butterfly-like sensations are the baby, making its presence felt for the first time!

You may also feel like there is a transition from feeling fat to looking pregnant. Total strangers in the grocery store might wish you well or inquire as to which month you're in. And if you take public transportation, something out of the ordinary may happen -- someone might actually offer you a seat!

Keep in mind that not all women at this point are without symptoms and sensations. There is, in fact, a whole new set of aches and pains, along with potential problems and complications that may set in. You might suffer from back, abdomen, or leg cramps, and you may experience heartburn. Your skin may act strangely (darken, grow more moles, or skin tags), and you might experience bouts of constipation. Look on the upside -- you're 1/3 of the way there!

On That Note: Trimester Two up Close:

As you enter this next stage of pregnancy, you might feel overwhelmed by the never-ending changes in your body, as well as the vast amount of information coming at you. You might also feel a deep-burning desire to know everything there is to know to be prepared -- both mentally and physically -- for pregnancy and parenthood. To learn more about how to prepare for your baby's arrival, click here.

Weekly Tip:

If you find yourself constantly unzipping and unbuttoning your normal-sized clothes, you might want to bring out the maternity wear at last! But before you go on a shopping spree, take some advice from women who've been there -- borrowing is best. Buy a few of the basics -- leggings, T-shirts, and lingerie -- but ask around from friends or family who have already been pregnant for the rest. And when their time comes next, you can lend them yours.