13 Weeks Pregnant

Here's what's happening during Week 13 of your pregnancy.

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Your Growing Baby:

The nose and lips are completely formed, and the fetus begins to produce and excrete urine.

Your baby is 2 1/2 to 3 inches long, the size of a medium goldfish. She weighs about one ounce. Your baby is shorter than a finger, but her face is already showing individual features and characteristics. Your baby spends her time in your womb flexing her new and developing muscles and joints. Bouts of prenatal hiccups are strengthening your baby's diaphragm, which is preparing her respiratory system for breathing. Less glamorous but highly necessary organ systems for making hormones, absorbing nutrients, and filtering waste are also in place this week. The pancreas, gall bladder, and thyroid have developed, the kidneys can make urine, and her bone marrow is making white blood cells to help fight infection after she's born.

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Your Growing Belly:

Good news—by week 13, you'll have more energy and less nausea (it could be gone entirely by weeks 14 to 15), as the placenta takes over hormone production. Your smell and taste aversions will probably stick with you for the rest of your pregnancy, but unless you're very unlucky, the spontaneous throwing up will ease. If you're starting to feel better, this could be a good time to try a new exercise. If you haven't tried swimming lately, check out why many care providers call it the perfect pregnancy exercise. Yoga is another low-impact activity that can help you feel better. Choose an establishment that offers a specialized prenatal yoga class. Feel calm, centered and prepared for labor with these safe yoga poses >>

Tips & To-Do's:

Water Baby

When you do exercises in water, your abdominal muscles are engaged and lengthened because they're working to keep you balanced. And the buoyancy of the water makes it easier to hold poses—such as yoga's Warrior III—that you might not be able to hold as well on land, providing you with more toning benefits and enabling deeper stretches. Ease pregnancy discomforts and stay in shape safely with this cool pool workout.

Things to think about this week

Now that you're entering your second trimester (it starts next week), you'll want to make the most of your renewed energy, mobility and good mood to prepare for giving birth. Your first step should be to sign up for a childbirth education course. Here's a rundown of the most common childbirth classes.

NEW:  Listen to Our Week-by-Week Podcast All About Your Pregnancy 

Each episode of the new Pregnancy Confidential podcast, hosted by our editors, walks listeners through the physical, emotional and all-round quirks of each week of pregnancy. This is real-talk, girlfriend-to-girlfriend stuff—no hard-to-understand medical information here—taking you through the real feelings of pregnancy so you're never alone. And it'll have you chuckling all along the way. All episodes available now!