29 weeks.

How your baby's growing:
Your baby now weighs about 2 1/2 pounds (like a butternut squash) and is a tad over 15 inches long from head to heel. His muscles and lungs are continuing to mature, and his head is growing bigger to make room for his developing brain. To meet his increasing nutritional demands, you'll need plenty of protein, vitamins C, folic acid, and iron. And because his bones are soaking up lots of calcium, be sure to drink your milk (or find another good source of calcium, such as cheese, yogurt, or enriched orange juice). This trimester, about 250 milligrams of calcium are deposited in your baby's hardening skeleton each day.

How your life's changing:
Your baby's very active now. Your healthcare provider may ask you to spend some time each day counting kicks and will give you specific instructions on how to do this. Let your provider know if you ever notice that your baby is becoming less active. You may need a nonstress test or biophysical profile to check on your baby's condition.

Some old friends — heartburn and constipation — may take center stage now. The pregnancy hormone progesterone relaxes smooth muscle tissue throughout your body, including your gastrointestinal tract. This relaxation, coupled with the crowding in your abdomen, slows digestion. Sluggish digestion can cause gas and heartburn — especially after a big meal — and contribute to constipation.

Your growing uterus may also be contributing to hemorrhoids. These swollen blood vessels in your rectal area are common during pregnancy. Fortunately, they usually clear up in the weeks after giving birth.

If they're itchy or painful, try soaking in a sitz bath or applying cold compresses medicated with witch hazel to the affected area. Avoid sitting or standing for long stretches. Talk with your provider before using any over-the-counter remedies during pregnancy, and let your provider know if you have any rectal bleeding. To prevent constipation, eat a high-fiber diet, drink plenty of water, and get some regular exercise.

Some women get something called "supine hypotensive syndrome" during pregnancy. This happens when lying flat on your back causes a change in heart rate and blood pressure that makes you feel dizzy until you change position. You might notice that you feel lightheaded if you stand up too quickly, too. To avoid "the spins," lie on your side rather than your back, and move slowly as you go from lying down to sitting and then standing.