Check your urine and blood pressure
Protein in your urine can be a sign of a urinary tract infection or, if accompanied by high blood pressure, a sign of preeclampsia. (If there's no protein in your urine but your blood pressure is high, you could have gestational hypertension.) It's not uncommon during pregnancy to have a small amount of sugar in your urine once in a while, but if you have a large amount or it happens often, your practitioner will order a blood test to check for gestational diabetes.
Listen to your baby's heartbeat
Your caregiver may have picked up your baby's heartbeat as early as 10 weeks, using a handheld ultrasound device called a Doppler. But it's more common to hear it for the first time at around 12 weeks, depending on your baby's position in your uterus, your weight, and the accuracy of your due date. Checking your baby's heartbeat will become a routine part of every prenatal visit from here on out. Bring your partner along so he can share in the thrill of hearing this dramatic sign of the life you've created together.
Examine your belly
Your practitioner will feel your abdomen to get a sense of the size of your growing uterus and baby. From midpregnancy on, she'll use a tape to measure your fundal height — the distance between your pubic bone and the top of your uterus — to estimate your baby's size and growth rate. From 20 weeks until late in your third trimester the measurement (in centimeters) should roughly correspond to how many weeks pregnant you are. So if you're 24 weeks pregnant, your fundal height should measure about 24 centimeters.
Provide education and counseling
Sometime in this trimester, your practitioner should talk to you about childbirth education classes. Ask her opinion about the classes offered in your community or at the hospital or birth center where you plan to deliver. You may also want to look into breastfeeding and baby care classes to take during your third trimester. And you'll want to start thinking about choosing a doctor for your baby — your caregiver should be able to give you some good leads.
Most practitioners routinely order an ultrasound between 16 and 20 weeks to check for physical abnormalities and to verify your baby's due date. You'll be offered a multiple marker screening (a blood test done between 15 and 20 weeks that can give you some information about your baby's risk of having certain chromosomal problems and other birth defects). And if you're going to be 35 or older on your due date or have other risk factors for genetic problems (such as a family history of genetic problems, a suspicious finding on your ultrasound, or abnormal results from a genetic screening test), your practitioner will offer you an amniocentesis (a test that can diagnose these problems).
Between 24 and 28 weeks, you'll also be given a glucose screening test to check for gestational diabetes, and possibly another blood test to check for anemia. If you're Rh-negative (but your baby's father isn't, or you don't know whether he is), an extra tube of blood may be drawn to check for Rh antibodies before you're given an injection of Rh immune globulin at 28 weeks.