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Common prenatal procedures

You are pregnant! With those two little pink lines comes a lot of excitement for the life-changing next 40 weeks of your life, but that little stick was just the start of your prenatal testing.

Woman getting early ultrasound

Over the next 9 months your body will be undergoing a major physical change as it works to develop and grow a healthy baby. Your doctor or midwife will order a variety of tests, starting with your first visit, to check both yours and baby’s health and development before birth. Read on for a run-down of the most common tests and what their purpose is.

1First and Second Trimester Blood Tests


You will likely have to have blood drawn at least a couple of times throughout your prenatal period. The first time will be around 10-14 weeks and will be used to test for your immunity to various diseases (rubella, chicken pox, etc.), sexually transmitted diseases, HIV, Hepatitis B- generally your overall health and what could affect the healthy development and delivery of your baby.

Another blood draw, done generally between 15-20 weeks, is referred to as a quad screen. This is a test that can be done to check for chromosomal or developmental abnormalities. Be mindful to not begin worrying at an initial positive result and expect additional testing (usually ultrasound) as there is a common false-positive result on this test.

2Early Dating Ultrasound and Genetic Screening Ultrasound

If you are unsure of your last menstrual period (LMP) start date your doctor may offer an ultrasound during your first trimester to date your pregnancy. Your doctor may also perform an early genetic ultrasound to detect possible Down syndrome risk or other chromosomal abnormalities. This ultrasound usually is performed between 10 and 14 weeks.

3Diagnostic Ultrasound

The one you have been waiting for! Performed between 18 and 20 weeks will be your diagnostic ultrasound. This ultrasound is used to check on the development of baby’s organs as well as to check that overall growth is on target for fetal age. They will also use this ultrasound to check placental placement. This is commonly when the new parents will discover if they are waiting on a blue or pink bundle!

4Glucose Tolerance Test

Often between 24 and 28 weeks you will have a glucose tolerance test to check for gestational diabetes. The test will be about an hour long beginning with an empty stomach before drinking a sugary liquid. About an hour later they will draw your blood and test to see how your pregnant body is processing glucose. If you fail this test, you will likely be referred for a three-hour study to verify gestational diabetes.

5Group B Strep Test

Around 35 to 37 weeks your doctor will do an internal smear test to check for Group B strep. This is a potentially harmful infection that will require antibiotics before you deliver to protect baby from receiving the infection during birth. Your doctor will let you know if you test positive as it will be one of the first things you will be asked about upon arrival at the hospital to deliver.

More tips for new moms

Gestational diabetes and pregnancy: What you need to know
Prenatal appointment timeline
Where to find low-cost health care for moms and babies

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