Arterial Blood Gases. Test Overview. An arterial blood gas (ABG) test measures the acidity (pH) and the levels of oxygen and carbon dioxide in the blood from an artery. This test is used to check how well your lungs are able to move oxygen into the blood and remove carbon dioxide from the blood.
How Often the Test Is Done During Your Pregnancy. Your doctor may use the Doppler often to listen to your baby's heartbeat during routine checkups, starting at about 8 to 10 weeks. Handheld Dopplers will not work quite this early.
What Does the Doctor Check? The doctor will come in and say hello, then ask you some questions, like how you're doing and if you have any problems or concerns. The doctor wants to make sure your body is working just like it should. To do this, your doctor will: Listen with a stethoscope: The stethoscope lets the doctor hear your heartbeat and the way your lungs sound. Doctors know just how healthy hearts and lungs should sound.