In week 18, blood tests to measure sugar and protein levels are routine. If your baby hasn't already been screened for genetic abnormalities, it's a good idea to begin these tests. An ultrasound can be used to detect your baby's gender. Depending on your baby's position, it's likely that your doctor will be able to tell you whether you're having a boy or a girl! The ultrasound is also used to measure your baby's growth and movements. Talk to your doctor if you have questions about the tests and procedures needed at this point of your pregnancy.