During the mid-pregnancy ultrasound (also called the anatomy scan), usually around 20 weeks, your doctor is basically checking to make sure baby's growing and developing properly. This generally includes listening to baby's heartbeat, checking for physical abnormalities, looking at organ structure, confirming any suspicions of twins or other multiples, measuring the amount of amniotic fluid (too much or too little could signal a problem), checking the location of your placenta to be sure it isn’t covering the cervix, and taking lots of measurements to make sure baby is the right size for his or her gestational age.
The truly exciting part about your midterm ultrasound (well, besides the assurance that you’re growing a healthy baby)? This is your chance to catch a glimpse of what baby looks like in there, and you’re likely to get a couple of printouts to show off to family. And, if you want to know baby’s sex, this is the moment of truth—your doctor should be able to detect your little one’s genitals on the ultrasound screen (if baby isn’t covering the goods with his or her arms or legs).