What is USG OBST 2ND TRIMESTER?

These days, it's pretty much routine for women in their second trimester to be scheduled for a level 2 ultrasound, commonly called the 20-week anatomy scan. That's because practitioners have found that this special pregnancy ultrasound is a great way to see how a baby is developing and offer reassurance that everything is going exactly the way it should be. It's fascinating to get a sneak peek of your baby — and fun to take home a souvenir photo to start the baby album.

Who a level 2 ultrasound is for

Virtually all practitioners order an ultrasound anatomy scan for all their moms-to-be. Even if you had a first-trimester (level 1) sonogram to confirm or date your pregnancy, or as part of a first-trimester screening test, the more detailed level 2 sonogram is important because of all the additional valuable information it gives your practitioner about what's going on with your baby.

When a level 2 ultrasound is done

Most anatomy scans are performed in the second trimester of pregnancy, typically at 20 weeks but they can be done anytime between 18 weeks and 22 weeks. If you have a condition that needs to be monitored (such as carrying multiples), you may have more than one detailed ultrasound.

How a level 2 ultrasound is done

You may need to drink water before your exam so you'll have a full bladder, which makes it easier to take ultrasound images. You'll recline on an exam table with your tummy exposed, and a sonographer will apply gel and then move a wand (transducer) over your abdomen. As sound waves emitted from the transducer bounce off internal organs and fluids inside, a computer converts them into a 2-dimensional image (or cross-sectional view) of the fetus on a screen. Sometimes 3D or even 4D ultrasound technology is used instead of 2D.

To get the most comprehensive anatomy assessment, the sonographer will be aiming for many different views from lots of different angles. When the technician gets a clear shot, he or she will freeze-frame the picture (that's the actual sonogram) and then measure a specific part of the body. During the scan, you may be able to spot your baby's beating heart, the curve of the spine, and the face, arms, and legs. You may even catch sight of your baby sucking a thumb.

Settle in to enjoy the show: The detailed level 2 scan can take 30 to 45 minutes (depending on how cooperative your little one wants to be). The perinatologist and your practitioner will review the rest, and you will likely go home with at least one or two good sonogram pictures.

What a level 2 ultrasound looks at

A level 2 ultrasound focuses closely on fetal anatomy to be sure everything is growing and developing as it should; images are much clearer and more detailed than the fuzzy ultrasound you got in your first trimester. Your baby will be measured from crown to rump, around the middle, and around the head, and his or her weight will be estimated. The four chambers of the heart will be looked at, as well as the kidneys, bladder, stomach, brain, spine, and sex organs. The sonographer will also be looking at your amniotic fluid levels, the location of the placenta, and fetal heart rate.

A level 2 scan also checks for hard and soft markers, characteristics that may indicate an increased risk of a chromosomal abnormality. Important to know before you head into your scan: Very few babies showing soft markers (choroid plexus cyst, echogenic foci, or pyelectasia, to name an unpronounceable few) end up having an abnormality. Your practitioner will let you know whether any follow-up testing is necessary (it often isn't).

Be aware that a level 2 ultrasound can also tell you the sex of your baby if you haven't already found out through noninvasive prenatal testing (NIPT) or a CVS, though with less than 100 percent reliability and depending on the baby's cooperation. Remember: Be sure to tell your sonographer if you don't want to know!

Risks

There are no significant risks associated with ultrasounds, though medical guidelines caution against unnecessary exposure to ultrasound — which is why your practitioner will schedule only a handful of them throughout your pregnancy. If you're concerned about the upcoming picture show (and what those grainy images reveal), talk to your practitioner about what he or she is looking for. Chances are you'll come away enlightened (and relieved).