My wife told her doctor she didn't know when her last mp was, so he sent her for an ultrasound!
During an ultrasound, a technician will spread a warm gel over the lower part of your abdomen and then press a tool called a transducer against your belly to examine your fetus using sound waves.
An image of your fetus will appear on an accompanying computer screen and while looking at this image, the technician will take some standard measurements from different angles and listen for a heartbeat.
Don't worry: This type of exam is painless and risk-free, and seeing your baby for the first time will likely be an enjoyable experience.
Naturally, one of the most common questions asked about ultrasound accuracy is: Just how accurate are the due dates that are predicted by an ultrasound?
Evidence suggests that, in the first 20 weeks of pregnancy, the first ultrasound may be the most accurate tool for predicting when your baby will be born.
But early ultrasound due dates have a margin of error of roughly 1.2 weeks, so doctors will usually keep the original due date (the one generated by the date of your last menstrual period) if the ultrasound due date is within that margin of error.If you can't remember your last menstrual period date or if you have consistently irregular cycles, the doctor can use an early ultrasound to give you a fairly reliable due date.If your first ultrasound gives you a due date that is more than 1.2 weeks away from what was expected, there is a good chance that everything is still fine.You may have simply conceived earlier or later than you thought you did (which can happen if your cycle is at all irregular or if you remembered your last menstrual period date incorrectly).Your doctor might want to repeat the ultrasound to make sure that your pregnancy is developing as it should.Assuming that the subsequent ultrasound shows the expected fetal growth for the time period between the scans, your doctor may revise your due date to match the first ultrasound's predictions.