Pregnancy dating scan accuracy
Transvaginal ultrasound usually produces better and clearer images of the female pelvic organs including the developing pregnancy, because the ultrasound probe lies closer to these structures.The transvaginal ultrasound probe is thin, about 2cm diameter.Every pregnant woman wants to know her due date, and a due date that is calculated from her last menstrual period often doesn't match the due date that is estimated by her first ultrasound (also known as a sonogram).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.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).
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.
The probe is covered with a disposable protective sheath.
A small amount of ultrasound gel is placed on the end of this probe.
Pregnancy ultrasounds are performed mainly using transabdominal ultrasound.
For many women, especially after 8 weeks gestation, sufficient information about the baby may be obtained with transabdominal ultrasound only.