A common use of ultrasound in early pregnancy is to calculate gestational age (obstetrical gestational age). For this purpose, ultrasound is considered a very precise method. It is not uncommon for a woman to have irregular periods, ovulate late or early, or not remember the first day of her last period at all. In these cases, ultrasound comes to the rescue. In a normal pregnancy, ultrasound results can give an estimate of gestational age with an accuracy of 5-7 days and answer one of the most worrying questions of many pregnant women - determining the expected date of conception.
When a woman has symptoms of a miscarriage, the doctor may order one or more ultrasounds to determine the viability of the embryo. Spotting spotting often accompanies an ectopic pregnancy and ultrasound is the only non-invasive method for diagnosing this complication before the development of a fallopian tube rupture clinic.