Irregular periods can be calculated using ultrasound in early pregnancy to calculate the week of pregnancy.
Early pregnancy ultrasound can look at the head and hip length of the fetus, the size of the gestational sac, etc., which can be used to project the week of pregnancy and then reverse the calculation to arrive at the correct last menstrual period.
However, for mid and late pregnancy, using ultrasound to calculate the week of pregnancy is not very accurate. Therefore, if a woman with irregular periods is pregnant, she should have an ultrasound as early as possible, and the calculated week of pregnancy will be more accurate.
The purpose of verifying the week of pregnancy is to facilitate the monitoring of pregnancy and childbirth, and to facilitate the early detection of high-risk pregnancies and the prevention of pregnancy complications, so it is recommended that pregnant women verify the week of pregnancy as soon as possible and follow the doctor’s instructions to do a good job of obstetric examination.