Many expectant mothers want to know when their due date is after getting pregnant. The calculation of the due date needs to start from the time of pregnancy, but when does the pregnancy start counting? Actually, most expectant mothers are not aware of it. So, in order to help expectant mothers understand the time of pregnancy, let me tell you about it.
For women with regular menstrual cycles, that is, those with normal ovulation and an interval of about 28 days between two menstrual cycles, the first day of the last menstrual cycle before pregnancy can be used as the start time of pregnancy, and then calculated every seven days as one gestational week. The pregnancy cycle is generally 40 gestational weeks, which means that the due date can be obtained by adding 280 days from the start time of pregnancy.
For women with irregular menstrual cycles, especially those with irregular ovulation dates, the start time of pregnancy cannot be calculated based on the first day of the last menstrual cycle before pregnancy. The most accurate inference should be based on the first B-ultrasound examination of the embryo in the early stages of pregnancy. The first B-ultrasound examination is usually conducted six to eight weeks after the woman stops menstruating. At this time, B-ultrasound can not only rule out ectopic pregnancy, but also infer the gestational period based on the B-ultrasound examination data.
Although some women have regular menstrual cycles, their menstrual cycles vary in length. Therefore, the first day of the last menstrual cycle cannot be used as the start time of pregnancy, and can only be inferred based on ultrasound examination data. In addition, if a woman is unsure of the last menstrual cycle time or did not undergo ultrasound examination in early pregnancy, the estimated due date can be inferred based on the time of morning sickness, fetal movement, uterine fundus height, mid pregnancy ultrasound, etc.
