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Ultrasound for dating pregnancy

In fact, when a woman who has very regular, "textbook" 28 day cycles presents for prenatal care, this often turns out to be the correct EDC more often than not.

Other information used to calculate the gestational age, or the number of weeks and days from the first day of the last menstrual period (LMP), includes the size of the uterus on pelvic bimanual examination.

Which was correct in the end – the LMP due date or the estimated date of the scan?

This can sometimes lead, if one isn't careful, to unnecessary induction of labor, which can result in unnecessary cesarean section, or delivery of a premature baby, who then requires transfer to a special care nursery.In fact, the only time that this doesn't apply is when the date of conception is known without doubt, as when an infertility patient conceives with timed intercourse or artificial insemination.Just wanting to know if any others have had an EDD from a scan that was different to the EDD calculated based on their LMP (last menstrual period).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.The timing of certain tests, the monitoring of the baby's growth, and the correct diagnosis of premature labor, or being truly "overdue," (postdates), as well as many other situations that arise in the course of a typical pregnancy, all depend on a correct determination of the EDC for appropriate management.In the past, the EDC was calculated by using Naegele's Rule, which determined the date by subtracting 3 months from the 1st day of the last period and then adding 7 days.Between 18 and 28 weeks of gestation, the margin of error increases to plus or minus two weeks.After 28 weeks, the ultrasound may be off by three weeks or more in predicting a due date.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.

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  1. Dating by ultrasound in the first half of pregnancy has become a routine part of antenatal care in many units around the world. A recent commentary in this journal questioned the accuracy of ultrasound and argued for the use of menstrual history with some modifications of Nagele's rule. This would be a regrettable and.

  2. Nov 8, 2017. New charts for ultrasound dating of pregnancy and assessment of fetal growth longitudinal data from a population-based cohort study. Ultrasound Obstet Gynecol 2008; 8. Taipale P, Hiilesmaa V. Predicting delivery date by ultrasound and last menstrual period in early gestation. Obstet Gynecol 2001.

  3. Oct 27, 2017. 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. Ultrasounds During Pregnancy. During an ultrasound, a technician will spread a warm.

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