New charts for ultrasound dating of pregnancy


19-Apr-2020 12:11

Human Chorionic Gonadotropin Pregnancy Test Human chorionic gonadotropin first becomes detectable in the mother's blood and urine between 6 and 14 days after fertilization (3 to 4 weeks gestational age) [11-13]. The gestational age would, therefore, be at least 3 to 4 weeks at the time of a reliable h CG pregnancy test. In order to use Medscape, your browser must be set to accept cookies delivered by the Medscape site.Medscape uses cookies to customize the site based on the information we collect at registration.Use of the LMP to establish the due date may overestimate the duration of the pregnancy, and can be subject to an error of more than 2 weeks [5-7]. In cases where the date of conception is known precisely, such as with in vitro fertilization, the EDD is calculated by adding 266 days to the date of conception. American College of Obstetricians and Gynecologists. The American College of Obstetricians and Gynecologists recommends that ultrasound-established dates should take preference over menstrual dates when the discrepancy between ultrasound dating and LMP is "Because of the risk of redating a small fetus that may be growth restricted, management decisions based on third-trimester ultrasonography alone are especially problematic; they need to be guided by careful consideration of the entire clinical picture and may require closer surveillance, including repeat ultrasonography to ensure appropriate interval growth." [24]. Birth weight from pregnancies dated by ultrasonography in a multicultural British population. Other Methods For Estimating the Gestational Age Clinical Examination A pelvic examination supported by good menstrual records in the first trimester has been reported to be a reliable method for dating of pregnancy [9].

Number 4, May 1999 (replaces educational bulletin Number 147, October 1990).

However, ultrasound determination of the date of ovulation has the same imprecision as does the ultrasound estimate of the gestational age and, therefore, a precise date of conception cannot usually be determined as with in vitro fertilization.