A patient present for her first antenatal visit after performing a home pregnancy test and gives a last menstrual period of about 8 weeks ago. She says she is not entirely sure of her dates, however because she has a long history of irregular menses. Which of the following is the most accurate way of dating the pregnancy?
High-Yield Explanation
Dating of pregnancy crown rump length is measured from the top of the head to the bottom of the buttocks excluding limbs CRL between 9 and 11 weeks is the most accurate method of dating CRL in cm + 6.5 gives a rough estimate of gestational age in weeks refer pgno:476 Sheila textbook of obstetrics 2 nd edition