A comparison between ultrasound and a reliable last menstrual period as predictors of the day of delivery in 15 000 examinations

Abstract

In a non-selected population comprising 15,241 women, an evaluation was performed of the ultrasonic measurement of the biparietal diameter compared with a reliable last menstrual period as the basis for estimation of the day of delivery. In women with a reliable menstrual history and spontaneous onset of labor, the ultrasound estimate was the significantly better predictor of the day of delivery in 52% of cases, and the last menstrual period estimate was the better predictor in 46% of cases. The percentages of women who delivered within 7 days of the predicted day were 61 and 56% for the ultrasound and the last menstrual period estimations, respectively. There was a significantly narrower distribution of births according to the ultrasound estimate (p < 0.001). The proportion of estimated postterm births was 4% using the ultrasound method and 10% using the last menstrual period method (p < 0.001). Even when the difference between the methods in predicting the day of delivery was less than 7 days, the ultrasound method was better than the last menstrual period method. It is concluded that ultrasonic measurement of the biparietal diameter between 15 and 22 weeks of pregnancy is the best method for the estimation of the day of delivery and should be used as a routine procedure.

The Generation R Study: design and cohort update 2012

“…These methods have previously been described in detail [111,112]. Establishing gestational age by using the first day of the last menstrual period is not reliable for a variety of reasons including the large number of women who do not know their exact date, have irregular menstrual cycles or amenorrhea, use oral contraceptive pills or bleed in early pregnancy [113]. Using fetal ultrasound data such as crown-rump length or biparietal diameter for pregnancy dating seems to overcome these problems but does not allow growth studies of these measurements since no growth variability between subjects is assumed.…”

Prolonged and Exclusive Breastfeeding Reduces the Risk of Infectious Diseases in Infancy

“…Gestational age was established by fetal ultrasound examination. 37 Information about siblings, day care attendance, and maternal smoking (no or yes) was obtained by questionnaire when the infants were 6 months old.…”

Insulin gene variable number of tandem repeats is not associated with weight from fetal life until infancy: the Generation R Study

“…These fetal ultrasounds were used for both establishing gestational age and assessing fetal growth characteristics (23). Pregnancydating curves were constructed on subjects in the study with complete data on gestational age measured by ultrasound and last menstrual period.…”