If an event occurs on a given date during a woman's pregnancy, then the gestational age at that moment can be calculated based on the ultrasound dates as determined on a separate date.
Example of an event: blood sample collection, trauma, drug exposure
(1) event date
(2) ultrasound date
(3) gestational age based on ultrasound in weeks and days
If the date of ultrasound is before the event date,
days between event and ultrasound =
= (event date) – (ultrasound date)
If the date of ultrasound is after the event date,
= (ultrasound date) – (event date)
date with t=0 based on ultrasound =
= (ultrasound date) – (7 * (weeks of gestation)) – (days of gestation)
weeks of conception at event =
= INT(((event date) – (date t=0)) / 7 )
additional days of conception at event =
= (event date) – (date t=0) – (7 * (weeks of gestation at event))
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Purpose: To estimate the gestational age of a fetus at the time of an event based on ultrasound data collected at a different time.
Specialty: Obstetrics & Gynecology
Objective: other testing
ICD-10: O00, Z34,