Gestational Age Calculator By Edc

Gestational age calculator by edc

Estimation methods[ edit ] Due date estimation basically follows two steps: Determination of which time point is to be used as the origin for gestational age.

This starting point is the woman's last normal menstrual period LMP or the corresponding time as estimated by a more accurate method if available. Such methods include adding 14 days to a known duration since fertilization as is possible in in vitro fertilization or by obstetric ultrasonography. Adding the estimated gestational age at childbirth to the above time point.

Calculating a Due Date

Childbirth on average occurs at a gestational see more of days 40 weekswhich is therefore often used as a standard estimation for individual gestational age calculator by edc. Estimation of gestational age[ edit ] According to American Congress of Obstetricians and Gynecologiststhe main methods to calculate gestational age are: [7] Directly calculating the days since the beginning of the last menstrual period Early obstetric ultrasoundcomparing the size of an embryo or fetus to that of a reference group of pregnancies of known gestational age such as calculated from last menstrual periodsand using the mean gestational age of other embryos or fetuses of the same size.

If the gestational age as calculated from an early ultrasound is contradictory to the one calculated directly from the last menstrual period, it is still the one from the early ultrasound that is used for the rest of the pregnancy. There is in any case considerable variation among individual pregnancies.

Variability[ edit ] Distribution of gestational age at childbirth among singleton live births, given both when gestational age is estimated by first trimester ultrasound and directly by last menstrual period. The median is merely a guideline for the day at which half of all births occur earlier, and half of all births occur later.

Births rarely occur on a due date, but they are clustered around due dates. The rule estimates the expected date of delivery EDD by adding a year, subtracting three months, and adding seven days to the origin of gestational age. Another method is by adding 9 months and 7 days to the first day of the last menstrual period.

Naegele's rule is named after Franz Karl Naegelethe German obstetrician who devised the rule. InNaegele became ordinary professor and director of the lying-in hospital in Heidelberg.

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His Lehrbuch der Geburtshilfe, published in for midwives, enjoyed a successful 14 editions. Using the example above, 8 May is a Friday. The calculated date 15 February is a Monday; adjusting to the closest Friday produces 12 February, which is exactly days past 8 May.

The calculation method does not always result in days because not gestational age calculator by edc calendar months are the same length; it does not account for leap years. Mobile apps[ edit ] Mobile apps essentially always give consistent estimations compared to each other and correct for leap yearwhile pregnancy wheels made of paper can differ from each other by 7 days and generally do not correct for leap year.]