Estimated Decomposition Date (EDC), also known as expected delivery date / estimated due date (EDD) or just due date , is a term that describes the approximate delivery date for a pregnant woman. Normal pregnancy lasts between 37 and 42 weeks.
Video Estimated date of confinement
The origin of the term
Confinement is a traditional term referring to the period of pregnancy when an upper-class lady, noble or nobleman will retreat from medieval society and the time of tudor is limited to their room with midwives, waiting women and female family members just to attend them. It is believed to calm the mother and reduce the risk of premature birth. Except in a threatened pregnancy (eg, in pre-eclampsia), "lying-in" or bed rest is no longer part of antenatal care.
Maps Estimated date of confinement
Estimation method
The due date assessment basically follows two steps:
- Determining which time points will be used as the origin of pregnancy. This starting point is the woman's last normal menstrual period (LMP) or the appropriate time as predicted by more accurate methods if available. Such methods include adding 14 days to the known duration since conception (as is possible in in-vitro fertilization), or with midwifery ultrasonography.
- Increase the estimated pregnancy age at delivery to the point above. Birth averages occur at 280 days of gestation (40 weeks), which is therefore often used as a standard estimate for individual pregnancies. However, alternative durations and more individual methods have also been suggested.
Estimated gestational age
According to the American Congress of Obstetricians and Gynecologists, the main methods for calculating gestational age are:
- Immediately count the days since the beginning of the last menstrual period
- Initial obstetric ultrasound, comparing the size of the embryo or fetus with a known pregnancy reference cohort (as calculated from the last menstrual period), and using the mean gestational age of another embryo or fetus of the same size. If the gestational age calculated from the initial ultrasound conflicts with those calculated directly from the last menstrual period, it is still one of the earliest ultrasound used for the remainder of pregnancy.
- In the case of in-vitro fertilization, count the days since oocyte retrieval or co-incubation and add 14 days.
Estimated gestational age at delivery
Birth averages occur at 280 days of gestation (40 weeks), which is therefore often used as a standard estimate for individual pregnancies. However, alternative durations and more individual methods have also been suggested. There are many variations among individual pregnancies.
Variability
Given that the length of this pregnancy is only an average estimate, it would be helpful to consider pregnancy time as a date range and not as a single "due date". The median is just a guideline for the day in which half of all births occur before, and half of all births occur later. Births are rarely on due dates, but they are clustered around maturing. A study of single live births in the US comes to the outcome that labor has a standard 14-day deviation when gestational age is estimated by first trimester ultrasound, and 16 days when estimated directly by the last menstrual period.
Standard 280 days
Naegele Rules
Naegele Rules is the standard way of calculating due dates for pregnancy when it assumes 280 days of gestational age at delivery. This rule estimates the expected delivery date (EDD) by adding one year, reducing three months, and adding seven days to the origin of gestational age. The result is about 280 days (40 weeks) from the beginning of the last menstrual period. Another method is to add 9 months and 7 days to the first day of the last menstrual period.
The Naegele Rule was named after Franz Karl Naegele (1778-1851), a German obstetrician who drafted the rule. Naegele was born July 12, 1778, in DÃÆ'¼sseldorf, Germany. In 1806, Naegele became professor and director of public hospitals in Heidelberg. His Lehrbuch der Geburtshilfe , published in 1830 for midwives, enjoyed a successful 14 editions.
Example:
LMP = 8 May 2009
- 1 year = 8 May 2010
- -3 months = February 8, 2010
- 7 days = February 15, 2010
280 days past the beginning of the last menstrual period was found by checking the LMP week day and adjusting the calculated date to land on the same day of the week. Using the example above, May 8, 2009 is Friday. The counting date (February 15) is Monday; adjusting to the nearest Friday yielded Feb. 12, which is exactly 280 days past May 8. The calculation method does not always yield 280 days because not all calendar months have the same length; it does not take into account leap year.
Mobile app
Mobile applications basically always provide consistent estimates compared to each other and are true for leap years, while paper-made gears can be different from each other for 7 days and are generally not true for leap years.
Other suggested duration
- 276 days for estimated gestational age and LMP forecast in US study of 1867 single live births.
- 281 days after LMP with a standard deviation of 13 days, is the result of a population-based study of 427,581 single births in Sweden.
- 281 days after LMP for first-time mother and 280 days for all others is the median found by American study in 1995 about 1,970 spontaneous births. Standard deviation is 7-9 days.
- 282 days after LMP is recommended for cases where LMP is the only known factor, in a study of 17,450 patients combining LMP and ultrasound measurement techniques.
- Median 288 days (274 days from the date of ovulation) for first-time mothers and 283 days (269 days from the date of ovulation) for mothers with at least one previous pregnancy discovered by a 1990 study of 114 private care patients with uncomplicated pregnancies and spontaneous labor. The authors suggest that excluding pregnancies involving complications (which often lead to premature delivery) contributes to longer periods.
Individualized
- The Parikh formula is a calculation method that takes into account the cycle duration. The Naegele rule assumes a 28-day average cycle, which does not apply to everyone. EDD is calculated using the Parikh formula by adding nine months to the beginning of the last menstrual period, minus 21 days, then adding the duration of the previous cycle.
- Several linear regression models have also been developed that take into account the parity of mothers, ages, and races, all of which have been found to be important variables that determine the duration of human pregnancy. Multiparous women, women younger than 19 or older than 34, and black women were found to have shorter pregnancies than primiparous women, women aged 19 to 34, or white women.
References
Source of the article : Wikipedia
0 Comments