Esther Vasquez, 26 years old
One of the most important aspects of obstetrical care is to date, as precisely as possible, the beginning of pregnancy so that the estimated time of arrival ETA can be calculated sometimes referred dating your pregnancy as the estimated date of confinement — EDC. And yet, even with all of the available technology, one of the puzzles of modern obstetrics, is that the obstetrician has not yet learned how to accurately date the beginning of a pregnancy. Pregnancy can be measured in two different ways. The most common and most often used in clinical obstetrics is the measurement of the gestational age of the pregnancy. The gestational age of the pregnancy is measured from the first day of the last menstrual period. In this way of dating the pregnancy, the pregnancy is 40 weeks in duration on average instead of the actual 38 weeks. In other words, it dates the pregnancy, on average, two weeks longer than it is.
You can calculate your due date by subtracting three months from the first day of your last menstrual period LMP dating your pregnancy then add a week. Use our pregnancy calculator. A pregnancy is based on being days long, which is 40 weeks more like 10 months not 9! When we give you a due date we consider 37 to 42 weeks to be full-term, so even if your baby is born two weeks before your due date it is not considered premature.
A searchable database of the laws, people, organizations, and litigation involved in sexual and reproductive health and justice in the United States. Medical professionals use a standard set of up to three methods to date pregnancies: last menstrual period, ultrasound, and a physical exam. That way, regardless of where they trained or where they practice, any two doctors dating a pregnancy will predict the same due date or gestational age.
More about dating your pregnancy:
Because the human egg is capable of fertilization for only 12 to 24 hours after ovulation the date of ovulation may be taken as being the date of conception. However, ultrasound determination of the date of ovulation has the same imprecision as does the ultrasound estimate of the gestational age and, therefore, a precise date of conception cannot usually be determined as with in vitro fertilization. In addition, although a woman is most likely to become pregnant if she has sex on the day of ovulation conception may also occur from live sperm still in her reproductive tract on the day of ovulation if she had sex dating your pregnancy up to five days before ovulation [26,27]. The due date may be estimated by adding days 9 months and 7 days to the first day of the last menstrual period LMP. This is the method used by "pregnancy wheels". The accuracy of the EDD derived by this method depends on accurate recall by the mother, assumes regular 28 day cycles, and that ovulation and conception occurs on day 14 of the cycle. Use of the LMP to establish the due date may overestimate the duration of the pregnancy, and can be subject to an error of more than 2 weeks . In cases where the date of conception is known precisely, such as with in vitro fertilization, the EDD is calculated by adding days to the date of conception. Ultrasound uses the size of the fetus to determine the gestational age the time elapsed since the the first day of the last menstrual period. The accuracy of the ultrasound estimate of the gestational age varies according to the gestational age.
dating your pregnancy