Importance height dating
Gestational age (GA) refers to the length of pregnancy after the first day of the last menstrual period (LMP) and is usually expressed in weeks and days. Conceptional age (CA) is the true fetal age and refers to the length of pregnancy from the time of conception.This terminology does vary geographically and over time, and it may need clarification if not explicitly defined in relevant articles.Knowing the date of the first positive pregnancy test result allows the calculation of a minimum GA. For example, if the test was performed 4 weeks ago and the test is known to return positive results as early as 1 week after conception, then the minimum conceptional age (CA) would be 5 weeks (GA, 5 2 = 7 wk of amenorrhea).This information can be useful in clinical practice if the test finding has been documented by a health care professional.Scientists from the Animal Cell Technology Unit published a paper in Scientific Reports journal that was now selected as one of the top 100 read papers in Cell Biology for Scientific Reports in 2017.
The GA of pregnancies resulting from in vitro fertilization can be precisely calculated from the time of embryo replacement; however, conception may be delayed for a few days in pregnancies resulting from intrauterine insemination.
The fallacy in this assumption is that the time of ovulation varies greatly in relation to the menstrual cycle, both from cycle to cycle and individual to individual.
Basing GA on the LMP tends to result in an overestimation.
The first 2 are subject to considerable error and should only be used when ultrasonography facilities are not available.
The date of feeling the first fetal movements (quickening) is far too unreliable to be useful.The perception of fetal movement by the patient, often referred to as quickening, is a relatively late sign of pregnancy, usually occurring at 19-21 weeks' gestation in nulliparous women and 17-19 weeks' in multiparous women.Before the advent of pregnancy tests and ultrasonography, quickening was often the method by which a suspected pregnancy was confirmed; however, at present, it has little diagnostic value.The estimation of pregnancy dates is important for the mother, who wants to know when to expect the birth of her baby, and for her health care providers, so they may choose the times at which to perform various screening tests and assessments,such as serum screening, assessment of maturity, and induction of labor for postdate pregnancies.