Biomaterial Database

Assessment of gestational age based on ultrasonic femur length after the first trimester: a simple mathematical correlation between gestational age (GA) and femur length (FL). 2000

M Honarvar, and M Allahyari, and S Dehbashi

Department of Obstetrics & Gynecology, Shiraz University Of Medical Sciences, Shiraz, Iran.

OBJECTIVE The ultrasonic measurement of the fetal femur length is a sensitive and precise variable for estimation of fetal growth and development. The objective of this study was to predict gestational age in fetuses more than 13 weeks of gestation by ultrasound measurement of the femur length. METHODS In this study, pregnant mothers were identified by the criteria of normalities such as: well-known LMP, regular menstrual cycles, no use of OCP for the last 3 months, no smoking, no history of diabetes, etc. RESULTS The relation between gestational age and fetal femur length has been determined by cross-sectional analysis of 900 normal fetuses (> or = 14 weeks of gestation) using real time ultrasonography. Mathematical modeling of the data has demonstrated that the femur growth curve is non-linear beyond 13 weeks of gestation. With the aid of a scientific calculator the data were analyzed and a simple second grade equation has been derived: GA (weeks) = 0.262(2) FL (cm) + 2 FL + 11.5, S.D. approximately +/- 5 days(Honarvar's Formula 3). With the use of this data, the error in the estimation of GA given as FL is +/-5 days. CONCLUSIONS This simple, new and accurate equation appears to be clinically reliable and easy to use and suggests that previous normal ultrasonic fetal femur length curves for another population may under- or overestimate normal fetal age for the Iranian population. Thus, our formula is an excellent means of estimating true gestational age.

UI	MeSH Term	Description	Entries
D011247	Pregnancy	The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.	Gestation,Pregnancies
D005260	Female		Females
D005269	Femur	The longest and largest bone of the skeleton, it is situated between the hip and the knee.	Trochanter,Greater Trochanter,Lesser Trochanter,Femurs,Greater Trochanters,Lesser Trochanters,Trochanter, Greater,Trochanter, Lesser,Trochanters,Trochanters, Greater,Trochanters, Lesser
D005865	Gestational Age	The age of the conceptus, beginning from the time of FERTILIZATION. In clinical obstetrics, the gestational age is often estimated from the onset of the last MENSTRUATION which is about 2 weeks before OVULATION and fertilization. It is also estimated to begin from fertilization, estrus, coitus, or artificial insemination.	Embryologic Age,Fetal Maturity, Chronologic,Chronologic Fetal Maturity,Fetal Age,Maturity, Chronologic Fetal,Age, Embryologic,Age, Fetal,Age, Gestational,Ages, Embryologic,Ages, Fetal,Ages, Gestational,Embryologic Ages,Fetal Ages,Gestational Ages
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000886	Anthropometry	The technique that deals with the measurement of the size, weight, and proportions of the human or other primate body.
D016216	Ultrasonography, Prenatal	The visualization of tissues during pregnancy through recording of the echoes of ultrasonic waves directed into the body. The procedure may be applied with reference to the mother or the fetus and with reference to organs or the detection of maternal or fetal disease.	Fetal Ultrasonography,Prenatal Diagnosis, Ultrasonic,Ultrasonography, Fetal,Diagnosis, Prenatal Ultrasonic,Diagnosis, Ultrasonic Prenatal,Prenatal Ultrasonic Diagnosis,Prenatal Ultrasonography,Ultrasonic Diagnosis, Prenatal,Ultrasonic Prenatal Diagnosis,Diagnoses, Prenatal Ultrasonic,Diagnoses, Ultrasonic Prenatal,Prenatal Diagnoses, Ultrasonic,Prenatal Ultrasonic Diagnoses,Ultrasonic Diagnoses, Prenatal,Ultrasonic Prenatal Diagnoses