Determination of Gestational Age using Crown-Rump Length and its Associated Maternal Correlates in Igbos Living in Nnewi: An Ultrasound Study

Purpose: The objective was to determine the accuracy of gestational age measured by CRL in fetuses of black women and also to identify the maternal factors affecting this accuracy in determining the gestational age by CRL measurement in fetuses of black women. Methodology: This prospective cross-sectional study was conducted in Life and Trinity Specialist hospitals both in Nnewi, South-East, Nigeria. The gestational ages of the fetuses by CRL were determined using Siemens 2D ultrasound scan within 14 weeks and the accuracy compared with the gestational ages obtained from the Last Menstrual Period (LMP). Factors affecting the accuracy of CRL in determining the gestational age in women like the maternal heights and ages were measured. The ultrasound scan was done by a consultant in the department of Obstetrics. Analysis was done using SPSS Package version [20]. Regression analysis was used to compare dependent ad independent variables. Paired t-test was carried out on gestation period by LMP and gestation period by CRL to know if the mean difference between the gestation period by LMP and gestation period by CRL is significant. Multiple correlation analysis was used to ascertain the degree of relationship between maternal weight and age and gestational age by LMP and CRL. Findings: The result showed that two hundred and sixty-­five women met the inclusion criteria but two were lost to follow up and two hundred and sixty-three were used finally for analysis. The accuracy of ultrasound scan in estimating the gestational age using CRL is within one week in majority of the cases. Maternal height, weight and age are poorly correlated to age of the fetus using the CRL. The fetuses of black women showed a marginal increase in length at gestational age below eight weeks but afterwards this difference is not pronounced. In conclusion, the accuracy of CRL in determining the gestational age is within one week in majority of cases. The maternal height and age are poorly correlated to the CRL of the fetus and thus to the gestational age. Unique Contributor to Theory, Policy and Practice: Ultrasound scan incorporated with growth chart for fetuses of white women can be equally used to ascertain the gestational ages of fetuses of black women with insignificant difference