BACKGROUND: The accurate determination of gestational age (GA) is necessary for
optimal obstetric care, both for diagnostic and interventional purposes. This important
obstetric tool is determined traditionally using the last menstrual period (LMP). However,
there are other methods of determining the gestational age including the
sympyhsiofundal height (SFH) and the early ultrasound scan before the 20th week of
gestation which is considered the gold standard. The LMP is fraught with many challenges
including woman’s poor recollection of the first day of her last normal menstrual period
which is compounded in the developing countries by illiteracy. The availability, cost,
properly trained manpower and late presentation of women in a resource-constrained
country like Nigeria limits the usefulness of early ultrasound scan.
With available evidence suggesting that the SFH may be more accurate than the LMP,
this study was conducted in our institution to compare the accuracy of the SFH and LMP
using the early ultrasound scan as reference.
AIMS: This study used an early ultrasound scan as a reference in comparing the mean
percentage accuracy of the LMP and the SFH, to ascertain the more accurate parameter
for gestational age assessment.
METHOD: Ethical clearance was obtained and 289 consecutive consenting women
carrying singleton uncomplicated pregnancies at gestational ages of less than or equals
to 20 weeks were recruited for this study in the maternity unit of Jos university teaching
hospital between December 2012 and April 2013. Ultrasound scan was used to confirm
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eligibility after which other information including the LMP were collected on a
questionnaire. The women returned after 22 weeks of ultrasound recorded gestational
age for SFH assessment and some weeks after for a second SFH assessment in a
standardised fashion.