A COMPARISON OF EARLY ULTRASOUND SCANNING AND A RELIABLE MENSTRUAL PERIOD AS PREDICTORS OF THE DAY OF DELIVERY.

Abstract

The objective of htis study is to compare the accuracy of early ultrasonograhic
biometry versus reliable menstual dates in predicting the date of spontaneous
confinements in pregnant women at the Obafemi Awolowo University Teaching
hospital Complex. Ile-Ife .Nigeria.

This prospective study was done over a period of twenty four months. The
study population included singleton pregnant women recruited at a gestational
age of 22 weeks or less who have an unequivocal,reliable last menstrual period
with hitherto regular cycles, and corresponding uterine size. They were
subjected to ultrasound scanning for pregnancy dating after due counselling,and
obtaining informed consent. Every effort was made to keep the sinologist ‘blind’
to their menstrual date as applicable. The estimated gestational age and expected
date of delivery were ascertained by fetal biometric variables using the linear
regression models. The patient were subsequently followed up in the antenatal
clinic according to departmental protocol. At delivery in the hospital,the actual
date of spontaneous delivery was noted. A neonatologist assessed the true
neonatal age using the Dubowitz score. All patients who were delivered for
obstetric emergencies, elective vaginal or abdominal deliveries or complicated
pregnancies were excluded. The resulting data were analyzed and categorized into tables, calculating
predictive errors, and comparing proportions with chi square, with level of
significance of P<0.05. Delivery occurred in 73.3% of cases within +/- 7 days
of date predicted by CRL; in 72.7% of cases predicted by FL; approximately
70.8% of cases according to BPD predictions; and 58.1% of cases followed the
LMP predictions. P< 0.05 in all cases.
It is concluded that early ultrasound scanning is a better predictor of the
day of spontaneous delivery than a reliable menstrual date.