THE FAULT IN OUR MOONS- THE EFFECT OF FESTIVALS AND PUBLIC HOLIDAYS IN THE INTRODUCTION OF ERROR IN RECALLED LMP DATES BY PREGNANT SUBJECTS UNDERGOING FIRST TRIMESTER SCAN.

Corresponding Author:
Rodriguez Mario Jose,
Associate Professor,
Department of Radiology,
PK Das Institute of Medical Sciences,
Ottapalam- 682522, Kerala, India.
E-mail: mariojoserod@gmail.com

ABSTRACT

BACKGROUND

An accurate estimation of gestational age is the cornerstone of decision making in obstetric practice. Dating by recalled last menstrual period is frequently inaccurate due to memory related sources of error. Ultrasound in the first trimester is an accepted method of accurately dating the duration of gestation.

MATERIALS AND METHODS

The study was designed as a cross-sectional study. First trimester patients undergoing a dating scan were assessed and gestational ages were obtained by recalled LMP and by ultrasound Crown-Rump Length (CRL). Subjects were grouped into a festival group if their LMP fell on a festival date and into a non-festival group if it did not. Differences between gestational age by recalled LMP and by ultrasound were analysed for both groups.

RESULTS

Out of 312 pregnant subjects, majority of 181 (58%) belonged to 18 - 25 age group, 100 (32.1%) belonged to 26 - 30 age group, 29 (9.3%) belonged to 31 - 35 age group and remaining 2 (0.6%) belonged to 36 - 40 age group. Out of 312 pregnant subjects, in 249 (79.8%) of subjects LMP fell on normal days and in 63 (20.2%) of pregnant subjects LMP fell on festival days. Out of total 63 mothers with festival LMP, majority 45 (71.4%) of mothers belonged to 18 - 25 age group and in remaining mothers 16 (25.4%) 2 (3.2%) belonged to 26 - 30 and 36 - 40 age group respectively. This difference in age distribution among festival and non-festival LMP is statistically significant- P value of 0.03. Out of total 63 mothers with festival LMP majority 35 (55.6%) were multigravida and remaining 28 (44.4%) were primigravida. This difference is statistically significant. P value - < 0.01 the mean difference in gestational period among festival LMP group is 5.68 + 4.76, higher than non-festival group 3.43 + 3.32. This difference is statistically significant. P value- 0.001.

CONCLUSION

Dating by recalled LMP shows systemic bias with statistically significant clustering of recalled LMP in proximity to public holidays and festivals in a study of first trimester patients undergoing a dating scan.

KEYWORDS

Dating ultrasound, Festivals, First Trimester, Gestational Age, Last Menstrual Period, LMP Recall Error.