Cohort study of the impact of maternal packed cell volume at antenatal care booking on the birth weight of babies at Baptist Medical Centre, Ogbomoso, Nigeria

Abstract

Background: Extremes of poverty resulting from political instability in conjunction with infections, infestations and some armful cultural practices in some parts of Nigeria may make pregnant women to enter pregnancy with less than optimal Packed Cell Volume. The aim of this study was to determine the impact of maternal PCV at booking on the foetal birth weight and to identify other possible confounding factors that impact on foetal birth weight among pregnant women attending Antenatal care at BMCO, Nigeria.

Method: Statistical analyses were performed using the STATA 13 software package. The data were controlled for maternal age, parity, birth interval, maternal educational level, gestational age at delivery and pre-pregnancy BMI. Anonymized secondary data was analysed using descriptive statistics, chi square, Fisher exact, t-test and univariate and multivariate logistic regression analysis. A 2x2 categorical table and chi square (or Fisher exact test where cell values are less than 5) were used to test the association between the outcome variable-birth weight and maternal PCV with PCV less than 33% as measure of exposure and PCV greater than 33% as non-exposure. Logistic regression analysis was used to examine the association between maternal PCV and birth weight of the babies. Unadjusted and adjusted Odds ratios (OR) and their 95% CI were calculated from the logistic regression coefficients.

Results: Prevalence of low Packed Cell Volume among pregnant mothers at entrance in ANC was 55.45% while the prevalence of Low Birth Weight was 16.50%. Only estimated gestational age was found to be associated with birth weight {(OR 11.79, 95% CI (2.1545 – 64.4749) and p-value 0.004)}. All other confounding factors examined did not show any significant association with birth weight. The maternal age at booking ranged between 15 and 40 years. The mean age of the women was 30.61 ± 4.67 years. The mean maternal PCV at booking was 32.02% with 23% being the smallest PCV while the highest PCV was 43%. The median booking PCV of mothers who delivered a baby weighing less than 2500gm was 31% while the median booking PCV of mother who delivered a baby weighing between 2500gm and 4500gm was 32%.

Conclusion: The prevalence of low PCV and Low Birth Weight was 55.45% and 16.50% respectively. Women should be encouraged to attend ANC early in pregnancy and measures to prevent premature delivery should be instituted during ANC.

Keywords: Maternal PCV at Booking, Antenatal, Infant birth weight, retrospective cohort study, Ogbomoso, Nigeria