Association between post partum non-diabetic maternal HbA1c and fetal macrosomia at Kenyatta National Hospital : a case control study

Abstract

Introduction: The World Health Organization (WHO) defines macrosomia as an absolute birth weight of 4000 grams and above. Globally, it occurs in 0.5%- 15% of pregnancies and is associated with adverse maternal, fetal and neonatal outcomes and even later on in early childhood regardless of the maternal diabetes Mellitus (DM) status. Although there is a clear association between DM and macrosomia, not much has been studied between macrosomia and their non-diabetic counterparts, yet a majority of the macrosomic infants are born to non-diabetic mothers. HbA1c has been studied and used as a measure of existing high blood sugar levels, mainly for screening and monitoring treatment outcomes. HbA1c levels of 6.5% and abovehave been associated with DM. This study aimed at using non-diabetic maternal HbA1c levels taken in the immediate post-partum period, to identify any possible association between maternal HbA1c and fetal macrosomia. Any association would allow possible use HbA1c as a predictor of fetal macrosomia, warranting aggressive management, thus enabling its use as a screening tool even in non-diabetic patients. Broad Objective:To determine the association between postpartum non-diabetic maternal HbA1c and fetal macrosomia at Kenyatta National Hospital. Methodology: Ahospital-based case-control study in which immediatepostpartum non-diabetic maternal HbA1c of 85 women who delivered babies with macrosomia, birth weight of 4000g and above,were compared tothoseof 83 non-diabetic mothers who delivered normal weight babies, birth weight of 2500g-3999g. Daily birth registers andstructured questionnaires were used for screening and data collection. Blood samples were taken and HbA1c determined using latex agglutination method.Statistical analysis was performed using R software. Women were described using sociodemographic and obstetric factors. Characteristics of the cases were compared with the controls using appropriate statistical tests. Maternal age, weight, parity,and HbA1c were summarized into means and compared between the two groups using Student’s t-test. Simple logistic regression was used to determine the correlates of elevated HbA1c. Chi-square test of association was used to determine the association. Adjusted Odds Ratio was used to quantify association. Results:Out of the 83 women delivering normal weight babies, 7(8.4%) mothers had elevated HbA1c, while 7(8.2%) out of the 85 who delivered macrosomic infants had elevated HbA1c.There was no correlation between Age, BMI, Number of ANC visits, history of LGA, previous family planning use and fetal sex a with elevated HbA1c at a cut off of 6.5%. There was also no significant association between elevated HbA1c and fetal macrosomia. Conclusion:Age, BMI, Number of ANC visits, history of LGA, previous family planning use and fetal sex are not predictors of HbA1c. HbA1c is not a predictor of fetal macrosomia. Key words:Macrosomia, Glycated Hemoglobin, Obesity, Non-diabetes, Post-partum.