Maternal obesity as a risk factor for caesarean section: a case control study

Abstract

INTRODUCTION Obesity is the most common nutritional disorder in the affluent industrialized and developed world. 1 Body mass index is nowadays accepted as a reasonable measure of overweight and underweight. Worldwide obesity, as defined by a BMI>30, exists at a prevalence of 15-20% and accounts for substantial amount of health care costs. In India no data regarding the magnitude of obesity in pregnancy is available. High pre-pregnancy BMI is associated with adverse maternal outcomes like early miscarriage, PIH, preeclampsia, gestational Diabetes mellitus, thrombo-embolic phenomena, prolonged labour and rising C.S rates. 2-4 Additional complications include intra operative and post-operative complications, and difficulties related to anaesthesia management. ABSTRACT Background: Obesity is the most common nutritional disorder in the affluent, industrialized and developed world. Worldwide it exists at a prevalence of about 20% when Body Mass Index of more than 30 was considered. According to the current Asian Guidelines a BMI >25 in pregnancy is considered to be obese. Maternal obesity is on the rise and so are the maternal and perinatal complications. The objective of the study was to find out if maternal obesity was an independent risk factor for Caesarean section. Over the years, there have been innumerable accounts of obstetricians coming under the media and public ire, blaming them for the rising Caesarean section rates. This study was undertaken to know if changing socio-demographic characteristics have also contributed to the rise. Methods: This was a case control study. In order to have uniformity amongst 'cases' and 'controls', in terms of age group and other co morbidities, only primigravida were included in this study. It was conducted in, a tertiary reference centre in Thiruvananthapuram under government sector which mostly caters to low and medium socioeconomic groups. The 'cases' were defined as 'all subjects who underwent Caesarean section' and the 'controls' were defined as 'all those who underwent vaginal delivery'. Data were collected, after informed consent, by going through patient records and interview method using a questionnaire. Sample size was statistically calculated using data conducted from a pilot study done, using few subjects. Current Asian guidelines for obesity were used with BMI >25 being considered as obese and weight of the pregnant women in the very first visit was considered, if in the first trimester. Literature search has shown very few studies that were done considering current Asian guidelines. Results: This study conclusively proved that maternal obesity is an independent risk factor for Caesarean section. The odds of ending up in caesarean section are about 2.8 times more amongst the obese than the non-obese. When the overweight and obese were considered together, the odds of ending up in Caesarean section was 2.3 times more. Conclusions: Since obesity is an independent risk factor for Caesarean section, it is imperative that weight control measures are initiated from adolescence. Preconceptional counseling regarding weight control is also important to prevent complications of obesity in reproductive years.