Screening of gestational diabetes mellitus in pregnant women in public hospitals of urban Bengaluru

Introduction

Gestational diabetes mellitus (GDM) is one of the most common metabolic complications of pregnancy and is increasing rapidly. GDM is defined as carbohydrate intolerance of varying degrees of severity with onset or first recognition during the pregnancy.1 Gestational diabetes mellitus is caused when insulin receptors do not respond to glucose levels, this is primarily due to pregnancy hormones like human placental lactogen.2 Gestational Diabetes Mellitus poses a risk to pregnant women and the infant. Maternal complications of GDM are Pre-eclampsia, Polyhydramnios, elevated rates of operative delivery and preterm labour. Main Morbidities associated with infants of diabetic mothers include respiratory distress, Macrosomia, Polycythaemia, Hypoglycaemia, Hypocalcaemia and congenital malformations.3,4 Several risk factors are associated with the development of GDM. The most common risk factors include age, history of macrosomia, polycystic ovarian syndrome, gestational hypertension, spontaneous abortions and unexplained stillbirths and family history of diabetes.5-7

It is important to identify a pregnant woman with GDM because GDM is associated with increased perinatal mortality and morbidity, maternal morbidity and future risk of NCDs among mothers and their offspring. More than 70 million people are living with diabetes in India, and 3-42% of pregnant women have GDM.8 In India, it is difficult to predict universal prevalence levels because of wide differences in living conditions, socioeconomic levels and dietary habits. The data regarding the prevalence of GDM and the related risk factors are important to allow for rational planning and allocation of resources and the preventive strategies. Different prevalence rates have been observed in different regions of India, several regional studies in different subtypes of populations are needed for quantifying prevalence data as well as risk factors associated with it. The objective of this study is to find out the proportion of GDM in the women attending public hospitals and to find out the association between the socioeconomic and anthropometric factors with GDM.

Materials and methods

Study Settings

The study was conducted at Srirampuram Referral Hospital of Bruhat Bengaluru Mahanagara Palike and Jayanagar General Hospital.

This study included pregnant women in the vicinity of the above-mentioned public hospitals; women in the gestational age of14 weeks to 36 weeks of pregnancy irrespective of parity were recruited. The study duration was from 18th December 2017 to 3rd March 2018. Ethical approval was obtained from the IIPH/Bengaluru Institution Ethics Committee. Permission was granted from Chief Health Officer (Public Health) Bruhat Bengaluru Mahanagara Palike and Directorate of Health and Family Welfare. Considering17% prevalence,95% Confidence Interval, 10% Precision and 80% Power and calculated sample size were 170. It was a cross-sectional study done; we collected data in 184 women and included the same in analysis. Pregnant women are irrespective of parity who were residing in the same study location and willing to give written informed consent were included. We excluded pregnant women who had previous history of diabetes, a major illness like carcinoma, tuberculosis, HIV, HBsAg and VDRL positive.

Procedure

The orientation program was conducted for the doctors and hospital staff. Trained research assistant and phlebotomist were involved in the study for data collection and sample withdrawal. The research assistant informed about the study and obtained a signed written consent for the participation. A baseline questionnaire was administered, which included socioeconomic status details, obstetric history, family history of NCDs, weight, height and head circumference was recorded. Blood pressure was recorded using an automated B.P. apparatus.

Pregnant women who completed 24 weeks of gestational age were invited for haemoglobin and oral glucose tolerance test (OGTT) with instructions to come fasting for a minimum of 8 hours since the previous night. On the day of investigation, fasting venous blood sample was collected that was followed by 75gms of an oral load of glucose and second venous blood sample was collected after 2 hours. The women were given the blood report results and in case of blood glucose was higher than (FBS ≥92 or PPBS ≥153) they were referred to the doctor at the hospital. They were counselled about diet and lifestyle modification by research team.

Lab Analysis

5ml of fasting venous blood sample was collected and 2ml postprandial sample 2hours after following a 75g oral load of glucose for the laboratory investigations. The fasting sample was collected in EDTA and sodium fluoride vacutainers for haemoglobin and glucose assays, respectively. Blood samples for glucose test were centrifuged and transferred in cool boxes to a central laboratory.

Statistical analysis

Descriptive analysis of data was done and presented as frequency, mean and %. Univariate and multivariate regression analysis were carried out for finding association in SPSS software.

Results

Majority of the respondents belong to the age category of 18- 25 years (69.56%) with Hindu women in a relatively larger proportion compared to Muslims (54.89% vs 41.30%). Majority of them have studied till high school (60.32%) and the same applies to their husbands as well (67.39%). Majority of the respondents are unemployed (92.39%) while 50% of the husbands are unskilled workers. 66.3% of the respondents belong to the Upper lower socioeconomic class. A relative majority of the women (34.23%) were pre-obese as per Asian BMI criteria. 90.65% of them had normal blood pressure levels. 38.04% of the respondents were anaemic, and 16.84% were diagnosed with gestational diabetes. Majority of the women were first-time expectant mothers.

15.76% of mothers of the respondents had diabetes, and 22.28% were hypertensive. Amongst the fathers, 11.95% were diabetic, and 11.41% were hypertensive. 21.73% of the Mothers-in-law had diabetes, and 22.28% were hypertensive. 11.95% of the Fathers-in-law had diabetes, and 8.15% were hypertensive

Majority of the GDM and non-GDM respondents belonged to the age category of 18- 25 years (64.51% and 70.58%). However, no significant statistical association between age and GDM (p value= 0.76). Both GDM and non-GDM respondents largely had normal blood pressure levels (80.64% and 92.71%). A significant association was seen between blood pressure and GDM (p value= 0.04). As per Asian BMI criteria, the majority of the GDM respondents were obese (38.7%), and majority of the non-GDM respondents were pre-obese (35.29%). A significant association was seen between BMI and GDM (p value= 0.01).

Both GDM and non-GDM respondents were largely belonging to the Upper lower socioeconomic class (61.29% and 67.32%). No significant statistical association was seen between Socioeconomic Status and GDM (p-value = 0.78, which >0.05). Majority of the GDM and non-GDM respondents had studied till high school (48.38% and 62.74%) and there was no significant statistical association between respondent education and GDM (p-value = 0.45 which is > 0.05). Relationship between husband's education and GDM showed similar results with p-value = 0.87. 

Respondent’s anthropometric measurements like standing height and head circumference did not have any association with GDM. Neither was education and parity associated.

Discussion

Our study assessed the characteristics of gestational diabetes in pregnant women who were screened in a public health facility. Our study found a high burden of GDM (16%) in relatively younger women, mostly from a lower socioeconomic class. The prevalence of GDM in our study is similar to that reported in another study in South India (Tamil Nadu, Chennai urban population) –GDM in (17.8%) women in urban, (13.8%) in semi-urban and (9.9%) in rural areas.12

Most of the respondents had completed a high school education and were unemployed. However, we did not find any significant association between socioeconomic status and other associated parameters like age, education, and salary to be associated with GDM. This could be because our study population is relatively very young, 70% of them were less than 25 years of age, and only 35% of them attended college. Over 92% of the respondents were unemployed and belonged to the upper-lower socioeconomic class.

One-third of the population were anaemic both in GDM and Non-GDM categories. We found that mothers who were anaemic had higher odds of developing GDM than those with normal Hb; however, the results were not statistically significant. Blood pressure of the respondents was significantly associated with GDM in our study.

Majority of the GDM respondents were obese(38.7%) and BMI association was statistically significant with GDM in unadjusted model. Several studies have provided enough evidence that increasing maternal BMI were the important determinants of GDM.13-16 Obesity in pregnancy is a recognized risk factor for many maternal and neonatal adverse outcomes including increased rate of caesarean section, macrosomia, preeclampsia and gestational diabetes (GDM).17

A few studies investigated the independent effect of obesity and maternal hyperglycemia on the pregnancy outcome. Ricard et al., who investigated the independent effects of obesity and GDM on fetal weight, caesarean section delivery and pregnancy-induced hypertension, found that obesity had a greater independent effect on these adverse outcomes compared to GDM.18 HAPO study cohort, the research group, reached a similar conclusion.; however, the greater impact of obesity was not consistent across all the studied adverse outcomes.3 In our study the association was not strong, reasons for the weak or missing impact of BMI on GDM risk may be that BMI determinations were based on the weight in gestational week 17–36, as well as the possibility that the effect of BMI to some extent may be mediated via other factors. Other recent studies have reported a weak impact of BMI on the risk of T2D in a low-income country.19

Conclusion

The present study reports a high prevalence of GDM from a public hospital in Bengaluru. The rising prevalence highlights the importance of carrying out prevalence studies in different geographical regions of India to delineate the exact prevalence of GDM in the country. Women with GDM are at an increased risk for adverse obstetric and perinatal outcomes. With effective screening and management of GDM, we can prevent its adverse effects on pregnancy outcome.