Australian study examines diabetes and birth outcomes: pregnancy can be affected by diabetes, but are the outcomes as serious as we believe?
Gestational diabetes mellitus (GDM) is a common disease, and its incidence is increasing. Previous studies have shown a correlation between pre-diabetes and gestational diabetes, with age, maternal obesity, and socioeconomic status to be risk factors in developing the disease. Gestational diabetes can cause problems with pregnancy, with labor, and after the birth. A person with GDM has an increased risk of developing T2DM and the offspring has a higher chance as well.
This study aimed to examine changes in the trends in diabetes during pregnancy (GDM and pre-existing diabetes) from 2011 to 2017 among pregnant women in Western Sydney, Australia. The secondary objectives were to determine the risk factors of the trend of diabetes over the study period and to investigate trends in the birth outcomes over the study period in association with diabetes and other confounding factors. Birth outcomes included C-section, episiotomy, admission to the SCN/NICU, postpartum hemorrhage and neonatal birth weight.
This retrospective cohort obtained patients from a single hospital in Sydney, Australia. Population characteristics did not affect the trends in the incidence of diabetes and birth outcomes. GDM was determined by allowing women who were at a gestational age of 24-28 weeks to fast 8 to 10 hours over the night before the test and record the fasting plasma glucose level. If the level was less than 5.5 mmol/L, then it was normal. Then an oral glucose tolerance test was given and if the 2-hour glucose level was higher than eight mmol/L, gestational diabetes was diagnosed. Descriptive statistics were used to summarize the demographic data and multivariate regression modeling was used to estimate adjusted trends and effects of factors of interest.
From 2011 to 2017, 37,450 women gave birth and were considered for analysis. Of these, 17% gave birth more than once in the study period. A total of 4,504 had GDM (12%), and 1% had pre-existing diabetes. The rate of diabetes in pregnant women increased from 9.5% in 2011 to 15.6% in 2017 (p<0.001). The incidence of diabetes was 6% greater in women who received doctor-led care compared to midwifery-led care during pregnancy (RR = 1.06, 95% CI = 1.01-1.13), 42% greater in women who had other endocrine diseases (RR = 1.42, 95% CI = 1.31-1.53), and 61% greater in women with hypertension (RR = 1.61, 95% CI = 1.47-1.78).
The analysis of maternal and neonatal outcomes found incidences of episiotomy, PPH and neonatal admission to the SCN/NICU increased from 2011 to 2017 (p<0.05). The rate of cesarean section and the average birth weight for babies was slightly decreased (p<0.05). A regression model was used to focus on variables that increased the risk of untoward birth outcomes. The risk of having a C-section was higher in women who were over 35 years old, were non-Australian born, had a high BMI, had undergone assisted conception, received antenatal doctor–led care and who had neurological diseases.
Advanced maternal age, being non-Australian born, and having undergone assisted conception were significant risk factors for postpartum hemorrhage, but the risk was smaller in parous women and women with overweight and obesity p<0.05. The risk of episiotomy was lower in women who were over 35 years old, were parous, smoked, and had a high BMI. The risk was more significant in non-Australian born women. NICU/SCN admission was lower if their mothers were parous, over 35 years old, smoked, had a high BMI and received antenatal doctor-led care. The risk was higher in babies of non-Australian born mothers. Women who were non-Australian born, smoked and had assisted conception were at higher risk for having smaller babies.
After adjusting for all the risk factors in the regression model, total diabetes (pre-existing and gestational) was shown to be associated with the doctor-led model of care, endocrine diseases and hypertension. The increasing rate of diabetes reported from the study supported findings from previous studies and aligns with global forecasts for diabetes. Being at one site is a limitation of this study so the results can not represent a world population. In the future, research at multiple locations and different risk factors should be measured to analyze all factors adequately.
- The rate of diabetes during pregnancy is increasing yearly.
- Women who received doctor–led care and had hypertension or thyroid, adrenal and or pituitary disease during pregnancy had higher rates of diabetes.
- Adverse outcomes were not related to diabetes.
Khajeheiand H. Assareh, Temporal trend of diabetes in pregnant women and its association with birth outcomes, 2011 to 2017, Journal of Diabetes and Its Complications(2020)
Antonio Bess, Pharm D Candidate, Florida A&M University