Combination of a structured aerobic and resistance exercise improves glycaemic control in pregnant women diagnosed with gestational diabetes mellitus. A randomised controlled trial

Abstract

Problem

Gestational diabetes mellitus, defined as any carbohydrate intolerance first diagnosed during pregnancy, is associated with a variety of adverse outcomes, both for the mother and her child.

Aim

To investigate the impact of a structured exercise programme which consisted of aerobic and resistance exercises on the parameters of glycaemic control and other health-related outcomes in pregnant women diagnosed with gestational diabetes mellitus.

Methods

Thirty-eight pregnant women diagnosed with gestational diabetes mellitus were randomised to two groups. Experimental group was treated with standard antenatal care for gestational diabetes mellitus, and regular supervised exercise programme plus daily brisk walks of at least 30 min. Control group received only standard antenatal care for gestational diabetes mellitus. The exercise programme was started from the time of diagnosis of diabetes until birth. It was performed two times per week and sessions lasted 50–55 min.

Findings

The experimental group had lower postprandial glucose levels at the end of pregnancy (P < 0.001). There was no significant difference between groups in the level of fasting glucose at the end of pregnancy. Also, there were no significant differences in the rate of complications during pregnancy and birth, need for pharmacological therapy, maternal body mass and body fat percentage gains during pregnancy, and neonatal Apgar scores, body mass and ponderal index. Neonatal body mass index was higher in the experimental group (P = 0.035).

Conclusion

The structured exercise programme had a beneficial effect on postprandial glucose levels at the end of pregnancy.

Introduction

Gestational diabetes mellitus (GDM) is defined as any carbohydrate intolerance first diagnosed during pregnancy.¹ It accounts for 90–95% of all cases of diabetes in pregnancy and is the most common metabolic disorder encountered during pregnancy.² The prevalence of GDM is rising, and it is directly related to the prevalence of type 2 diabetes in a given population.2, 3

GDM is associated with a variety of adverse outcomes, both for the mother and for the fetus. Possible consequences for the mother include an increased rate of perinatal complications, hypertension during pregnancy and preeclampsia. Long term, there is an increased risk of developing type 2 diabetes, metabolic syndrome, obesity, cardiovascular morbidities and recurrent GDM.2, 4 Maternal hyperglycaemia causes an excessive transfer of nutrients – specifically glucose – to the fetus, resulting in fetal hyperinsulinaemia, fetal adiposity, macrosomia and perinatal complications. Long term, these children are also at increased risk of developing obesity, metabolic syndrome, type 2 diabetes and hypertension.⁵

The primary aim of treating GDM is to optimize glycaemic control and improve pregnancy outcomes.⁶ Changes in diet and lifestyle are usually recommended as the primary therapeutic strategy to achieve acceptable glycaemic control.³ If these measures fail to establish adequate glycaemic control within 1–2 weeks, pharmacological therapy is introduced. It is also recommended to continue or initiate exercise at moderate intensity for all pregnant women without contraindications.2, 3

Exercise is associated with significant, beneficial physiological and metabolic changes and responses to exercise are not different in comparison to the non-pregnant population.⁷ Today, physical activity is recommended as a part of antenatal care.⁸ Furthermore, exercise leads to improved insulin sensitivity and blood glucose levels in patients with type 2 diabetes.⁹ Both aerobic and resistance exercises, especially in combination, have shown beneficial effects in patients with type 2 diabetes.¹⁰ Studies have shown a correlation between higher levels of physical activity before and during early pregnancy with a lower risk of developing GDM.¹¹

While the use of exercise in the treatment of type 2 diabetes is supported by plenty of evidence, there is a limited body of evidence exploring the effects of exercise on the course and outcomes of GDM. Only nine prospective trials were found that investigate this subject, seven randomised,12, 13, 14, 15, 16, 17, 18 and two non-randomised.19, 20 Seven of these trials examined the effects of aerobic exercise programmes,12, 13, 14, 17, 18, 19, 20 whereas only two examined the role of resistance exercises.15, 16 None of the trials examined the effects of combining aerobic and resistance exercises.

Hence, the purpose of this trial was to investigate the health-related effects of implementing a supervised, individualised, structured exercise programme, consisting of aerobic and resistance exercises, on the course and outcomes of GDM. We hypothesized that this exercise programme would improve: glycaemic control, the rate of complications during pregnancy, weight gain and body fat percentage changes during the pregnancy, the rate of complications and mode of birth, and the health status and weight of the newborn.