Exercise as it relates to Disease/Exercise to Prevent Gestational Diabetes

Exercise to Prevent Gestational Diabetes
This wiki will critique the following article: A randomized clinical trial of exercise during pregnancy to prevent gestational diabetes mellitus and improve pregnancy outcome in overweight and obese pregnant women by Chen Wang, PhD1; Yumei Wei, MD1; Xiaoming Zhang, MD; Yue Zhang, MD; Qianqian Xu, MD; Yiying Sun, MD; Shiping Su, BS; Li Zhang, BS; Chunhong Liu, BS; Yaru Feng, BS; Chong Shou, PhD; Kym J. Guelfi, PhD; John P. Newnham, MD, PhD; Huixia Yang, MD, PhD ￼￼￼￼￼￼￼￼￼

What is the background to Gestational Diabetes
Gestational diabetes mellitus (GDM) is a condition that can occur in pregnancy, where the pregnant woman's blood sugar is too high, and her body cannot produce enough insulin. Development of GDM can lead to other risks in pregnancy for both child and mother. Typically babies are much larger, resulting in the need for more intervention and sometimes caesarian birth. There is often more amniotic fluid in the womb, which can lead to premature birth. Premature birth is another risk, where babies are born before 37 weeks of gestation. Post birth, babies may continue to have high blood sugar, and may develop jaundice, which can require hospitalisation. In some rare cases it can also lead to still birth.

Recent studies have shown that being an overweight or obese woman can double the chances of developing GDM. With obesity on the rise, this can lead to more women developing GDM, increasing the risk to mothers and their unborn children.

As such, there is currently a lot of research being undertaken, to evaluate what may work in reducing the prevalence of GDM in overweight and obese women. The following critique will look at one such example of this research.￼￼￼￼￼￼￼￼￼

Where is the research from?
This study was undertaken at the Department of Obstetrics and Gynaecology, Peking University First Hospital, China. The women involved in the study would come to the hospital to participate in exercise 3 times a week. Currently, a lot of research has been undertaken in caucasian women, with less being done in other populations. This study hopes to look at the effect of exercise on development of GDM in Chinese women.

What type of study is this?
The study was a randomised control trial consisting of an exercise intervention. The intervention had women come in three times a week to exercise on a stationary bike, with a control group who were not discouraged to undertake exercise, but were otherwise encouraged to continue their normal everyday activities. A randomised control trial such as this provides strong evidence that the intervention, exercise, will work in regards to preventing GDM.

What did the research involve?
This study had 300 pregnant overweight or obese women recruited in the trial. The average BMI was 26.78kg/m2 of 10 weeks gestational age, with an average age of 32years. They were computer allocated into a control and intervention group. The control group were given standard prenatal care and advice and were encouraged to continue their daily physical activity. Whereas the intervention group participated in an exercise intervention, involving interval training on a stationary bike three times a week. The participants intensity was measured through calculating age predicted heart rate max and using the Borg scale. Compliance with the exercise programme was 80%. At the end of the trial analysis was undertaken on 132 women in the exercise group and 133 in the control group, due to drop out. The researchers were looking for changes in primary and secondary outcomes. The primary outcome was the incidence of GDM in overweight and obese women. Secondary outcomes were related to both mother and child, maternal outcomes were; physical activity levels, gestational weight gain, biochemical outcomes, insulin resistance and lipid profiles, gestational hypertension, preeclampsia, proteinuria and mode of delivery. Neonatal outcomes were gestational age, preterm, Apgar score, birthweight and macrosomia.

What were the basic results?
The results of the study were:

1: That incidence of GDM was significantly reduced in the exercise group (22% compared to 40.6% in the control group) 2: Less gestational weight gain in the mid-second trimester and final trimester 3: Lower insulin levels compared to the control group 4: Reduced birth weight in the exercise group

How did the researchers interpret the results?
The researchers found that supervised exercise three times a week reduced the incidence of GDM in overweight and obese women. They found that their results were inline with a similar study by Cordero, who similarly started their exercise intervention earlier in pregnancy. However there are other papers that state that exercise with a similar exercise protocol of this study has no difference in GDM incidence. However, the authors argued that this was to do with selection criteria issues as well as that this study, similar to Cordero's was initiated earlier in pregnancy, meaning that the timing initiation of exercise in pregnancy may have an effect. The authors also noted that the significantly different birth weight in the exercise group was similar to another study which also exercised women at a higher intensity than other studies. This led to the authors believing that exercise intensity may also influence the effectiveness of the intervention.

What conclusions should be taken away from this research?
This study has shown that supervised exercise three times a week is clinically significant in reducing the incidence of GDM in overweight and obese pregnant women. However, the authors believe that this is dependent on starting the exercise intervention early in pregnancy (from 10 weeks), and that doing exercise in a supervised manner will increase compliance and effectiveness of the intervention. They also state that this is an area that requires further research, with a multi-centre and different ethnicities, to ensure its effectiveness. It would also be important to evaluate the use of dietary interventions along with exercise in reducing the incidence of GDM, these are weaknesses that the authors point out in their research, and may effect the reliability of the research.

What are the implications for this research?
This study has shown that a supervised exercise programme on a stationary bike utilising interval training and using the Borg and age predicted heart rate maximums, is a useful protocol in reducing the incidence of GDM in overweight and obese pregnant women, when started early in pregnancy. This helps to improve the body of evidence currently available that exercise began in early pregnancy can reduce GDM incidence. The protocols used in this study should be used again to assess reliability and validity, across not only the Chinese population but other ethnicities as well. If proven successful, this intervention could improve the outcomes for women and their children worldwide, especially for those who are more at risk, such as the overweight and obese.

For Further Information
Diabetes Australia Webpage: https://www.diabetesaustralia.com.au/managing-gestational-diabetes

If you are concerned about gestational diabetes, please do not hesitate to talk to your GP, Midwife or Obstetrician about management.

If you are in the ACT and are interested in supervised pregnancy exercise classes please contact the following:

Hughes Hydro: https://www.hugheshydro.com.au/classes Bub and Me: https://www.bubandme.com.au/