title: The Association Between Physical Activity During Pregnancy and Gestational Diabetes Mellitus: A Case-Control Study.
abstract: BACKGROUND
  Gestational diabetes mellitus is one of the most common complications of pregnancy. Physical activity is associated with a lower risk of type 2 diabetes mellitus. A recent meta-analysis study suggested that more research is needed to investigate the type, duration and intensity of physical activity that can help to reduce the risk of gestational diabetes mellitus.
  
  
  OBJECTIVE
  The present study aimed to understand the association between physical activity and gestational diabetes mellitus through comparing the type and intensity of physical activity performed by pregnant females with gestational diabetes and healthy pregnant females in the first 20 weeks of their pregnancy.
  
  
  METHODS
  In the current case-control study, 100 pregnant females with gestational diabetes mellitus as the case group and 100 pregnant females as the non-diabetic control group were recruited. The age range of the participants was 18 - 40 years with the gestation of 20 - 28 weeks. To diagnose gestational diabetes mellitus using the criteria introduced by carpenter and coustan females with abnormal glucose challenge test (> 140 mg/dL) were asked to perform the three-hour 100 g oral glucose tolerance test. The details of physical activity were collected by a modified version of the pregnancy physical activity questionnaire. Anthropometric and relevant data were recorded for all of the participants. Data were analyzed by SPSS version 21. Risk estimates were obtained by logistic regression and adjusted for confounders.
  
  
  RESULTS
  Females who had low total physical activity according to the pregnancy physical activity questionnaire during early pregnancy were at a significantly higher risk of developing gestational diabetes mellitus (OR = 4.12, 95% CI (2.28 - 7.43), P = 0.001) compared to the ones who reported higher levels of physical activity. Moreover, after adjusting for age, body mass index (BMI), gravidity and a family history of diabetes, females with low physical activity in the domain of transportation activity during 20 weeks of pregnancy were at a significantly higher risk of developing gestational diabetes mellitus. The statistical findings indicate that females with the low intensity of sedentary, light and moderate physical activity are at a higher risk of developing gestational diabetes mellitus (OR 2.32; 95% CI 1.21-4.43, P = 0.010, OR 6.26; 95% CI 2.95 - 13.30, P = 0.001 and OR 6.73; 95% CI 3.15 - 14.38, P = 0.001) compared to females with a higher intensity of sedentary, light and moderate physical activity.
  
  
  CONCLUSIONS
  The amount and intensity of physical activity during pregnancy is associated with a lower risk of gestational diabetes mellitus. As a result, the pregnant Iranian females have to be encouraged to do regular daily physical activity during pregnancy, if there is no specific contraindication to it.
authors.affiliation: Assistant Professor, Department of Midwifery, Babol University of Medical Sciences, Babol, IR Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Nasiri-Amiri
authors.affiliation: Assistant Professor, Department of Midwifery, Babol University of Medical Sciences, Babol, IR Iran.
authors.forename: Afsaneh
authors.initials: A
authors.lastname: Bakhtiari
authors.affiliation: Assistant Professor, Fatemeh Zahra Infertility and Reproductive Health Research Center, Department of Psychiatry, Faculty of Medicine, Babol University of Medical Sciences, Babol, IR Iran.
authors.forename: Mahbobeh
authors.initials: M
authors.lastname: Faramarzi
authors.affiliation: Infertility and Reproductive Health Research Center, Health Research Institute, Department of Midwifery, Babol University of Medical Sciences, Babol, IR Iran.
authors.forename: Hajar
authors.initials: H
authors.lastname: Adib Rad
authors.affiliation: Infertility and Reproductive Health Research Center, Health Research Institute, Department of Midwifery, Babol University of Medical Sciences, Babol, IR Iran.
authors.forename: Hajar
authors.initials: H
authors.lastname: Pasha
keywords: Gestational Diabetes Mellitus; Physical Activity; Pregnancy Physical Activity Questionnaire; Risk Factors