1. ACOG Committee opinion. Number 267, January 2002: exercise during pregnancy and the postpartum period;ACOG Committee Obstetric Practice;Obstet Gynecol,2002
2. Royal College of Obstetricians and Gynaecologists Exercise in Pregnancy (RCOG Statement 4) http://www.rcog.org.uk/womens-health/clinical-guidance/exercise-pregnancy
3. Centers for Disease Control and Prevention Physical Activity. Healthy Pregnant or Postpartum Women http://www.cdc.gov/physicalactivity/everyone/guidelines/pregnancy.html
4. Leisure-time physical activity among pregnant women in the US;Evenson;Paediatr Perinat Epidemiol,2004
5. Compliance with leisure-time physical activity recommendations in pregnant women;Amezcua-Prieto;Acta Obstet Gynecol Scand,2011