Obesity among women of childbearing age and excessive weight gain during pregnancy are prevalent and steadily increasing health care issues. Regular physical activity is recommended to maintain healthy weight gain for pregnant women, however, a majority of pregnant women are sedentary. The investigators proposed to conduct a pilot study to estimate the potential efficacy of a mobile phone based physical activity intervention in 30 physically inactive pregnant women.

Inclusion Criteria:

• pregnant, gestational week (10-20 weeks)
• pre-pregnancy BMI ≥ 18.5 kg•m2
• physically inactive at work and during leisure time
• intent to be physically active
• access to a home telephone or a mobile phone
• have a personal computer access
• ability to communicate (speak and read) in English.

Exclusion Criteria:

• known medical or obstetric complication that restricts physical activity
• history of eating disorders
• current participation in lifestyle modification programs
• history of bariatric surgery.

12 weeks