1. Infection Control Section, Mae Sot Hospital, Tak Province, Thailand.
2. Division of Nursing Science, Faculty of Nursing, Chiang Mai University, Chiang Mai Province, Thailand.
3. Obstetrics and Gynecology Department, Chiang Mai University, Chiang Mai Province, Thailand.
4. Obstetrics and Gynecology Department, Lampang Hospital, Lampang Province, Thailand.
5. Obstetrics and Gynecology Department, Nakornping Hospital, Chiang Mai Province, Thailand.