1. Faculty of Medicine, Universitas Sumatera Utara, Medan, 20155, Indonesia
2. Obstetrics and Gynecology Department/SMF, Faculty of Medicine Universitas Sumatera Utara, RSUP Haji Adam Malik, Medan, 20155, Indonesia
3. Physiology Department, Faculty of Veterinary Medicine, Universitas Gadjah Mada, Yogyakarta, 55821, Indonesia