[1] Aminu Kano Teaching Hosp, Dept Obstet & Gynaecol, Kano, Nigeria
[2] Bayero Univ, Coll Hlth Sci, Dept Obstet & Gynaecol, Kano, Nigeria
[3] Murtala Muhammad Specialist Hosp, Dept Obstet & Gynaecol, Kano, Nigeria
[4] Gombe State Univ, Dept Community Med, Gombe, Nigeria
[5] Bayero Univ, Coll Hlth Sci, Dept Pathol, Kano, Nigeria
[6] Bayero Univ, Coll Hlth Sci, Dept Med Microbiol & Parasitol, Kano, Nigeria
[7] Aminu Kano Teaching Hosp, Dept Ophthalmol, PMB 3452,1 Zaria Rd, Kano, Nigeria