Purpose: To review the placenta weight birth weight ratio (PWBW ratio) and determine an association between PWBW ratio and gestational age in patients with placenta previa. Methodology: This descriptive cross sectional study took place in Gynae A unit, Medical Teaching Institute, Lady Reading Hospital, Peshawar, Pakistan, from March 2018 to February 2020.Ethical approval from IRB (institutional review board) was taken before start of study. Patients with genital tract bleeding were admitted throughout patient department and Emergency with 28 weeks gestation and onwards. Diagnosis of placenta previa was confirmed and were included in study after taking consent. Results: Total of 173 patients with placenta previa were admitted in gynae A. Patients with major placenta previa were 151 (87.2%) while 22 (12.7%) patients had minor placenta previa. Birth weight placental weight ratio was calculated by measuring weight of placenta and baby after the delivery. Most of the patients, 92 (53.2%) had PWBW ratio less than 1:6 (relatively large placenta), patients with BWPW ratio of 1:6 (normal ratio) were 14 (8.1%) and 67 (38.7%) patients had PWBW ratio of 1:6 (relatively smaller placenta). Patients with placenta previa have relatively larger placenta (PWBW ratio less than 1:6) to compensate for lesser vasculature of lower uterine segment. Patients with larger placenta are prone to necrosis and abruption. Recommendation: igilant antenatal care and surveillance in these patients due to higher incidence of antepartum and postpartum hemorrhage, as well as invasive propensity of lager placenta.
