INTRODUCTIONPlacental migration is a phenomenon that was described by serial sonographic examinations by many authors. The presence of a lowlying also termed as placenta previa in the second trimester of pregnancy can be converted to an upper uterine segment placenta by the end of the third trimester [1]. This phenomenon is important when a complete or marginal placenta previa is encountered in the second trimester of gestation because of the need to predict possible antepartum complications and mode of delivery [2]. Placenta previa can be defined as one that covers the internal os of the cervix and lowlying placenta as one of which the edge is 1mm to 20mm of the internal os [3]. A distance of more than 20 mm from the lower placental edge and cervical internal os in the second trimester is a normal finding that does not represent a lowlying placenta and does not require followup.In cases of suspected placenta previa or lowlying placenta, the first step in determining accurate placental position in relation to the cervix is to perf orm a trans-vaginal-ultrasound-scan (TVUS) on patient whose bladder is empty [4,5,6,7]. In at least one quarter of all cases of placenta previa or lowlying placenta suspected on the basis of transabdominal sonograph y in the second trimester, the diagnosis will change after TVU is performed [3,5,7].Those patients who do not have placenta previa or lowlying placenta can then be reassured and will require no further follow up. The aim of the present study was to compare the rates and patterns of placental migration in the third trimester of pregnancy and to correlate these findings with the mode of delivery. MATERIALS AND METHODS Study design: Prospective analytical studyEthics approval: The study was approved by the Institutional Ethics Committee, and informed consent was obtained from each participant. Place of research: The ABSTRACT Introduction: The presence of a lowlying in the second trimester of pregnancy can be converted to an upper uterine segment placenta by the end of the third trimester. This phenomenon is important when a complete or marginal placenta previa is encountered in the second trimester of gestation because of the need to predict possible antepartum complications and mode of delivery. Aim: To examine the migration of placenta and the placental marginal sinus to predict the eventual route of delivery in low-lying placenta. Methodology: Women with a low-lying placenta with 30 weeks of gestation were included for study. The distance between the internal os and leading edge of the placenta was measured fortnightly using transvaginal ultrasonography until 36 weeks gestation. The relationship between the rate of placental migration, the presence of a placental marginal sinus and the eventual mode of delivery was investigated. Results: In the present study cesarean section rate was 60 % (39/65) in the slow migration group (0 -2.0 mm/week) group, six patients (6/35) in the fast (more than 2.0 mm/week) migration group underwent a cesarean section (p < 0.01) because of other...

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