<prompt> A positive Stallwohy;s sign is suggestive of which of the following conditions:Twin pregnancyBreech presentationVesicular moleLow lying placenta  <response>: If the earlier scan showed placenta completely over the internal os it is most likely to persist in the later scans.If the 18 -20 weeks scan revealed a low lying placenta or marginal placenta prae,placental localization is best repeated around 32 weeks refer pgno:130 sheila textbook of obstetrics 2 nd edition 