Is lower socio-economic status a risk factor for Helicobacter pylori infection in pregnant women with hyperemesis gravidarum? - KARACA, Çetin; GÜLER, Nilay; YAZAR, Aziz; ÇAMLICA, Hakan; DEMİR, Kadir and YILDIRIM, Gonca (Turkish Journal of Gastroenterology, 2004)