pls help

hi mommies,i just ask this behalf of my fren, now she pregnant 7 weeks ,wen check wit upt its positive but at gh said can't see the baby n suspect baby sangkut kat tiub follopion... then they gv 2 weeks time for scan again n confirm... little confuse her last period on 14 feb, but on feb she nvr make love wit husband, she make love on march 10 selang seli... so is it possible she ovulate witout period on march.. on april she check upt +ve.. n one more question y baby stil cant see? mayb baby too small or wrongly calculate of last period... anybody pls help ..