“…These included doctor' s advice (Baric et al, 1976;Valbo & Schioldberg, 1991, intervention2), ultrasound feedback (Reading et al, 1982, midwife training (Dunkley, 1997), and telephone support (Bullock et al, 1995). Moreover, unlike the 31 studies employing lea ets or manuals, none of these ve interventions used any additional intervention components.…”