Her appointment follows a two-month stint as acting editor, covering the role following the departure in October of Jayne Marsden.
Before joining the magazine she worked at IPC's Ideal Home title, joining first as art director in 1998 and in 2001 was promoted to associate editor.
She has previously worked at NatMags as deputy art director on Prima.
Developments since Pates joined have included using photographs of parents on the front cover for the first time. Previous covers only featured babies and toddlers.
Magazine developments last year included a 12-week run of a stand alone baby products title Buying for Baby.