The present invention relates to a wind turbine blade (10) comprising an elongate reinforcing structure (62). The reinforcing structure (62) comprises a plurality of strips (63, 64, 65) of fibre-reinforced polymer arranged into adjacent stacks (66) of strips, and at least one alignment member (68). The latter comprises a plurality of alternating horizontal segments (70) and vertical segments (72), wherein a vertical segment of the alignment member is arranged between adjacent stacks of strips, and wherein a horizontal segment of the alignment member is arranged on top of or below each stack of strips. At least one of the vertical segments (72) comprises one or more apertures (84) for allowing resin to flow from one side of the vertical segment to the other side of the vertical segment.