The use of an agent for controlling vascular permeability within the cervix is disclosed for controlling cervical ripening. To hasten cervical ripening, the agent is one which increases vascular permeability and is selected from VEGF₁₂₁, VEGF₁₄₅, VEGF₁₆₅, VEGF₁₈₉, VEGF₂₀₆, a smaller, active VEGF fragment, and placenta growth factor (PlGF). If cervical ripening is to be delayed, the agent is one which reduces vascular permeability, e.g. a VEGF receptor antagonist or antibody. The agents of the present invention can be used as a means of managing labor.