Utero-vaginal differential pressure during the first stage of labour.
D003371:Cough; D005260:Female; D006801:Humans; D007743:Labor, Obstetric; D009119:Muscle Contraction; D010298:Parity; D011187:Posture; D011247:Pregnancy; D011312:Pressure; D001743:Urinary Bladder / Q000502:physiology; D014599:Uterus / Q000502:physiology*; D014621:Vagina / Q000502:physiology*