Not enough evidence to know how best to treat women with hypertension after birth. After birth, it is not uncommon for women to experience high blood pressure (hypertension), but it can have serious consequences. It can lead to stroke and, very rarely, death. It is unclear what causes hypertension after childbirth, or which women may develop the problem, although women with antenatal severe pre-eclampsia appear to be at highest risk. The review of nine trials found no reliable evidence to guide care for these women. Further research is needed, particularly as the problem occurs most commonly three to six days after birth when most women have left hospital.