Both low and high maternal diastolic blood pressures during pregnancy are associated with lower birth weight of firstborn babies and higher perinatal mortality. Steer and colleagues (p 1312) prospectively observed 210 814 babies of mothers without high blood pressure before 20 weeks' gestation and found a U shaped relation between maternal blood pressure and both birth weight and perinatal death. Perinatal outcomes were best when the mother's highest recorded diastolic blood pressure during pregnancy was between 70 and 90 mm Hg.
Figure 1.
Credit: FAYE NORMAN/SPL