Abstract--We previously reported that in 2003 people from the Helsinki birth cohort whose blood pressures were measured, 2 different paths of growth preceded the development of hypertension. People already diagnosed with hypertension were small at birth but of average body size at age 11 years. People newly diagnosed with hypertension grew slowly in utero and through childhood. We have now examined how the mother’s body size, placental size, and living conditions after birth, 3 influences that affect growth, affect hypertension. Diagnosed hypertension was associated with low placental weight and poor living conditions after birth. The odds ratios were 1.6 (95% CI, 1.1 to 2.3) in people with placental weights <550 g, compared with those with weights >750 g, and 2.2 (95% CI, 1.5 to 3.3) in people whose fathers were laborers compared with those in upper middle-class families. Newly diagnosed hypertension was associated with a small anteroposterior diameter of the mother’s bony pelvis, a known consequence of rickets or lesser degrees of malnutrition in infancy. The odds ratio was 2.2 (95% CI, 1.4 to 3.5) in people whose mothers’ pelvic external conjugate diameters were <18 cm when compared with people whose mothers’ diameters were 19 cm. We conclude that one path of growth that leads to hypertension is initiated by fetal undernutrition, which may make a baby vulnerable to postnatal stress, whereas the other originates in a functional incapacity in the mother’s metabolism, possibly protein metabolism, which she acquired through undernutrition during her infancy.