Objective: To investigate whether low maternal haemoglobin and ferritin levels are associated with increased placental volume by mid-pregnancy.
Design: Prospective study of women attending hospital for shared antenatal care.
Setting: A teaching hospital in the south of England.
Subjects: Five hundred and sixty-eight women booking for delivery in the hospital.
Main outcome measures: Placental volume measured by ultrasound at 18 weeks gestation.
Results: At 14 weeks gestation 9% of women had haemoglobin levels < or = 11 g/dl and 26% had ferritin levels < 13 micrograms/l. Placental volume at 18 weeks was inversely related to the maternal haemoglobin and ferritin levels. The influence of haemoglobin and ferritin concentrations was independent of maternal social class, parity, smoking, and weight. Larger placentae were found in taller women, those who had previously been pregnant, and in those who were smoking more than 15 cigarettes daily at the time of their last menstrual period.
Conclusion: These data suggest that placental development is influenced from early in pregnancy by the intrauterine environment provided by the mother. In conjunction with other studies they support the proposal that, as a result of these changes, programming of adult blood pressure may be initiated in early pregnancy.