Is malarial placental infection related to peripheral infection at any time of pregnancy?

Placental infection measured by placental smear at delivery is a standard indicator, widely used to characterize malaria infection in pregnant women. However, a single measure can hardly reflect the entire history of infection during pregnancy. To investigate the relation between this indicator and peripheral infection during pregnancy, we used data collected in a randomized trial of malaria prophylaxis in 928 pregnant women in Burkina Faso, 1987-1988, during which repeated measures of peripheral infection were taken. We analyzed placental infection using a logistic model, with two methods for handling missing data. Peripheral infection during two periods of pregnancy was significantly related to placental infection at delivery, before the fifth month: OR = 2.9 [1.3; 6.3]; after 7 months: OR = 4.9 [2.7; 8.8]). Therefore, an early peripheral infection may persist throughout gestation, and placental infection is a good indicator of the women's parasitological status during pregnancy.