The band 3 deletion for southeast Asian ovalocytosis (SAO) occurs commonly in southeast Asia and the western Pacific. Southeast Asian ovalocytosis is associated with protection against cerebral malaria in children and therefore could reduce sequestration of erythrocytes parasitized by Plasmodium falciparum in the brain microvasculature. Sequestration of parasitized erythrocytes in the placenta accounts for much of the pathology of malaria during pregnancy. Therefore, we investigated the effect of SAO on malaria during pregnancy in the malaria-hyperendemic north coastal region of Papua New Guinea. The frequency of SAO in 927 women attending hospital for delivery was 8.7% (95% confidence interval = 6.9-10.5). Markers of fertility, the frequency of miscarriages and stillbirths, maternal anemia, placental and peripheral malaria at delivery, and birth weight were similar in women with and without SAO. In summary, although we can not exclude an interaction between SAO and malaria during pregnancy, we found no evidence that it provided a clinical benefit in this population.