α⁺‐Thalassaemia and pregnancy in a malaria endemic region of Papua New Guinea

Abstract

SummaryThe effect of maternal a + -thalassaemia on pregnancy was assessed in the north coastal region of Papua New Guinea (PNG), where malaria is hyperendemic and a + -thalassaemia is extremely common. In a prospective study of 987 singleton hospital deliveries, we correlated maternal a-globin genotype with markers of reproductive fitness (age in primigravidae, gravidity, pregnancy interval and the number of miscarriages and stillbirths), Plasmodium falciparum (P. falciparum) infection of the mother and placenta, maternal haemoglobin, preterm delivery and birthweight. The frequency of the )a genotype in mothers was 0AE61. Markers of reproductive fitness were similar in women with and without a + -thalassaemia. Median haemoglobin concentration during pregnancy and after delivery was about 1AE0 g/dl lower in homozygous a + -thalassaemia than in women with a normal a-globin genotype (P £ 0AE001). The frequency of placental P. falciparum infection and systemic malaria infection after delivery showed no consistent relationship to a-globin genotype. The frequency of preterm delivery and low birthweight did not vary significantly according to maternal a-globin genotype. Maternal a + -thalassaemia does not affect reproductive fitness or susceptibility to malaria during pregnancy. Although median haemoglobin concentration was significantly lower in mothers homozygous for a + -thalassaemia than those with a normal a-globin genotype, this did not result in an adverse outcome of pregnancy.

Risk factors for malaria and adverse birth outcomes in a prospective cohort of pregnant women resident in a high malaria transmission area of Papua New Guinea

“…SAO was associated with a non-significant increase in risk of LBW, and decrease in mean birth weight (but not preterm birth). Previous studies in Madang have not shown a significant relationship between SAO and pregnancy outcome, 8,15,16 and in the absence of a clear mechanism by which it might affect fetal growth it seems unlikely to be a true effect. CR1 and a + -thalassaemia polymorphisms were not significantly associated with birth weight, or with risk of LBW and preterm birth.…”

“…13,14 Studies of SAO and a + -thalassaemia in pregnant PNG women did not show clear evidence of protection against placental malaria, but suggested a decrease in intensity of placental infection in SAO heterozygotes, particularly in first-time mothers. 8,15,16 To determine the prevalence, risk factors and consequences of malaria during pregnancy in Madang province, PNG, we performed a longitudinal study of women followed from first antenatal visit to delivery. The associations between malaria infections diagnosed by microscopy, PCR and placental histology and pregnancy outcomes were examined, and potential associations between locally prevalent red blood cell genetic polymorphisms and pregnancy outcomes were investigated.…”

Haemoglobinopathies and the clinical epidemiology of malaria: a systematic review and meta-analysis

“…72 In one study in Papua New Guinea that assessed birth outcomes, α-thalassaemia was not associated with placental malaria, birth weight, placental parasite density, maternal peripheral parasitaemia, or maternal anaemia. 73 On the whole, there are few data on the effect of haemoglobin variants on pregnancy-associated malaria or placental parasitization.…”

Malaria in pregnancy in the Asia-Pacific region

“…Although southeast Asian ovalocytosis and α thalassaemia protect young children in Papua New Guinea against cerebral malaria, 64,65 neither genetic trait seems to change the eff ects of malaria in pregnancy. 42,59,66 The risk of thrombocytopenia is more than two times higher in pregnant women with malaria than in non-pregnant women infected with malaria, but this disorder is rarely severe (less than 10 000 platelets per μL). 60,67 Prompt antimalarial treatment can normalise platelet counts within a week.…”