Malaria in Pregnancy Is a Predictor of Infant Haemoglobin Concentrations during the First Year of Life in Benin, West Africa

Abstract

Background: Anaemia is an increasingly recognized health problem in Africa, particularly in infants and pregnant women. Although malaria is known to be the main risk factor of anaemia in both groups, the consequences of maternal factors, particularly malaria in pregnancy (MiP), on infant haemoglobin (Hb) concentrations during the first months of life are still unclear.

Methods: We followed-up a cohort of 1005 Beninese pregnant women from the beginning of pregnancy until delivery. A subsample composed of the first 400 offspring of these women were selected at birth and followed until the first year of life. Placental histology and blood smear at 1st clinical antenatal visit (ANC), 2nd ANC and delivery were used to assess malaria during pregnancy. Infant Hb concentrations were measured at birth, 6, 9 and 12 months of age. A mixed multi-level model was used to assess the association between MiP and infant Hb variations during the first 12 months of life.

Results: Placental malaria (difference mean [dm] = - 2.8 g/L, 95% CI [-5.3, -0.3], P = 0.03) and maternal peripheral parasitaemia at delivery (dm = - 4.6 g/L, 95% CI [-7.9, -1.3], P = 0.007) were the main maternal factors significantly associated with infant Hb concentrations during the first year of life. Poor maternal nutritional status and malaria infection during infancy were also significantly associated with a decrease in infant Hb.

Conclusion: Antimalarial control and nutritional interventions before and during pregnancy should be reinforced to reduce specifically the incidence of infant anaemia, particularly in Sub-Saharan countries.

Fig 1. Study procedures.

During follow-up, socio-demographic, economic, clinical and biological data were collected in mothers at 1^st antenatal clinical visit (ANC), 2^nd ANC and delivery. The same data were also recorded in infants at birth, 6, 9 and 12 months of life. Outside of scheduled visit, haemoglobin concentration and blood smear were performed when malaria signs were present.

Fig 2. Flowchart diagram of follow-up.

Infants who were absent more than 3 consecutive months, and not seen before their 12 months were considered as lost to follow-up. During the study, five infants (0.1%) were lost to follow-up and sixteen (0.4%) died. The main reasons of death were: acute respiratory infection (4), neonatal icterus (1), severe malaria (2), unknown disease (7), congenital biliary atresia (1). Among these deaths, only 1.2% (2/16) of infants have been bring to hospital by parents.

Fig 3. Changes of mean haemoglobin level of children during the first year of life according to mother's malaria status at delivery.

Children born to mothers infected by malaria had a lower haemoglobin concentration than children born to non-infected mothers and this trend persisted during all first year of life.