Vitamin A intake and status and associations with iron status, anaemia and birth outcomes of pregnant women in the Free State Province, South Africa: the Nutritional Status of Expectant Mothers and their newborn Infants (NuEMI) study

Vitamin A deficiency (VAD) is common among pregnant women (PW) and has been associated with anaemia and adverse birth outcomes. However, in the Free State Province of South Africa, evidence regarding this is limited. Hence, this cross-sectional study investigated the vitamin A (vitA) intake and status of PW in Bloemfontein and its association with anaemia, iron status and birth outcomes. Blood was taken from 427 PW to assess the status of vitA (retinol-binding protein 4 (RBP4)), iron (ferritin, soluble transferrin receptor (sTfR)) and anaemia (Hb). Sociodemographic, HIV, birth outcomes (birthweight and gestational age) and dietary vitA intake data were obtained using a questionnaire in an interview and medical records. Descriptive statistics and linear regression were used to describe variables and the association between vitA and iron status and birth outcomes. Median vitA intake was 1007 µgRAE/d with 19 % of participants' intake below the estimated average requirement of 550 µgRAE/d. Median (IQR) RBP4 was 1·51 (0·78) µmol/l. Insufficient vitA status and VAD prevalence were 12·2 % and 1·2 %, respectively. VitA intake was positively associated with RBP4 (<i>β</i> = 0·068; 95 % CI 0·020, 0·116; P = 0·006). RBP4 was positively associated with Hb (<i>β</i> = 0·363; 95 % CI 0·186, 0·539; P < 0·001) and ferritin (<i>β</i> = 0·359; 95 % CI 0·139, 0·579; P = 0·001) but negatively with sTfR (<i>β</i> = -0·125; 95 % CI -0·246, -0·005; P = 0·041). No significant association between plasma RBP4 and birth weight, as well as preterm birth, was observed. There was a low prevalence of VAD in the study population. Nonetheless, the positive association between RBP4 and Hb and ferritin highlights the importance of optimal vitA status in preventing anaemia in pregnancy.