Purpose The purpose of the study was to assess the association between iron intake and the incidence of anaemia during pregnancy as well as estimate the prevalence and magnitude of anaemia in pregnancy. Design/methodology/approach A retrospective case-control study was conducted on 383 postnatal women at four health-care facilities. Data on iron supplementation and haemoglobin (Hb) levels during pregnancy was collected from the respondents. Spearman, Pearson Chi-square tests of independence were used to measure associations between variables, a log-linear model was adopted to ascertain the association and level of interaction among variables. All p-values < 0.05 were considered statistically significant. Findings Results show 54.3% prevalence of anaemia at registration and 33.6% at 36 weeks of pregnancy, p < 0.001. Iron supplement intake during pregnancy was 96.3%. The log-linear analysis model retained the Parity × Marital Status interaction across the levels of anaemia (p < 0.001). Compared to married pregnant women, single pregnant women were almost equally likely to be anaemic (OR = 1.06). Research limitations/implications One of the limitations of retrospective studies is recall bias; however, this was likely to be minimal, as participants were approached within 8 days after delivery. Despite this, this study still holds promise as it reports a rather high prevalence of anaemia at 36 weeks even with the high intake of iron. Originality/value Anaemia in pregnancy is a major public health issue because of the consequential outcomes on maternal and child health. The study identified a high prevalence of anaemia at registration; which could be the basis for intensifying pre-natal iron supplementation before pregnancy.