Maternal Anemia in Various Trimesters and Related Pregnancy Outcomes: Results from a Large Cohort Study in Iran

Background: Undesirable health outcomes of anemia impact all different groups of people within a society especially pregnant women (PW). Objectives: This study aimed to evaluate other fetal and maternal complications of anemia in various trimesters of pregnancy. Methods: A large retrospective cohort study was conducted on Iranian PW in 2017. The first and third trimesters of pregnancy were assessed as a separate study. The first study included 1038 anemic and 2463 non-anemic PW and the second comprised 756 anemic and 1986 non-anemic PW. The outcome-related pregnancies were analyzed for each study. Results: After adjusting for the potential confounding factors, the odds of neonatal mortality (OR = 1.63; CI 95%, 1.25 - 2.13) were significantly higher and the odds of cesarean delivery (OR = 0.6; CI 95%, 0.46 - 0.75) were significantly lower in women who had anemia during the first trimester. The chance of pre-term delivery (< 37 weeks; OR = 2.15; CI 95%, 1.6 - 2.91) and abortion (OR = 1.68; CI 95%, 1.11 - 2.53) was significantly higher in women who had anemia during the third trimester, while the chance of low birth weight (< 2500 kg) (OR = 0.66; CI 95%, 0.46 - 0.93) was lower in anemic women during the third trimester than in those without anemia. Conclusions: Pregnant women who experience anemia in both first and third trimesters of pregnancy have different unpleasant pregnancy outcomes. Since anemia is preventable during pregnancy, many of these outcomes such as neonatal mortality, low birth weight, preterm and cesarean delivery, and abortion could be prevented and decreased by providing health education before pregnancy.