Maternal second‐trimester serum ferritin concentrations and subsequent risk of preterm delivery

Abstract

We studied the relationship between maternal second-trimester serum ferritin concentrations and preterm delivery. The 312 preterm delivery cases, studied in aggregate and in subgroups [spontaneous preterm labour, preterm premature rupture of membranes, medically induced preterm delivery, moderate preterm delivery (gestational age at delivery 34-36 weeks) and very preterm delivery (gestational age at delivery <34 weeks)] were compared with 424 randomly selected women who delivered at term. Maternal ferritin concentrations, measured in serum collected at 17 weeks gestation on average, was determined using a two-site chemiluminometric immunoassay. Using multiple logistic regression, we derived maximum likelihood estimates of adjusted odds ratios (OR) and 95% confidence intervals [CI]. Elevation in maternal second-trimester ferritin was weakly associated with the risk of preterm delivery overall. After adjusting for possible confounding by maternal age, race/ethnicity, parity, Medicaid payment status and smoking during the index pregnancy, the OR for extreme quartiles (>64.5 vs. <26.0 ng/mL) of ferritin was 1.3 [95% CI 0.8, 2.1]. Stratified analyses indicated that elevated maternal serum ferritin was associated with an increased risk of preterm premature rupture of membranes (OR = 2.1; 95% CI 1.1, 4.1), but not with spontaneous preterm labour (OR = 0.9; 95% CI 0.4, 1.7) or medically induced preterm delivery (OR = 1.1; 95% CI 0.6, 2.0). The relationship between elevated maternal second-trimester serum ferritin concentrations and preterm delivery was strongest for spontaneous very preterm deliveries (<34 weeks gestation). Women with ferritin concentrations in the highest decile (>96 ng/mL) experienced a 2.7-fold increased risk of delivering before 34 completed weeks, compared with women with concentrations <26.0 ng/mL. These results are consistent with some previous reports, and further underline the potential for heterogeneity in the aetiology of preterm delivery.

Predictors of preterm birth in patients with mild systemic lupus erythematosus

“…While CRP and ESR correlated well with each other in this study, neither measure correlated with SLE activity or pregnancy outcomes in this cohort. On the other hand, studies in healthy women suggest that an elevated serum ferritin level mid-gestation is associated with an increased risk for preterm delivery 12 13. In our study, ferritin was associated with earlier delivery, suggesting a role of inflammation in the preterm delivery in this population.…”

Can Preterm Labour Be Predicted in Low Risk Pregnancies? Role of Clinical, Sonographic, and Biochemical Markers

“…One of them reported that, after adjusting for various possible confounding factors, the odds ratio for extreme quartiles (>64.5 versus <26.0 ng/mL) of ferritin was 1.3 (95% CI 0.8, 2.1). Stratified analyses indicated that elevated maternal serum ferritin was associated with an increased risk of preterm premature rupture of membranes (OR = 2.1; 95% CI 1.1, 4.1), but not with spontaneous preterm labour (OR = 0.9; 95% CI 0.4, 1.7) or induced preterm delivery (OR = 1.1; 95% CI 0.6, 2.0) [25]. Considering 60% prevalence rate of anaemia during pregnancy in India, serum iron levels were also done to eliminate anaemia as the confounding factor.…”

Assessment and interpretation of micronutrient status during pregnancy

“…The relationship between serum ferritin and pregnancy outcome is confounded by several of the same factors that complicate the assessment of anaemia. Maternal infection, inflammation and hypertensive disorders are all associated with a higher incidence of preterm delivery and fetal growth restriction (70)(71)(72)(73) . Thus, whilst it appears from observational studies that serum ferritin concentrations < 30 mg/l during the second half of pregnancy are protective (62) , this is most probably because the risks associated with these confounders are much greater than those associated with depletion of maternal Fe stores.…”