Association between iron deficiency and fertility.

Abstract

Introduction: This retrospective, observational cohort study investigated the association between treatment of iron deficiency with conception results and pregnancy outcomes in women with infertility and iron deficiency, before and after intravenous ferric carboxymaltose infusion.

Material and methods: Data were collected from electronic health records from the Dextra Fertility Clinic (Helsinki, Finland) between 2015 and 2020. The cohort included 292 women (<43 years) with infertility and iron deficiency (s-ferritin ≤30 μg/L), treated with a ferric carboxymaltose infusion (Ferinject®, 500 mg i.v.). The main outcomes were live birth and miscarriage rates before and after treatment of iron deficiency. The main explanatory variable studied was the administered iron infusion.

Results: Mean s-ferritin levels increased from 16.2 ± 7.0 μg/L before to 81.5 ± 49.8 μg/L after iron infusion. The proportion of patients who conceived increased from 65% before to 77% after treatment of iron deficiency (p < 0.001). Of the study population, 28% of patients experienced miscarriages and 26% gave a live birth before iron infusion, and 13% and 51% after treatment of iron deficiency (p < 0.001). In the model adjusted for age, use of preimplantation genetic testing for aneuploidy, and repeated iron infusions, treatment of iron deficiency with iron infusion was associated with a higher live birth rate (OR = 3.19; 95% CI = 2.21-4.66; p < 0.001). In the model adjusted for age, reason for infertility, and total number of pregnancies, treatment of iron deficiency was associated with lower miscarriage rates (OR = 0.32; 95% Cl = 0.20-0.52; p < 0.001).

Conclusions: Filling of depleted iron stores was positively associated with conception results (higher number of pregnancies) and pregnancy outcomes (higher live birth rates and lower miscarriage rates), regardless of the assisted reproductive technology method used. Screening of iron status seems to be important in patients seeking help for infertility problems.