Prevalence of chronic kidney disease in women of reproductive age and observed birth rates

Introduction: Women of reproductive age with chronic kidney disease (CKD) are recognised to have decreased fertility and a higher risk of adverse pregnancy outcomes. How often CKD afflicts women of reproductive age is not well known. This study aimed to evaluate the burden of CKD and associated birth rates in an entire region.

Methods: This was a retrospective cohort study including women of childbearing age in Stockholm during 2006-2015. We estimated the prevalence of "probable CKD" by the presence of an ICD-10 diagnosis of CKD, a single estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m² or history of maintenance dialysis. By linkage with the Swedish Medical Birth Register we identified births during the subsequent three years from study inclusion and evaluated birth rates.

Results: We identified 817,730 women in our region, of whom 55% had at least one creatinine measurement. A total of 3938 women were identified as having probable CKD, providing an age-averaged CKD prevalence of 0.50%. Women with probable CKD showed a lower birth rate 3 years after the index date (35.7 children per 1000 person years) than the remaining women free from CKD (46.5 children per 1000 person years).

Conclusion: As many as 0.50% of individuals in this cohort had probable CKD, defined on the basis of at least one eGFR<60 ml/min1.73 m² test result, dialysis treatment (i.e. CKD stages 3-5) or an ICD-10 diagnosis of CKD. This prevalence is lower than previous estimates. Women with probable CKD, according to a study mainly capturing CKD 3-5, had a lower birth rate than those without CKD, illustrating the challenges of this population to successfully conceive.