We thank you for giving us the opportunity to respond to the Letter to the Editor regarding our recent publication on maternal and fetal outcomes in CKD pregnancies in Ontario.1 The authors, correctly, point out that we only studied the effect of CKD on maternal and fetal pregnancy outcomes but not the effect of pregnancy on CKD progression.2 As practicing obstetric-focused nephrologists, we have a deep appreciation for the role that pregnancy may play in CKD progression and that the current published literature does not adequately quantify this risk. Members of our group (L.B., A.G., and M.H.) have already begun to analyze CKD progression outcomes using updated data from this cohort, so stay tuned.
Regarding the letter writers' second concern, we agree that knowing more about GFR changes in pregnancy will enhance our understanding of the interplay between kidney function, placental development, and maternal/fetal outcomes. Because we used real-world data for this study, and serial assessments of kidney function are not part of the standard of care in pregnancy in Canada (or elsewhere in the world), we do not have this information available to analyze. One of our authors (J.T.) is currently studying longitudinal changes in renal filtration markers across pregnancy in two large pregnancy cohorts as part of a National Institutes of Health–funded study on kidney disease in pregnancy.
Thank you for reading our paper and taking the time to draw attention to the need for ongoing studies to improve maternal fetal outcomes in our patients with CKD.
Footnotes
Published online ahead of print. Publication date available at www.jasn.org.
See related letter to the editor, “Renal Function and the Adverse Maternal and Fetal Outcomes: New Evidence,” on page 1471, and original article, “Pre-Pregnancy eGFR and the Risk of Adverse Maternal and Fetal Outcomes: a Population-Based Study,” in Vol. 34, Iss. 4, on pages 656–667.
Disclosures
M.A. Hladunewich reports Research Funding: Calliditas Therapeutics, Chemocentryx, Chinook, Ionis, Pfizer, and Roche; Honoraria: Uptodate; and Other Interests or Relationships: Medical Lead for Glomerular Disease Ontario Renal Network. The remaining author has nothing to disclose.
Funding
None.
Author Contributions
Writing – original draft: Jessica Tangren.
Writing – review & editing: Michelle A. Hladunewich.
References
- 1.Tangren J Bathini L Jeyakumar N, et al. Pre-pregnancy eGFR and the risk of adverse maternal and fetal outcomes: a population-based study. J Am Soc Nephrol. 2023;34(4):656–667. doi: 10.1681/ASN.0000000000000053 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Wei S, Ouyang Z, Wu L. Renal function and the adverse maternal and fetal outcomes: new evidence. J Am Soc Nephrol. 2023;34(8):1485. doi: 10.1681/ASN.0000000000000168 [DOI] [PMC free article] [PubMed] [Google Scholar]