Abstract
Kidney stones can be a source of considerable morbidity for pregnant women. Although there is a body of literature confirming that different stone compositions predominate for different age and sex cohorts, there have been no similar reports characterizing the nature of stone disease during pregnancy. We performed a multi-institutional study to define the composition of renal calculi diagnosed during pregnancy. We retrospectively reviewed the records from two stone referral centers of all patients diagnosed with a de novo kidney stone during pregnancy who underwent a procedure for the purpose of stone removal from June 2001 through September 2007. A total of 27 patients were identified, with a mean age of 26.8 years (range, 21–34). Twenty patients (74%) had no history of prior stone formation. Seven patients (26%) had previously formed stones, although none of these patients had a known kidney stone at the time they became pregnant. Stones were removed in the first, second, third trimester and immediately post-partum in 4, 52, 22, and 22% respectively. Stone removal was performed without complication in all cases. Analysis found that in 74% of all cases (20 patients) stones were composed predominantly of calcium phosphate (hydroxyapatite). In 26% of cases, (7 patients) the stones were composed predominantly of calcium oxalate. Of the seven patients with prior stone history, three patients had previously formed calcium phosphate stones and four patients had previously formed calcium oxalate stones. Calcium oxalate calculi are the most common stone in non-pregnant women of a comparable age as our subjects. However, our present data suggest that stones detected during pregnancy are most commonly composed of calcium phosphate (hydroxyapatite). Indeed, it is the minority of stones that are composed of calcium oxalate. Although the reason for this unusual preponderance of calcium phosphate calculi is unclear, physiologic alterations that occur during pregnancy may be influential.
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Drago JR, Rohner TJ Jr, Chez RA (1982) Management of urinary calculi in pregnancy. Urology 20:578
Strong DW, Murchison RJ, Lynch DF (1978) The management of ureteral calculi during pregnancy. Surg Gynecol Obstet 146:604
Swartz MA, Lydon-Rochelle MT, Simon D et al (2007) Admission for nephrolithiasis in pregnancy and risk of adverse birth outcomes. Obstet Gynecol 109:1099
Gabert HA, Miller JM Jr (1985) Renal disease in pregnancy. Obstet Gynecol Surv 40:449
Costa-Bauza A, Ramis M, Montesinos V et al (2007) Type of renal calculi: variation with age and sex. World J Urol 25:415
Gault MH, Chafe L (2000) Relationship of frequency, age, sex, stone weight and composition in 15,624 stones: comparison of resutls for 1980 to 1983 and 1995 to 1998. J Urol 164:302
Parks JH, Worcester EM, Coe FL et al (2004) Clinical implications of abundant calcium phosphate in routinely analyzed kidney stones. Kidney Int 66:777
Mandel N, Mandel I, Fryjoff K et al (2003) Conversion of calcium oxalate to calcium phosphate with recurrent stone episodes. J Urol 169:2026
Resim S, Ekerbicer HC, Kiran G et al (2006) Are changes in urinary parameters during pregnancy clinically significant? Urol Res 34:244
Gertner JM, Coustan DR, Kliger AS et al (1986) Pregnancy as state of physiologic absorptive hypercalciuria. Am J Med 81:451
Howarth AT, Morgan DB, Payne RB (1977) Urinary excretion of calcium in late pregnancy and its relation to creatinine clearance. Am J Obstet Gynecol 129:499
Maikranz P, Holley JL, Parks JH et al (1989) Gestational hypercalciuria causes pathological urine calcium oxalate supersaturations. Kidney Int 36:108
Cass AS, Smith CS, Gleich P (1986) Management of urinary calculi in pregnancy. Urology 28:370
Horowitz E, Schmidt JD (1985) Renal calculi in pregnancy. Clin Obstet Gynecol 28:324
Coe FL, Parks JH, Lindheimer MD (1978) Nephrolithiasis during pregnancy. N Engl J Med 298:324
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Ross, A.E., Handa, S., Lingeman, J.E. et al. Kidney stones during pregnancy: an investigation into stone composition. Urol Res 36, 99–102 (2008). https://doi.org/10.1007/s00240-008-0138-4
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DOI: https://doi.org/10.1007/s00240-008-0138-4