Lyall Vikram, Asplin John R, Brandes Eileen, Ficko Zita, Johnson Elizabeth, Sur Roger L, Pais Vernon
Darmouth Hitchcock Medical Center, Section of Urology, Lebanon, NH 03766.
Litholink Corp, Itasca, IL 60143.
Urology. 2025 Jun 30. doi: 10.1016/j.urology.2025.06.071.
To measure lithogenic changes during pregnancy in patients on a standardized diet without a prior history of nephrolithiasis.
IRB approval was obtained. The metabolic needs of pregnant participants were determined, and standardized diet administered with Boost shakes and unlimited water. 24-hour urine collections were obtained during the third trimester, post-partum, and post-lactation. Subjects remained on the controlled diet for 24-hour prior to and during the collection. Standard statistical analysis was performed.
Of 18 patients, 6 had a de novo stone event during pregnancy. Of these, 83% were composed of calcium phosphate. Stone events with calcium phosphate presented later than calcium oxalate. Stone-formers had an intra-partum body mass index greater than non-stone formers (33.1 vs 26.7, P <.05). All participants had hypercalciuria, but stone-formers were found to have a nearly 2X greater urine calcium compared to non-stone formers on their controlled diet (392.1 vs 205.9, P <.05). Post-partum, we observed a decrease in urine calcium, citrate, pH, and supersaturation of calcium oxalate and phosphate (P <.05).
This is the first study to identify lithogenic changes during pregnancy in de novo stone formers on a standardized diet. We show that stone-formers have primarily calcium phosphate stones. They also have an elevated body mass index and are significantly more hypercalciuric without other demonstratable lithogenic differences compared to non-stone formers. Post-partum, we demonstrate reduction in intra-partum lithogenicity that may mitigate stone risk. These data suggest an underlying mechanism exists in stone formers that increases urine calcium above what would be expected in gestational hypercalciuria.
在无肾结石病史且饮食标准化的患者中，测量孕期结石形成相关变化。
获得机构审查委员会（IRB）批准。确定怀孕参与者的代谢需求，并给予含Boost奶昔的标准化饮食及不限量饮水。在孕晚期、产后和哺乳期收集24小时尿液。在收集尿液之前及期间，受试者保持控制饮食24小时。进行标准统计分析。
18名患者中，6名在孕期出现新发结石事件。其中，83%的结石由磷酸钙组成。磷酸钙结石事件比草酸钙结石出现得晚。结石形成者的产时体重指数高于非结石形成者（33.1对26.7，P<0.05）。所有参与者均有高钙尿症，但在控制饮食的情况下，结石形成者的尿钙水平几乎是非结石形成者的2倍（392.1对205.9，P<0.05）。产后，我们观察到尿钙、枸橼酸盐、pH值以及草酸钙和磷酸盐的过饱和度均下降（P<0.05）。
这是第一项在饮食标准化的新发结石形成者中识别孕期结石形成相关变化的研究。我们发现结石形成者主要形成磷酸钙结石。他们的体重指数也较高，并且与非结石形成者相比，高钙尿症明显更严重，且无其他可证明的结石形成差异。产后，我们证明产时结石形成能力降低，这可能会降低结石风险。这些数据表明结石形成者存在一种潜在机制，使尿钙升高超过妊娠期高钙尿症的预期水平。
