JJ stents have been reported to become obstructed by mechanical impingement of the fetal head (Hellawell et al. 2002) and they may migrate down the ureter and into the bladder and subsequently be voided per urethra as a consequence of the dilatation of the ureter that is normally a feature of pregnancy (Stothers et al. 1992).
Ureteroscopic stone extraction can be performed in pregnancy, but again its use depends on available expertise. Distortion of the distal third of the ureter during the latter stages of pregnancy makes rigid ureteroscopy technically more challenging, as does the presence of a large stone (European Association of Urology 2001). For these reasons the less experienced uretero-scopist may decide that nephrostomy tube drainage or a JJ stent is a better option later on in pregnancy, with subsequent uretero-scopic treatment being used if the stone fails to pass within a few weeks of delivery. In solitary kidneys nephrostomy tube drainage or a JJ stent may also be safer options rather than attempting
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ureteroscopic stone extraction under the difficult conditions of late pregnancy.
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