Doppler waveform of the ureteric jet in pregnancy.

We have shown that the function of the bladder vesicoureteric junction (VUJ) can be studied by the Doppler waveform of the ureteric jet, and this reflects the active sphincteric mechanism of the VUJ. We wished to investigate if the hormonal changes of pregnancy cause any alteration of VUJ function. A total of 107 pregnant women and 375 nonpregnant women were recruited. Three scans, 20 and 32 weeks of gestational age and 3 months postpartum, were done. The occurrence of a monophasic waveform in the nonpregnant group was 1.9%. In the pregnancy group, this was 18.7%, 41.1% and 1.6% at 20, 32 weeks of gestational age and 3 months postpartum, respectively. The difference in occurrence of the monophasic waveforms was statistically significant (both p = 0.0005 at 20 and 32 weeks). This suggests an adverse hormonal effect on the vesicoureteric junction during pregnancy, and may be a factor in the increased risk of UTI in pregnancy.