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J Matern Fetal Med. 1999 Nov-Dec;8(6):262-9.

Effect of cocaine on fetal kidney and bladder function.

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Department of Obstetrics and Gynecology, St. Michael's Medical Center, Newark, New Jersey, USA.



To study the relationship between the bladder cycle and urine output by the fetus and the effect of intrauterine exposure to cocaine on both.


Fetal hourly urine production rate and bladder cycle length were measured in two groups of pregnant women between 20 and 40 weeks of gestation. A control group of 59 normal pregnancies were examined longitudinally to establish reference ranges. A study group of 36 women with a history of cocaine abuse; urine was positive for cocaine only. They were examined once. The diameters of fetal bladder were measured to calculate bladder volume and hourly urine output. The bladder cycle was the time interval between two successive acts of voiding by the fetus.


In the normal group, fetal hourly urine production had a positive linear correlation with the gestational age, with mean urine volume of 3.38 ml/h at 20 weeks and 48.36 ml/h at 40 weeks. The bladder cycle also had positive linear association with the advancing gestational age, with 26+/-4.76 min at 20 weeks and 65.2+/-14.85 min at 40 weeks. When compared with the corresponding gestational ages, the cocaine-exposed group showed a significant decrease (P < 0.0001) in the hourly urine production and the bladder cycle. There was significant correlation (r = 0.95, P < 0.001) between bladder cycle and hourly urine output in the control group, but not in the cocaine group.


Cocaine decreases fetal urine output and bladder cycle.

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