Pregnancy in women receiving renal dialysis or transplantation in Japan: a nationwide survey

BACKGROUND: Since a report on the first successful pregnancy of a woman on long-term haemodialysis in Japan in 1977, there has been a growing number of case reports on successful pregnancy in patients on dialysis. We undertook a nationwide survey on pregnancy in women on renal replacement therapy in 1996. METHODS: A preliminary questionaire was sent to 2504 dialysis units and 143 renal transplant units in Japan. For each reported pregnancy, a more detailed questionaire was sent to collect nephrological, obstetric and neonatal information. RESULTS: There were 172 pregnancies (0.44%) reported in 38889 women on dialysis, with 90 successful pregnancies (0.23%), and 194 pregnancies reported in 852 female renal transplant recipients. Detailed pregnancy information was collected from 74 women on dialysis and 194 renal transplant recipients. Of the 74 pregnancies in the women on dialysis, 36 (48.6%) resulted in surviving infants, nine (12.2%) in neonatal death, nine (12.2%) spontaneous abortions and 14 (18.9% elective abortions were reported. The outcome of six pregnancies (8.1%) was unknown. Of 194 pregnancies in renal transplant recipients, 159 (82.0%) resulted in surviving infants, two (1.4%) in neonatal death and 28 (14.4%) in spontaneous or elective abortion. In five cases the pregnancy outcome was not reported. No congenital anomalies were reported, except two infants with mental retardation and one with epilepsy. CONCLUSION: The current survey revealed that the rate of successful pregnancy in women on dialysis has improved. More than half of the pregnancies resulted in infant survival. But, premature birth is a major problem for the children of women on dialysis and there is a higher rate of neonatal death. There are significant differences in gestational age, birth weight, frequency and severity of prematurity and rates of neonatal death between pregnancies of women undergoing dialysis and those who are renal transplant recipients.