The children of dialysis: live-born babies from on-dialysis mothers in Italy--an epidemiological perspective comparing dialysis, kidney transplantation and the overall population.

BACKGROUND

A successful pregnancy is an exceptional event on dialysis. Few data are available comparing pregnancy rates on dialysis, transplantation and the overall population. The aim of the study was to assess the incidence of live births from mothers on chronic dialysis compared with the overall population and with kidney transplant patients.

METHODS

The setting of the study is in Italy between 2000-12. Data on dialysis was aquired by phone inquiries that were carried out between June and September, 2013, involving all the public dialysis centres in Italy; the result was a 100% response rate. The date included was end-stage renal disease, type of dialysis, residual glomerular filtration rate, changes in dialysis and therapy, hospitalization; week of birth, birth weight, centile; and outcome of mother and child. Information on transplantation was acquired by inquiry by the kidney and pregnancy study group who were contacted by phone or e-mail; the result was a 60% response rate. Data concerning prevalence of women in childbearing age (20-45) were obtained from the Italian Dialysis and Transplant Registries (2010-11 update). Official site of the Italian Ministry of Health.

RESULTS

During the study period, 23 women on dialysis (three on peritoneal dialysis) delivered live-born babies and one woman delivered twins (24 babies). Three babies died in the first weeks-months of life (including one twin); 19 of 21 singletons with available data were pre-term (33.3% <34 weeks); the prevalence of children <10th gestational age-adjusted centile was 33.3%. Birth weight and gestational age were lower in children from on-dialysis mothers as compared with 110 pregnancies following kidney graft, (weight: 1200 versus 2500 g; gestational age: 30 versus 36 weeks; P < 0.001). Incidence of live-born babies was inferred as 0.7-1.1 per 1000 female dialysis patients aged 20-45 and 5.5-8.3 per 1000 grafted patients in the same age range (Italian live-birth rates: 72.5 per 1000 women aged 20-45 years).

CONCLUSIONS

Having a baby while on dialysis is rare but not impossible, though early mortality remains high. There is a 'scale of probability' estimating that women on dialysis have a 10-fold lower probability of delivering a live-born baby than those who have undergone renal transplantation, who in turn have a 10-fold lower probability of delivering a live-born baby as compared with the overall population.