SAT-026 BIRTHS AND FERTILITY RATES IN AUSTRALIAN WOMEN RECEIVING RENAL REPLACEMENT THERAPY: ANALYSIS OF LINKED DATA FROM THE ANZDATA REGISTRY

Abstract

Pregnancy in women receiving dialysis or after kidney transplantation is uncommon and clinically challenging. The Australia and New Zealand Dialysis and Transplant Registry (ANZDATA) collects parenthood data for renal replacement therapy (RRT) recipients but it is limited, and birth events are potentially under-reported. To better enumerate births and outcomes, ANZDATA records were linked to state-based perinatal datasets to identify all births within the RRT cohort and determine birth rates and fertility rates of RRT mothers compared with non-RRT mothers. In Australia, perinatal datasets capture mandatory data on all births of ≥ 20 weeks gestation. Using probabilistic record linkage, ANZDATA data (1970-2015) was linked to perinatal data (1991-2013) of 2 states of Australia (South Australia, SA, and Western Australia, WA). Babies born to mothers who appeared at any time within the ANZDATA cohort were identified. Births given after the start of RRT were observed and compared to ANZDATA reported births. The crude birth rates of RRT and Non-RRT cohort were calculated as the number of births per 1000 population and age-specific fertility rates (ASRF) of mothers as the number of live births given by women at a specific age-group to total number of females in that age-group. Of 440,863 births in SA, 299 babies were born to 192 mothers receiving RRT at some stage in the study period. Of these, 49 (16%) births occurred after mothers (33) started RRT; 10 babies were born to 9 dialysing mothers and 39 to 24 transplanted mothers. Similarly Of 632,658 births in WA, 310 babies were born to 186 mothers receiving RRT at some stage in the study period. Of these, 62 (20%) births occurred after mothers (42) started RRT; 12 babies were born to 9 dialysing mothers and 50 to 34 transplanted mothers. In comparison to ANZDATA, only 38 births in SA and 36 births in WA at gestational age ≥ 20 weeks were reported for the same period clearly showing under reporting of birth events. The overall crude birth rate of combined SA and WA births for RRT cohort was 2.1 births per 1000 renal population where it was 13.3 births per 1000 non-renal population for Non-RRT cohort. The age-specific fertility rates for SA and WA are shown in table 1. For SA, the rates were highest for women aged 30-34 years in renal cohort, in contrast to the non-renal cohort. The general fertility rate for RRT females were 18.2 births/1000 renal women of age 15-44 years, very low in comparison to Non-RRT females’ rate of 59.5 births per 1000 non-renal women. Similar results were found for WA data. The fertility rates were lower for RRT cohort. Table 1 We have received more detailed information on renal pregnancies and births through linkage and found more births in cohort than reported to ANZDATA directly. Using this linked data, we have been able to define the birth rates and fertility rates for Australian women receiving RRT. We are now intending to explore differences in pregnancy and perinatal outcomes and define maternal risks factors associated with adverse outcomes in this high-risk cohort.