Pregnancy after kidney transplantation: outcome and anti-human leucocyte antigen alloimmunization risk

Kidney transplantation increases the chances for pregnancy and live birth for women with end-stage kidney disease. The aims of this study were to describe the outcomes of pregnancies in women with a kidney transplant and to evaluate the impact on anti-human leucocyte antigen (HLA) alloimmunization.

We analysed 61 pregnancies that occurred in 46 patients after having excluded 10 miscarriages during the first trimester and 10 other pregnancies from which important data were missing. Anti-HLA antibodies were screened using the Luminex assay.

Overall, the live birth rate was 83% (94% after exclusion of miscarriages during the first trimester). Pre-eclampsia and gestational diabetes occurred in 26 and 21% of cases, respectively. The use of tacrolimus was an independent predictive factor for gestational diabetes. Twenty-four newborns (42%) were premature (<37 weeks). The median birth weight was 2720 (1040-3730) g. Nine newborns (15%) had low birth weights (<2.5 kg). At least one severe complication occurred in 56% of pregnancies. A high glomerular-filtration rate (GFR) before pregnancy was the sole independent protective factor that avoided a severe complication. Death-censored kidney-allograft survival was 80.4% at 6 years. De novo donor-specific anti-HLA antibodies were detected after only 5.9% of pregnancies: for two women, the father had the same HLA antigens as those from the deceased organ donor. The determination of the HLA of the father before pregnancy can better inform the woman about the possible impact of pregnancy on her kidney-allograft function.

Despite many complications, the outcomes for pregnancy and kidney allografts are good. The risk of anti-HLA alloimmunization was low.