Transplant Trial Watch

Pregnancy outcomes in women with kidney transplant: Metaanalysis and systematic review.

Shah, S., Venkatesan, R. L. et al. (2019).

BMC Nephrology [record in progress].

The primary aim of this study was to identify all studies of pregnancy-related outcomes in kidney transplant recipients from all around the world, and estimate pooled incidences of pregnancy outcomes, maternal complications, and foetal complications. Secondary aims of this review examined the impact of pregnancy on the kidney allograft loss, allograft rejection, identify ideal maternal age of conception, and determine ideal time of conception between kidney transplant and pregnancy.

The PubMed/MEDLINE, Elsevier EMBASE, Scopus, BIOSIS Previews, ISI Science Citation Index Expanded, and the Cochrane Central Register of Controlled Trials were searched for studies reporting pregnancy with kidney transplant.

87 studies met the inclusion criteria; representing a sample size of 6712 pregnancies in 4174 kidney transplant recipients. The mean maternal age was 29.6 ± 2.4 years.

Preganancy outcomes assessed included live-birth, induced abortions, miscarriages, stillbirths, ectopic pregnancies, preeclampsia, gestational diabetes, pregnancy induced hypertension, cesarean section and preterm delivery.

6 months

CET Conclusions
This is the first systematic review of this topic to be published since 2011. It provides a new look at this field, including 6712 pregnancies in 4174 kidney transplant recipients, compared to 4706 pregnancies in 3570 recipients in the earlier review. This review was well-conducted and multiple databases were searched to identify relevant evidence. The included studies were observational as one would expect; however they can still be assessed for quality and sources of potential bias, which is not explicitly described in this paper. Abstracts were screened for eligibility in duplicate and data extraction was confirmed by 3 reviewers, so this phase of the review was conducted to a high standard. There is also a clear description of the statistical analysis plan. Multiple meta-analyses are presented, all with moderate to high levels of heterogeneity, which is presumably attributable to the multitude of different populations included from around the world. Rightly random effects meta-analyses were used so as to not narrow confidence intervals without basis. Live birth rate was approximately 73% (higher than the USA general population at 62%) however complications were high; pre-eclampsia rates were approximately 22% (versus 4%), caesarean rates were approximately 63% (versus 32%), stillbirth rates were 5% (versus 0.6%) and neonatal mortality was approximately 4% compared to 0.4%. Overall acute rejection rates during pregnancy were no higher than expected and 2-year graft loss was as expected in a small number of studies that reported this outcome. This is a very large and well conducted meta-analysis that shows a significant increase in maternal and foetal adverse events amongst renal transplant recipient mothers compared to the general population. However, life birth rates appear to exceed that in the general population and there does not appear to be any harmful effect of pregnancy on renal allograft function. The authors acknowledge that there may be some degree of selection bias, with only relatively healthy women pursuing pregnancy.

Quality notes
SR - QA not necessary.

Trial registration

Funding source
Non-industry funded