A nationwide Dutch cohort study shows relatively good pregnancy outcomes after kidney transplantation and finds risk factors for adverse outcomes

Reassuring pregnancy outcomes in women with mild COL4A3-5-related disease (Alport syndrome) and genetic type of disease can aid personalized counseling

Individualized pre-pregnancy counseling and antenatal care for women with chronic kidney disease (CKD) require disease-specific data. Here, we investigated pregnancy outcomes and long-term kidney function in women with COL4A3-5 related disease (Alport Syndrome, (AS)) in a large multicenter cohort. The ALPART-network (mAternaL and fetal PregnAncy outcomes of women with AlpoRT syndrome), an international collaboration of 17 centers, retrospectively investigated COL4A3-5 related disease pregnancies after the 20th week. Outcomes were stratified per inheritance pattern (X-Linked AS (XLAS)), Autosomal Dominant AS (ADAS), or Autosomal Recessive AS (ARAS)). The influence of pregnancy on estimated glomerular filtration rate (eGFR)-slope was assessed in 192 pregnancies encompassing 116 women (121 with XLAS, 47 with ADAS, and 12 with ARAS). Median eGFR pre-pregnancy was over 90ml/min/1.73m2. Neonatal outcomes were favorable: 100% live births, median gestational age 39.0 weeks and mean birth weight 3135 grams. Gestational hypertension occurred during 23% of pregnancies (reference: 'general' CKD G1-G2 pregnancies incidence is 4-20%) and preeclampsia in 20%. The mean eGFR declined after pregnancy but remained within normal range (over 90ml/min/1.73m2). Pregnancy did not significantly affect eGFR-slope (pre-pregnancy β=-1.030, post-pregnancy β=-1.349). ARAS-pregnancies demonstrated less favorable outcomes (early preterm birth incidence 3/11 (27%)). ARAS was a significant independent predictor for lower birth weight and shorter duration of pregnancy, next to the classic predictors (pre-pregnancy kidney function, proteinuria, and chronic hypertension) though missing proteinuria values and the small ARAS-sample hindered analysis. This is the largest study to date on AS and pregnancy with reassuring results for mild AS, though inheritance patterns could be considered in counseling next to classic risk factors. Thus, our findings support personalized reproductive care and highlight the importance of investigating kidney disease-specific pregnancy outcomes.

Anemia in Pregnancy With CKD

Chronic kidney disease (CKD), anemia, and iron deficiency are global health issues affecting individuals in both high-income and low-income countries. In pregnancy, both CKD and iron deficiency anemia increase the risk of adverse maternal and neonatal outcomes, including increased maternal morbidity and mortality, stillbirth, perinatal death, preterm birth, and low birthweight. However, it is unknown to which extent iron deficiency anemia contributes to adverse outcomes in CKD pregnancy. Furthermore, little is known regarding the prevalence, pathophysiology, and treatment of iron deficiency and anemia in pregnant women with CKD. Therefore, there are many unanswered questions regarding optimal management with oral or i.v. iron and recombinant human erythropoietin (rhEPO) in these women. In this review, we present a short overview of the (patho)physiology of anemia in healthy pregnancy and in people living with CKD. We present an evaluation of the literature on iron deficiency, anemia, and nutritional deficits in pregnant women with CKD; and we evaluate current knowledge gaps. Finally, we propose research priorities regarding anemia in pregnant women with CKD.

Modelling changes in the pharmacokinetics of tacrolimus during pregnancy after kidney transplantation: A retrospective cohort study

AIMS

Pregnancy after kidney transplantation is realistic but immunosuppressants should be continued to prevent rejection. Tacrolimus is safe during pregnancy and is routinely dosed based on whole-blood predose concentrations. However, maintaining these concentrations is complicated as physiological changes during pregnancy affect tacrolimus pharmacokinetics. The aim of this study was to describe tacrolimus pharmacokinetics throughout pregnancy and explain the changes by investigating covariates in a population pharmacokinetic model.

METHODS

Data of pregnant women using a twice-daily tacrolimus formulation following kidney transplantation were retrospectively collected from 6 months before conception, throughout gestation and up to 6 months postpartum. Pharmacokinetic analysis was performed using nonlinear mixed effects modelling. Demographic, clinical and genetic parameters were evaluated as covariates. The final model was evaluated using goodness-of-fit plots, visual predictive checks and a bootstrap analysis.

RESULTS

A total of 260 whole-blood tacrolimus predose concentrations from 14 pregnant kidney transplant recipients were included. Clearance increased during pregnancy from 34.5 to 41.7 L/h, by 15, 19 and 21% in the first, second and third trimester, respectively, compared to prior to pregnancy. This indicates a required increase in the tacrolimus dose by the same percentage to maintain the prepregnancy concentration. Haematocrit and gestational age were negatively correlated with tacrolimus clearance (P ≤ 0.01), explaining 18% of interindividual and 85% of interoccasion variability in oral clearance.

CONCLUSIONS

Tacrolimus clearance increases during pregnancy, resulting in decreased exposure to tacrolimus, which is explained by gestational age and haematocrit. To maintain prepregnancy target whole-blood tacrolimus predose concentrations during pregnancy, increasing the dose is required.

Pregnancy after kidney transplantation: an observational study on maternal, graft and offspring outcomes in view of current literature

Introduction

Pregnancy after kidney transplantation (KTx) is considered to have a high risk of non-negligible complications for the mother, the allograft, and the offspring. With an increased incidence of these pregnancies over the past decades, transplant nephrologists and specialized obstetricians face increasing challenges, with scarce literature regarding long-term outcomes.

Methods

We retrospectively collected data from all women with at least one live birth pregnancy after KTx who were followed at our tertiary hospital between 2000 and 2021 to study maternal, graft and fetal outcomes.

Results

Ten patients underwent 14 live birth pregnancies after KTx. Preponderant maternal complications were stage 1 acute kidney injury (43%), urinary tract infections (UTI, 43%), progression of proteinuria without diagnostic criteria for preeclampsia (29%), and preeclampsia (14%). Median baseline serum creatinine at conception was 126.5 µmol/L [median estimated glomerular filtration rate (eGFR) 49 mL/min/1.73m2], and eGFR tended to be lower than baseline at follow-ups. Overall, there was no increase in preexisting or occurrence of de novo donor-specific antibodies. No graft loss was documented within the 2-year follow-up. There were nine premature births (64%), with a median gestational age of 35.7 weeks. The median birth weight, height, and head circumference were 2,560 g, 45.5 cm, and 32.1 cm, respectively. These measurements tended to improve over time, reaching a higher percentile than at birth, especially in terms of height, but on average remained under the 50th percentile curve.

Discussion

Overall, pregnancies after KTx came with a range of risks for the mother, with a high prevalence of cesarean sections, emergency deliveries, UTI, and preeclampsia, and for the child, with a high proportion of prematurity, lower measurements at birth, and a tendency to stay under the 50th percentile in growth charts. The short- and long-term impact on the allograft seemed reassuring; however, there was a trend toward lower eGFR after pregnancy. With these data, we emphasize the need for a careful examination of individual risks via specialized pre-conception consultations and regular monitoring by a transplant nephrologist and a specialist in maternal-fetal medicine during pregnancy. More data about the long-term development of children are required to fully apprehend the impact of KTx on offspring.

Successful pregnancies in post-kidney transplant couples: four case reports

Background

The fertility of female kidney transplant recipients is increasing with the progression of transplant management. This article aims to evaluate the clinical prognosis of mothers and newborns for post-kidney transplant couples.

Methods

From January 2019 to April 2022, a total of four couples, all kidney transplant recipients, were successfully prepared for pregnancy after a rigorous preconception evaluation, including three cases of natural conception and one case of in vitro fertilization. Data regarding the mother and newborn, including general clinical condition and laboratory results, were recorded and assessed throughout the pregnancy and up until 12 months after delivery.

Results

The mean conception age of the mothers was 34.8 years (30-38 years), and the mean interval between renal transplantation and pregnancy was 6.6 years (3.7-8.7 years). All deliveries were by cesarean section and took place without incident. There were three premature births (<37 weeks; average 35.1 weeks). In case 1 (in vitro fertilization), pre-eclampsia occurred during maternity, and this was the only case in which the fetal weight was less than 2,500 g (average 2,576.7 g). The mean Apgar score (1 min) was 7.8 (6-9) and reached 9 in all cases at 5 min. The mothers' eGFR rose during mid-gestation, decreased in late pregnancy, and was largely restored along with proteinuria 1 year postpartum. Postnatal evaluation at 6 months showed normal neurological development. In addition, NK cell and IFN-γ levels increased and Treg cell and IL-10 levels decreased along with the onset of pre-eclampsia.

Conclusions

Pregnancies can succeed in couples who are both kidney transplant recipients. However, there might be higher risks of infertility, prematurity, and low birth weight.

Chronic kidney disease, female infertility, and medically assisted reproduction: a best practice position statement by the Kidney and Pregnancy Group of the Italian Society of Nephrology

Fertility is known to be impaired more frequently in patients with chronic kidney disease than in the general population. A significant proportion of chronic kidney disease patients may therefore need Medically Assisted Reproduction. The paucity of information about medically assisted reproduction for chronic kidney disease patients complicates counselling for both nephrologists and gynaecologists, specifically for patients with advanced chronic kidney disease and those on dialysis or with a transplanted kidney. It is in this context that the Project Group on Kidney and Pregnancy of the Italian Society of Nephrology has drawn up these best practice guidelines, merging a literature review, nephrology expertise and the experience of obstetricians and gynaecologists involved in medically assisted reproduction. Although all medically assisted reproduction techniques can be used for chronic kidney disease patients, caution is warranted. Inducing a twin pregnancy should be avoided; the risk of bleeding, thrombosis and infection should be considered, especially in some categories of patients. In most cases, controlled ovarian stimulation is needed to obtain an adequate number of oocytes for medically assisted reproduction. Women with chronic kidney disease are at high risk of kidney damage in case of severe ovarian hyperstimulation syndrome, and great caution should be exercised so that it is avoided. The higher risks associated with the hypertensive disorders of pregnancy, and the consequent risk of chronic kidney disease progression, should likewise be considered if egg donation is chosen. Oocyte cryopreservation should be considered for patients with autoimmune diseases who need cytotoxic treatment. In summary, medically assisted reproduction is an option for chronic kidney disease patients, but the study group strongly advises extensive personalised counselling with a multidisciplinary healthcare team and close monitoring during the chosen medically assisted reproduction procedure and throughout the subsequent pregnancy.

Counselling on Conceiving: Attitudes and Factors Influencing Advice of Professionals in Transplantation

Pregnancy after kidney transplantation (KT) conveys risks of adverse pregnancy outcomes (APO). Little is known about performance of pre-pregnancy counselling after KT. This study investigated perceptions of risk, attitudes towards pregnancy and factors influencing advice given at pre-pregnancy counselling after KT. A web-based vignette survey was conducted among nephrologists and gynaecologists between March 2020 and March 2021, consisting of five vignettes containing known risk factors for APO and general questions on pre-pregnancy counselling after KT. Per vignette, attitudes towards pregnancy and estimation of outcomes were examined. In total 52 nephrologists and 25 gynaecologists participated, 56% from university hospitals. One third had no experience with pregnancy after KT. All gave positive pregnancy advice in the vignette with ideal circumstances (V1), versus 83% in V2 (proteinuria), 81% in V3 (hypertension), 71% in V4 (eGFR 40 ml/min/1.73 m²). Only 2% was positive in V5 (worst-case scenario). Chance of preeclampsia was underestimated by 89% in V1. 63% and 98% overestimated risk for graft loss in V4 and V5. Professionals often incorrectly estimated risk of APO after KT. As experience with pregnancy after KT was limited among professionals, patients should be referred to specialised centres for multidisciplinary pre-pregnancy counselling to build experience and increase consistency in given advice.

Pre-eclampsia after Kidney Transplantation: Rates and Association with Graft Survival and Function

BACKGROUND

Transplanted women have high rates of pre-eclampsia. However, determinants of pre-eclampsia and association with graft survival and function remain uncertain. We aimed to determine rates of pre-eclampsia and its association with kidney transplant survival and function.

METHODS

Retrospective cohort study analyzing post-kidney transplantation pregnancies (≥20 weeks gestation) from the Australia and New Zealand Dialysis and Transplant Registry (2000-2021). Graft survival was assessed in 3 models accounting for repeated pregnancies and episodes of pre-eclampsia.

RESULTS

Pre-eclampsia status was captured in 357/390 pregnancies and occurred in 133 pregnancies (37%). The percentage of pregnancies reported to have pre-eclampsia rose from 27% in 2000-2004, to 48% from 2018-2021. Reported prior exposure to calcineurin inhibitors was high overall, and higher in women who had pre-eclampsia (97% vs 88%, p=0.005). Seventy-two (27%) graft failures were identified after a pregnancy, with median follow-up of 8.08 years. Although women with pre-eclampsia had higher median preconception serum creatinine concentration (1.24 ((IQR) 1.00-1.50) vs. 1.13 (0.99-1.36) mg/dL; p=0.02), in all survival models, pre-eclampsia was not associated with higher death-censored graft failure. In multivariable analysis of maternal factors (age, body mass index, primary kidney disease and transplant-pregnancy interval, preconception serum creatinine concentration, era of birth event and Tacrolimus or Cyclosporin exposure) only era and preconception serum creatinine concentration ≥1.24 mg/dL (odds ratio 2.48, 95% CI 1.19-5.18) was associated with higher pre-eclampsia risk. Both preconception eGFR <45 ml/min/1.73m 2 (adjusted HR 5.55, 95% CI 3.27-9.44, p<0.001) and preconception serum creatinine concentration ≥1.24 mg/dL (adjusted HR 3.06, 95% CI 1.77-5.27, p<0.001) were associated with a higher risk of graft failure even after adjusting for maternal characteristics.

CONCLUSIONS

In this large and contemporaneous registry cohort, pre-eclampsia was not associated with worse graft survival or function. Preconception kidney function was the main determinant of graft survival.

Pregnancy after Kidney Transplantation-Impact of Functional Renal Reserve, Slope of eGFR before Pregnancy, and Intensity of Immunosuppression on Kidney Function and Maternal Health

Women of childbearing age show increased fertility after kidney transplantation. Of concern, preeclampsia, preterm delivery, and allograft dysfunction contribute to maternal and perinatal morbidity and mortality. We performed a retrospective single-center study, including 40 women with post-transplant pregnancies after single or combined pancreas-kidney transplantation between 2003 and 2019. Outcomes of kidney function up to 24 months after the end of pregnancy were compared with a matched-pair cohort of 40 transplanted patients without pregnancies. With a maternal survival rate of 100%, 39 out of 46 pregnancies ended up with a live-born baby. The eGFR slopes to the end of 24 months follow-up showed mean eGFR declines in both groups (-5.4 ± 14.3 mL/min in pregnant versus -7.6 ± 14.1 mL/min in controls). We identified 18 women with adverse pregnancy events, defined as preeclampsia with severe end-organ dysfunction. An impaired hyperfiltration during pregnancy was a significant risk contributor for both adverse pregnancy events (p < 0.05) and deterioration of kidney function (p < 0.01). In addition, a declining renal allograft function in the year before pregnancy was a negative predictor of worsening allograft function after 24 months of follow-up. No increased frequency of de novo donor-specific antibodies after delivery could be detected. Overall, pregnancies in women after kidney transplantation showed good allograft and maternal outcomes.

Pregnancy outcomes after kidney transplantation: the challenges of success

Pregnancy after kidney transplantation is highly successful, though not without risk. A new national Dutch study of a large series of pregnancies in transplanted women highlights the complexities of pregnancy in this cohort and notes a move toward pregnancies in women with "less-than-perfect" graft function. We discuss these new data defining pregnancy outcomes and the ethical and clinical challenges that may arise in these mothers.