Impact of pregnancy on kidney transplant

Pregnancy outcomes in renal transplant recipients: A systematic review and meta-analysis

BACKGROUND

Kidney transplantation is a superior treatment for end-stage renal disease (ESRD), compared with hemodialysis, offering better quality of life and birth outcomes in women with ESRD and lower fertility rates.

OBJECTIVES

To investigate the pregnancy, maternal, fetal, and graft outcomes following kidney transplantation in women with ESRD and evaluate the improvements in quality of life and associated risks.

DESIGN

A systematic review and meta-analysis performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and the Meta-analysis of Observational Studies in Epidemiology guidelines.

DATA SOURCES AND METHODS

A thorough search of multiple databases, including PubMed, Embase, Scopus, ATC abstracts, and Cochrane Central Register of Controlled Trials, was conducted to identify studies that analyzed pregnancy outcomes in kidney transplant patients. The search was conducted from the inception of each database to January 2023.

RESULTS

The study reviewed 109 studies that evaluated 7708 pregnancies in 5107 women who had undergone renal transplantation. Of these, 78.48% resulted in live births, 9.68% had induced abortion, and 68.67% had a cesarean section. Miscarriage occurred in 12.54%, preeclampsia in 20.87%, pregnancy-induced hypertension in 24.30%, gestational diabetes in 5.08%, and preterm delivery in 45.30% of cases. Of the 853 recipients, 123 had graft loss after pregnancy and 8.06% suffered acute rejection.

CONCLUSION

Pregnancy after kidney transplantation is associated with risks for mother and fetus; however, live births are still possible. In addition, there are reduced overall risks of stillbirths, miscarriages, neonatal deaths, and gestational diabetes.

REGISTRATION

PROSPERO (CRD42024541659).

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.

Effect of Pregnancy on eGFR After Kidney Transplantation: A National Cohort Study

BACKGROUND

The effect of pregnancy on the course of estimated glomerular filtration rate (eGFR) is unknown in kidney transplant recipients (KTRs).

METHODS

We conducted a nationwide multicenter cohort study in KTRs with pregnancy (>20 wk) after kidney transplantation (KT). Annual eGFRs after KT until death or graft loss and additional eGFRs before each pregnancy were collected according to protocol. Changes in eGFR slope before and after each pregnancy were analyzed by generalized estimating equations multilevel analysis adjusted for transplant vintage.

RESULTS

We included 3194 eGFR measurements before and after pregnancy in 109 (55%) KTRs with 1, 78 (40%) with 2, and 10 (5%) with 3 pregnancies after KT. Median follow-up after first delivery post-KT was 14 y (interquartile range, 18 y). Adjusted mean eGFR prepregnancy was 59 mL/min/1.73 m2 (SEM [standard error of the mean] 1.72; 95% confidence interval [CI], 56-63), after the first pregnancy 56 mL/min/1.73 m2 (SEM 1.70; 95% CI, 53-60), after the second pregnancy 56 mL/min/1.73 m2 (SEM 2.19; 95% CI, 51-60), and after the third pregnancy 55 mL/min/1.73 m2 (SEM 8.63; 95% CI, 38-72). Overall eGFR slope after the first, second, and third pregnancies was not significantly worse than prepregnancy (P = 0.28). However, adjusted mean eGFR after the first pregnancy was 2.8 mL/min/1.73 m2 (P = 0.08) lower than prepregnancy.

CONCLUSIONS

The first pregnancy has a small, but insignificant, effect on eGFR slope in KTRs. Midterm hyperfiltration, a marker for renal reserve capacity, was associated with better eGFR and death-censored graft survival. In this KTR cohort with long-term follow-up, no significant effect of pregnancy on kidney function was detected.

Obstetric and long-term graft outcomes in pregnant kidney transplant recipients: A single-center experience

BACKGROUND

Kidney transplantation (KT) is the best option for many women with end-stage renal disease desiring pregnancy. The aim of this study was to investigate obstetric and graft outcomes among KT recipient women in our center.

METHODS

Maternal and fetal data were assessed in 29 pregnancies of 18 female KT recipients. Each patient was matched with two controls without pregnancy history for factors known to affect graft function. According to pre-pregnancy levels, serum creatinine and eGFR slope in the gestational and postpartum periods were calculated as percentages.

RESULTS

The main maternal and fetal complications were preeclampsia (38%) and preterm births (38%), respectively. Pregnancy (odds ratio [OR]: 5.09; p = .02), proteinuria in the third trimester (OR: 5.52; p = .02), proteinuria in postpartum third months (OR: 7.4; p = .008) and stable creatinine levels in the first 6 months of pregnancy (OR: 11.25 p = .03) were associated with graft dysfunction. Postpartum first year eGFR decline (-16.8% vs. -6.7%; p = .04) and second-year eGFR decline (-18.5% vs. -8.3%; p = .04) were significantly higher in the pregnancy group than those matched controls.

CONCLUSION

Pregnancy after KT is associated with high rates of maternal and fetal complications. The sustained decline of eGFR may suggest an increased risk of graft loss compared to recipients with similar clinical characteristics.

Long-term Graft Survival and Graft Function Following Pregnancy in Kidney Transplant Recipients: A Systematic Review and Meta-analysis

BACKGROUND

The incidence of pregnancy in kidney transplantation (KT) recipients is increasing. Studies report that the incidence of graft loss (GL) during pregnancy is low, but less data are available on long-term effects of pregnancy on the graft.

METHODS

Therefore, we performed a meta-analysis and systematic review on GL and graft function, measured by serum creatinine (SCr), after pregnancy in KT recipients, stratified in years postpartum. Furthermore, we included studies of nulliparous KT recipients.

RESULTS

Our search yielded 38 studies on GL and 18 studies on SCr. The pooled incidence of GL was 9.4% within 2 years after pregnancy, 9.2% within 2-5 years, 22.3% within 5-10 years, and 38.5% >10 years postpartum. In addition, our data show that, in case of graft survival, SCr remains stable over the years. Only within 2 years postpartum, Δ SCr was marginally higher (0.18 mg/dL, 95%CI [0.05-0.32], P = 0.01). Furthermore, no differences in GL were observed in 10 studies comparing GL after pregnancy with nulliparous controls. Systematic review of the literature showed that mainly prepregnancy proteinuria, hypertension, and high SCr are risk factors for GL.

CONCLUSIONS

Overall, these data show that pregnancy after KT has no effect on long-term graft survival and only a possible effect on graft function within 2 years postpartum. This might be due to publication bias. No significant differences were observed between pre- and postpartum SCr at longer follow-up intervals.

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

BACKGROUND

Reproductive function in women with end stage renal disease generally improves after kidney transplant. However, pregnancy remains challenging due to the risk of adverse clinical outcomes.

METHODS

We searched PubMed/MEDLINE, Elsevier EMBASE, Scopus, BIOSIS Previews, ISI Science Citation Index Expanded, and the Cochrane Central Register of Controlled Trials from date of inception through August 2017 for studies reporting pregnancy with kidney transplant.

RESULTS

Of 1343 unique studies, 87 met inclusion criteria, representing 6712 pregnancies in 4174 kidney transplant recipients. Mean maternal age was 29.6 ± 2.4 years. The live-birth rate was 72.9% (95% CI, 70.0-75.6). The rate of other pregnancy outcomes was as follows: induced abortions (12.4%; 95% CI, 10.4-14.7), miscarriages (15.4%; 95% CI, 13.8-17.2), stillbirths (5.1%; 95% CI, 4.0-6.5), ectopic pregnancies (2.4%; 95% CI, 1.5-3.7), preeclampsia (21.5%; 95% CI, 18.5-24.9), gestational diabetes (5.7%; 95% CI, 3.7-8.9), pregnancy induced hypertension (24.1%; 95% CI, 18.1-31.5), cesarean section (62.6, 95% CI 57.6-67.3), and preterm delivery was 43.1% (95% CI, 38.7-47.6). Mean gestational age was 34.9 weeks, and mean birth weight was 2470 g. The 2-3-year interval following kidney transplant had higher neonatal mortality, and lower rates of live births as compared to > 3 year, and < 2-year interval. The rate of spontaneous abortion was higher in women with mean maternal age < 25 years and > 35 years as compared to women aged 25-34 years.

CONCLUSION

Although the outcome of live births is favorable, the risks of maternal and fetal complications are high in kidney transplant recipients and should be considered in patient counseling and clinical decision making.

Pregnancy outcomes in kidney transplant recipients: a systematic review and meta-analysis

Approximately 50,000 women of reproductive age in the United States are currently living after kidney transplantation (KT), and another 2800 undergo KT each year. Although KT improves reproductive function in women with ESRD, studies of post-KT pregnancies are limited to a few voluntary registry analyses and numerous single-center reports. To obtain more generalizable inferences, we performed a systematic review and meta-analysis of articles published between 2000 and 2010 that reported pregnancy-related outcomes among KT recipients. Of 1343 unique studies, 50 met inclusion criteria, representing 4706 pregnancies in 3570 KT recipients. The overall post-KT live birth rate of 73.5% (95%CI 72.1-74.9) was higher than the general US population (66.7%); similarly, the overall post-KT miscarriage rate of 14.0% (95%CI 12.9-15.1) was lower (17.1%). However, complications of preeclampsia (27.0%, 95%CI 25.2-28.9), gestational diabetes (8.0%, 95%CI 6.7-9.4), Cesarean section (56.9%, 95%CI 54.9-58.9) and preterm delivery (45.6%, 95%CI 43.7-47.5) were higher than the general US population (3.8%, 3.9%, 31.9% and 12.5%, respectively). Pregnancy outcomes were more favorable in studies with lower mean maternal ages; obstetrical complications were higher in studies with shorter mean interval between KT and pregnancy. Although post-KT pregnancy is feasible, complications are relatively high and should be considered in patient counseling and clinical decision making.

Outcome of 234 pregnancies in 140 renal transplant recipients from five middle eastern countries

OBJECTIVE

To study the pregnancy and offspring outcomes in postrenal transplant recipients.

METHODS

This is a retrospective case-note review study investigating the outcome of 234 pregnancies in 140 renal transplant recipients from five different Middle Eastern countries.

RESULTS

Of the overall pregnancies 74.4% were successful albeit with high prevalences of preterm and Caesarean deliveries (40.8% and 53%, respectively). The mean serum creatinine did not rise significantly during pregnancy in the group as a whole but did so in patients who had serum creatinine of or above 150 micromol/L at the beginning of their pregnancies. The mean birth weight was (2,458 g) with 41.3% of the newborns being of low birth weight (<2,500 g). The prevalences of stillbirths were 7.3% and of spontaneous abortion was 19.3%. Preeclampsia and gestational diabetes were observed in 26.1% and 2% of pregnancies, respectively.

CONCLUSIONS

In the presence of good allograft function, the majority of pregnancies in renal transplant recipients have a good outcome but with increased incidence of preeclampsia, reduced gestational age, and low birth weights. Patients with baseline serum creatinine of above 150 micromol/L have an increased risk of allograft dysfunction resulting from the pregnancy.