Tacrolimus as Basic Immunosuppression in Pregnancy After Renal Transplantation. A Single-Center Experience

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).

Usage of Tacrolimus and Mycophenolic Acid During Conception, Pregnancy, and Lactation, and Its Implications for Therapeutic Drug Monitoring: A Systematic Critical Review

BACKGROUND

Conception, pregnancy, and lactation following solid organ transplantation require appropriate management. The most frequently used immunosuppressive drug combination after solid organ transplantation consists of tacrolimus (Tac) plus mycophenolic acid (MPA). Here, the effects of Tac and MPA on fertility, pregnancy, and lactation are systematically reviewed, and their implications for therapeutic drug monitoring (TDM) are discussed.

METHODS

A systematic literature search was performed (August 19, 2019) using Ovid MEDLINE, EMBASE, the Cochrane Central Register of controlled trials, Google Scholar, and Web of Science, and 102 studies were included. Another 60 were included from the reference list of the published articles.

RESULTS

As MPA is teratogenic, women who are trying to conceive are strongly recommended to switch from MPA to azathioprine. MPA treatment in men during conception seems to have no adverse effect on pregnancy outcomes. Nevertheless, in 2015, the drug label was updated with additional risk minimization measures in a pregnancy prevention program. Data on MPA pharmacokinetics during pregnancy and lactation are limited. Tac treatment during conception, pregnancy, and lactation seems to be safe in terms of the health of the mother, (unborn) child, and allograft. However, Tac may increase the risk of hypertension, preeclampsia, preterm birth, and low birth weight. Infants will ingest very small amounts of Tac via breast milk from mothers treated with Tac. However, no adverse outcomes have been reported in children exposed to Tac during lactation. During pregnancy, changes in Tac pharmacokinetics result in increased unbound to whole-blood Tac concentration ratio. To maintain Tac concentrations within the target range, increased Tac dose and intensified TDM may be required. However, it is unclear if dose adjustments during pregnancy are necessary, considering the higher concentration of (active) unbound Tac.

CONCLUSIONS

Tac treatment during conception, pregnancy and lactation seems to be relatively safe. Due to pharmacokinetic changes during pregnancy, a higher Tac dose might be indicated to maintain target concentrations. However, more evidence is needed to make recommendations on both Tac dose adjustments and alternative matrices than whole-blood for TDM of Tac during pregnancy. MPA treatment in men during conception seems to have no adverse effect on pregnancy outcomes, whereas MPA use in women during conception and pregnancy is strongly discouraged.

Effect of deflazacort on pregnancy outcome in kidney transplant patients: should we change the immunosuppressant before conception?

Background

Despite the good prognosis in patients with transplant organs, limited evidence is available on how immunosuppressants affect pregnancy. The aim of this study was to determine whether immunosuppressant use affects the pregnancy outcome and to identify whether there is any need to change the immunosuppressant before the patient tries to conceive.

Methods

This retrospective cohort study included women with previous kidney transplantation history who visited the Department of Obstetrics and Gynecology for either infertility or antenatal care between January 2005 and May 2016. A total of 40 cases (36 women) met the inclusion criteria. Statistical analyses were performed using SAS version 9.4.

Results

There were no differences in the immunosuppressant regimen between the pregnant and non-pregnant groups (never-pregnant+miscarriage) (P = 0.73). Individual immunosuppressant use was significantly different in terms of pregnancy outcome among the never-pregnant, miscarriage, and clinical pregnancy groups (azathioprine, P = 0.01; deflazacort, P < 0.0001). Only deflazacort use differed significantly between the clinical pregnancy and non-pregnant groups (P = 0.003). After adjusting for factors that may affect pregnancy outcome, deflazacort use remained significantly associated with a decreased odds ratio for clinical pregnancy (P = 0.02). Cox regression analysis also showed that deflazacort use was the only remaining factor that could hinder the success of clinical pregnancy (P = 0.03).

Conclusions

Our study suggests that the type of immunosuppressive regimen may not affect the success of clinical pregnancy. However, deflazacort may decrease the possibility of clinical pregnancy in women with kidney transplant when they try to conceive.

Tacrolimus treatment for infertility related to maternal-fetal immune interactions

Many approaches have been used to achieve successful pregnancies in patients with infertility, though existing treatments remain unsatisfactory in patients with infertility caused by abnormal maternal-fetal immunity. However, our understanding of the immunological aspects of infertility has steadily progressed, aided by recent research into organ transplantation and cancer. The results of these recent analyses have led to the development and evaluation of several candidate immunological treatments, but the use of immunological treatments remains a novel approach. The current paper presents the hypothesis that tacrolimus may have potential as a candidate agent for the treatment of maternal-fetal immunity-related infertility.

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.

[Sexuality, fertility and pregnancy after kidney transplantation]

AIMS

To describe sexuality and fertility alterations secondary to chronic kidney disease and their outcomes after renal transplantation.

MATERIAL AND METHODS

An exhaustive systematic review of the scientific literature was performed in the Medline database (http://www.ncbi.nlm.nih.gov) and Embase (http://www.embase.com) using different associations of the following keywords: erectile dysfunction; impotence; sexuality; pregnancy; fertility; renal transplantation. Publications obtained were selected based on methodology, language, date of publication (last 10 years) and relevance. Prospective and retrospective studies, in English or French, review articles; meta-analysis and guidelines were selected and analyzed. This search found 706 articles. After reading titles and abstracts, 76 were included in the text, based on their relevance.

RESULTS

The observed prevalence of erectile dysfunction is high in men with chronic kidney disease. The causes of erectile dysfunction are numbers and its origin is often multifactorial. Most of the time, kidney transplantation improves sexuality and the management of erectile dysfunction in transplanted men is similar to the general population. Improvement in sexuality in men and women after kidney transplantation may conduct to pregnancy. The outcomes of pregnancy after transplantation are quite good in absence of risk factors such as time to pregnancy less than 1 year after transplantation, uncontrolled high blood pressure, and decreased renal function of the graft. Adaptation of immunosuppression may be required to avoid any teratogenicity for the fetus.

CONCLUSION

Kidney transplantation improves sexuality and fertility in men and women with chronic kidney disease.

Safety of Drugs during Pregnancy and Breastfeeding in Cystic Fibrosis Patients

Health management of cystic fibrosis (CF) patients should be maximized during pregnancy and breastfeeding because of its significant impact on the maternal and newborn outcomes. Thus, numerous drugs will have to be continued during pregnancy and lactation. Most of the drugs representing CF treatment lines cross the placenta or are excreted into human milk. Research addressing the risks and benefits of drugs used in CF patients during pregnancy and lactation is often incomplete or challenged by limited methodology, which often leads to conflicting or inconclusive results. Yet, potential treatment benefits for CF pregnant patients most often outbalance potential risks for the unborn child.

Interpreting tacrolimus concentrations during pregnancy and postpartum

Pregnancy after solid organ transplantation, although considered high risk for maternal, fetal, and neonatal complications, has been quite successful. Tacrolimus pharmacokinetic changes during pregnancy make interpretation of whole blood trough concentrations particularly challenging. There are multiple factors that can increase the fraction of unbound tacrolimus, including but not limited to low albumin concentration and low red blood cell count. The clinical titration of dosage to maintain whole blood tacrolimus trough concentrations in the usual therapeutic range can lead to elevated unbound concentrations and possibly toxicity in pregnant women with anemia and hypoalbuminemia. Measurement of plasma or unbound tacrolimus concentrations for pregnant women might better reflect the active form of the drug, although these are technically challenging and often unavailable in usual clinical practice. Tacrolimus crosses the placenta with in utero exposure being approximately 71% of maternal blood concentrations. The lower fetal blood concentrations are likely due to active efflux transport of tacrolimus from the fetus toward the mother by placental P-glycoprotein. To date, tacrolimus has not been linked to congenital malformations but can cause reversible nephrotoxicity and hyperkalemia in the newborn. In contrast, very small amounts of tacrolimus are excreted in the breast milk and are unlikely to elicit adverse effects in the nursing infant.

Pharmacokinetics of tacrolimus during pregnancy

BACKGROUND

Information on the pharmacokinetics of tacrolimus during pregnancy is limited to case reports despite the increasing number of pregnant women being prescribed tacrolimus for immunosuppression.

METHODS

Blood, plasma, and urine samples were collected over 1 steady-state dosing interval from women treated with oral tacrolimus during early to late pregnancy (n = 10) and postpartum (n = 5). Total and unbound tacrolimus as well as metabolite concentrations in blood and plasma were assayed by a validated liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS) method. A mixed-effect linear model was used for comparison across gestational age and using postpartum as the reference group.

RESULTS

The mean oral clearance (CL/F) based on whole-blood tacrolimus concentration was 39% higher during mid-pregnancy and late pregnancy compared with postpartum (47.4 ± 12.6 vs. 34.2 ± 14.8 L/h, P < 0.03). Tacrolimus-free fraction increased by 91% in plasma (f(P)) and by 100% in blood (f(B)) during pregnancy (P = 0.0007 and 0.002, respectively). Increased fP was inversely associated with serum albumin concentration (r = -0.7, P = 0.003), which decreased by 27% during pregnancy. Pregnancy-related changes in f(P) and f(B) contributed significantly to the observed gestational increase in tacrolimus whole-blood CL/F (r² = 0.36 and 0.47, respectively, P < 0.01). In addition, tacrolimus whole-blood CL/F was inversely correlated with both hematocrit and red blood cell counts, suggesting that binding of tacrolimus to erythrocytes restricts its availability for metabolism. Treating physicians increased tacrolimus dosages in study participants during pregnancy by an average of 45% to maintain tacrolimus whole-blood trough concentrations in the therapeutic range. This led to striking increases in unbound tacrolimus trough concentrations and unbound area under the concentration-time curve, by 112% and 173%, respectively, during pregnancy (P = 0.02 and 0.03, respectively).

CONCLUSIONS

Tacrolimus pharmacokinetics are altered during pregnancy. Dose adjustment to maintain whole-blood tacrolimus concentration in the usual therapeutic range during pregnancy increases circulating free drug concentrations, which may impact clinical outcomes.

Pregnancy after transplantation

The National Transplantation Pregnancy Registry (NTPR) was established in 1991 to study the outcomes of pregnancies in female transplant recipients and pregnancies fathered by male transplant recipients. Data from the NTPR have helped to endorse the reassurances from publications of smaller experiences that successful pregnancies are possible in the transplant population. In our last review for this journal (2000), we noted that important future issues would include the reassessment of prepregnancy guidelines, gestational and organ-specific problems, the role of new immunosuppressive drugs, and the long-term effects of pregnancy on both graft and child. Data collected by the NTPR over the last 7 years have addressed these issues, thus providing additional information for health care providers of transplant recipients of childbearing age. There has been some refinement of prepregnancy guidelines, but there is a need for additional data collection so that organ-specific outcomes and risks can further be identified. To date, the outcomes of the children followed have been encouraging, and specific remote effects have not been identified, but continued surveillance is still vital. Of special concern are the new immunosuppressive drugs, specifically for mycophenolate mofetil (CellCept, Roche Laboratories Inc., Nutley, New Jersey), where data reported to the NTPR and through postmarketing surveillance have shown an increased incidence of nonviable outcomes and a specific pattern and increased incidence of malformation in the newborn, which has resulted in a pregnancy category change. Newer information points to an increased need for vigilance among centers and continued monitoring of pregnancy outcomes in this population. As the first reported pregnancy after transplantation occurred in a kidney recipient 50 years ago, in March 1958, this review also highlights the first reported pregnancies in other solid organ recipients.

Cholestasis in pregnancy associated with ciclosporin therapy in renal transplant recipients

Obstetric cholestasis (OC) presents with pruritus in the second half of pregnancy and is associated with increased risk of foetal distress, intra-uterine death and premature delivery. From a tertiary referral, renal-obstetric clinic, we report the occurrence of OC in 5/23 pregnancies of women with renal transplants maintained on ciclosporin treatment (European incidence 0.1-1.5% of pregnancies). All required premature delivery for foetal reasons at 33-37/40 (median 34/40). Ciclosporin, at therapeutic concentrations, inhibits bile salt excretion pump (BSEP) function in rats and humans. We propose that OC developed in our patients because the mild inhibition of the canalicular pumps by ciclosporin was only revealed in pregnancy when increases in progesterone metabolites overwhelmed pump function. We suggest that all pregnant women receiving ciclosporin should be closely monitored from the second trimester for the development of OC. If detected, enhanced foetal and maternal monitoring to optimize time of delivery and pregnancy outcome is required.