CRISTEL Study: Monitoring of Pregnancies in Women After Solid Organ Transplantation (CRISTEL)

According to North American and Australian registries, pregnancy is both a joyful and high-risk event for women who have received a solid organ transplant. Typically, a transplanted woman has a probability comparable to that of the general population of giving birth to a live infant, but she is likely to deliver prematurely (median gestational age: 32 weeks), to have a growth-restricted baby (median birth weight around 2.3 kg), and often in a context of preeclampsia (in at least 30% of cases)(1).

Today, these are the data shared with patients planning a pregnancy, despite uncertainty as to their accuracy and applicability in France or even Europe.

Among the unknowns that remain despite these registry data, the following should be noted:

Uncertainty about the level of pregnancy planning in this specific context: What proportion of women of childbearing age have been informed of the possibility of becoming pregnant, of the associated risks, and of necessary precautions (e.g., stopping mycophenolate mofetil at least 6 weeks before conception);

Variability in the information provided from one center to another, due to the absence of a national, consensus-based document addressing fertility and contraception in the post-transplantation setting;

Monitoring frequency specific to the graft, especially regarding exposure to immunosuppressive drugs (and consequently actual exposure to calcineurin inhibitors, the cornerstone of anti-rejection therapy, whose residual blood concentration varies from the second trimester onward)(2);

The true risk of preeclampsia, at a time when diagnosis can be refined by measuring levels of placental-derived anti-angiogenic factors in maternal serum (sFlt-1/PlGF ratio)(3), and by uterine artery Doppler;

The incidence of de novo anti-HLA immunization (HLA antigens expressed by the fetus and inherited from the father), which can now be assessed using the Luminex technique(4);

Maternal morbidity: What is the impact of pregnancy on graft function? Conversely, how does renal function influence pregnancy outcomes, regardless of the transplanted organ?

Infant morbidity in the short and medium term.

To establish these data and to provide accurate information to patients, we aim to conduct a study among pregnant women who have undergone solid organ transplantation (kidney, heart, lung, liver, or pancreas). The objective of this research is to collect standardized and independent data on the number of pregnancies occurring in France and to monitor them up to one year postpartum (or after pregnancy termination).

The study will then aim to describe the clinical characteristics and maternal and perinatal outcomes of pregnancies in this specific population. These data will help disseminate clear and up-to-date information to the medical community, thus improving patient counseling and, more broadly, support for couples. They will also serve to develop recommendations to optimize the planning and management of pregnancies in women with solid organ transplants.

Finally, this initiative aims to promote clinical research on pregnancy in the context of transplantation, particularly through clinical trials and the development of biobanks.