Multifetal Pregnancies in Women with CKD: Risk Assessment and Indications for Counselling

Background – CKD is a risk factor for adverse pregnancy outcomes (APOs) in singleton pregnancies. Little is known about multifetal pregnancies in women with CKD. Due to higher maternal age and the wider use of medically assisted fertilization, multifetal pregnancies are increasing. We aimed to review pregnancy outcomes in the largest multicentre series of multifetal pregnancies in women affected by CKD.Methods – This retrospective study gathered data from three Italian units with long-standing experience in the follow-up of pregnancy in women with CKD (2000-2023). Propensity-score matched (age, parity, BMI, year of delivery) multifetal low-risk pregnancies and singleton pregnancies served as controls; multifetal pregnancies were also matched for chorionicity, amnionicity and mode of conception. Intrauterine death of at least one fetus, given the low number of events, was explored in the overall multifetal cohorts.Results – In this propensity score matched-cohort study, 52 multifetal pregnancies in women with CKD were associated with a significantly lower gestational age compared to 104 low-risk non-CKD controls (median 34.0 vs 36.0 gestational weeks - GW) and with lower term-delivery rate (9.6% vs 28.8%). NICU admission was more frequent in multifetal pregnancies with CKD (50.9% vs 25.2%, p=0.003).Cox regression and Kaplan-Meier analyses confirmed the independent impact of CKD on gestation duration. In women with CKD, multifetal pregnancies had a markedly shorter gestation than singletons (median 34 vs 39 GW, p< 0.00001), with significantly higher risk of preterm birth <34 GW (OR 9.733), SGA (OR 5.155), and NICU admission (OR 8.033). The difference was sharper than in low-risk non-CKD pregnancies (35 and 39 GW respectively).Conclusions – This study, the largest assessing the risks of APOs in women with CKD carrying more than one fetus, suggests that multifetal gestation is a strong additional risk. These findings highlight the need for further investigation and demonstrate the importance of careful counselling, particularly in medically assisted reproduction.