The impact of previous conservative treatment of atypical hyperplasia on pregnancy outcomes after IVF/ICSI-embryo transfer: a propensity score-matched retrospective cohort study

STUDY QUESTION: Do women have worse pregnancy and neonatal outcomes of IVF/ICSI-fresh embryo transfer (ET) after conservative treatment of atypical hyperplasia (AH)?SUMMARY ANSWER: AH has no impact on live birth but is associated with increased risks of pregnancy loss and preterm delivery (PTD).WHAT IS KNOWN ALREADY: AH is a precancerous lesion of endometrial cancer. Several recognized AH risk factors include nulliparity, increased body mass index, ovulation disorders, diabetes mellitus, and others. As such, patients are suggested to attempt conception upon achieving AH regression. Recently, successful pregnancies with IVF/ICSI have been increasingly reported.STUDY DESIGN, SIZE, DURATION: Forty-two patients with AH regression and 18 700 women with no evidence of endometrial abnormality, who underwent their first autologous oocytes' retrieval and fresh ET cycles of IVF/ICSI in the Center for Reproductive Medicine, Shandong University, from May 2008 to July 2021, were retrospectively enrolled.PARTICIPANTS/MATERIALS, SETTING, METHODS: First, 42 AH patients were propensity score matched with control women (n = 168) at a 1:4 ratio. Reproductive outcomes and maternal/neonatal complications were compared between the matched pairs. Binary logistic regression analyses were conducted to assess odds ratios (ORs) of AH for live birth, pregnancy loss, and PTD from AH women and all 18 700 eligible controls.MAIN RESULT AND THE ROLE OF CHANCE: Patients with AH achieved a numerically lower live birth rate (LBR) as compared to the matched controls, but without significant difference (26% versus 37%, P = 0.192). However, compared with the matched controls, AH patients showed significantly higher rates of pregnancy loss (52% versus 21%, P = 0.003) and PTD (45% versus 16%, P = 0.041). Further analyses revealed a statistically significantly increased rate of late pregnancy loss (17% versus 3%, P = 0.023), but not early miscarriage (35% versus 18%, P = 0.086), in the AH group. Furthermore, after correcting for potential confounders, the likelihood of a live birth in AH patients narrowly failed to be statistically significantly different from controls (adjusted OR [aOR]: 0.51, 95% CI: 0.25-1.04, P = 0.064). Nonetheless, the logistic regression reconfirmed that AH was an independent risk factor for pregnancy loss (aOR: 3.62, 95% CI: 1.55-8.46, P = 0.003), late pregnancy loss (aOR: 9.33, 95% CI: 3.00-29.02, P < 0.001), and PTD (aOR: 5.70, 95% CI: 1.45-22.38, P = 0.013).LIMITATIONS, REASONS FOR CAUTION: Selection bias was an inherent drawback of this study. First, because of the low AH prevalence among women receiving IVF/ICSI treatment, and consequently, limited sample size, the relationship between AH with LBR and adverse complications might be concealed and underestimated. Hence, the results should be interpreted cautiously. Similarly, the impacts of diverse clinical features of AH patients on the pregnancy outcomes need further studies in a larger population. Second, although most data used in this study were obtained by reviewing the medical records, missing data did exist and so did the recall bias. Third, although the propensity score matching and multivariable logistic models were performed collectively in order to minimize potential confounders between AH and controls, the intrinsic disadvantages of the retrospective nature of this study could not be avoided completely, and additional confirmation bias might be induced with reduplication of statistical analyses. WIDER IMPLICATION OF THE FINDINGS: Our results highlight the necessity of adequate counseling and intensive pregnancy monitoring for AH individuals and their families.