Maternal prior pregnancy outcome subtype and offspring cryptorchidism: A retrospective case-control study.
OBJECTIVE: To determine whether maternal prior pregnancy outcome subtype and frequency are associated with cryptorchidism in male offspring, and whether first-trimester exogenous progesterone exposure mediates any observed association. MATERIALS AND METHODS: We conducted a hospital-based retrospective case-control study of 1220 mother-son pairs (610 cryptorchidism cases; 610 controls). Maternal prior pregnancy outcome subtype was defined using a prespecified proximal-event approach based on the most recent qualifying pregnancy event before the index pregnancy: no prior pregnancy loss or termination, miscarriage, or pregnancy termination. Subtype-specific frequency was categorized as 0, 1, or ≥2. Adjusted odds ratios (aORs) were estimated using multivariable logistic regression; robustness was examined using 1:1 propensity score matching with conditional logistic regression. Exploratory mediation analysis estimated indirect effects through first-trimester exogenous progesterone exposure. RESULTS: In fully adjusted models, miscarriage was associated with higher odds of cryptorchidism compared with no prior pregnancy loss or termination (aOR 1.97; 95% CI 1.26-3.09), whereas pregnancy termination was not (aOR 1.14; 95% CI 0.86-1.52). In joint subtype-frequency analyses, odds increased with the number of miscarriages (one: aOR 1.74; 95% CI 1.07-2.83; two or more: aOR 3.77; 95% CI 1.22-11.66) and were higher for two or more pregnancy terminations (aOR 1.77; 95% CI 1.10-2.84). Matched analyses were directionally consistent. Mediation analyses suggested a modest indirect effect through first-trimester progesterone exposure for the miscarriage association. CONCLUSIONS: Maternal prior miscarriage was associated with cryptorchidism in male offspring, whereas pregnancy termination showed higher odds only among women with two or more prior procedures. First-trimester exogenous progesterone exposure may account for a modest proportion of the miscarriage-cryptorchidism association.