Prevalence, Temporal Trends, Diversity, and Associated Risk Factors of Isolated Cleft Lip With or Without Cleft Palate: A 20-Year Retrospective Hospital-Based Study in Iran (2003-2023).

BACKGROUND

Cleft lip with or without cleft palate (CL/P) is a prevalent congenital anomaly influenced by multifactorial genetic and environmental factors. This study investigated the prevalence, temporal trends, diversity, unclassified cases, and associated risk factors for isolated CL/P in a tertiary Iranian hospital setting over two decades.

METHODS

A retrospective analysis of 767 isolated CL/P cases from 620,000 live births at 15 Khordad Hospital (Tehran, Iran) from 2003 to 2023 was conducted. Data were extracted from anonymized medical records, focusing on demographic, perinatal, and clinical variables. Prevalence was calculated per 10,000 live births, with Cochran-Armitage trend tests for temporal patterns. Univariable and multivariable logistic regression assessed associations, adjusted for confounders (p < 0.05).

RESULTS

Prevalence was 1.24 per 1000 live births (95% CI: 1.15-1.33), with male predominance (59.7%; ratio 1.59:1). A significant non-linear temporal pattern was observed (p = 0.045), with fluctuations peaking mid-2010s. Diversity included 48.4% combined CL/P, 71.6% unilateral (42.1% left), and 58.7% complete forms; 4.3% were unclassified "nasal-dominant variants." Multivariable models identified maternal smoking (11-20 cigarettes/day: aOR 1.52, 95% CI 1.30-1.78), obesity (extreme: aOR 1.37, 95% CI 1.23-1.53), pre-pregnancy diabetes (aOR 2.00, 95% CI 1.68-2.38), hypertension (aOR 1.20, 95% CI 1.05-1.37), previous preterm birth (aOR 1.44, 95% CI 1.30-1.60), and assisted reproductive technology (aOR 1.42, 95% CI 1.18-1.71) as risks; higher education (aOR 0.82, 95% CI 0.74-0.91) and maternal age 30-34 years (aOR 0.90, 95% CI 0.81-1.00) were protective (Nagelkerke R2 = 0.18).

CONCLUSION

Isolated CL/P in Iran exhibits stable yet fluctuating trends, driven by modifiable maternal risks amenable to preconception interventions. Enhanced public health strategies targeting smoking and obesity could reduce incidence by 15%-25%, aligning with global goals for congenital anomaly prevention.