eng Oriental Scientific Publishing Company Biomedical and Pharmacology Journal 0974-6242 2026-06-10 19 2 72248 article Boumehdi Boutaina 1 Mochhoury Latifa 2 Iaziji Lamya 3 Barkat Amina 4 Chebabe Milouda 2 Laboratory of Health Sciences and Technologies, Higher Institute of Health Sciences, Hasan 1st Settat University, Morocco Laboratory of Health Sciences and Technologies, Higher Institute of Health Sciences, Hassan 1st Settat University, Morocco The Neonatal Resuscitation Department at the Children’s Hospital in Rabat, research team in health and nutrition mother child laboratory of biostatistics and epidemiological studies of the faculty of medicine Rabat, Mohammed 5 Rabat University, Morocco Down syndrome newborns often have abnormal levels of thyroid hormones, requiring systematic screening for congenital hypothyroidism (HC) if untreated, which can lead to stunted growth and cognitive deficits. A better understanding of the links between Down syndrome and HC is essential to improve care and quality of life for those affected. This study examined the records of 108 trisomy newborns between January 2013 and December 2023, comparing 33 cases with trisomy 21 with HC to 75 trisomy controls without HC. Data included risk factors such as sex, environment, maternal age, birth weight, term of pregnancy, date of delivery, and associated malformations. The analysis was performed with Epi Info, using statistical methods with a p-value < 0.05 considered significant. The results highlight the importance of increased clinical attention for children with Down syndrome, especially in CH. Factors such as seasonality, namely winter season [OR= 3.63 (1.47-8.91)] and spring season [OR= 3.41 (1.34-8.66)], consanguinity [OR= 11.2(4.20-30.24)], prematurity [OR= 4.2 (1.75- 10.31)], Advanced maternal age [OR= 4.42 (1.83-10.6)] and heart defects [OR= 3.41 (1.34- 8.66)] may increase the risk of HC in these newborns. It is essential to consider these factors to prevent this pathology in this vulnerable population better. These findings reinforce our understanding of the issues related to Down syndrome and CH. Several factors contribute to the development of CH in Down syndrome newborns. A multidimensional approach is essential for better understanding these mechanisms and for improving prenatal care and counseling strategies. https://biomedpharmajournal.org/vol19no2/down-syndrom-in-newborns-with-congenital-hypothyroidism-a-cross-sectional-analysis-of-data-from-trisomy-newborns/ Congenital hypothyroidism Consanguinity Prematurity Risk factor Seasonality Trisomy 21