Topical Distribution of Blood Group Type and Rhesus Factor Among Autism Spectrum Disorder Patients

Abstract

Background:  Autism  Spectrum  Disorder  (ASD)  is  a  complex neurodevelopmental condition influenced by genetic, immunological, and environmental  factors.  The  potential  association  between  ABO  blood groups, Rhesus (Rh) factor, and ASD remains underexplored, particularly in Iraq.
Objective:     To investigate the distribution of blood groupe type and rhesus factor among autism spectrum disorder Patients.
Patient and Methods: A cross-sectional study was conducted from March 2025 to January 2026 in Diyala, Anbar, and Basra. A total of 72 patients diagnosed with ASD were included using a convenience sampling method. Data  were  collected  through  structured  questionnaires  completed  by parents either via direct interview or electronic forms. Variables assessed included socio-demographic characteristics, blood group type, Rh factor, maternal health, pregnancy-related factors, and family history.
Results: The majority of patients were male (75%) and aged 5–10 years (43.1%). Blood group A (36.1%) and O (34.7%) were most common among patients,  while  Rh  positivity  was  predominant  (92.4%).  Maternal distribution showed blood group O (45.5%) and Rh positivity (92.4%) as most frequent. Rh incompatibility was observed in 9.7% of cases, with only one mother reporting anti-D immunoglobulin administration. More than half  of  the  patients  (51.4%)  had  a  positive  family  history  of  autism. Associated  disorders were  reported  in  81%  of cases,  most  commonly speech delay and epilepsy.
Conclusion: The study revealed a predominance of blood groups A and O, and Rh-positive status among ASD patients. While no definitive causal relationship was established, these findings highlight potential biological associations that warrant further large-scale studies. Greater attention to maternal health, perinatal factors, and family history is recommended for early detection and risk assessment. It is recommended that future studies with larger sample sizes and control groups be conducted to better clarify the potential  role of blood groups and Rh factor in Autism Spectrum Disorder and to support early risk identification strategies.