To investigate whether there is a relationship between sepsis and blood groups in preterm infants.This retrospective cohort study included preterm neonates born at <32 weeks of gestation with a birth weight <1500 g. Neonates were grouped by blood type (O, A, B, AB) and sepsis were compared among these groups.

This retrospective study was conducted on data collected between 1 January 2011 and 31 August 2018 in the neonatal intensive care unit (NICU) of the Health Sciences University Zekai Tahir Burak Women's Health Education and Research Hospital.

Neonates born at GA <32 weeks with birth weight (BW) <1500 g were included in the study.

Data pertaining to the neonates were recorded from medical records for each patient, and their ABO blood type was recorded.

The neonates were grouped by blood type (O, A, B, AB) and also separated into non-O (A, B, AB) and O groups and non-A (O, B, AB) and A groups for comparison of early and late onset sepsis.

Inclusion Criteria:

• Preterm neonates born at <32 weeks of gestation with a birth weight <1500 g.

Exclusion Criteria:

• Neonates born with severe congenital defects, birth weight ≥1500 g and gestational age ≥32 weeks were excluded.

Neonates born at gestational age <32 weeks with birth weight <1500