Predictors of Blood Transfusion Following Cesarean Delivery in Resource-Constrained Settings: The Impact of Out-of-Hours Surgery

Background/Objectives: Perioperative red blood cell (RBC) transfusion after cesarean delivery reflects both obstetric hemorrhagic risk and the capacity of the care environment. We evaluated whether out-of-hours cesarean delivery was independently associated with transfusion in a Romanian tertiary maternity unit operating under constrained resources. Methods: We conducted a retrospective unmatched case–control study of cesarean deliveries performed from 2023 to 2025. All eligible transfused women were included as cases; two non-transfused controls per case were randomly selected within each calendar year. Eligibility required preoperative hemoglobin ≥ 10 g/dL and normal coagulation. The primary exposure was out-of-hours surgery, and multivariable logistic regression adjusted for maternal, obstetric, placental, and hematological factors. Results: The source population contained 6773 cesarean deliveries, with 608 transfusions (9.0%). The analytical sample comprised 401 cases and 802 controls. Out-of-hours procedures occurred in 64.1% of cases and 52.5% of controls (crude OR 1.62, 95% CI 1.26–2.07). After adjustment, out-of-hours delivery remained associated with transfusion (aOR 2.03, 95% CI 1.45–2.84). Placenta previa, suspected placenta accreta spectrum, and lower preoperative hemoglobin were the strongest clinical predictors. When postoperative/pre-transfusion hemoglobin was added, the out-of-hours association attenuated to an aOR of 1.02 (95% CI 0.63–1.65); sensitivity analyses remained consistent with the primary model. Conclusions: Out-of-hours cesarean delivery was associated with approximately two-fold higher transfusion odds after adjustment for the measured clinical factors. Because cesarean indication, urgency, and labor characteristics were not available, this association may partly reflect the different case mix and acuity of out-of-hours surgery rather than the working period itself. Attenuation after adjustment for post-exposure hemoglobin is compatible with, but does not establish greater perioperative blood loss. In high-cesarean, resource-constrained settings, standardized hemorrhage-risk identification and equivalent preparedness across duty periods warrant prospective evaluation in studies that also record indication and urgency.