Background:Prepectoral breast reconstruction is increasingly popular. This study compares complications between 2 subpectoral and 1 prepectoral breast reconstruction technique.Methods:Between 2008 and 2015, 294 two-staged expander breast reconstructions in 213 patients were performed with 1 of 3 surgical techniques: (1) Prepectoral, (2) subpectoral with acellular dermal matrix (ADM) sling (“Classic”), or (3) subpectoral/subserratus expander placement without ADM (“No ADM”). Demographics, comorbidities, radiation therapy, and chemotherapy were assessed for correlation with Clavien IIIb score outcomes. Follow-up was a minimum of 6 months.Results:Surgical cohorts (n = 165 Prepectoral; n = 77 Classic; n = 52 No ADM) had comparable demographics except Classic had more cardiac disease (P = 0.03), No ADM had higher body mass index (BMI) (P = 0.01), and the Prepectoral group had more nipple-sparing mastectomies (P < 0.001). Univariate analysis showed higher expander complications with BMI ≥ 40 (P = 0.05), stage 4 breast cancer (P = 0.01), and contralateral prophylactic mastectomy (P = 0.1), whereas implant complications were associated with prior history of radiation (P < 0.01). There was more skin necrosis (P = 0.05) and overall expander complications (P = 0.01) in the Classic cohort, whereas the No ADM group trended toward the lowest expander complications among the 3. Multivariate analysis showed no difference in overall expander complication rates between the 3 groups matching demographics, mastectomy surgery, risks, and surgical technique.Conclusions:Prepectoral and subpectoral Classic and No ADM breast reconstructions demonstrated comparable grade IIIb Clavien score complications. BMI > 40, stage 4 cancer, and contralateral prophylactic mastectomy were associated with adverse expander outcomes and a prior history of radiation therapy adversely impacted implant outcomes. Ninety-day follow-up for expander and implant complications may be a better National Surgical Quality Improvement Program measure.