Fig. 1

Study design and flowchart of the patient enrollment. (A) Flowchart showing the study design. (B) Flowchart of the patient enrollment. (C) Sketch of the hyperbaric oxygen therapy. HBOT, hyperbaric oxygen therapy; E2, estradiol; FET, frozen embryo transfer; AFS, the American Fertility Society’s (AFS) classification of intrauterine adhesions; PSM, propensity score matching