Abstract Multiple experiments were performed to optimize efficiency and fertility in recipients of fresh in vitro produced (IVP) embryos. In experiment 1, heifers (n = 520) were synchronized and received an embryo on d 6–8 after estrus or 6–8 d after GnRH in a fixed time ET (FTET) program using modified 5-d CIDR-Synch protocol (d-8: CIDR inserted; d-3: CIDR removed and PGF2α treatment; d-2: second PGF2α; d0: GnRH to induce ovulation). Pregnancy per ET (P/ET) at d 32 and d 60 were similar but pregnancy per treated potential recipient (efficiency of recipient utilization) was greater for FTET than estrus (+49.7%). Subsequent experiments sought to optimize FTET protocol by analyzing whether CIDRs could be used multiple times (up to 4 uses similar P/ET) and whether multiple PGF2α treatments were needed at end of program (no difference when no GnRH given at start of protocol). Thus, a simple, inexpensive FTET program has similar fertility as ET after estrus but is more efficient at recipient utilization. A large retrospective analysis (n = 12,569 ET) was performed using FTET program. Embryo stage and quality were major embryo factors impacting P/ET. Transfer of d 7 fresh embryo to d 7 or d 8 recipient was better than d 6 (+24.4%). Two experiments (GnRH or CIDR treatment) evaluated increasing circulating P4. In GnRH experiment, heifers (n = 1,562) on d5 received GnRH (200 μg) or Control (untreated). On D12, P4 was greater (P < 0.001) in GnRH-treated (7.2 ± 0.1ng/ml) vs Controls (6.0 ± 0.1ng/ml). There was greater P/ET at D33 and D60 of pregnancy for Stage 7 than 6 embryos. Treatment with GnRH did not alter P/ET but decreased pregnancy loss between D33 and D60 in heifers receiving Stage 7 embryos (11.6 vs 27.6% in recipients with accessory CL on d 33). In CIDR experiment, treatment with 2 CIDRs (from d 13; one new CIDR each 7 d) elevated circulating P4 and tended to decrease pregnancy loss (d 27 to 62; 25.9 vs 11.9%) and increase P/ET (40.4 vs 53.6% on d 62). Thus, elevating P4 decreased pregnancy loss during FTET program using fresh IVP embryos.