Table 1. Summary of the included studies.
| Study | Study arms | Country | Sample size | Age (year), mean±SD | Body mass index, mean±SD | GnRH analogue | GnRH protocol | Gn type | HCG dose | Number of oocytes retrieved, mean±SD | Number of embryos transferred, mean±SD | Infertility causes | Main findings | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
| ||||||||||||||||
| Tubal | PCOS | Unexplained | Male | |||||||||||||
| Singh et al. (2019)[25] | Fat emulsion group (Two doses of 4 mL of 20% fat emulsion in normal saline of 250 mL; 1 dose at oocyte recovery, 1 dose on day of embryo transfer) | India | 52 | 31.64±3.96 | 4.06±3.12 | Leuprolide acetate/Cetrorelix | Agonist/Antagonist | rFSH | 250 μg rHCG | 5.96±3.45 | 2.09±1.1 | 13 | 6 | 19 | 13 | Showed a significant increase in live birth rate and implantation rates in women who received the fat emulsion infusion after IVF/ICSI |
| Control group (normal saline) | 50 | 32.12±3.50 | 24.61±3.32 | 4.62±1.99 | 2.48±1.07 | 21 | 3 | 18 | 11 | |||||||
| Al-Zebeidi et al. (2019)[27] | Fat emulsion group (Two doses 20% 20% fat emulsion 100 mL diluted in 500 mL normal saline; 1 dose on day of embryo transfer, 1 dose on day of pregnancy test) | Saudi Arabia | 71 | 35.32±4.23 | 28.30±4.66 | Cetrorelix | Long antagonist | rFSH/HMG | 10,000 IU | NA | 1.8±0.54 | 5 | 3 | 10 | 39 | There was an improvement in the pregnancy rate among women with unexplained RIF who received the fat emulsion therapy; however, this improvement did not reach statistical significance. |
| Control group (no intervention) | 71 | 35.21±4.77 | 28.30±4.66 | NA | 1.9±0.51 | 2 | 5 | 10 | 45 | |||||||
| Dakhly et al. (2016) [29] | Fat emulsion group (Multiple doses of 2mL 20% fat emulsion diluted at 20% in 250 mL saline; infusions within 1 week of positive pregnancy test and every 2 weeks until end of first trimester) | Egypt | 144 | 35.5±3.7 | 22.6±2.6 | Triptorelin acetate | Long agonist | HMG | 10,000 IU | 8.5±2.8 | 2.5±0.5 | NA | NA | NA | NA | Fat emulsion therapy did not increase chemical pregnancy rates. However, live birth and ongoing pregnancy rates were increased in the fat emulsion group. |
| Control group (normal saline) | 152 | 36±3.7 | 22.9±2.2 | 8.8±2.4 | 2.6±0.5 | NA | NA | NA | NA | |||||||
| El-Khayat and El Sadek (2015)[26] | Fat emulsion group (Two doses of 2 mL 20% fat emulsion in 250 mL normal saline; infusion between days 4–9 of ICSI and 1 dose within first week of positive pregnancy test) | Egypt | 101 | 35.1±3.5 | 24.7±4.7 | Triptorelin acetate | Long agonist | HMG | 10,000 IU | 5.1±1.4 | 1.94±0.31 | NA | NA | NA | N | Fat emulsion infusion significantly improved clinical pregnancy rate, implantation rate, and the live birth rates in IVF/ICSI in women with RIF. |
| Control group (normal saline) | 102 | 35±3.6 | 24.1±4.3 | 4.9±1.7 | 1.93±0.33 | NA | NA | NA | NA | |||||||
| Gamaleldin et al. (2018)[28] | Fat emulsion group (Two doses of 2 mL 20% fat emulsion in 250 mL normal saline) | United Kingdom (UK) | 48 | 35±3.4 | NA | Triptorelin acetate | Long agonist | HMG | 10,000 IU | NA | NA | NA | NA | NA | NA | Fat emulsion therapy did not significantly improve live birth rates in women with unexplained RIF undergoing IVF treatment. |
| Control group (normal saline) | 49 | 35.4±3.2 | NA | NA | NA | NA | NA | NA | NA | |||||||
NA: Not available, IVF/ICSI: In vitro fertilization/intracytoplasmic sperm injection, RIF: Recurrent implantation failure, HMG: Human menopausal gonadotropin, HCG: Human chorionic gonadotropin, GnRH: Gonadotropin-releasing hormone, Gn: Gonadotropin, rFSH: Recombinant Follicle-stimulating hormone, rHCG: Recombinant human chorionic gonadotropin, IU: International unit, SD: Standard deviation