Objective:To compare the the cultivation effects of human embryos in dry and humid incubators.Methods:A total of 479 infertile patients who underwent in vitro fertilization (IVF) treatment at Reproductive Center of Guiyang Maternal and Child Health Care Hospital from October 2020 to April 2022. The study was divided into two stages. The first stage of the study was a self-comparative research with 95 cases from the same period and source. The embryos were divided into dry and humid incubator groups to compare the embryo development indicators. In the second stage of the study, the patients were divided into six groups, including 10 μL humid incubator group ( n=64), 20 μL humid incubator group ( n=64), 30 μL humid incubator group ( n=64), 10 μL dry incubator group ( n=64), 20 μL dry incubator group ( n=64), and 30 μL dry incubator group ( n=64). The general clinical data, embryo development indicators, pregnancy outcomes, and the osmotic pressure and pH values of each group at 24 h, 48 h and 72 h were detected and compared. Results:After cultivation of the same patient's embryos in dry and humid incubator, the total blastocyst formation rate [62.3% (162/260)] and high-quality blastocyst rate [24.6% (64/260)] in dry incubator were lower than those in the humid incubator [71.6% (252/352), P=0.015; 32.1% (113/352), P=0.043]. Compared with the other microdroplet groups, the osmotic pressure of cleavage culture medium in 10 μL group of dry incubator at 48 h and 72 h and blastocyst culture medium were significantly increased, the differences among the groups were significant (cleavage culture medium, all P<0.001; blastocyst culture medium, P=0.006, P=0.008). There was no significant difference in pH value among different microdroplet volume groups at the same period (all P>0.05). There were no significant differences in general data among the different microdroplet groups (all P>0.05). Compared with the other microdroplet groups, 10 μL dry incubator group exhibited significantly lower transferable embryo rate (all P<0.001). When compared with 20 μL and 30 μL groups in both dry and humid incubators, 10 μL dry incubator group showed a lower day 5 blastocyst formation rate, lower total blastocyst formation rate, and lower high-quality blastocyst formation rate, the differences among the groups were significant (all P<0.05). There were no significant differences in the number of transferred embryos, the ratio of cleavage-stage embryos and the ratio of high-quality embryos among different groups (all P>0.05). Compared with the other microdroplet groups, the clinical pregnancy rate, the embryo implantation rate, the live birth rate of fresh transplanted embryos and the cumulative pregnancy rate in 10 μL group in the dry incubator decreased, and the miscarriage rate increased, but all were not significant (all P>0.05). Conclusion:Compared with humid incubators, there are no significant differences in embryo development and pregnancy outcomes for droplet volumes of 20 μL or above in dry incubators. However, the 10 μL microdroplet culture in the dry incubator is not conducive to embryonic development, which may be related to the increased osmotic pressure of the microdroplet.

Objective:To compare the the cultivation effects of human embryos in dry and humid incubators.Methods:A total of 479 infertile patients who underwent in vitro fertilization (IVF) treatment at Reproductive Center of Guiyang Maternal and Child Health Care Hospital from October 2020 to April 2022. The study was divided into two stages. The first stage of the study was a self-comparative research with 95 cases from the same period and source. The embryos were divided into dry and humid incubator groups to compare the embryo development indicators. In the second stage of the study, the patients were divided into six groups, including 10 μL humid incubator group ( n=64), 20 μL humid incubator group ( n=64), 30 μL humid incubator group ( n=64), 10 μL dry incubator group ( n=64), 20 μL dry incubator group ( n=64), and 30 μL dry incubator group ( n=64). The general clinical data, embryo development indicators, pregnancy outcomes, and the osmotic pressure and pH values of each group at 24 h, 48 h and 72 h were detected and compared. Results:After cultivation of the same patient's embryos in dry and humid incubator, the total blastocyst formation rate [62.3% (162/260)] and high-quality blastocyst rate [24.6% (64/260)] in dry incubator were lower than those in the humid incubator [71.6% (252/352), P=0.015; 32.1% (113/352), P=0.043]. Compared with the other microdroplet groups, the osmotic pressure of cleavage culture medium in 10 μL group of dry incubator at 48 h and 72 h and blastocyst culture medium were significantly increased, the differences among the groups were significant (cleavage culture medium, all P<0.001; blastocyst culture medium, P=0.006, P=0.008). There was no significant difference in pH value among different microdroplet volume groups at the same period (all P>0.05). There were no significant differences in general data among the different microdroplet groups (all P>0.05). Compared with the other microdroplet groups, 10 μL dry incubator group exhibited significantly lower transferable embryo rate (all P<0.001). When compared with 20 μL and 30 μL groups in both dry and humid incubators, 10 μL dry incubator group showed a lower day 5 blastocyst formation rate, lower total blastocyst formation rate, and lower high-quality blastocyst formation rate, the differences among the groups were significant (all P<0.05). There were no significant differences in the number of transferred embryos, the ratio of cleavage-stage embryos and the ratio of high-quality embryos among different groups (all P>0.05). Compared with the other microdroplet groups, the clinical pregnancy rate, the embryo implantation rate, the live birth rate of fresh transplanted embryos and the cumulative pregnancy rate in 10 μL group in the dry incubator decreased, and the miscarriage rate increased, but all were not significant (all P>0.05). Conclusion:Compared with humid incubators, there are no significant differences in embryo development and pregnancy outcomes for droplet volumes of 20 μL or above in dry incubators. However, the 10 μL microdroplet culture in the dry incubator is not conducive to embryonic development, which may be related to the increased osmotic pressure of the microdroplet.