OBJECTIVE
Previous studies demonstrated that female body mass index (BMI) is associated with alterations in embryo morphokinetics as seen by time-lapse microscopy (TLM). Here we examined the effect of paternal BMI on embryo morphokinetics.
MATERIALS AND METHODS
445 IVF cycles from 320 unique patients were studied. From these cycles, 1314 embryos were produced. Embryos were cultured and observed until developing into a blastocyst in Vitrolife EmbryoScope™ time-lapse incubator. Univariate generalized linear mixed effects models (GLMM) were fit to examine the association between BMI categories (normal, overweight, and obese BMI) and variables of interest (the embryo’s development). Multivariate GLMMs with a random intercept of cycles nested within participants were fit to explore the relationship between embryo timelapse parameters and paternal BMI when adjusting the potential confounders (maternal confounders: age, anti-mullerian hormone [AMH] levels, days of stimulation, number of mature eggs, and the usage of intracytoplasmic sperm injection [ICSI]). A sub-analysis of euploid embryos was also conducted.
RESULTS
Mean maternal age was 36.9 years while paternal age was 42.7 years; mean maternal and paternal BMI was 25.04 (±5.04) kg/㎡ and 27.64 (±4.50) kg/㎡ respectively. We found that paternal BMI did not affect the timing of syngamy, 2-cell, 3-cell, 4-cell, 8-cell, morula, or blastocyst formation in the genetically untested embryos. Embryos remained in the EmbryoScope™ for 5 to 6 days; however, majority of embryos developed into blastocysts after 6 days of incubation. Of the 723 euploid embryos, 640 had paternal BMI data available. When examining only euploid embryos, the obese BMI group (BMI>30.0 kg/㎡) exhibited a prolonged 5-hour delay to reach the blastocyst stage compared to the normal and overweight BMI groups (p=0.0008).
CONCLUSIONS
Higher paternal BMI may increase time to blastulation in euploid embryos. Future studies investigating if weight loss or lifestyle interventions reverse the negative impact of high BMI on preimplantation embryo development are warranted.
https://link.springer.com/content/pdf/10.1007/s10815-024-03030-y.pdf
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