Body mass index, not race, may be associated with an alteration in early embryo morphokinetics during in vitro fertilization

Luce A. Kassi, Dana B. McQueen, Dana Kimelman, Rafael Confino, Chen Yeh, Anne Hutchinson, Tarun Jain, Christina Boots, John Zhang, Jaclyn Steinmiller, Mary Ellen Pavone*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Objective: To assess the relationship between maternal body mass index (BMI) and embryo morphokinetics on time-lapse microscopy (TLM). Design: Retrospective cohort study. Methods: All IVF cycles between June 2015 and April 2017 were reviewed. Female BMI prior to egg retrieval was collected through chart review. BMI (kg/m2) classification included underweight (< 18.5), normal weight (18.5–25), overweight (25–30), and obese (≥ 30). Embryos’ morphokinetic parameters were assessed with TLM and included time to syngamy, 2-cell, 3-cell, 4-cell, and 8-cell. A generalized linear mixed model was used to control for potential confounders and multiple embryos resulting from a single IVF cycle. Results: A total of 2150 embryos from 589 IVF cycles were reviewed and included in the analysis. Classification based on BMI was as follows: underweight (N = 56), normal weight (N = 1252), overweight (N = 502), and obese (N = 340). After adjusting for race and use of intracytoplasmic sperm injection, the mean time to the 8-cell stage in the underweight group was 4.3 (95% CI: − 8.31, − 0.21) h less than in the normal weight group (P = 0.025) and 4.6 (95% CI: − 8.8, − 0.21) h less than in the obese group (p = 0.022). No significant difference was noted between race and TLM after controlling for possible confounders. Conclusions: Embryos from underweight women were demonstrated to have a faster time to the 8-cell stage than normal weight or obese women. No significant difference was noted for race. This study demonstrates that weight can be a factor contributing to embryo development as observed with TLM.

Original languageEnglish (US)
Pages (from-to)3091-3098
Number of pages8
JournalJournal of Assisted Reproduction and Genetics
Issue number12
StatePublished - Dec 2021


  • Body mass index
  • Embryo morphokinetics
  • IVF
  • In vitro fertilization
  • Racial disparities
  • Time-lapse imaging

ASJC Scopus subject areas

  • Genetics(clinical)
  • Genetics
  • Obstetrics and Gynecology
  • Reproductive Medicine
  • Developmental Biology


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