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

Impact of body weight on IVF: pathophysiology, outcomes, and clinical considerations

PURPOSE OF REVIEW

This study aimed to examine if excess body weight impacts the outcomes of IVF treatment cycles.

RECENT FINDINGS

While data on the effect and/or association of excess weight on IVF outcomes continue to produce mixed results, recent studies stratifying analyses by age are yielding clarity on a detrimental potential of obesity on IVF outcomes. Specifically, IVF outcomes in the third decade of life are susceptible to adverse implications of excess weight, as reflected in lower clinical pregnancy and live birth rates. Plausible pathogenic mechanisms underlying the detrimental impact of excess weight on IVF outcomes include inflammation, DNA repair, insulin resistance, and the targets of such mechanisms that include the spectrum of players critical to reproductive success, including the oocyte, sperm, embryo, and uterine receptivity.

SUMMARY

The detrimental implications of excess weight on IVF outcomes are more pronounced by age, and inflammatory processes seem to be particularly relevant to the interplay of weight excess, adiposity, and IVF cycle outcomes.

Polycystic ovary syndrome and morphokinetic embryonic development: a case-control study evaluating 791 embryos

OBJECTIVE

To investigate the association between polycystic ovary syndrome (PCOS) and the rate of embryo development, using time-lapse monitoring systems, compared with a control group of women with mechanical (tubal) factor infertility.

DESIGN

A retrospective case-control study conducted in a university-affiliated in vitro fertilization (IVF) unit.

SUBJECTS

Women with PCOS undergoing IVF treatments and those with non-PCOS controls with tubal factor infertility only. Development morphokinetic milestones were compared and analysis of covariance for time to distinct cell number as well as logistic mixed models to determine predictors for embryos over the 75th percentile was performed.

EXPOSURE

Not applicable.

MAIN OUTCOME MEASURES

Embryo development morphokinetic parameters in women with and without PCOS undergoing IVF treatments.

RESULTS

The study included 791 embryos from 115 women, 364 embryos from 52 women with PCOS and 427 embryos from 63 women with non-PCOS controls with tubal factor infertility. The PCOS group was 4 years younger (30.07 ± 6.03 vs. 34.08 ± 4.84 years) and had higher number of oocytes retrieved (16.00 vs. 11.00), mature oocytes (11.00 vs. 7.00) and fertilized oocytes (8.00 vs. 5.00). The PCOS and control groups demonstrated comparable clinical pregnancy rates (55.8% vs. 32.1%), miscarriage rate (12.5% vs. 11.8%), and live birth rate (48.8% vs. 31.2%). Morphokinetic parameters were comparable between the groups. Although age was associated with later time to 5 and 8 discrete cells and start of blastulation (tSB), PCOS was only associated with later tSB, including tSB >75th percentile.

CONCLUSION

This study demonstrated comparable IVF outcomes in women with PCOS and non-PCOS controls. An analysis of time-lapse monitoring data from these patients showed no evidence that PCOS negatively affects embryonic development rate in women undergoing IVF cycles.

Maternal underweight does not adversely affect the outcomes of IVF/ICSI and frozen embryo transfer cycles or early embryo development

OBJECTIVE

To compare assisted reproductive technology (ART) outcomes and preimplantation embryo development between underweight and normal-weight women.

METHODS

This retrospective cohort study included 26 underweight women (body mass index [BMI] < 18.50 kg/m²) and 104 normal-weight women (BMI >20 and <24.9 kg/m²) who underwent a total of 204 in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycles and 358 fresh/frozen embryo transfers (ET) in our institution between January 2016 and December 2018. Statistical analyses compared selected ART outcomes (ovarian stimulation, fertilization, and pregnancy) between both weight groups. Morphokinetic and morphological parameters were also compared between 346 and 1467 embryos of underweight and normal-weight women, respectively.

RESULTS

The mean ± standard deviation age of the underweight and normal-weight women was similar (31.6 ± 4.17 vs 32.4 ± 3.59 years; p = .323). There were no differences in the peak estradiol levels, the number of retrieved oocytes, the number of metaphase II oocytes, and the oocyte maturity rates between the two groups. The IVF/ICSI fertilization rates and the number of embryos suitable for transfer or cryopreservation were similar for both groups. All morphokinetic parameters that were evaluated by means of time-lapse imaging as well as the morphological characteristics were comparable between low and normal BMI categories. There were no significant differences in pregnancy achievement, clinical pregnancy, live births, and miscarriage rates between the suboptimal and optimal weight women.

CONCLUSION

Underweight status has no adverse impacts on the outcomes of IVF/ICSI with either fresh or frozen ET or on preimplantation embryo development and quality.