BACKGROUND AND PURPOSE:

• Li et al. (AJOG, 2021) assessed the relationship between preimplantation genetic testing (PGT) and risk for adverse perinatal outcomes of singleton pregnancies conceived following frozen embryo transfer

METHODS:

• Retrospective analysis
• Data source
  • The Society for Assisted Reproductive Technology (SART) Clinical Outcomes Reporting System
  • Cycles initiated between 2014 and 2015
• Population
  • Autologous frozen embryo transfer cycles that led to singleton live births
• Exposure
  • PGT
• Study design
  • Multivariable linear regression analyses were used for the birthweight and Z-score and logistic regression for the binary outcomes
  • Covariates adjusted for: Year of transfer | Maternal age | BMI | Smoking status | Obstetrical history | Infertility diagnosis | Infant sex
• Primary outcomes
  • Birthweight
  • Birthweight Z-score (SD above or below the mean)
  • Small for gestational age (SGA)
  • Large for gestational age (LGA)
  • Macrosomia
  • Preterm birth

RESULTS:

• 16,246 frozen embryo transfers were analyzed
  • PGT: 6244 transfers
  • No testing: 10,002 transfers

Maternal characteristics

• Women from the PGT group were older (P< 0.001)
  • Testing: 35.8 years
  • No testing: 33.7 years
• Women from the PGT group had a higher prevalence of prior spontaneous abortion (P< 0.001)
  • Testing 37.3%
  • No testing: 27.7%

Outcomes Following Adjustment

• PGT was associated with increased risk for preterm birth
  • Adjusted odds ratio 1.20 (95% CI, 1.09 to 1.33; P < 0.001)
  • Seen in both unadjusted and adjusted calculations
• No differences were identified between groups for the following
  • Birthweight
    • –14.63 g (95% CI, –29.65 to 0.38; P = 0.056)
  • Birthweight Z-score
    • –0.03 (95% CI, –0.06 to 0.00; P = 0.081)
  • Odds of SGA
    • aOR 1.17 (95% CI, 0.99 to 1.38; P = 0.066)
  • Odds of LGA
    • aOR 0.96 (95% CI, 0.88 to 1.06; P = 0.418)
  • Odds of macrosomia
    • aOR 0.96 (95% CI, 0.85 to 1.07; P = 0.427)
• Subgroup analysis based on infertility diagnosis did not change the above results

CONCLUSION:

• PGT was associated with approximately a 20% higher risk of preterm birth in frozen embryo transfer cycles
• Other adverse perinatal outcomes were not found in this cohort
• The authors conclude

Although the optimal utilization of PGT in IVF is debated, PGT may lower the risk of a pregnancy with a fetus with a single-gene disorder or aneuploidy

To better gauge the relative risks and benefits of this technique in clinical practice, the perinatal outcomes related to PGT procedures should continue to be examined

Learn More – Primary Sources:

Embryo biopsy and perinatal outcomes of singleton pregnancies: an analysis of 16,246 frozen embryo transfer cycles reported in the Society for Assisted Reproductive Technology Clinical Outcomes Reporting System

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