Polycystic ovary syndrome: letrozole use during frozen embryo transfer improves live birth rate

  • Zhang J & al.
  • Fertil Steril
  • 21 May 2019

  • curated by Sarfaroj Khan
  • UK Clinical Digest
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Takeaway

  • In women with polycystic ovary syndrome (PCOS), use of letrozole during frozen-thawed embryo transfer (L-FET) cycles is associated with a higher live birth rate (LBR) compared with artificial cycle frozen-thawed embryo transfer (AC-FET).

Why this matters

  • A preliminary study focusing on patients with PCOS showed that letrozole use for ovulation induction increased several endometrial receptivity markers, which may have a positive effect on embryo implantation.
  • However, little is known whether the L-FET cycles may benefit the pregnancy outcomes for patients with PCOS.

Study design

  • A retrospective cohort study included 2664 women with PCOS who underwent L-FET (n=1571) cycles and AC-FET (n=1093).
  • Primary outcome: LBR per embryo transfer.
  • Secondary outcomes: ongoing and clinical pregnancy rate, cancellation rate, endometrial thickness and miscarriage rate.
  • Funding: None disclosed.

Key results

  • Compared with AC-LET group, the endometrial thickness was significantly greater in the L-FET group, both on the day of progesterone supplementation and ET (11.91±3.12 vs 10.10±1.84 and 11.97±3.00 vs 10.20±1.85, respectively; P<.001 for both>
  • No difference was observed in LBR per ET between 2 groups (P=.100).
  • L-FET group had a lower miscarriage rate vs AC-FET group (9.1% vs 17%; P<.001>
  • After adjustment for confounders, the LBR was significantly higher in the L-FET group vs AC-FET group (adjusted OR [aOR], 1.33; 95% CI, 1.09-1.61).
  • The miscarriage rate was consistently lower in the L-FET group vs AC-FET group (aOR, 0.51; 95% CI, 0.35-0.74).

Limitations

  • Retrospective design.
  • Risk of bias.