How to proceed with a donor embryo transfer in a patient with primary infertility, an endometrium thickness of 9.5 mm on day 4, an 11 mm ovarian cyst, and a mildly adenomyotic uterus?

Proceed with Single Embryo Transfer After Addressing the Ovarian Cyst

For donor embryo transfer, you should proceed with elective single embryo transfer (eSET) regardless of the endometrial thickness, mild adenomyosis, or small ovarian cyst, as current ESHRE guidelines mandate eSET for all donated embryo transfers. 1

Management of the Ovarian Cyst

The 11 mm ovarian cyst does not require intervention before proceeding with embryo transfer.

• Small ovarian cysts (<4 cm) should not be treated surgically, especially in the context of fertility treatment 2
• Surgical treatment of small endometriotic cysts reduces ovarian reserve and the number of retrievable oocytes without improving outcomes 3
• Cyst aspiration may only be considered after several failed IVF attempts, not as initial management 3
• The cyst size of 11 mm poses minimal risk of rupture or torsion, which are concerns primarily with cysts >4 cm 2

Endometrial Assessment

The endometrial thickness of 9.5 mm on day 4 is adequate and should not influence the decision to proceed with transfer.

• ESHRE guidelines explicitly state that endometrial characteristics should not determine whether to perform single versus double embryo transfer in frozen embryo transfer cycles 1
• While historical data suggested endometrial thickness >9 mm correlates with better outcomes 4, current guidelines prioritize avoiding multiple pregnancy risks over marginal endometrial optimization 1
• The patient's endometrium meets the threshold associated with acceptable pregnancy outcomes 4

Adenomyosis Considerations

Mild adenomyosis does not contraindicate embryo transfer and should not alter the standard eSET approach.

• No guideline evidence suggests modifying embryo transfer protocols based on mild adenomyosis
• The focus should remain on preventing multiple pregnancy complications, which would be particularly problematic in a uterus with adenomyosis 1

Mandatory Single Embryo Transfer

Only eSET should be practiced for patients undergoing ART with donated embryos, with no exceptions. 1

• This is a strong recommendation that applies regardless of:

  • Number of previous unsuccessful treatments 1
  • Duration of infertility 1
  • Previous pregnancy or live birth history 1
  • Endometrial characteristics 1
  • Patient age or ovarian response 1

• Double embryo transfer increases multiple pregnancy rates 30-fold compared to repeated SET (OR 30.54,95% CI 7.46-124.95) 5

• Cumulative live birth rates with repeated eSET equal those of double embryo transfer while avoiding twin-related morbidity and mortality 5

Patient Counseling Requirements

Counsel the patient on the rationale for eSET and the risks of multiple pregnancy before proceeding. 1, 6

• Discuss that eSET is the standard of care for donor embryo transfers to minimize maternal and neonatal complications 1
• Explain that multiple pregnancies carry increased risks of pre-eclampsia, gestational diabetes, emergency cesarean section, and preterm labor 5
• Inform that even singleton pregnancies after double embryo transfer carry higher neonatal risks than those after eSET 5
• Provide information on cumulative success rates with repeated eSET cycles 5

Common Pitfalls to Avoid

• Do not delay transfer to surgically address the small ovarian cyst, as this reduces ovarian reserve without improving outcomes 2, 3
• Do not consider double embryo transfer based on the mild adenomyosis or suboptimal endometrial findings, as guidelines explicitly prohibit this 1
• Do not assume the patient needs additional endometrial preparation beyond standard protocols, as endometrial characteristics should not dictate transfer decisions 1
• Do not aspirate the cyst before the first transfer attempt, as this intervention is only potentially beneficial after multiple failed cycles 3