CHAMGAP
APPROVEDReviewed and approved by the Chamgap Editorial Team (2026-08-07). The draft was written by AI, the existence of all 3 cited sources was verified at the original page, and the verdict passed blind grading and adversarial audit. Methodology v0.7.
Verdict No. 2351 · Search date 2026-08-07 · Methodology v0.7

Repeated single-embryo transfer,
does it really help with Reduction of multiple birth in good-prognosis IVF?

30-Second Summary
B
Evidence Grade B · 76 · Safety caution
One fresh-cycle success rate can be lower, while repeated single transfer largely preserves cumulative live birth and greatly reduces multiples.
The strategy reduces multiple gestation and related preterm and low-birthweight outcomes, but may require an additional frozen transfer with extra time, cost, and procedural burden.
What the
research shows
B. A single fresh transfer lowers per-cycle live birth compared with double transfer, but adding another single frozen or fresh transfer preserves cumulative live birth while sharply reducing multiple birth. Independent author teams were confirmed, but funding for one pivotal trial was not reported, precluding the strictest replication rating.
What the
ads claim
A large reduction in twins does not mean equal success from one fresh transfer; cumulative success requires the additional transfer opportunity.
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Useful facts when choosing a product

  • The complete Thurin author list is Ann Thurin, Jon Hausken, Torbjörn Hillensjö, Barbara Jablonowska, Anja Pinborg, Annika Strandell, and Christina Bergh.
  • The complete Lukassen author list is H G M Lukassen, D D Braat, Alex M M Wetzels, Gerhard A Zielhuis, Eddy M M Adang, Eduard Scheenjes, and Jan A M Kremer. No author overlaps.
  • Thurin states, 'Supported by a grant from Serono Nordic,' alongside academic and foundation support. The Lukassen evidence table states 'Source of funding: Not reported.'
Gap Measurement · Verdict 2351 · B 76
What advertising claims
What independent, higher-quality research supports
△ GAP
01

What the research actually shows

Thurin randomized 661 good-prognosis women: cumulative live birth was 128/330 versus 142/331 and multiple birth 1/128 versus 47/142. An eight-trial IPD analysis found fresh live birth of 181/683 versus 285/683 and multiple birth of 3/181 versus 84/285; after an additional frozen single transfer, cumulative live birth was 132/350 versus 149/353 and multiple birth 1/132 versus 47/149. Lukassen reported preterm delivery of 2/54 versus 5/53. Absolute low-birthweight counts could not be confirmed in the accessible primary tables.

02

Why this is classified as B (76)

Randomized hard-endpoint evidence shows a large multiple-birth reduction with broadly preserved cumulative live birth, but unreported funding in one pivotal trial prevents the strictest independent-replication designation, yielding B with 76 points.

Counterpoint. These absolute rates should not be generalized to older or poor-prognosis patients.

Rejudgment record. New verdict — Accepted preserved cumulative live birth and reduced multiple birth in randomized trials, but did not assert independent replication because funding was unreported for one pivotal trial

Scoring profile behind this grade
EndpointHHard endpoint - actual events such as death
ReplicationR1Single confirmatory trial
IndependenceI1Mixed funding sources
Effect sizeE+Meets the clinically important threshold

The scoring table and the verdict agree (B).

Sub-claim grades by effect

This ingredient is marketed for several effects. A single overall grade blends strong and weak claims together, so each effect is graded separately here. The overall grade reflects the strongest disconfirming or core claim.

Effect (sub-claim)GradeBasis
Multiple-birth reductionBLarge absolute reduction in randomized trials
Preserved cumulative live birth after repeat transferBDistinct from one-cycle results

Cross-check — Codex and Claude

This verdict was drafted by Codex through literature review and source-existence checks, cross-checked through blind grading and adversarial audit, and settled by reapplying the methodology boundary rules. Cases with split grades were resolved through rejudgment.
03

Evidence Table

StudyDesignSampleFundingEndpointResultWeight
Thurin et al. 2004Multicenter randomized equivalence trial331Original wording: Supported by a grant from Serono Nordic; academic and foundation support was also reportedCumulative live birth and multiple birth38.8% versus 42.9%; 0.8% versus 33.1%Large pivotal RCT
Lukassen et al. 2005Randomized trial of two single-transfer cycles versus one double-transfer cycle53Not reportedCumulative live birth, multiple pregnancy, and preterm delivery41% versus 36%; 0% versus 37%; preterm delivery 2/54 versus 5/53Independent author-team replication with unreported funding
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Receipt — 3 References

All 3 cited sources were verified for existence at the original page (as of 2026-08-07).

Thurin A, Hausken J, Hillensjö T, Jablonowska B, Pinborg A, Strandell A, Bergh C. Elective Single-Embryo Transfer versus Double-Embryo Transfer in In Vitro Fertilization. N Engl J Med. 2004;351:2392-2402. DOI: 10.1056/NEJMoa041032.
checked
Lukassen HGM, Braat DD, Wetzels AMM, Zielhuis GA, Adang EMM, Scheenjes E, Kremer JAM. Two cycles with single embryo transfer versus one cycle with double embryo transfer: a randomized controlled trial. Hum Reprod. 2005;20:702-708. DOI: 10.1093/humrep/deh672.
checked
McLernon DJ, Harrild K, Bergh C, et al. Clinical effectiveness of elective single versus double embryo transfer: meta-analysis of individual patient data from randomised trials. BMJ. 2010;341:c6945. DOI: 10.1136/bmj.c6945.
checked
Draft and rewrite: Codex (AI) · Verification: Codex blind grading and adversarial audit · Final adjudication: Claude
Reviewed and approved: Chamgap Editorial Team · Approval date: 2026-08-07 · Corrections: none

Cite this verdict

Repeated single-embryo transfer × multiple-birth reduction Evidence Grade B card
[Chamgap] Repeated single-embryo transfer × multiple-birth reduction — Evidence Grade B·76. 3 cited sources checked. Source: https://chamgap.com/en/verdicts/womens/repeated-single-embryo-transfer-multiple-birth/ · CC BY 4.0

CC BY 4.0 — free to use with attribution; do not distort grades, numbers, or verdict meaning.

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