Cumulative live birth rate of a blastocyst versus cleavage stage embryo transfer policy during in vitro fertilisation in women with a good prognosis: multicentre randomised controlled trial
Bibliographic record
Abstract
Abstract Objectives To evaluate whether embryo transfers at blastocyst stage improve the cumulative live birth rate after oocyte retrieval, including both fresh and frozen-thawed transfers, and whether the risk of obstetric and perinatal complications is increased compared with cleavage stage embryo transfers during in vitro fertilisation (IVF) treatment. Design Multicentre randomised controlled trial. Setting 21 hospitals and clinics in the Netherlands, 18 August 2018 to 17 December 2021. Participants 1202 women with at least four embryos available on day 2 after oocyte retrieval were randomly assigned to either blastocyst stage embryo transfer (n=603) or cleavage stage embryo transfer (n=599). Interventions In the blastocyst group and cleavage group, embryo transfers were performed on day 5 and day 3, respectively, after oocyte retrieval, followed by cryopreservation of surplus embryos. Analysis was on an intention-to-treat basis, with secondary analyses as per protocol. Main outcome measures The primary outcome was the cumulative live birth rate per oocyte retrieval, including results of all frozen-thawed embryo transfers within a year after randomisation. Secondary outcomes included cumulative rates of pregnancy, pregnancy loss, and live birth after fresh embryo transfer, number of embryo transfers needed, number of frozen embryos, and obstetric and perinatal outcomes. Results The cumulative live birth rate did not differ between the blastocyst group and cleavage group (58.9% (355 of 603) v 58.4% (350 of 599; risk ratio 1.01, 95% confidence interval (CI) 0.84 to 1.22). The blastocyst group showed a higher live birth rate after fresh embryo transfer (1.26, 1.00 to 1.58), lower cumulative pregnancy loss rate (0.68, 0.51 to 0.89), and lower mean number of embryo transfers needed to result in a live birth (1.55 v 1.82; P<0.001). The incidence of moderate preterm birth (32 to <37 weeks) in singletons was higher in the blastocyst group (1.87, 1.05 to 3.34). Conclusion Blastocyst stage embryo transfers resulted in a similar cumulative live birth rate to cleavage stage embryo transfers in women with at least four embryos available during IVF treatment. Trial registration International Clinical Trial Registry Platform NTR7034.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.005 | 0.012 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.005 | 0.004 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.003 | 0.003 |
| Insufficient payload (model declined to judge) | 0.007 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".