Day three versus day two embryo transfer following in vitro fertilization or intracytoplasmic sperm injection
Bibliographic record
Abstract
BACKGROUND: Embryo transfer (ET) was traditionally performed two days after oocyte retrieval; however, developments in culture media have allowed embryos to be maintained in culture for longer periods. Delaying transfer from day two to day three would allow for further development of the embryo and might have a positive effect on pregnancy outcomes. OBJECTIVES: To determine if there is any difference in live birth and pregnancy rates when ET is performed on day three, compared with day two, in infertile couples undergoing treatment with in vitro fertilization (IVF), including intracytoplasmic sperm injection (ICSI). SEARCH STRATEGY: We searched the Cochrane Menstrual Disorders & Subfertility Group trials register (17th December 2003), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 1, 2003), MEDLINE (1966 to 2003), EMBASE (1980 to 2003) and Biological Abstracts Databases (1980 to 2003), the National Research Register (NRR), the Medical Research Council's Clinical Trials Register, the NHS Centre for Reviews and Dissemination, citation lists of relevant publications, review articles and included studies, as well as abstracts of appropriate scientific meetings. SELECTION CRITERIA: Randomized controlled trials that compared day three versus day two embryo transfer after oocyte retrieval during an IVF or ICSI treatment cycle in subfertile couples. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed trial quality and extracted data. Study authors were contacted for additional information. The primary outcome measures were live birth rate and ongoing pregnancy rate. MAIN RESULTS: Ten studies involving 2027 women were included, but only three studies reported live birth and four reported ongoing pregnancy rates. The pooled odds ratios (day three compared to day two) were 1.07, 95% CI 0.84 to 1.37 for live birth and 1.05, 95% CI 0.83 to 1.32 for ongoing pregnancy. From ten studies, the pooled odds ratio for clinical pregnancy was 1.26, 95% CI 1.06 to 1.51. Sub-group analysis revealed that this advantage occurred in those undergoing ICSI cycles. A higher miscarriage rate with day 3 ET in ICSI cycles works to negate the increased clinical pregnancy rate, in agreement with the finding of no significant difference between treatments in live birth rate. REVIEWERS' CONCLUSIONS: Although an increase in clinical pregnancy rate with day three embryo transfer was demonstrated, at present there is not sufficient good quality evidence to suggest an improvement in live birth when embryo transfer is delayed from day two to day three.
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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 | 0.018 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.008 | 0.006 |
| Bibliometrics | 0.002 | 0.003 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.009 | 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".