clomiphene citrate for PCOS
A single PCOS pregnancy trial suggests clomiphene citrate is more likely than letrozole to result in first-trimester intrauterine fetal demise.
Hypothesized mechanism
Mechanism not yet characterized in the substrate.
This is the model’s proposed mechanism from the sources on file, not a demonstrated causal pathway. How well the published record supports it is reflected in the rigor and plausibility dimensions of the score, and traced to the verbatim sources at the foot of the page.
How the score was reached, for this pair
The composite score is the sum of five dimensions, each scored 0 to 2 by the model from the evidence on file. Below is the sub-score this specific pair received on each, with what that dimension measures. It scored 4 of 10 overall, a emerging reading, from a direct rated emerging in strength.
The model’s overall reasoning for this pair is the summary at the top of the page, and the mechanism it proposed is in the section above.
Scored for women. Evidence generated in women (female population, ~100% female). (band F1, ×1.00).
Corroboration
Only a single source is cited (Pregnancy in Polycystic Ovary Syndrome II) making one comparative claim about first-trimester fetal demise. There is no independent replication, so this scores at the bottom of the single-source range.
Rigor
The claim derives from a single trial/study (PPCOS II) without a stated design quality, sample size, or effect estimate. Absent evidence of a large, low-bias RCT or meta-analysis, this is scored as observational/small-trial level.
Specificity
The claim explicitly names clomiphene citrate and is in the context of PCOS (Pregnancy in Polycystic Ovary Syndrome), with a direct safety comparison to letrozole. Both the drug and condition are directly identified.
Plausibility
The claim states an outcome (higher fetal demise with clomiphene) but provides no mechanistic explanation for why this occurs. No mechanism is asserted or evidenced in the verified quote.
Consistency
Only a single source/claim is available, so directional consistency across studies cannot be assessed. Per scoring rules, a single study is not penalized and defaults to 1.
Scored for women. Evidence generated in women (female population, ~100% female). (band F1, ×1.00).
Corroboration
Three independent adverse-event signals (ovarian cyst, weight increased, infertility) from the same FDA AEMS source converge on clomiphene acting on the reproductive/ovarian system relevant to PCOS. However, all derive from a single pharmacovigilance database, limiting true independence of lines.
Rigor
Data come from human reports in FDA AEMS (human-relevant), which favors a higher score, but each claim explicitly states these are raw counts, not disproportionality statistics, and are subject to reporting bias and confounding. This limits the strength of the model.
Specificity
Ovarian cyst and infertility signals plausibly reflect clomiphene's known action on the hypothalamic-pituitary-ovarian axis, supporting target relevance. But the counts are raw and unadjusted, so they do not specifically demonstrate the drug's targeted action versus background reporting.
Plausibility
Ovarian cyst and weight changes fit well with clomiphene's mechanism as an ovulation inducer acting on estrogen receptors and the ovarian axis, directly relevant to PCOS phenotype. The target-phenotype fit is strong even though causation is not established.
Consistency
All three signals (ovarian cyst, weight increased, infertility) point in the same direction — clomiphene engaging the reproductive/metabolic system relevant to PCOS. No contradictory signals are present among the verified claims.
Layers not covered for this pair
Not covered for this pair. This layer holds documented sex-specific pharmacokinetics for a limited set of drugs, and this compound is not among them yet. A blank here means the drug is not covered by the layer, not that no sex difference exists.
More on the sex-specific pharmacokinetics layer and its sources →Not covered for this pair. The cycle-phase layer is seeded for the strongest-evidence cases so far (PMDD), and this pair is not among them yet. A blank here means the pair is not covered by the layer, not that the effect was found to be phase-independent.
More on the cycle-phase layer and its sources →Source evidence · what the pipeline ingested
These are the sources the pipeline ingested to detect and score this signal, the published literature the model actually read, each tagged by study type. Where the model combined findings the claim is marked as a synthesis (S), and where the literature disagrees the contradiction is shown (!).
Every source below belongs to this signal’s evidence arm, Direct research. Whel reads each drug-condition pair through four such arms, each held to its own inclusion bar; a signal is surfaced through one of them.
- 1Treatment with letrozole will less likely result in a first trimester intrauterine fetal demise than treatment with clomiphene citrate. ClinicalTrials.gov · NCT00719186 ↗
- 2In FDA AEMS (the FDA Adverse Event Reporting System, formerly FAERS; retrieved 2026-06-16), 23 report(s) of OVARIAN CYST were recorded for clomiphene citrate among female patients (of 887 female reports for clomiphene citrate in the analysed sample). This is a raw adverse-event report count, not a disproportionality statistic or evidence of causation, and is subject to reporting bias and confounding. Read two ways: as a safety consideration, and — because it suggests clomiphene citrate acts on a system relevant to PCOS — as a mechanistic lead for further investigation, not evidence of benefit. AEMS · adverse-event report ↗
- 3In FDA AEMS (the FDA Adverse Event Reporting System, formerly FAERS; retrieved 2026-06-16), 20 report(s) of WEIGHT INCREASED were recorded for clomiphene citrate among female patients (of 887 female reports for clomiphene citrate in the analysed sample). This is a raw adverse-event report count, not a disproportionality statistic or evidence of causation, and is subject to reporting bias and confounding. Read two ways: as a safety consideration, and — because it suggests clomiphene citrate acts on a system relevant to PCOS — as a mechanistic lead for further investigation, not evidence of benefit. AEMS · adverse-event report ↗
- 4In FDA AEMS (the FDA Adverse Event Reporting System, formerly FAERS; retrieved 2026-06-16), 16 report(s) of INFERTILITY were recorded for clomiphene citrate among female patients (of 887 female reports for clomiphene citrate in the analysed sample). This is a raw adverse-event report count, not a disproportionality statistic or evidence of causation, and is subject to reporting bias and confounding. Read two ways: as a safety consideration, and — because it suggests clomiphene citrate acts on a system relevant to PCOS — as a mechanistic lead for further investigation, not evidence of benefit. AEMS · adverse-event report ↗
These are the verbatim sources the pipeline surfaced and read; they may not be the full published record for a pair, and the score reflects the strength and agreement of the evidence rather than its volume. The strength of these source types is what the rigor dimension of the score reads off. MATRIX, sex-specific pharmacokinetics, and cycle phase are separate layers the pipeline does not ingest, external cross-references reported beside the score, and they link to their own sources in their sections above.
The primary sources and pipelines this evidence is drawn from →