Drug · FAERS side-effect profile with label screen

Norethindrone side effects: what 304 FDA adverse event reports show

Norethindrone Acetate/Ethinyl Estradiol And Ferrous Fumarate · 9 reaction terms · 62 drug–reaction co-reports · data 2026-09-14

Drug class

Progestin

FDA label (Established Pharmacologic Class) · compare the class

Who reports

304 reports · 32% serious · 3 with death outcome · 99% female

openFDA FAERS counts, all years, deduplication not applied

Used for

1. Indications Progestin-only oral contraceptives are indicated for the prevention of pregnancy. 2. Efficacy If used perfectly, the first-year failure rate for progestin-only oral contraceptives is 0.3%. However, the typical failure rate is estimated to be closer to 9%, due to late or omitted pills. Table 1 lists the pregnancy rates for users of all major methods of contraception.

FDA label, Indications and Usage

Boxed warning

None in the current label

How to read this page. FAERS is a spontaneous-reporting system: counts are not incidence rates and a signal is not proof of causation. Each reaction below is run through an automated screen — is the term in the FDA label (known), in the indications (the disease being treated), an administrative/coding term, or none of these (unlabeled)? That screen is mechanical text matching, not a causality assessment. The 30 hand-written Bradford Hill assessments are on the causality assessment page. Not medical advice.

Causality screen of the 7 strongest signals

Labeled adverse reaction 2Labeled (related wording) 1Likely indication confounding 1Reporting / coding artifact 1Not in label — unassessed 2

What the badges mean

Labeled adverse reaction The exact term appears in the label's warnings or adverse-reactions sections: a known, expected effect. The FAERS signal confirms the label rather than discovering anything.
Labeled (related wording) The label describes this effect under different wording (e.g. 'neutropenia' for 'neutrophil count decreased'). Treated as known.
Likely indication confounding The term appears in the label's indications: reports probably describe the disease being treated (or its progression), not a drug effect. Classic confounding by indication.
Reporting / coding artifact An administrative, monitoring or exposure term (product issue, off-label use, 'test normal', overdose...). Not a biological reaction; a high PRR here reflects how reports are coded.
Not in label — unassessed Not found in the label text, not an artifact pattern. This is a genuine candidate for a formal causality assessment (Bradford Hill / WHO-UMC); it has NOT had one here.

Strongest disproportionality signals

Flagged terms (PRR ≥ 2, χ² ≥ 4, n ≥ 10), ranked by PRR; infinite PRRs (no comparator reports) excluded. The EBGM column is a second, shrinkage-based estimate (MGPS) with its 5th percentile EB05 and the BCPNN IC025; a pair flagged by PRR alone is marked PRR-only and should be read as fragile. The strata column recomputes the PRR on serious reports only and flags pairs whose reports are unusually skewed by sex or come mostly from consumers rather than clinicians. 2 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.

Show: hide coding/lab/outcome terms hide indication terms unlabeled only hide PRR-only

Reaction	Reports	PRR 95% CI · ROR · χ²/p	EBGM EB05 · IC025	Label screen	Serious-only & strata	Trial cross-check
Metrorrhagia	14	55.9 33.5–93.2ROR 58.5 · χ² 701 / p 1e-154	52.1 EB05 33.0 · IC025 +3.4 3/3 methods agree	Not in label — unassessed	serious n=2	no trial data cached
Menstruation irregular	11	28.6 16.0–51.1ROR 29.6 · χ² 266 / p 4e-60	27.3 EB05 16.1 · IC025 +2.7 3/3 methods agree	Labeled (related wording) related wording	serious n=1	no trial data cached
Dysmenorrhoea	5	26.4 11.1–62.9ROR 26.8 · χ² 98 / p 2e-23	22.3 EB05 7.5 · IC025 +1.4 3/3 methods agree	Not in label — unassessed	serious n=1	no trial data cached
Amenorrhoea (missed periods)	6	24.8 11.2–54.8ROR 25.3 · χ² 114 / p 6e-27	21.9 EB05 8.8 · IC025 +1.7 3/3 methods agree	Likely indication confounding shares a disease stem with the indications wording	serious PRR 33.8	no trial data cached
Drug dispensing error	5	22.3 9.3–53.1ROR 22.6 · χ² 81 / p 9e-20	18.1 EB05 5.8 · IC025 +1.4 3/3 methods agree	Reporting / coding artifact	–	no trial data cached
Menorrhagia (heavy periods)	5	17.3 7.3–41.3ROR 17.6 · χ² 61 / p 2e-15	12.9 EB05 4.2 · IC025 +1.2 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 27.9	no trial data cached
Vaginal haemorrhage	9	14.6 7.7–27.8ROR 15.0 · χ² 101 / p 5e-24	12.5 EB05 5.9 · IC025 +1.9 3/3 methods agree	Labeled adverse reaction exact term	–	no trial data cached

Trial evidence (ClinicalTrials.gov)

Trial cross-check not yet run for this drug (ClinicalTrials.gov pull covers the 800 most-reported drugs first).

Most frequently reported reactions

By raw co-report count, regardless of disproportionality. Common terms here are often the illness itself or generic outcomes.

Reaction	Reports	PRR 95% CI · ROR · χ²/p	EBGM EB05 · IC025	Label screen	Serious-only & strata	Trial cross-check
Metrorrhagia	14	55.9 33.5–93.2ROR 58.5 · χ² 701 / p 1e-154	52.1 EB05 33.0 · IC025 +3.4 3/3 methods agree	Not in label — unassessed	serious n=2	no trial data cached
Menstruation irregular	11	28.6 16.0–51.1ROR 29.6 · χ² 266 / p 4e-60	27.3 EB05 16.1 · IC025 +2.7 3/3 methods agree	Labeled (related wording) related wording	serious n=1	no trial data cached
Vaginal haemorrhage	9	14.6 7.7–27.8ROR 15.0 · χ² 101 / p 5e-24	12.5 EB05 5.9 · IC025 +1.9 3/3 methods agree	Labeled adverse reaction exact term	–	no trial data cached
Amenorrhoea (missed periods)	6	24.8 11.2–54.8ROR 25.3 · χ² 114 / p 6e-27	21.9 EB05 8.8 · IC025 +1.7 3/3 methods agree	Likely indication confounding shares a disease stem with the indications wording	serious PRR 33.8	no trial data cached
Menorrhagia (heavy periods)	5	17.3 7.3–41.3ROR 17.6 · χ² 61 / p 2e-15	12.9 EB05 4.2 · IC025 +1.2 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 27.9	no trial data cached
Drug dispensing error	5	22.3 9.3–53.1ROR 22.6 · χ² 81 / p 9e-20	18.1 EB05 5.8 · IC025 +1.4 3/3 methods agree	Reporting / coding artifact	–	no trial data cached
Dysmenorrhoea	5	26.4 11.1–62.9ROR 26.8 · χ² 98 / p 2e-23	22.3 EB05 7.5 · IC025 +1.4 3/3 methods agree	Not in label — unassessed	serious n=1	no trial data cached
Injection site warmth	4	13.4 5.1–35.5ROR 13.6 · χ² 34 / p 2e-9	8.0 EB05 2.7 · IC025 +0.7 3/3 methods agree	Not in label — unassessed	–	no trial data cached
Complication of device insertion	3	11.2 3.6–34.4ROR 11.3 · χ² 19 / p 8e-6	5.6 EB05 1.9 · IC025 +0.1	Likely indication confounding shares a disease stem with the indications wording	–	no trial data cached

Unlabeled candidate signals

Every screened signal with n ≥ 20 was either labeled, an indication term, or an artifact pattern — no unlabeled candidate stood out in the top signals.

✓ A hand-written Bradford Hill causality assessment exists for this drug: Medroxyprogesterone acetate ↔ Meningioma.

Want to assess one of these properly? The runbook describes the Bradford Hill / trial-evidence workflow used on the assessment page, and handoff_top1000_signals.csv lists the strongest unassessed pairs across all drugs.

Common questions

What are the most reported side effects of Norethindrone?

In FDA FAERS, the most frequently co-reported reaction terms for Norethindrone are metrorrhagia, menstruation irregular, vaginal haemorrhage, amenorrhoea, menorrhagia, dysmenorrhoea. These are report counts, not rates: FAERS has no denominator, reporting is voluntary and uneven, and a term can be reported because of the illness being treated rather than the drug.

Does Norethindrone have an FDA boxed warning?

No. The FDA label retrieved for Norethindrone has no boxed warning; see the label's Warnings and Precautions for the recognised risks.

Do FAERS signals prove that Norethindrone causes these side effects?

No. A disproportionality signal (PRR, ROR) means a reaction is reported more often with this drug than with others in the database. That can reflect a real effect, but also the disease being treated, stimulated reporting after news or litigation, co-medications, or how reports are coded. Causality needs temporality, dose-response, biological plausibility, consistency across data sources and, ideally, trial or cohort evidence. This page screens each term against the FDA label and ClinicalTrials.gov results; it does not establish causation.

Sources & methods

FDA label via openFDA (set ID 0d2f8fea-3675-40d2-afd9-9fcb148dbd4b, effective 20260131; matched on openfda.generic_name.exact:"NORETHINDRONE")
Bayesian shrinkage measures computed offline over all 1,317,300 cached pairs: BCPNN information component (IC, with Norén closed-form IC025) and MGPS empirical-Bayes geometric mean (EBGM, EB05) with a two-component gamma prior fitted by maximum marginal likelihood (α₁=0.57, β₁=0.02, α₂=1.42, β₂=0.70, w=0.17); unstratified
FAERS pair statistics from the OpenPV build of 2026-09-14 (openFDA count= aggregation, field patient.drug.openfda.generic_name.exact, 9 reaction terms, min 3 co-reports); PRR/ROR with 95% CI, chi-square with Yates correction
Serious-only and stratified counts (serious:1, patient.patientsex, primarysource.qualification) from openFDA count queries; serious-only PRR uses the drug serious report total and the term global serious total (N_serious=11,882,979); strata shown only when n ≥ 20
Seriousness and sex counts from openFDA count=serious, patient.patientsex, seriousnessdeath

Page generated 2026-10-08. Label and PubChem text are retrieved automatically and may lag the current label; always check the current prescribing information. OpenPV is a beta research tool of the Open Source Medicine Foundation.