{"doi":"10.1016/j.contraception.2022.03.022","title":"Mechanism of action of norgestrel 0.075 mg a progestogen-only pill. I. Effect on ovarian activity","abstract":"OBJECTIVE: To explore the effect on ovarian activity and ovulation of 28 days of correct daily use of a progestogen-only pill containing norgestrel 0.075 mg. STUDY DESIGN: We performed a prospective, randomized, crossover study at 2 US sites, recruiting healthy women of reproductive age to use norgestrel 0.075 mg daily for three 28-day treatment cycles. We monitored ovarian activity every 3 to 4 days with reproductive hormone measurements and ovarian ultrasonography. Participants recorded pill use in daily diaries. An adjudication committee independent of the research sites assessed ovarian activity using a modified Hoogland score combining hormone concentrations and follicle diameter and appearance (quiescence 1-3, ovarian activity without ovulation 4-5, and ovulatory/postovulatory 6-7). RESULTS: We report here the findings of the initial 28-day treatment cycle in which 51 of 52 recruited participants provided data sufficient for analysis. Two thirds of subjects had no evidence of ovulation (34/51, 66.6%); eight of these (15.7%) had quiescent ovaries (follicle <13 mm diameter) and 26 (51%) had follicular development (follicle >13 mm diameter) without ovulation. Seventeen participants ovulated, of whom 12 (23.5%) had a normal, and 5 (9.8%) an abnormal luteal phase. Persistent ovarian follicles were common among women who had ovarian activity without ovulation, 17 of 26 participants (65.4%) had a large follicle which persisted beyond 28 days. CONCLUSION: During 28 days of exposure to a norgestrel 0.075 mg progestogen-only pill, most women had no evidence of ovulation. IMPLICATIONS: Ovulation inhibition and follicle growth disturbance are important in the mechanism of action of a progestogen-only pill containing norgestrel 0.075 mg.","journal":"Contraception","year":2022,"id":269196,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":16,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9614,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2022-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":350956,"name":"Alison Edelman","orcid":"0000-0001-5040-7288","position":1,"is_corresponding":false},{"id":356485,"name":"Mitchell D. Creinin","orcid":"0000-0001-5967-8180","position":2,"is_corresponding":false},{"id":422633,"name":"Leo Han","orcid":"0000-0003-2018-6028","position":3,"is_corresponding":false},{"id":794753,"name":"Melissa C. Matulich","orcid":null,"position":4,"is_corresponding":false},{"id":666407,"name":"Vivian Brache","orcid":"0000-0003-2621-4739","position":5,"is_corresponding":false},{"id":454365,"name":"Carolyn Westhoff","orcid":"0000-0002-3622-8846","position":6,"is_corresponding":false},{"id":931943,"name":"Agnes Hemon","orcid":"0000-0002-9354-6656","position":7,"is_corresponding":false},{"id":760584,"name":"Anna Glasier","orcid":"0000-0002-5697-255X","position":0,"is_corresponding":true}],"reference_count":22,"raw_metadata":null,"created_at":"2026-07-19T00:27:18.142851Z","pmid":"35351445","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}