What you need to know Fertility awareness based methods of contraception are increasingly being used for pregnancy prevention.1 In the US, the proportion of contraceptive users who choose such methods has grown from 1% in 2008 to approximately 3% in 2014.12 Relative to other methods of pregnancy prevention, however, substantial misinformation exists around fertility awareness based methods of contraception, particularly about the effectiveness of specific methods and how to use them. Providers who offer family planning counselling can promote correct and consistent use of the chosen method by helping people find a method that best fits their individual lifestyle, preferences, and goals.3 This article aims to help clinicians counsel people about fertility awareness based methods for pregnancy prevention by explaining the different methods, the evidence base for their effectiveness, and practical considerations for use. Fertility awareness based methods are devised on the premise that sexual intercourse can only lead to pregnancy during approximately 6-9 days of the menstrual cycle, commonly referred to as the “fertile window” (or fecund window, box 1).5 …
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PMID 31296535 31296535 DOI 10.1136/bmj.l4245 10.1136/bmj.l4245
Cite this article
Urrutia, R. P., & Polis, C. B. (2019). Fertility awareness based methods for pregnancy prevention. BMJ (Clinical research ed.), 366, l4245. https://doi.org/10.1136/bmj.l4245
Urrutia RP, Polis CB. Fertility awareness based methods for pregnancy prevention. BMJ. 2019;366:l4245. doi:10.1136/bmj.l4245
Urrutia, R. P., and C. B. Polis. "Fertility awareness based methods for pregnancy prevention." BMJ (Clinical research ed.), vol. 366, 2019, pp. l4245.
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To evaluate the association between contemporary hormonal contraceptive use and the risk of incident ischaemic stroke and myocardial infarction.
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Denmark, by use of national registries. All women aged 15-49 years residing in Denmark between 1996 and 2021, with no history of arterial or venous thrombosis, antipsychotics use, cancer, thrombophilia, liver disease, kidney disease, polycystic ovary syndrome, endometriosis, infertility treatment, hormone therapy use, oophorectomy, and hysterectomy. First time diagnosis of ischaemic stroke or myocardial infarction at discharge. Among 2 025 691 women followed up for 22 209 697 person years, 4730 ischaemic strokes and 2072 myocardial infarctions occurred. Standardised ischaemic stroke rate per 100 000 person years were 18 (95% confidence interval 18 to 19) for no use, 39 (36 to 42) for combined oral contraception, 33 (25 to 44) for progestin-only pills, and 23 (17 to 29) for intrauterine device. Standardised myocardial infarction rate per 100 000 person years were 8 (8 to 9) for no use, 18 (16 to 20) for combined oral contraception, 13 (8 to 19) for progestin-only pills, and 11 (7 to 16) for intrauterine device. Compared with no use, current use of combined oral contraception was associated with an adjusted rate ratio of 2.0 (1.9 to 2.2) for ischaemic stroke and 2.0 (1.7 to 2.2) for myocardial infarction. These corresponded to standardised rate differences of 21 (18 to 24) extra ischaemic strokes and 10 (7 to 12) extra myocardial infarctions per 100 000 person years. Compared with no use, current use of progestin-only pills was associated with an adjusted rate ratio of 1.6 (95% CI 1.3 to 2.0) for ischaemic stroke and 1.5 (1.1 to 2.1) for myocardial infarction, equating to 15 (6 to 24) extra ischaemic strokes and four (-1 to 9) extra myocardial infarctions per 100 000 person years. Increased arterial thrombotic risk was also observed with use of the combined vaginal ring (adjusted incidence rate ratio of 2.4 (1.5 to 3.7) for ischaemic stroke and 3.8 (2.0 to 7.3) for myocardial infarction), patch (3.4 (1.3 to 9.1) and no myocardial infarctions), and progestin-only implant (2.1 (1.2 to 3.8) and ≤3 myocardial infarctions), whereas no increased risk was observed with progestin-only intrauterine device (1.1 (1.0 to 1.3) for ischaemic stroke and 1.1 (0.9 to 1.3) for myocardial infarction). Use of contemporary oestrogen-progestin and progestin-only contraceptives was associated with an increased risk of ischaemic stroke and, in some cases, myocardial infarction except for the levonorgestrel-releasing intrauterine device, which was not associated with either. Although absolute risks were low, clinicians should include the potential risk of arterial thrombosis in their assessment of the benefits and risks when prescribing a hormonal contraceptive method.
To assess the risk of intracranial meningioma associated with the use of selected progestogens. National case-control study. French National Health Data System (ie, Système National des Données de Santé). Of 108 366 women overall, 18 061 women living in France who had intracranial surgery for meningioma between 1 January 2009 and 31 December 2018 (restricted inclusion periods for intrauterine systems) were deemed to be in the case group. Each case was matched to five controls for year of birth and area of residence (90 305 controls). Selected progesterone, hydroxyprogesterone, dydrogesterone, medrogestone, medroxyprogesterone acetate, promegestone, dienogest, and intrauterine levonorgestrel. For each progestogen, use was defined by at least one dispensation within the year before the index date (within three years for 13.5 mg levonorgestrel intrauterine systems and five years for 52 mg). Conditional logistic regression was used to calculate odds ratio for each progestogen meningioma association. Mean age was 57.6 years (standard deviation 12.8). Analyses showed excess risk of meningioma with use of medrogestone (42 exposed cases/18 061 cases (0.2%) v 79 exposed controls/90 305 controls (0.1%), odds ratio 3.49 (95% confidence interval 2.38 to 5.10)), medroxyprogesterone acetate (injectable, 9/18 061 (0.05%) v 11/90 305 (0.01%), 5.55 (2.27 to 13.56)), and promegestone (83/18 061 (0.5%) v 225/90 305 (0.2 %), 2.39 (1.85 to 3.09)). This excess risk was driven by prolonged use (≥one year). Results showed no excess risk of intracranial meningioma for progesterone, dydrogesterone, or levonorgestrel intrauterine systems. No conclusions could be drawn concerning dienogest or hydroxyprogesterone because of the small number of individuals who received these drugs. A highly increased risk of meningioma was observed for cyproterone acetate (891/18 061 (4.9%) v 256/90 305 (0.3%), odds ratio 19.21 (95% confidence interval 16.61 to 22.22)), nomegestrol acetate (925/18 061 (5.1%) v 1121/90 305 (1.2%), 4.93 (4.50 to 5.41)), and chlormadinone acetate (628/18 061 (3.5%) v 946/90 305 (1.0%), 3.87 (3.48 to 4.30)), which were used as positive controls for use. Prolonged use of medrogestone, medroxyprogesterone acetate, and promegestone was found to increase the risk of intracranial meningioma. The increased risk associated with the use of injectable medroxyprogesterone acetate, a widely used contraceptive, and the safety of levonorgestrel intrauterine systems are important new findings.
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