Contraception

Also known as Birth control · Family planning · Contraceptive methods · LARC

GP-fellowship guide to contraception: typical versus perfect use and why long-acting methods dominate real-world effectiveness, UKMEC categories applied to migraine with aura, VTE history and breastfeeding, the combined pill with its simplified missed-pill rules, the desogestrel progestogen-only pill's 12-hour window, LNG-IUS and copper IUD including copper as the gold-standard emergency contraception within 5 days, the implant that beats sterilisation in practice, DMPA's reversible bone-density effect, levonorgestrel versus ulipristal timing, and dual protection counselling.

high16 referencesUpdated 21 Aug 20268 min readVerification in progress

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Key points

Effectiveness is decided in the real world, not on paper: pills, patch and ring failed 4.55 per 100 woman-years versus 0.27 for long-acting reversible contraception in the same cohort — a 17-fold difference driven by discontinuation, not biology.^[1]
UKMEC category 4 means do not use: combined hormonal contraception with migraine with aura, previous VTE, or severe established cardiovascular disease. Category 3 usually means use another method — for example, combined methods in breastfeeding women before 6 weeks.
The etonogestrel implant is the most effective reversible method available; copper IUD is the gold-standard emergency contraception within 5 days of intercourse (or ovulation) and provides ongoing contraception from insertion.^[1]^[12]
Emergency contraception: levonorgestrel up to 72 hours, ulipristal up to 120 hours (pregnancies 1.8% vs 2.6% within 72 h), but both fail far more often around ovulation and in obesity — which is when the copper IUD matters most.^[5]^[6]

Overview

Contraception is one of general practice's highest-yield activities: most women will spend three decades avoiding pregnancy. The consultation has four jobs — establish eligibility (UKMEC), match effectiveness to fertility intention, counsel on bleeding and side-effects honestly, and protect against sexually transmitted infections where relevant.^[2]

Effectiveness tables list two numbers. Perfect use reflects ideal adherence; typical use reflects real life. The gap between them decides outcomes: in the Contraceptive CHOICE cohort, pills, patch and ring failed at 4.55 per 100 woman-years while long-acting reversible contraception failed at 0.27 — and the excess was concentrated in young women.^[1] When cost and knowledge barriers were removed in CHOICE, two-thirds of participants chose long-acting methods.^[2]

References16Show

[1]Winner B, Peipert JF, Zhao Q, et al. Effectiveness of long-acting reversible contraception N Engl J Med, 2012.PMID 22621627
[2]Secura GM, Allsworth JE, Madden T, et al. The Contraceptive CHOICE Project: reducing barriers to long-acting reversible contraception Am J Obstet Gynecol, 2010.PMID 20541171
[3]Birgisson NE, Zhao Q, Secura GM, et al. Preventing Unintended Pregnancy: The Contraceptive CHOICE Project in Review J Womens Health (Larchmt), 2015.PMID 25825986
[4]Sundaram A, Vaughan B, Kost K, et al. Contraceptive Failure in the United States: Estimates from the 2006-2010 National Survey of Family Growth Perspect Sex Reprod Health, 2017.PMID 28245088
[5]Glasier AF, Cameron ST, Fine PM, et al. Ulipristal acetate versus levonorgestrel for emergency contraception: a randomised non-inferiority trial and meta-analysis Lancet, 2010.PMID 20116841
[6]Glasier A, Cameron ST, Blithe D, et al. Can we identify women at risk of pregnancy despite using emergency contraception? Data from randomized trials of ulipristal acetate and levonorgestrel Contraception, 2011.PMID 21920190
[7]Banh C, Rautenberg T, Duijkers I, et al. The effects on ovarian activity of delaying versus immediately restarting combined oral contraception after missing three pills and taking ulipristal acetate 30 mg Contraception, 2020.PMID 32474062
[8]Lidegaard Ø, Nielsen LH, Skovlund CW, et al. Risk of venous thromboembolism from use of oral contraceptives containing different progestogens and oestrogen doses: Danish cohort study, 2001-9 BMJ, 2011.PMID 22027398
[9]Lidegaard O, Nielsen LH, Skovlund CW, et al. Venous thrombosis in users of non-oral hormonal contraception: follow-up study, Denmark 2001-10 BMJ, 2012.PMID 22577198
[10]Beral V, Doll R, Hermon C, et al. Ovarian cancer and oral contraceptives: collaborative reanalysis of data from 45 epidemiological studies including 23,257 women with ovarian cancer and 87,303 controls Lancet, 2008.PMID 18294997
[11]Korver T, Klipping C, Heger-Mahn D, et al. Maintenance of ovulation inhibition with the 75-microg desogestrel-only contraceptive pill (Cerazette) after scheduled 12-h delays in tablet intake Contraception, 2005.PMID 15639065
[12]Rice CF, Killick SR, Dieben T, et al. A comparison of the inhibition of ovulation achieved by desogestrel 75 micrograms and levonorgestrel 30 micrograms daily Hum Reprod, 1999.PMID 10221231
[13]Ramanadhan S, Goldstuck N, Henderson JT, et al. Progestin intrauterine devices versus copper intrauterine devices for emergency contraception Cochrane Database Syst Rev, 2023.PMID 36847591
[14]Kaiser JE, Turok DK, Gero A, et al. One-year pregnancy and continuation rates after placement of levonorgestrel or copper intrauterine devices for emergency contraception: a randomized controlled trial Am J Obstet Gynecol, 2023.PMID 36427600
[15]Kaunitz AM, Arias R, McClung M Bone density recovery after depot medroxyprogesterone acetate injectable contraception use Contraception, 2008.PMID 18226668
[16]Van der Wijden C, Manion C Lactational amenorrhoea method for family planning Cochrane Database Syst Rev, 2015.PMID 26457821