Contraceptives

Overview
Contraceptives are agents, devices, or methods designed to prevent pregnancy by interfering with one or more stages of the reproductive process. They can act by inhibiting ovulation, preventing fertilization, or impeding implantation of a fertilized ovum. Contraceptives are available in hormonal, barrier, intrauterine, and permanent forms, as well as emergency contraception for post-coital prevention. The choice of contraceptive depends on medical suitability, convenience, reversibility, side-effect profile, and personal preference.

---

Mechanisms of Action
Contraceptives can act through one or more of the following mechanisms:

• Inhibition of ovulation via suppression of gonadotropin secretion (estrogen-progestin combinations or high-dose progestins).

• Thickening of cervical mucus to hinder sperm penetration (progestin-containing methods).

• Altering endometrial receptivity to prevent implantation (progestin effect).

• Direct sperm immobilization or killing (spermicides).

• Physical barrier preventing sperm from reaching the ovum (condoms, diaphragms, cervical caps).

• Intrauterine environment alteration that inhibits fertilization and implantation (IUDs).

---

Types of Contraceptives

1. Hormonal Contraceptives

   • Combined hormonal contraceptives (CHCs): Contain estrogen + progestin

     • Oral contraceptive pills (OCPs) – monophasic, biphasic, triphasic

     • Transdermal patch – applied weekly (e.g., ethinylestradiol/norelgestromin)

     • Vaginal ring – releases hormones locally for 3 weeks (e.g., ethinylestradiol/etonogestrel)

   • Progestin-only contraceptives

     • Oral progestin-only pills ("mini-pill") – taken daily without breaks

     • Injectable progestins (e.g., depot medroxyprogesterone acetate – DMPA) every 12 weeks

     • Implants (etonogestrel implant – up to 3 years)

2. Intrauterine Devices (IUDs)

   • Hormonal IUDs (levonorgestrel-releasing) – effective 3–6 years

   • Copper IUDs – non-hormonal, effective 5–10 years; copper ions toxic to sperm and ova

3. Barrier Methods

   • Male condoms

   • Female condoms

   • Diaphragms and cervical caps (used with spermicide)

   • Contraceptive sponges

4. Spermicides

   • Chemicals (e.g., nonoxynol-9) that destroy sperm cell membranes

   • Available as gels, creams, foams, suppositories, films

5. Emergency Contraception

   • Levonorgestrel (single or split dose, within 72 hours after intercourse)

   • Ulipristal acetate (selective progesterone receptor modulator – up to 120 hours)

   • Copper IUD (most effective – can be inserted up to 5 days after intercourse)

6. Permanent Methods (Sterilization)

   • Female sterilization: Tubal ligation or hysteroscopic tubal occlusion

   • Male sterilization: Vasectomy

---

Contraindications (for hormonal methods)

• History of thromboembolic disorders or stroke

• Estrogen-dependent tumors (e.g., breast cancer)

• Uncontrolled hypertension

• Active liver disease or hepatic tumors

• Migraine with aura

• Pregnancy

• Smoking ≥15 cigarettes/day and age ≥35 years (for estrogen-containing contraceptives)

---

Precautions

• CHCs require daily adherence or consistent application (patch/ring) for optimal efficacy

• Barrier methods protect against sexually transmitted infections (STIs) – hormonal methods do not

• Hormonal methods may affect bone density (especially DMPA with prolonged use)

• Monitor for side effects such as mood changes, weight change, headaches, breakthrough bleeding

---

Adverse Effects

• Hormonal: Nausea, breast tenderness, mood changes, headache, breakthrough bleeding, reduced libido; rare but serious – venous thromboembolism, myocardial infarction, stroke

• IUDs: Irregular bleeding (hormonal), heavier menses and cramps (copper), risk of expulsion or uterine perforation (rare)

• Barrier methods: Allergic reactions to latex or spermicide, irritation

• Injectables: Delayed return to fertility after discontinuation, weight gain, amenorrhea

---

Drug Interactions (mainly for hormonal contraceptives)

• Enzyme inducers (rifampicin, rifabutin, carbamazepine, phenytoin, phenobarbital, St. John’s wort) → reduce efficacy; backup contraception needed

• Certain antibiotics (rifampicin/rifabutin) → clinically significant reduction in hormone levels

• Antiretrovirals → some may decrease contraceptive hormone concentration

• Antifungals (griseofulvin) → reduced efficacy reported

---

Monitoring and Follow-up

• Blood pressure check before and during CHC use

• Weight and menstrual pattern tracking

• Cervical screening as per guidelines

• STI testing where indicated

Contraceptives: comprehensive comparative guide

The overview below organizes modern contraceptive options by effectiveness, duration, key benefits, limitations, and suitability in special populations. Figures for typical and perfect use reflect widely used public health references and clinical guidelines.

Quick-reference comparison table

Method	Typical failure rate (first year)	Perfect-use failure rate	Duration	Return to fertility	Key advantages	Important limitations and adverse effects	Notes for special populations
Copper IUD	~0.8%	~0.6%	5–10 years by model	Immediate on removal	Hormone-free, highest ongoing efficacy, works as emergency contraception if inserted ≤5 days after intercourse	Heavier or more painful periods at first, cramping, rare perforation or expulsion	Suitable for adolescents and nulliparous users; immediate postpartum or post-abortion insertion possible when clinically appropriate
Levonorgestrel IUDs (LNG-IUDs)	~0.1–0.4%	~0.1%	3–8 years by product	Immediate on removal	Very light bleeding or amenorrhea common, reduces dysmenorrhea, high satisfaction	Irregular bleeding first months, functional ovarian cysts, rare perforation or expulsion	Appropriate in adolescents, anemia, heavy menstrual bleeding; safe in breastfeeding
Etonogestrel implant	~0.1%	~0.1%	Up to 3 years	Rapid (days to weeks)	Highest efficacy, low maintenance, can reduce dysmenorrhea	Unpredictable bleeding patterns, acne or mood changes in some	Safe in breastfeeding; insert immediately postpartum including after cesarean
DMPA injection	~4%	~0.2%	12–13 weeks per dose	Delayed (median ~9–10 months to ovulation)	Private, quarterly dosing, may reduce seizures and sickle pain crises	Irregular bleeding then amenorrhea, weight gain, reversible bone mineral density loss, mood changes	Use with caution in adolescents at high fracture risk; compatible with breastfeeding after 6 weeks postpartum in some guidelines
Combined oral pill	~7%	~0.3%	Daily	Rapid on cessation	Regulates cycles, reduces dysmenorrhea and acne, treats PCOS symptoms	Estrogen-related risks (VTE, hypertension), nausea, headaches, breakthrough bleeding if missed pills	Avoid with migraine with aura, high VTE risk, heavy smokers aged ≥35; start ≥3–6 weeks postpartum depending on VTE risk and breastfeeding
Progestin-only pill (traditional norethindrone)	~7%	~0.3–0.5%	Daily at same time	Rapid	Suitable when estrogen contraindicated, safe in lactation	Narrow dosing window (missed by >3 hours needs backup), irregular bleeding	Preferred early postpartum and during breastfeeding
Drospirenone 4 mg POP	~4–7%	~0.3–0.5%	Daily	Rapid	24-hour missed-pill window, less breakthrough bleeding in some users	Hyperkalemia risk with interacting drugs, irregular bleeding	Safe in breastfeeding after early postpartum period
Transdermal combined patch	~7%	~0.3%	Weekly for 3 weeks then 1 patch-free week	Rapid	Convenient weekly schedule	Skin irritation, higher estrogen exposure; possible decreased efficacy at high body weight	Some labels caution reduced efficacy at ≥90 kg; same estrogen contraindications as combined pills
Vaginal combined ring (monthly)	~7%	~0.3%	3 weeks in, 1 week out	Rapid	Steady hormones, monthly handling	Vaginal discharge or irritation, estrogen risks	Similar contraindications as combined pills; self-placement is straightforward
Vaginal annual ring (segesterone/ethinyl estradiol)	~7%	~0.3%	Reusable for 1 year (cyclic)	Rapid	Annual device with monthly cycles	Estrogen risks, device care needed	Avoid where estrogen is contraindicated
Male external condom	~13%	~2%	Per act	Immediate	STI protection, accessible, non-hormonal	Breakage or slippage, latex allergy in some	Essential for STI prevention; fits with dual-protection strategies
Female internal condom	~21%	~5%	Per act	Immediate	Female-controlled barrier, STI protection	Insertion learning curve, displacement	Useful when male condom not acceptable
Diaphragm or cervical cap (with spermicide)	~17–21%	~4–8%	Per act (up to 24 h)	Immediate	Non-hormonal, reusable	Requires fitting and correct placement, UTI risk, spermicide irritation	Less effective in parous users for some devices
Contraceptive sponge	~14% (nulliparous) ~27% (parous)	~9–20%	Up to 24 h	Immediate	Over-the-counter, pericoital method	Higher failure after childbirth, irritation	Contains nonoxynol-9; not for frequent STI risk contexts
Spermicide alone (nonoxynol-9)	~21%	~16%	Per act	Immediate	OTC, low cost	Local irritation, no STI protection	Frequent use may increase HIV risk with high-exposure populations
Fertility awareness-based methods	~24%	~2–5%	Continuous with daily tracking	Immediate	Hormone-free, body awareness	Requires training, daily effort, abstinence or barrier during fertile window	Effectiveness depends heavily on method and adherence; postpartum and irregular cycles need expert guidance
Withdrawal	~20%	~4%	Per act	Immediate	No cost, accessible	High failure with typical use	Not STI protective
Lactational amenorrhea method (LAM)	~2% (first 6 months, strict criteria)	~0.5–1%	Up to 6 months postpartum if fully or nearly fully breastfeeding and amenorrheic	Immediate	Naturally available early postpartum	Stops being effective when menses return, supplemental feeds increase, or after 6 months	Bridge to another method; safe and compatible with breastfeeding
Female sterilization (tubal occlusion)	~0.5%	~0.1–0.3%	Permanent	Not intended to be reversible	One-time procedure, very effective	Surgical risks, regret if fertility desires change	Consider long-acting reversible methods if unsure about permanence
Male sterilization (vasectomy)	~0.15%	~0.05%	Permanent	Not intended to be reversible	Safer, less costly than female sterilization	Requires semen analysis to confirm azoospermia; backup until clear	Very effective after clearance; minimal long-term effects
Vaginal pH modulator gel (lactic–citric–tartaric)	~13–14%	~7%	Per act	Immediate	Non-hormonal, on-demand	Vaginal irritation, no STI protection	Can be combined with condoms for higher efficacy
Emergency contraception: levonorgestrel	Use within 72 hours (some effect up to 120 h)	—	One-time dose	Cycles resume	Widely available, no exam needed	Less effective with higher body weight and after ovulation	Start or resume regular contraception immediately; use condoms for 7 days if starting a hormonal method
Emergency contraception: ulipristal acetate	Up to 120 hours	—	One-time dose	Cycles resume	More effective late in the window and at higher body weight than LNG	Interaction with progestins; delay starting progestin methods for 5 days	Copper IUD remains most effective EC
Emergency contraception: copper IUD	Most effective EC up to 5 days	—	5–10 years if retained	Immediate on removal	Ongoing contraception after EC	Requires insertion by trained clinician	Consider for those desiring long-term, hormone-free contraception

Method selection in practice

Risk assessment and eligibility
• Screen for pregnancy and evaluate medical eligibility, with attention to venous thromboembolism risk, migraine with aura, uncontrolled hypertension, ischemic heart disease or stroke history, active liver disease or tumors, breast cancer history, and postpartum status
• For estrogen-containing methods, avoid in migraine with aura and in heavy smokers aged thirty-five or older; delay post-partum use based on venous thromboembolism risk and breastfeeding plans
• For copper IUD, consider baseline anemia or dysmenorrhea because of potential for heavier bleeding early on
• For depot medroxyprogesterone acetate, discuss weight gain propensity and reversible bone density loss, especially in adolescents and those with additional osteoporosis risks

Drug and product interactions
• Hepatic enzyme inducers such as rifampicin and rifabutin, certain antiepileptics like carbamazepine, phenytoin, phenobarbital, topiramate at higher doses, and herbal St John’s wort can reduce the effectiveness of combined pills, patch, ring, and some progestin-only pills
• Enzyme inducers do not meaningfully lower the effectiveness of copper IUDs, LNG-IUDs, or the etonogestrel implant; these are preferred in such settings
• Certain antiretrovirals and antifungals may interact with estrogen–progestin methods; choose IUDs or implant where feasible
• Drospirenone-containing pills can raise potassium, so use caution with ACE inhibitors, ARBs, potassium-sparing diuretics, and strong CYP3A4 inhibitors

Counseling and adherence
• Emphasize correct and consistent use: daily timing for pills, weekly changes for patches, monthly cycles for rings, timely repeat DMPA injections, and correct barrier placement
• Discuss expected bleeding changes, especially with implants, IUDs, and DMPA, and provide strategies to manage unscheduled bleeding (for example, short courses of NSAIDs or, if eligible, combined hormonal pills)
• Promote dual protection with condoms for those at risk of sexually transmitted infections
• Provide a clear plan for missed or late pills, patch detachments, ring expulsions, or delayed injections, including backup contraception intervals
• Encourage advance supply of emergency contraception and outline how to transition from EC to an ongoing method

Special clinical scenarios
• Postpartum and breastfeeding: Progestin-only methods, implants, and IUDs are preferred early postpartum; combined hormonal contraception is typically delayed several weeks depending on breastfeeding and thrombosis risk
• Adolescents: Long-acting reversible contraception such as implants and IUDs offer top-tier efficacy with minimal adherence burden and are appropriate for nulliparous users
• Perimenopause: LNG-IUDs can control heavy bleeding and serve as the progestin component of menopausal hormone therapy; combined methods may be used if no estrogen contraindications
• High body weight: Copper IUD, LNG-IUDs, and the etonogestrel implant maintain excellent effectiveness; some evidence suggests reduced efficacy of levonorgestrel emergency pills and the transdermal patch at higher body weight, so consider ulipristal or copper IUD for EC and IUD or implant for ongoing contraception
• Heavy menstrual bleeding and dysmenorrhea: LNG-IUD is usually first-line for combined contraception and symptom control
• Acne or hirsutism: Certain combined pills improve acne; progestin-only methods may worsen acne in some users

Monitoring
• Check blood pressure before and during use of combined hormonal methods
• Review new headaches, visual or neurologic symptoms, chest pain, shortness of breath, unilateral leg swelling, severe abdominal pain, or heavy/prolonged bleeding
• For DMPA, consider periodic assessment of weight and, in long-term users with additional risk factors, bone health counseling including calcium, vitamin D, and weight-bearing exercise
• IUD users should return for evaluation if they develop severe pain, fever, abnormal discharge, or suspect expulsion; routine string checks are optional based on user preference

Method change and discontinuation
• Switching can be same-day if pregnancy can reasonably be excluded; use condoms for seven days when transitioning to methods that need hormone build-up unless inserting an IUD or implant
• After ulipristal emergency contraception, delay starting progestin methods for five days, then use condoms for seven additional days

Emergency contraception at a glance
• Copper IUD is the most effective option and provides long-term contraception if retained
• Ulipristal acetate is preferred over levonorgestrel for use between 72 and 120 hours after intercourse or in individuals with higher body weight
• Levonorgestrel is most accessible and works best the sooner it is taken