How to Use This Article

Disclaimer: this is a concise educational article on non-emergency contraception:

• It lists only the most common or clinically significant UKMEC category 3 and 4 conditions for each contraceptive method.
  • Conditions that are UKMEC category 1 or 2 (generally safe to use) are not shown.
• It lists only the most common or clinically significant adverse effects for each contraceptive method.

 

This article organises everything important on non-emergency contraceptives into 2 main categories:

• By contraceptive method – information is grouped under each type of contraceptive method.
• By common clinical scenarios – information on various contraceptive methods is grouped under each clinical theme.

Note that there are significant overlaps between these 2 categories, but both should be read and studied to cover most of contraception.

Background Information

Contraceptive Efficacy

The following data is extracted from the FSRH UKMEC and arranged in ascending order of failure rate (from most effective to least effective), by perfect use rate.

Method	Typical Use Failure Rate	Perfect Use Failure Rate
Implant	0.05%	0.05%
Levonorgestrel intrauterine system	0.2%	0.2%
Copper intrauterine device	0.6%	0.6%
DMPA injection	6%	0.2%
COCP	9%	0.3%
POP	9%	0.3%
Patch / Ring	9%	0.3%
Fertility awareness methods	24%	0.4%–5%
Male condom	18%	2%
Female condom	21%	5%
Diaphragm	12%	6%
Withdrawal	22%	4%

UK Medical Eligibility Criteria (UKMEC)

UKMEC is a system used to classify the safety of contraceptive methods:

UKMEC	Interpretation
1	No restriction
2	Advantages generally outweigh risks
3	Risks usually outweigh advantages (avoid)
4	Unacceptable health risk (absolute contraindication)

Contraception by Method

Combined Hormonal Contraception (CHC)

This section covers:

• Combined oral contraceptive pill (COCP)
• Transdermal patch
• Vaginal ring

Mechanism of Action

Primary action: inhibition of ovulation (by suppressing mid-cycle LH surge)

Secondary action:

• Thickening of cervical mucus (from the progesterone component)
• Endometrial thinning

Route and Schedule

Combined Oral Contraceptive Pill (COCP)

There are 3 main regimens:

Regimen	Description
Standard cyclic regimen	2 cyclic regimens: 21/7: each cycle is made up of 21 days of active pill, followed by a 7-day hormone-free break 24/4: each cycle is made up of 24 days of active pill, followed by a 4-day hormone-free break (offers less hormonal fluctuation and more consistent ovarian suppression) The patient would experience withdrawal bleeding during the hormone-free interval.
Extended regimen	Each cycle is made up of 63 days (3 packs) of active pill, followed by a 4-7 day hormone-free break The patient would experience withdrawal bleeding during the hormone-free interval.
Continuous regimen	No scheduled hormone-free break Withdrawal bleeding is not expected, although some users may experience light breakthrough bleeding or spotting over time.

CHC Transdermal Patch

Standard cyclic regimen: one patch changed every week for 3 weeks, followed by 1 patch-free week.

Just like COCP, extended and continuous use is possible.

CHC Vaginal Ring

Standard cyclic regimen: inserted for 3 weeks, then removed for 1 week.

Just like COCP, extended and continuous use is possible.

Time Until Reliable Contraception

• If started on day 1-5 of the menstrual cycle → immediately effective (no additional protection needed)

 

• If started on any other days → use additional contraception (e.g. condoms) for 7 days (only effective after taking 7 consecutive pills)

Adverse Effect

Less serious adverse effects:

• Breakthrough bleeding  – common in the first month of use
• Mood changes
• Weight gain
• Nausea
• Breast tenderness

Serious adverse effects:

• Venous thromboembolism
• Arterial events (stroke, myocardial infarction)
• Hypertension
• Breast cancer
• Cervical cancer (small increase)

Caution and Contraindications

UKMEC 4 (unacceptable health risk of CHC is used), grouped according to its rationale:

Rationale	Conditions
Hormone-sensitive tumour risk	Current breast cancer Hepatocellular adenoma or carcinoma
Thrombosis risk	Current or past VTE +ve Antiphospholipid antibodies Thrombogenic mutation (e.g. Factor V Leiden, prothrombin mutation, deficiencies in Protein S, Protein C, and antithrombin) Major surgery with prolonged immobilisation Postpartum <3 weeks with additional risk factors (not breastfeeding)
Cardiovascular disease risk	Migraine with aura (↑ risk of stroke) ≥35 y/o + smoke ≥15 cigarettes / day Uncontrolled hypertension (≥160/110 mmHg) Atrial fibrillation
Oestrogen impact on infant	Breastfeeding <6 weeks postpartum
Liver function risk	Severe cirrhosis

Selected important UKMEC 3 (risk usually outweighs benefits, specialist input needed):

• Past breast cancer
• ≥35 y/o + migraine without aura
• Smoking ≥35 y/o + smoke <15 cigarettes / day
• Hypertension 
• BMI ≥35 kg/m²
• 1st-degree relative with VTE event at <45 y/o
• Diabetes with vascular complications
• Gallbladder disease
• Cholestasis (past COC-related)
• Use of liver enzyme-inducing drugs

Management of Incorrect Use

Note this section applies only to CHC being used in the standard cyclic regimen:

• COCP: 21/7 regimen without placebo pills
• Combined vaginal ring: 21 days of ring in place, followed by 7 day ring-free interval
• Combined transdermal patch: patch replaced weekly for 3 weeks, followed by 7 day patch-free interval

The management depends on how many doses are missed and at what time of the cycle the dose is missed.

Incorrect Use of COCP

The management depends on how many pills are missed and at what time of the cycle the dose is missed.

1 Missed Pill (>48 hours since last pill was taken)

ALL patients (regardless of what week the pill is missed):

• Take the missed pill as soon as possible (2 pills would be taken on the same day: 1 missed pill + 1 scheduled pill)
• Continue the remaining pills at the usual time

 

• No additional contraception needed
• Emergency contraception is NOT required

2 or More Missed Pill (>72 hours since last pill was taken)

ALL patients:

• Take the most recent missed pill as soon as possible (2 pills would be taken on the same day: 1 missed pill + 1 scheduled pill. But do not take both missed pills)
• Continue the remaining pills at the usual time
• Use condoms / avoid sex until pills have been taken for 7 consecutive days

Additional action, depending on which week the pills are missed:

• Week 1 → consider emergency contraception if UPSI has taken place during the hormone-free interval or week 1
• Week 2 → nothing else (emergency contraception not required)
• Week 3 → omit hormone-free interval and start new pack immediately at week 4

Late Restarting After Hormone-Free Interval

Defined by ≥9 days since last active pill was taken:

• Take the most recent missed pill as soon as possible
• Continue the remaining pills at the usual time

 

• Use condoms / avoid sex until pills have been taken for 7 consecutive days
• Consider emergency contraception if UPSI has taken place during or after the hormone-free interval

Incorrect Use of Combined Vaginal Ring

The management is essentially identical to the incorrect use of COCP, the only difference is:

• Unscheduled ring removal for <48 hours corresponds to 1 missed COCP pill
• Unscheduled ring removal for ≥48 hours corresponds to 2 or more missed COCP pills

Unscheduled Ring Removal for <48 Hours

ALL patients (regardless of what week it is):

• Insert the ring as soon as possible
• Keep the ring in until scheduled ring removal day

 

• No additional contraception needed
• Emergency contraception is NOT required

Unscheduled Ring Removal for ≥48 Hours

ALL patients:

• Insert the ring as soon as possible
• Keep the ring in until scheduled ring removal day
• Use condoms / avoid sex until ring has been used for 7 consecutive days

Additional action, depending on which week the ring is removed:

• Week 1 → consider emergency contraception if UPSI has taken place during the hormone-free interval or week 1
• Week 2 → nothing else (emergency contraception not required)
• Week 3 → omit hormone-free interval and start new cycle immediately

Incorrect Use of Combined Transdermal Patch

The management is essentially identical to incorrect use of COCP, the only difference is:

• Unscheduled patch removed for <48 hours OR <48 hours of delayed schedule removal corresponds to 1 missed COCP pill
• Unscheduled patch removed for ≥48 hours OR ≥48 hours of delayed schedule removal corresponds to 2 or more missed COCP pills

Unscheduled Patch Removed for <48 hours OR <48 hours of Delayed Schedule Removal

ALL patients (regardless of what week it is):

• Attach a new patch as soon as possible
• Keep the new patch on until scheduled removal day

 

• No additional contraception needed
• Emergency contraception is NOT required

Unscheduled Patch Removed for <48 hours OR <48 hours of Delayed Schedule Removal

ALL patients:

• Attach a new patch as soon as possible
• Keep the new patch on until scheduled removal day
• Use condoms / avoid sex until ring has been used for 7 consecutive days

Additional action, depending on which week it is:

• Week 1 → consider emergency contraception if UPSI has taken place during the hormone-free interval or week 1
• Week 2 → nothing else (emergency contraception not required)
• Week 3 → omit hormone-free interval and start new cycle immediately

Progestogen-Only Pill (POP)

The FSRH UKMEC 2019 only included 3 POPs that are licensed in the UK at the time of publication:

• Norethisterone (1st generation)
• Levonorgestrel (2nd generation)
• Desogestrel (3rd generation)

Mechanism of Action

Primary action: thicken cervical mucus → impermeable to sperm

Route and Schedule

Oral, once daily with no pill-free interval (to be taken continuously every day).

• Traditional POP (levonorgestrel and norethisterone) must be taken within 3 hours of the usual time
• Desogestrel (3rd generation POP) must be taken within 12 hours of the usual time

Time Until Reliable Contraception

• If started on day 1-5 of the menstrual cycle → immediately effective (no additional protection needed)

 

• If started on any other days → use additional contraception (e.g. condoms) for 2 days (only effective after taking 2 consecutive pills)

Adverse Effect

• Menstrual changes
  • Irregular bleeding – most common
  • Spotting
  • Amenorrhoea
• Breast tenderness
• Acne
• Headache
• Functional ovarian cysts

Caution and Contraindications

There are very few contraindications for POP, important ones:

• Current breast cancer (UKMEC 4)
• Past breast cancer (within the past 5 days)
• Severe decompensated liver cirrhosis
• Use of enzyme-inducing drugs (due to reduced efficacy)
• Unexplained vaginal bleeding (before evaluation)

Management of Incorrect Use

The cut-off to guide management differs slightly depending on the POP, but the management concept is the same:

• Traditional POP (levonorgestrel and norethisterone): 3-hour window
• Desogestrel POP: 12-hour window

Approach:

• If the pill is <3 hours late (levonorgestrel and norethisterone) or <12 hours late (desogestrel) → take the missed pill ASAP and no further action

 

• If the pill is >3 hours late (levonorgestrel and norethisterone) or >12 hours late (desogestrel) →
  • Take the missed pill ASAP
  • Use condoms or avoid sex for the next 48 hours
  • Consider emergency contraception if UPSI occurred

Contraceptive Implant

The only contraceptive implant licensed in the UK is the etonogestrel implant (Nexplanon®)

Etonogestrel is a progesterone-only hormone.

Mechanism of Action

Primary action: inhibit ovulation

Route and Schedule

Subdermal implant in the upper non-dominant arm.

Inserted once and remains effective for 3 years.

Time Until Reliable Contraception

• If inserted on day 1-5 of the menstrual cycle → immediately effective (no additional protection needed)

 

• If started on any other days → use additional contraception (e.g. condoms) for 7 days (only effective after 7 consecutive days)

Adverse Effects

Adverse effects of the contraceptive implant are largely same as those of POP:

• Menstrual changes
  • Irregular bleeding – most common
  • Spotting
  • Amenorrhoea
• Breast tenderness
• Acne
• Headache

Caution and Contraindications

Contraindications of the contraceptive implant are largely same as those of POP:

• Current breast cancer (UKMEC 4)
• Past breast cancer (within the past 5 days)
• Severe decompensated liver cirrhosis
• Use of enzyme-inducing drugs (due to reduced efficacy)
• Unexplained vaginal bleeding (before evaluation)

Injectable Contraception

Injectable contraception contains depo-medroxyprogesterone acetate (DMPA)

Mechanism of Action

Primary action: inhibit ovulation

Route and Schedule

There are 2 preparations of DMPA:

• Intramuscular DMPA: every 12 weeks
• Subcutaneous DMPA: every 12-13 weeks

Time Until Reliable Contraception

• If inserted on day 1-5 of the menstrual cycle → immediately effective (no additional protection needed)

 

• If started on any other days → use additional contraception (e.g. condoms) for 7 days

Adverse Effects

• Menstrual changes
  • Irregular bleeding – most common
  • Amenorrhoea
• Headache
• Acne

Important adverse effects that are significant in DMPA but not in other contraceptive methods:

• Weight gain – common (well-documented and more significant compared to other contraceptive methods)
• Delay in return to fertility (median 7-8 months after last injection)
• Reduction in bone mineral density (mostly reversible on discontinuation)

Caution and Contraindications

Important contraindications:

• Current breast cancer (UKMEC 4)
• Past breast cancer (within the past 5 days)
• Severe decompensated liver cirrhosis
• Unexplained vaginal bleeding (before evaluation)

 

• Known osteoporosis / significant fracture risk
• Current / history of ischaemic heart disease or stroke
• Current or recent VTE (not on anticoagulation)
• Multiple cardiovascular disease risk factors (e.g. smoking, diabetes, hypertension, dyslipidemia)

Levonorgestrel Intrauterine System (LNG-IUS)

Levonorgestrel is a progesterone-only hormone.

Mechanism of Action

Primary action: cervical mucus thickening

Route and Schedule

Intrauterine placement.

Inserted once and remains in place for:

• Up to 8 years (Mirena®)
• 6 years (Levosert®)
• 5 years (Kyleena®)
• 3 years (Jaydess®)

Time Until Reliable Contraception

• If inserted on day 1-5 of the menstrual cycle → immediately effective (no additional protection needed)

 

• If started on any other days → use additional contraception (e.g. condoms) for 7 days

Adverse Effects

LNG-IUS specific adverse effects

• Irregular bleeding and spotting – especially in the first 6 months
• Possible amenorrhea

Other shared adverse effects of copper IUD:

• Risk of expulsion (1 in 20), more likely in first 3 months
• Risk of uterine perforation (rare, up to 2 in 1000)
• Risk of ectopic pregnancy (overall risk of ectopic pregnancy is reduced but if pregnancy does occur while using an LNG-IUS, there is a higher relative risk of it being ectopic)
• Risk of PID in first 20 days (after 20 days, risk of PID returns to baseline population levels

Caution and Contraindications

Important contraindications:

• Breast cancer (current is UKMEC 4 and past 5 years is UKMEC 3)
• Cervical or endometrial cancer (UKMEC 4)
• Unexplained vaginal bleeding (prior to evaluation) (UKMEC 4)

 

• Distorted uterine cavity (e.g. due to submucosal fibroids, intrauterine adhesions, large endometrial polyps, congenital uterine anomalies – typically seen on ultrasound / other imaging) (UKMEC 4)
• Current PID (UKMEC 4)
• Postpartum sepsis (UKMEC 4)

Copper Intrauterine Device (IUD)

Mechanism of Action

Primary action: copper ions are toxic to sperm → prevents fertilisation by reducing sperm motility and viability

Secondary action: inhibit implantation if fertilisation occurs

Route and Schedule

Intrauterine placement.

Various copper IUDs are available, they differ in shape, copper surface area and licensed duration of use:

• TCu380A: up to 10 years
• TT380 Slimline: up to 10 years
• Multi-load Cu375: up to 5 years

Time Until Reliable Contraception

Immediate effect upon insertion, no need for additional contraception​​​​​.

Adverse Effects

Copper IUD-specific adverse effects

• Menstrual bleeding may become heavier, longer or more painful – especially in the first few months

Other shared adverse effects of copper IUD:

• Risk of expulsion (1 in 20), more likely in first 3 months
• Risk of uterine perforation (rare, up to 2 in 1000)
• Risk of ectopic pregnancy (overall risk of ectopic pregnancy is reduced but if pregnancy does occur while using an LNG-IUS, there is a higher relative risk of it being ectopic)
• Risk of PID in first 20 days (after 20 days, risk of PID returns to baseline population levels)

Contraindications

UKMEC 4	Current PID Current purulent cervicitis or chlamydial / gonococcal infection Distorted uterine cavity (e.g. due to submucosal fibroids, intrauterine adhesions, large endometrial polyps, congenital uterine anomalies – typically seen on ultrasound / other imaging) Cervical or endometrial cancer Unexplained vaginal bleeding (before evaluation)
UKMEC 3	Increased risk of STIs History of PID in the past 3 months Severe thrombocytopenia or bleeding disorder Copper allergy or Wilson’s disease

Contraception by Clinical Scenarios

Postpartum Contraception

Contraception is needed after 21 days postpartum.

Type of contraception	Description
Combined hormonal contraception (including COCP)	Breastfeeding postpartum: <6 weeks postpartum: contraindicated (UKMEC 4) Not breastfeeding postpartum: <3 weeks postpartum: contraindicated (UKMEC 4 if with VTE risk factors, 3 without risk factors) 3-6 weeks postpartum + VTE risk factors: UKMEC 3
POP	Can be started immediately postpartum (always UKMEC 1)
Contraceptive implant	Can be started immediately postpartum (always UKMEC 1)
DMPA	Can be used safely postpartum (no UKMEC 3 / 4)
LNG-IUS and copper IUD	Can be safely inserted (UKMEC 1) if: <48 hours postpartum, OR ≥4 weeks postpartum Contraindicated if: Postpartum sepsis (UKMEC 4) 48 hours – 4 weeks postpartum (UKMEC 3)

Contraception in Smokers

The only precaution is with CHC:

• Age ≥35 y/o + smoke ≥15 cigarettes / day: UKMEC 4
• Age ≥35 y/o + smoke <15 cigarettes / day: UKMEC 3
• Age ≥35 y/o + stopped smoking <1 year: UKMEC 3

UKMEC 1 for all other contraceptive methods, regardless of age and quantity of smoking.

Contraception in Obese Individuals

The only precaution is with CHC:

• BMI  ≥35 kg/m²: UKMEC 3
• BMI 30-34 kg/m²: UKMEC 2

UKMEC 1 for all other contraceptive methods, regardless of BMI.

Contraception in Oestrogen-sensitive Cancers (e.g. breast cancer)

All hormonal methods are UKMEC 4 (for current breast cancer) and UKMEC 3 (for past breast cancer).

Only UKMEC 1 is a copper IUD.

Contraception and Enzyme-Inducing Antiepileptic Drugs

The only UKMEC 1s are:

• LNG-IUS
• Copper IUD
• DMPA injection

All other contraceptive methods are UKMEC 3.

Contraception in Hypertension

The 2 implicated contraceptive methods are CHC and DMPA.

CHC contraindications:

• UKMEC 4: BP ≥160/100 mmHg and presence of vascular disease
• UKMEC 3: BP ≥140/90 mmHg (even if adequately controlled)

DMPA contraindications:

• UKMEC 3 if there is vascular disease

Contraception in VTE

The only precaution is with CHC:

• UKMEC 4 if
  • History or current VTE
  • Major surgery with prolonged immobilisation

 

• UKMEC 3 if
  • 1st degree relative <45 y/o with VTE
  • Immobility (unrelated to surgery) (e.g. wheelchair use, debilitating illness)

All other contraceptive methods are UKMEC 1 or 2.

References