Contraception

Unfortunately no complete list exists of all medications which pose a safety issue to pregnancy, however we do have emerging data coming through with safety reviews happening. Medication risk can also vary depending on stage of pregnancy or time before conception. All patients taking medications, particularly those on long term treatment should be supported to make informed decisions about their contraceptive needs and pregnancy planning.

Medicines with teratogenic potential: what is effective contraception and how often is pregnancy testing needed? New guidance from the MHRA from March 2019 on contraception methods and frequency of pregnancy testing to reduce inadvertent exposures during pregnancy in women/ people taking a medicine of teratogenic potential.

The Medicines for Women’s Health Expert Advisory Group of the Commission on Human Medicines has developed an aide-memoire table to provide guidance to prescribers of medicines with teratogenic potential on the frequency of pregnancy testing needed to avoid exposure in pregnancy during treatment, depending on the chosen contraceptive method.

Topiramate- NB. See the FSRH Guidance: Drug Interactions with Hormonal Contraception (May 2022) for information on contraception during the use of a teratogen that is an enzyme inducer or a potential enzyme inducer (or if an enzyme inducing drug is also being taken)

• Use of the copper IUD, a levonorgestrel-releasing IUS, or depot medroxyprogesterone acetate PLUS condoms is recommended.
• Use of combined hormonal contraception, progestogen-only pills and the etonogestrel implant is not recommended.

See FSRH Guidelines & Statements FSRH to access information on all methods of contraception. The FSRH also share their position statement on FSRH CEU Statement: Contraception for women using known teratogenic drugs or drugs with potential teratogenic effects 14 February 2018

See the Medication Safety page for latest MHRA and Drug alerts for teratogenic medication. 

People of childbearing potential should be advised to use highly effective contraception if they or their male partners are taking known teratogenic drugs or drugs with potential teratogenic effects. Highly effective contraception should be used both during treatment and for the recommended duration after discontinuation to avoid unintended pregnancy. Pregnancy testing should be performed before treatment initiation to exclude pregnancy and repeat testing may be required.

Methods of contraception considered to be ‘highly effective’ include the long-acting reversible contraceptives (LARC) copper intrauterine device (Cu-IUD), levonorgestrel intrauterine system (LNG-IUS) and progestogen-only implant (IMP), and male and female sterilisation. For more information see the FSRH CEU statement, MHRA drug safety update, and the UK teratogenic information service.

Valproate medicines must not be used in women of childbearing potential unless the Pregnancy Prevention Program is in place. If you are involved in the care of female patients on valproate in the UK, see a reminder of actions required for this medicine.

In April 2022 the MHRA published guidance on pregabalin and risks in pregnancy. This information is relevant to patients taking pregabalin who are able to become pregnant.

• Progestogen-only contraceptives offer a suitable alternative to combined hormonal contraceptives when oestrogens are contra-indicated.

• NB: Some progestogen-only contraceptive pills only have a 3 hour window, including Noriday^® and Norgeston^®.

• Desogestrel has a 12 hour window. First line oral progestogen-only choice on formulary – prescribe generically.

• Slynd^® (drospirenone) has a 24 hour window. Last line oral progestogen- only choice on formulary- prescribe where clinically indicated and other oral options aren't suitable.

• Intra-uterine POP system, LARCs remain a cost-effective and reliable choice.

• FSRH Combined Hormonal Contraception Guideline suggests that the traditional 21/7 Combined Hormonal Contraception (CHC) regimen with a monthly withdrawal bleed confers no health benefit over other patterns of CHC use. In addition, symptoms associated with the hormone-free interval (HFI) can be problematic and ovarian activity during a 7-day HFI could risk escape ovulation (particularly with lower doses of Ethinylestradiol (EE) and if use is not perfect). ‘Tailored’ CHC regimens in which there are fewer (or no) HFI and/or shortened HFI can be safely used to avoid withdrawal bleeds and associated symptoms and theoretically reduce the risk of contraceptive failure. Suggested tailored regimens (using a monophasic EE CHC) are described in the document linked above. Women should be told about tailored regimens and given their choice of regimen based on their preference. Tailored CHC regimens can reduce the frequency of withdrawal bleeds and can reduce withdrawal symptoms associated with the HFI; however, unscheduled bleeding is common.

• For information on advice to give to patients on switching between CHC and other contraception, and the management of incorrect CHC use, see FSRH clinical guidance: Combined Hormonal Contraception and Incorrect use of Combined Hormonal Contraception (see Useful resources).

See the contraception formulary page for formulary approved options.

FSRH Clinical Guideline: Intrauterine contraception (March 2023, Amended July 2023)

• A full history should be taken to confirm whether emergency contraception is indicated. The possibility of pregnancy should be reasonably excluded.

• The choice of emergency contraception should be made with the patient, taking additional factors into consideration (such as the UK Medical Eligibility Criteria, the patient’s preference, current medication, and timing of sexual intercourse). They should be advised about the efficacy, adverse effects, advantages, and disadvantages of each method. 

• The copper coil (Cu-IUD) is the most effective emergency contraception method, it should be offered to all patients seeking emergency contraception unless contraindicated or unsuitable.

• Levonorgestrel 1500mcg tablet is available via PGD through many pharmacies across Somerset, free of charge to all patients under 25 years. Patients aged over 25 years should contact their GP. Levonorgestrol 1500mcg (as Upostelle) is the first-line oral preparation for patients presenting within 72 hours of unprotected sexual intercourse (UPSI) or contraceptive failure. DO NOT PRESCRIBE AS THE OTC PREPARATION: Levonelle One Step® (as over twice the cost of the prescription-only product.)

• Patients presenting between 72 hours and 120 hours may be offered the choice of ulipristal acetate or intrauterine device and the risks and benefits of each method should be discussed with the patient. Ulipristal is licensed for emergency contraception within 120 hours (5 days) after UPSI. Pregnancy should be excluded before ulipristal is taken. EllaOne is excluded from the MHRA alert affecting ulipristal for uterine fibroid treatment.

• Levonorgestrel remains the preferred emergency hormonal contraception option for breastfeeding parents. Both levonorgestrel and ulipristal acetate can be taken while breastfeeding without interruption to breastfeeding, there is no need to "pump and dump" for any particular time. (The manufacturing licencing does not take into account post-marketing evidence base.) Please see the Breastfeeding Network and Specialist Pharmacy Service: Using emergency contraception during breastfeeding for further information. The Cu-IUD also remains a suitable option if required.

• Please note that patients who have a BMI >26 or are greater than 70kg may require more than the standard 1.5mg dose of levonorgestrel. Consider double dose (3mg) or Cu-IUD or ulipristal. See FSRH Clinical Guideline: Emergency Contraception for more information.

• Women taking enzyme inducing medication may require further measures. EC providers should advise women using enzyme-inducing drugs that the effectiveness of ulipristal and levonorgestrel could be reduced. Women requiring EC who are using enzyme-inducing drugs should be offered a Cu-IUD if appropriate. A 3mg dose of levonorgestrel can be considered but women should be informed that the effectiveness of this regimen is unknown. A double-dose of ulipristal is not recommended. See FSRH Clinical Guideline: Emergency Contraception for more information.

• Although the use of ellaOne does not contraindicate the continued use of regular hormonal contraception, ellaOne may reduce its contraceptive action. Therefore, if a woman wishes to start or continue using hormonal contraception, she can do so after using ellaOne, however, she should be advised to use a reliable barrier method until the next menstrual period. See summary of product characteristics for full details.

• See the British National Formulary for contraceptive interactions.

Topiramate- NB. See the FSRH Guidance: Drug Interactions with Hormonal Contraception (May 2022) for information on contraception during the use of a teratogen that is an enzyme inducer or a potential enzyme inducer (or if an enzyme inducing drug is also being taken)

• Use of the copper IUD, a levonorgestrel-releasing IUS, or depot medroxyprogesterone acetate PLUS condoms is recommended.
• Use of combined hormonal contraception, progestogen-only pills and the etonogestrel implant is not recommended.

The Specialist Pharmacy Service have published guidance on Using contraception with enzyme-inducing medicines.

• The effectiveness of combined oral contraceptives, progestogen-only oral contraceptives, contraceptive patches, and vaginal rings can be considerably reduced by interaction with drugs that induce hepatic enzyme activity (e.g. carbamazepine, eslicarbazepine, modafinil, nelfinavir, nevirapine, oxcarbazepine, phenytoin, phenobarbital, primidone, ritonavir, St John’s Wort, topiramate, and, above all, rifabutin and rifampicin) during use and for 28 days after stopping. Women using enzyme-inducing drugs should be offered a reliable contraceptive method that is unaffected by enzyme-inducers. See SPS link above for more information.

• Contraceptive hormones can affect serum levels of drugs such as lamotrigine with potential significant clinical side effects. Women taking lamotrigine should be advised that combined hormonal contraception may interact with lamotrigine; this could result in reduced seizure control or lamotrigine toxicity. The risks of using CHC could outweigh the benefits.

• Hormonal contraceptives and antibacterials that do not induce liver enzymes – Advice on interactions between combined hormonal contraceptives and antibacterials that do not induce liver enzymes has been updated to take into account the recommendations of the Faculty of Sexual and Reproductive Healthcare Clinical Guidance: Drug Interactions with Hormonal Contraception (January 2011). Additional contraceptive precautions are no longer necessary when antibacterials that do not induce liver enzymes are taken with combined oral contraceptives, (unless diarrhoea or vomiting occurs), contraceptive patches or vaginal rings. More information on enzyme inducing drugs can be found in the British National Formulary.

• Please note that the evidence is too limited to make a definite recommendation regarding the effectiveness of combined oral contraceptives after bariatric surgery. The FSHR GDG recommend that women who have had bariatric surgery should be advised of potential reduced effectiveness of COC and should consider a non-oral method of contraception. See also Specialist Pharmacy Service: The effect of bariatric surgery (gastric bypass) on certain medicines for more information on contraceptive options.

• See ‘Emergency Contraception’ for more information on interactions with EHC.

The European Medicines Agency (EMA) review in 2013 concluded that there was good evidence to suggest that the risk of VTE associated with different combined oral contraceptive (COCs) was influenced by progestogen type, with those COCs containing levonorgestrel, norethisterone or norgestimate having the lowest risk and drospirenone, desogestrel or gestodene having the highest risk.

Risk of VTE per 10,000 healthy women over one year:

• COC containing ethinylestradiol plus levonorgestrel, norgestimate or norethisterone: 5-7
• COC containing etonogestrel (ring) or norelgestromin (patch): 6-12
• COC containing ethinylestradiol plus gestodene, desogestrel or drospirenone: 9-12

However, the EMA noted that the benefits of combined hormonal contraceptive use generally outweighed the risk of venous thrombosis, which is low overall and is lower than the VTE risk associated with pregnancy and the postpartum period.

If a hormonal contraceptive is clinically appropriate, an oral progesterone-only contraceptive (POC) (desogestrel, norethisterone, or levonorgestrel) is preferred to longer-acting formulations, which are advised to be delayed until 6 weeks postpartum.
POCs are the contraceptives of choice at all stages of breastfeeding, once lactation fully established.

The oestrogen component of combined hormonal contraceptives (CHC) can have a significant effect on supressing milk production, especially in doses exceeding 30 micrograms ethinylestradiol, which normally precludes their use in breastfeeding mothers until weaning or for 6 months after birth. The oestrogen levels in currently available CHCs are not considered to be high enough to pose a risk of oestrogenic effects in infants.

Individual progestogens used in CHCs are not detailed here as the progestogen component is not considered to pose a risk to the infant or to lactation. This also applies to progestogens only used in combination with an oestrogen (drospirenone, norgestimate, nomegestrol and dienogest).
It is advised to avoid CHCs in the first 6 weeks postpartum due to possible effects on milk production and infant growth and increased risk of thromboembolism in the mother. If any adverse effects are experienced then please complete a yellow card report and review, considering use of POP instead. Progestogen-only contraceptives are preferred at all stages of lactation.

SPS: Safety in Lactation: Progestogen-only contraceptives

SPS: Safety in Lactation: Combined hormonal contraceptives

FSRH Clinical Guideline: Contraception After Pregnancy Executive Summary (January 2017)

Emergency contraception

Levonorgestrel remains the preferred emergency hormonal contraception option for breastfeeding parents.

Both levonorgestrel and ulipristal acetate can be taken while breastfeeding without interruption to breastfeeding, there is no need to "pump and dump" for any particular time. (The manufacturing licencing does not take into account post-marketing evidence base.)

Please see the Breastfeeding Network and Specialist Pharmacy Service: Using emergency contraception during breastfeeding for further information. The Cu-IUD also remains a suitable option if required.

For more information and resources around menopause and hormone replacement therapy see our menopause webpage.

FSRH Clinical Guideline: Contraception for Women Aged over 40 Years

People with premature ovarian insufficiency will be offered sex steroid replacement with a choice of HRT or a combined hormonal contraceptive (CHC). CHC (unless contraindicated) has the added benefit of providing contraceptive cover to people with premature ovarian insufficiency. 

See the 7.3 – Contraception – Somerset Prescribing Formulary for information on oral combined hormonal contraceptive choices.

For people with a uterus requiring protection from endometrial hyperplasia during oestrogen replacement therapy as well as contraception, Mirena^® 20 micrograms/24 hours intrauterine delivery system can be used. See SPC for detail on length of treatment. Mirena is effective for 5 years in the indication of contraception, but 4 years for the progesterone component of HRT.

For people who are perimenopausal, or menopausal, see the FSRH guidance above.

FSRH CEU Guidance: Supporting Contraceptive Choices for Individuals Who Have or Have Had Breast Cancer (November 2023)

Faculty of Sexual and Reproductive Healthcare contraception for acne:

FSRH Clinical Guideline: Combined Hormonal Contraception (January 2019, Amended November 2020)

• A combined oral contraceptive may be chosen for people with PCOS and acne if first line treatment options are not effective alone for their acne.
• Co-cyprindiol remains second line where an alternative combined oral contraceptive has not been effective. Patients should be aware of the increased risk of thrombosis when using co-cyprindiol.
• FSRH Clinical Guideline: Combined Hormonal Contraception (January 2019, Amended November 2020) – Faculty of Sexual and Reproductive Healthcare found few differences between the combined oral contraceptives studied in terms of their effectiveness in treating acne.
• FSRH CEU Statement: Strengthening of Warnings about use of Dianette and other brands of co-cyprindiol (June 2013)

Caution over choice of contraceptive should be taken after bariatric surgery.

Non-oral contraceptives are considered most effective options. See the FSRH Clinical Guideline: Overweight, Obesity and Contraception (April 2019) - Faculty of Sexual and Reproductive Healthcare This guide gives details about choices after surgery and other treatment, as well as safety considerations.