We thank Dr Mansour for her interest in our article1 and for her provocative questioning of the recommendations for use of progestogen-only contraceptives by women with systemic lupus erythematosus (SLE) who test positive for anti-phospholipid antibodies.2 We are sensitive to any reductions in choice of contraceptive methods, particularly for women in whom pregnancy has significant health consequences, such as women with SLE. As mentioned in our article, any considerations of contraceptive use in women with SLE must be weighed against the alternative of pregnancy, which brings many risks, particularly in women with active disease or those with positive anti-phospholipid antibodies.

We would first like to clarify an apparent misunderstanding by Dr Mansour that we believe that use of progestogen-only methods by women with SLE and positive anti-phospholipid antibodies is “unsafe”. The recommendations included in our article are those included in the World Health Organization (WHO) Medical Eligibility Criteria for Contraceptive Use (MEC)3 and subsequent adaptations by the UK and USA. In these recommendations, progestogen-only contraceptives, including progestogen-only pills (POPs), injectables, implants and the levonorgestrel-releasing intrauterine system (LNG IUS) are given a Category 3 rating, meaning the risks usually outweigh the benefits. However, a Category 3 rating does not automatically mean that this method should not be used in any circumstance. The introduction to the 4th edition of the WHO MEC states: “However, provision of a method to a woman with a condition classified as Category 3 requires careful clinical judgement and access to clinical services; for such a woman, the severity of the condition and the availability, practicality, and acceptability of alternative methods should be taken into account. For a method/condition classified as Category 3, use of that method is not usually recommended unless other more appropriate methods are not available or acceptable. Careful follow-up will be required”. In practice, this means that a woman with SLE and positive anti-phospholipid antibodies could be offered progestogen-only methods if more appropriate alternatives, such as a copper intrauterine device (IUD), are unavailable or unacceptable to her. The decision about which method is optimal for a particular woman would best be made through consultation with a specialist, such as a family planning specialist and/or a rheumatologist after thorough counselling regarding the potential risks and benefits and careful follow-up. The WHO MEC goes on to say (p. 10): “Where resources for clinical judgement are limited, such as in community-based services, the four category classification framework can be simplified into two categories. With this simplification, a classification of Category 3 indicates that a woman is not medically eligible to use the method”.

While we know that progestogen-only methods don't carry the same risk of thromboembolism as do methods containing estrogen, such as combined oral contraceptives (COCs), the evidence is insufficient to conclude that there is no risk of thromboembolism with progestogen-only methods. A recent meta-analysis of eight observational trials found that evidence on risk of venous thromboembolism (VTE) with use of progestogen-only methods was limited but that there appeared to be no increased risk with POPs or the LNG IUS, while there may be an increased risk with progestogen-only injectables.4 In addition, these studies were generally conducted among healthy women without other risk factors for VTE. The only evidence we have of use of progestogen-only methods by women with SLE is from the randomised controlled trial by Sanchez-Guerrero et al., included in our review, in which women were randomised to COC, POP or copper IUD use.5 There were four episodes of thromboembolism in the study, two in the COC group and two in the POP group, with none in the group assigned to copper IUD. All four of these patients were reported to have positive anti-phospholipid antibodies. The incidence of thromboembolism was therefore 4.75/100 woman-years in the COC group and 5.44/100 woman-years in the POP group. This study was not powered to detect a difference in the outcome of thromboembolism between the groups.

Based on the best available evidence, we agree with the WHO MEC recommendations of a Category 3 for use of progestogen-only contraceptives for women with SLE and positive anti-phospholipid antibodies, but also would agree that clinical judgment might lead to the use of progestogen-only methods in these women following adequate counselling regarding the risks, benefits and alternatives, including the alternative of non-use of contraception and subsequent pregnancy.