USE of a combined oral contraceptive pill could increase the risk of venous thromboembolism (VTE) for females who are obese by 24-fold, compared to females who are obese and not taking the combined oral contraceptive pill, according to a study authored by Giuseppe Rosano, Istituto di Ricovero e Cura a Carattere Scientifico, San Raffaele Pisana, Rome, Italy.
Whilst female sex, oestrogen-containing contraceptives, and obesity are well-documented as independent risk factors for venous thromboembolism, females who are obese continue to receive these drugs. Further to this, Rosano warned of statements in the scientific literature that highlight the synergistic effect of obesity and oestrogen-containing combined oral contraceptives and commented that this should be taken into consideration when making decisions around contraceptive prescribing for females who are obese.
Upon reviewing the literature to ascertain both the individual and combined impact of obesity and oestrogen-containing combined oral contraceptives on VTE risk, Rosano identified that there is between a three- and seven-fold increased risk of VTE in those using a combined oral contraceptive compared with non-users. Additionally, VTE risk serially increases with increasing BMI, highlighted by the fact that VTE risk in females who are obese is two-fold higher than the VTE risk in females who were not obese. Of note, Rosano found that obesity had the greatest impact on VTE risk in those under 40 years of age, and highlighted the significance of this, given that it is often females in this age category who seek out oral contraceptive prescriptions.
Moreover, when assessing the combined effect of obesity and oestrogen-containing combined oral contraceptives, the risk of VTE was 24-fold higher compared with non-combined oral contraceptive pill users with healthy body weight. Rosano also looked at progestin-only contraceptives and found that these were not associated with increased VTE risk.
These findings spotlight the increased impact when two independent risk factors are combined. Clinicians should consider these risks when discussing contraceptive options with females who are obese. Rosano emphasised that safer alternatives for females who are obese include “progestin-only products, including pills, intrauterine devices, or implants.”
