Progestin-only pills, injections and intrauterine devices are not associated with an increased risk of blood clots and may be used by women with a history of blood clots in their veins.[1][46] In those with a history of arterial blood clots, non-hormonal birth control or a progestin-only method other than the injectable version should be used.[39] Progestin-only pills may improve menstrual symptoms and can be used by breastfeeding women as they do not affect milk production.