If <6 weeks postpartum is a high risk factor for VTE, why is it UKMEC 2 for Combined hormonal HC for women 3-6 weeks following childbirth and not breastfeeding and have no other risk for VTE? What are the “other risk factors for VTE”?

Postpartum - Use of combined hormonal contraception (CHC) by women following childbirth

The UKMEC table (Section B) for CHC/ postpartum (in non-breastfeeding women) notes that:

VTE risk is elevated during pregnancy and the postpartum period; this risk is most pronounced in the first 3 weeks after delivery, and then declines rapidly to near baseline levels by 42 days postpartum. In the absence of other risk factors, it is acceptable to prescribe CHC after 3 week postpartum in non-breastfeeding women.

Use of CHC may pose an additional increased risk for VTE in the presence of other risk factors for VTE, such as immobility, transfusion at delivery, BMI ≥30 kg/m2, postpartum haemorrhage, immediately post-caesarean delivery, pre-eclampsia or smoking. See method section of UKMEC for clarification/ evidence.

View the UKMEC.