Starting combined hormonal contraception and requirement for additional contraceptive precautions
| Circumstance | When to start | Requirement for 7 days additional contraceptive precautions (9 days for estradiol valerate/dienogest COC) | Requirement for HSUPT 21 days after last UPSI |
| Women having natural menstrual cycles | Up to and including Day 5* | No | No |
| At any other time if it is reasonably certain she is not pregnant or a HSUPT is negative | Yes | Consider | |
| Women who are amenorrhoeic | At any time if it is reasonably certain she is not pregnant and/or a HSUPT is negative | Yes | Consider |
| After LNG-EC | Immediately | Yes | Yes |
| After UPA-EC | 5 days after taking UPA-EC | Yes | Yes |
| †After childbirth (breastfeeding) | From 6 weeks following childbirth | Yes | Consider |
| †After childbirth (not breastfeeding) | Without additional risk factors for VTE‡: from 3 weeks following childbirth | Yes | Consider |
| With additional risk factors for VTE‡: from 6 weeks following childbirth | Yes | ||
| †After abortion, miscarriage, ectopic pregnancy or gestational trophoblastic disease | Up to and including Day 5* following treatment | No | Follow-up pregnancy testing as per local protocol after these pregnancies |
| After Day 5* if it is reasonably certain she is not pregnant | Yes |
COC, combined oral contraception; Cu-IUD, copper-bearing intrauterine device; HSUPT, high-sensitivity urine pregnancy test; LNG-EC, levonorgestrel emergency contraception; UPA-EC, ulipristal acetate emergency contraception; UPSI, unprotected sexual intercourse; VTE, venous thromboembolism.
*Day 1 for estradiol-containing COC pill.
†See FSRH Guideline Contraception After Pregnancy.97
‡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, use of combined hormonal contraception may pose an additional increased risk for VTE.