FFinalistSouthampton · 2027
Obstetrics & gynaecology
AKT · Obstetrics & gynaecology/Contraception

Combined oral contraceptive (COCP)

Oestrogen + progestogen — inhibits ovulation

Overview

A combined oestrogen/progestogen pill that mainly inhibits ovulation. Highly effective with perfect use but typical-use failure ~9%. Offers non-contraceptive benefits (cycle control, ↓ovarian & endometrial cancer) but the oestrogen drives the key contraindications.

Recognise

  • Inhibits ovulation; taken 21 days then 7-day break (or continuous/tailored)
  • Benefits: predictable lighter periods, helps acne/PMS, ↓ovarian, endometrial & colorectal cancer risk
  • Effective immediately if started day 1–5 of cycle (otherwise 7 days extra precautions)
  • Small ↑risk of VTE, breast & cervical cancer, and arterial events

Red flags

  • UKMEC 4 (absolute): migraine WITH aura; ≥35y AND smoking ≥15/day; BP ≥160/100; history of VTE/known thrombophilia; <6 weeks postpartum + breastfeeding; current breast cancer; major surgery with immobility

Differentials & how to tell them apart

Progestogen-only pilloestrogen-free — the choice when COCP is UKMEC 4 (migraine with aura, breastfeeding, VTE risk)
Contraceptive implantLARC, fit-and-forget, far lower failure — better if adherence is the issue
Copper IUDnon-hormonal option when hormones are unwanted/contraindicated

Investigations

BP and BMI before starting (and at review); thorough history for the UKMEC 4 risks (migraine aura, VTE, smoking/age, breast cancer).

Management

Combined pill for a woman wanting cycle control with no oestrogen contraindication

  1. 1Check BP, BMI and the UKMEC 4 list. If none present, start (day 1–5 = immediate cover).Gate: Migraine WITH aura is UKMEC 4 for the COCP (stroke risk) → use a progestogen-only method instead
  2. 2≥35y and smoking ≥15/day, or BP ≥160/100, or VTE history → avoid oestrogen; switch to POP/implant/IUS/IUD.
Ethinylestradiol + progestogen — standard combined pill; levonorgestrel/norethisterone pills carry lower VTE risk than newer progestogens

Key points

Enzyme-inducing drugs reduce efficacy. Stop 4 weeks before major surgery with immobility (VTE). Migraine with aura, smoking+age, and VTE history are the classic exam UKMEC 4 traps.

Monitor & prognosis

BP at review; reassess UKMEC risks (new migraine aura, age, smoking).

Rapidly reversible; fertility returns quickly on stopping.

Source: FSRH UKMEC 2016; FSRH CHC guidance