Progesterone (Vaginal)

How it works

It provides progestational support to the endometrium, promoting secretory transformation and maintaining a quiescent uterus to support early pregnancy.

Prescribing in practice

• Vaginal use achieves high local endometrial exposure with first-uterine-pass targeting, but progesterone treatment must be stopped and pregnancy reassessed if signs of ectopic pregnancy, miscarriage or thromboembolism arise.
• In threatened or recurrent miscarriage and in prevention of preterm birth it is used in defined groups following an individualised assessment in line with national guidance.
• Local vaginal irritation or discharge is common, and absorption may be affected by concurrent intravaginal products.

Monitoring

Monitoring is largely clinical, following pregnancy viability and symptoms rather than routine progesterone levels.

Counselling the patient

• Insert the pessary or gel high into the vagina as directed, and expect some discharge.
• Continue treatment for the full course advised by your fertility or maternity team and do not stop abruptly without advice.
• Report severe abdominal pain, heavy bleeding, or calf swelling and breathlessness urgently.

Evidence & guidelines

NICE guidance supports vaginal progesterone to reduce preterm birth in women with a short cervix or previous preterm birth, and the PRISM trial informed its use in early pregnancy bleeding with prior miscarriage.