What steps are needed to reasonably exclude pregnancy (being pregnant) when considering contraception

Healthcare practitioners can be reasonably certain that a woman is not currently pregnant if any one or more of the following criteria are met and there are no symptoms or signs of pregnancy:

• she has not had intercourse since the start of her last normal (natural) menstrual period, since childbirth, abortion, miscarriage, ectopic pregnancy or uterine evacuation for gestational trophoblastic disease
• she has been correctly and consistently using a reliable method of contraception. (For the purposes of being reasonably certain that a woman is not currently pregnant, barrier methods of contraception can be considered reliable providing that they have been used consistently and correctly for every episode of intercourse.)
• she is within the first 5 days of the onset of a normal (natural) menstrual period
• she is less than 21 days postpartum (non-breastfeeding women)*
• she is fully breastfeeding, amenorrhoeic and less than 6 months postpartum*
• she is within the first 5 days after abortion, miscarriage, ectopic pregnancy or uterine evacuation for gestational trophoblastic disease
• she has not had intercourse for >21 days and has a negative high-sensitivity urine pregnancy test (able to detect human chorionic gonadotrophin (hCG) levels around
  20 mIU/ml).

* See UKMEC 2016 and FSRH Guideline Contraception After Pregnancy for recommendations regarding use of combined normonal contraception after childbirth.

A negative pregnancy test, if available, adds weight to the exclusion of pregnancy, but only if >=3 weeks since the last episode of unprotected sexual intercourse (UPSI).

NB. In addition to the conditions mentioned above, health professionals should also consider whether a woman is at risk of becoming pregnant as a result of UPSI within the last 7 days

Reference:

• FSRH (July 2019). Combined Hormonal Contraception
• FSRH Guidance (April 2015) Intrauterine Contraception
• Faculty of Sexual & Reproductive Healthcare. UK Selected Practice Recommendations for Contraceptive Use. 2002. http://www.fsrh.org/pdfs/archive/SelectedPracticeRecommendations2002.pdf