BACKGROUND AND PURPOSE:

• Kopp-Kallner et al. (Obstetrics & Gynecology, 2022) estimated the incidence rates for ectopic pregnancy by contraceptive method in a cohort of women using hormonal contraception

METHODS:

• Population-based national registry study
  • 3 national Swedish registries: Prescribed Drug Register | National Patient Register | Medical Birth Register
• Population
  • Women aged 15 to 49 years
  • With filled prescriptions for a hormonal contraceptive between 2005 and 2016
• Exposures
  • Hormonal contraception method
• Study design
  • For each individual, all exposed person-years were allocated to treatment episodes depending on the method of contraception
  • Treatment time
    • Started the day the prescription was filled
    • Ended on either the first day of the end of supply, new eligible dispensing, pregnancy-related diagnosis and its associated estimated last menstrual period, or removal procedure
  • Contraceptives
    • Hormonal IUDs | Combined hormonal contraceptives (patches, vaginal rings, pills) | Etonogestrel implants | Oral medium-dose progestogen-only | Oral low-dose progestogen-only | Medroxyprogesterone acetate injections 
  • Ectopic pregnancy defined based on ICD10 codes
  • Cox regression model used to adjust for confounders
    • Age | History of endometriosis | Previous ectopic pregnancy
• Primary outcome
  • Incidence rates of ectopic pregnancy per 1,000 woman-years

RESULTS:

• 1,663,242 women
  • Ectopic pregnancy: 1915
• Incidence of ectopic pregnancy
  • General: 0.28 per 1,000 woman-years (95% CI, 0.26 to 0.29)
  • History of endometriosis: 0.25 per 1,000 women years (95% CI, 0.12 to 0.44)
  • History of ectopic pregnancy: 6.09 (95% CI, 4.88 to 7.50) per 1,000 woman-years
• Incidence rates of ectopic pregnancy by method of hormonal contraception
  • 13.5-mg levonorgestrel (LNG) IUD
    • 2.76 (95% CI, 2.26 to 3.35) per 1,000 person-years
  • 52-mg LNG hormonal IUD
    • 0.30 (95% CI, 0.28 to 0.33) per 1,000 person-years
  • Combined oral contraception
    • 0.20 (95% CI, 0.19 to 0.22) per 1,000 person-years
  • Progestogen implants
    • 0.31 (95% CI, 0.26 to 0.37) per 1,000 person-years
  • Oral medium-dose progestogen (desogestrel 75 mg)
    • 0.24 (95% CI, 0.21 to 0.27) per 1,000 person-years
  • Oral low-dose progestogen (norethisterone 0.35 mg & lynestrenol 0.5 mg)
    • 0.81 (95% CI, 0.70 to 0.93) per 1,000 person-years

CONCLUSION:

• Ectopic pregnancy incidence was lower in individuals using hormonal contraception vs the general population
• Those using the 13.5-mg LNG IUD had an increased incidence of ectopic pregnancy, compared to other hormonal contraceptive methods, including the 52-mg LNG IUD
• The authors state

Hormonal IUDs are user-friendly and safe to use, providing women with highly effective and reversible long-acting contraception with few side effects

The results of the current study indicate that the 13.5-mg LNG hormonal IUD should not be recommended for women who are concerned about the risk of ectopic pregnancy

Learn More – Primary Sources:

Method of Hormonal Contraception and Protective Effects Against Ectopic Pregnancy

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