Regarding the pathophysiology and risk factors for ectopic pregnancy, all of the following are established associations EXCEPT:

Explanation

## Risk Factors and Associations in Ectopic Pregnancy ### Why the Correct Answer (Option 0) is Wrong **Key Point:** While IUD use is associated with ectopic pregnancy when conception occurs, the absolute risk of ectopic pregnancy is actually LOWER with IUD use compared to no contraception. IUDs are NOT contraindicated in women with a history of ectopic pregnancy. **High-Yield:** The misconception arises because: - IUDs are highly effective at preventing intrauterine pregnancy (~99% efficacy). - If pregnancy occurs despite an IUD, the relative proportion of ectopic pregnancies is higher (because intrauterine pregnancies are prevented). - However, the absolute risk of ectopic pregnancy is lower in IUD users than in women using no contraception or less effective methods [cite:ACOG Practice Bulletin #121]. - **IUDs are safe and appropriate** in women with a history of ectopic pregnancy, as they prevent future pregnancies overall. ### Validation of Other Options (All Correct) **Option 1 — PID and tubal damage:** - Chlamydial and gonococcal PID cause endosalpingitis, leading to tubal strictures, adhesions, and impaired ciliary function [cite:Berek Gynecology 16e Ch 19]. - Each episode of PID increases ectopic risk; multiple episodes compound the risk further. **Option 2 — Endometriosis and tubal dysfunction:** - Endometriosis is associated with altered tubal peristalsis, reduced ciliary beat frequency, and impaired oviductal contractility [cite:ACOG Practice Bulletin #114]. - These mechanical changes increase the risk of embryo retention in the tube, leading to ectopic implantation. **Option 3 — Recurrence after tubal surgery:** - Conservative surgical management (salpingostomy) for ectopic pregnancy carries a recurrence risk of 20–25% in the treated tube [cite:Cunningham Obstetrics 26e Ch 19]. - This is why medical management (methotrexate) or salpingectomy may be preferred in certain clinical scenarios, particularly if the contralateral tube is normal. ## Clinical Pearl **Clinical Pearl:** The distinction between relative and absolute risk is critical: IUDs reduce the absolute risk of ectopic pregnancy by preventing pregnancy altogether. They should NOT be withheld from women with a prior ectopic pregnancy if they are otherwise suitable candidates. ## Mnemonic **ECTOPIC RISK FACTORS — CHASED:** - **C** — Chlamydia/Gonorrhea (PID) - **H** — History of ectopic pregnancy - **A** — Assisted reproductive technology (ART) - **S** — Smoking (impairs tubal ciliary function) - **E** — Endometriosis - **D** — DES exposure (in utero), Diethylstilbestrol