Differential Diagnosis for Vaginal Bleeding in an IUD User Upon Squatting
The differential diagnosis for a woman with an IUD experiencing vaginal bleeding upon squatting must prioritize IUD displacement or expulsion, pregnancy, infection, and underlying uterine pathology before attributing symptoms to normal IUD effects.
Critical Life-Threatening Conditions to Rule Out First
- Ectopic pregnancy must be excluded immediately with a pregnancy test, as IUD users remain at risk for pregnancy (though the absolute risk is low), and any pregnancy that occurs is more likely to be ectopic 1, 2
- Uterine perforation should be considered, particularly if bleeding is associated with pain, as perforation can occur during insertion or later and may lead to serious visceral damage or peritonitis 3
- Pelvic inflammatory disease or endometritis can present with abnormal bleeding and must be evaluated, especially if fever, pain, or purulent discharge is present 1, 2
IUD-Specific Complications (Most Likely Given Positional Trigger)
- IUD displacement or partial expulsion is highly likely given the positional nature of bleeding (occurring with squatting), as displacement commonly causes abnormal bleeding and the squatting position may mechanically stress a malpositioned device 4, 5, 6
- Complete IUD expulsion should be assessed by checking for visible strings at the cervical os, as approximately 10% of IUDs placed immediately postpartum and variable rates at other times may expel 1, 7
- IUD malposition is more common in women with retroflexed uterine positions (7.6% vs 1.8% in controls), uterine anomalies, or submucosal fibroids, and presents with bleeding, pain, or missing strings 6
Underlying Gynecologic Pathology
- Endometrial or cervical polyps can develop during IUD use and cause bleeding, particularly with positional changes that may cause mechanical irritation 4, 5, 2
- Submucosal fibroids are associated with increased IUD malposition and bleeding, especially if they distort the uterine cavity 6, 8
- Cervical lesions including cervicitis, cervical erosion, or cervical cancer must be considered, as cervical cancer can present with bleeding and the IUD may increase bleeding risk at insertion in these patients 1, 2
- Endometrial hyperplasia or malignancy should be ruled out, particularly in perimenopausal women, as abnormal bleeding in this age group should be considered malignant until proven otherwise 2
Infectious Causes
- Sexually transmitted infections (gonorrhea, chlamydia) causing cervicitis or endometritis can present with abnormal bleeding 4, 5
- Pelvic inflammatory disease may develop in IUD users and cause bleeding along with pelvic pain 1, 2
Pregnancy-Related Complications
- Threatened or incomplete abortion if pregnancy has occurred despite IUD use 2
- Gestational trophoblastic disease (though rare) can cause bleeding and is a category 3-4 condition for IUD continuation depending on β-hCG levels 1
Systemic Causes (Less Likely but Important)
- Coagulopathy including von Willebrand disease or thrombocytopenia, particularly if menorrhagia is present, as these are more common than often recognized 1, 2
- Hypothyroidism or liver disease can cause abnormal uterine bleeding 2
- Medication effects from anticoagulants, antiplatelet agents, or other drugs affecting hemostasis 2
Anatomic Factors Predisposing to Complications
- Shorter uterine cavity length (mean 54.27 mm vs 60.25 mm) is associated with menorrhagia in copper IUD users 8
- Uterine anomalies including septate or bicornuate uterus increase malposition risk (31.9% vs 23.5% in controls) 6
- Retroflexed uterine position significantly increases malposition risk 6
Key Clinical Pitfall to Avoid
Do not attribute new-onset bleeding to "normal IUD effects" without systematic evaluation, as the positional trigger (squatting) strongly suggests mechanical displacement or underlying pathology requiring investigation 4, 5. The CDC explicitly warns against automatically attributing new bleeding to other factors without first investigating IUD-related and gynecologic causes 4, 5.