What could be causing heavy vaginal bleeding and left-sided pelvic pain in a woman of reproductive age with a recently placed Intrauterine Device (IUD) and negative at-home pregnancy tests?

Heavy Vaginal Bleeding and Left-Sided Pelvic Pain with Recently Placed IUD

This patient requires immediate ultrasound evaluation to rule out ectopic pregnancy, IUD malposition, and other serious pathology—despite negative home pregnancy tests, ectopic pregnancy remains a critical consideration given the symptom constellation. 1

Immediate Diagnostic Priorities

Rule Out Ectopic Pregnancy First

• Negative home pregnancy tests do not exclude ectopic pregnancy, particularly early in gestation when hCG levels may be below detection thresholds or with dilute urine. 1
• The combination of pelvic pain, vaginal bleeding, and recent IUD placement creates a clinical scenario where ectopic pregnancy must be definitively excluded with serum β-hCG and transvaginal ultrasound. 1, 2
• One-third of women with ectopic pregnancy have no known risk factors, and IUD presence itself is a risk factor for ectopic pregnancy when contraceptive failure occurs. 1

Evaluate IUD Position

• Perform transvaginal ultrasound immediately to determine IUD location, as the device may be properly positioned, malpositioned (low-lying, extending into cervix, or embedded in myometrium), expelled, or perforated through the uterine wall. 3, 4
• A malpositioned IUD that is low-lying and extending into the cervix should be removed as soon as possible, especially when associated with pelvic pain, without requiring updated ultrasound if previous imaging confirmed malposition. 5
• The CDC specifically recommends removal of malpositioned IUDs when they are low-lying, extending into the cervix, or embedded in the myometrium, particularly with persistent symptoms. 3, 5

Clinical Algorithm for Management

Step 1: Obtain Serum β-hCG and Transvaginal Ultrasound

• Serum β-hCG is mandatory regardless of negative home tests to definitively exclude pregnancy. 1, 2
• Transvaginal ultrasound identifies: intrauterine pregnancy, ectopic pregnancy location, IUD position, hemorrhagic cysts, ovarian torsion, and other pelvic pathology. 6, 2

Step 2: If Pregnancy Confirmed

• If ectopic pregnancy diagnosed: This is a surgical/medical emergency requiring immediate gynecologic consultation. 1
• If intrauterine pregnancy with IUD in place: Attempt IUD removal immediately if strings visible, as this reduces substantial risks of spontaneous abortion, septic abortion, preterm delivery, and infection. 4

Step 3: If Not Pregnant, Assess IUD Position

• If IUD malpositioned (low-lying, cervical extension, or embedded): Remove immediately, particularly with persistent pain symptoms. 3, 5
• If IUD appropriately positioned: The device can remain in place if patient is asymptomatic, though heavy bleeding warrants investigation for other pathology. 3, 4
• If IUD location uncertain on ultrasound: Obtain abdominal X-ray to rule out uterine perforation. 4
• If perforation confirmed: Remove as soon as possible, typically requiring laparoscopic removal. 4

Step 4: Evaluate for Other Serious Pathology

• Left-sided pain specifically raises concern for: hemorrhagic ovarian cyst rupture, ovarian torsion, tubo-ovarian abscess, or endometrioma rupture. 6, 7
• Ovarian torsion requires early diagnosis and treatment to preserve ovarian function. 6

Critical Guideline Context

Unexplained Vaginal Bleeding Classification

• The CDC Medical Eligibility Criteria classifies "unexplained vaginal bleeding with suspicion for serious condition" as Category 4 for IUD initiation (condition represents unacceptable health risk), though Category 2 for continuation. 8
• The guideline explicitly states: "Unusually heavy bleeding should raise suspicion of a serious underlying condition" and "if pregnancy or an underlying pathological condition (such as pelvic malignancy) is suspected, it must be evaluated." 8
• The IUD does not need to be removed before evaluation, but evaluation must occur promptly. 8

Common Pitfalls to Avoid

• Never rely solely on home pregnancy tests in symptomatic patients with IUDs—serum β-hCG is mandatory. 1
• Do not assume IUD placement is the sole cause of symptoms without imaging confirmation and exclusion of ectopic pregnancy. 1, 2
• Do not delay evaluation because "some bleeding is normal after IUD placement"—the combination of heavy bleeding and unilateral pain demands urgent assessment. 8
• Do not remove a properly positioned IUD prematurely if ultrasound confirms appropriate location and pregnancy is excluded, as it can remain effective contraception. 4

Red Flag Symptoms Requiring Emergency Department Referral

• Hemodynamic instability, severe pain, significant bleeding, peritoneal signs, or fever warrant immediate emergency department evaluation regardless of pregnancy test results. 1, 2
• These symptoms may indicate ruptured ectopic pregnancy, hemorrhagic cyst rupture, ovarian torsion, or tubo-ovarian abscess. 6, 7, 2