An intrauterine device (IUD) is one of the most effective forms of reversible contraception, with both hormonal and copper types boasting a failure rate of less than one percent per year. Despite this high effectiveness, pregnancy can occur if the device is expelled, moves out of position, or if the method fails. A pregnancy with an IUD in place presents a unique medical situation that requires immediate attention. The presence of the IUD significantly alters the management and potential outcomes of the gestation. If an individual suspects they are pregnant while using an IUD, they should seek medical evaluation immediately to determine the pregnancy location and discuss the appropriate next steps.
Diagnosing Pregnancy and Assessing Location
Symptoms of pregnancy can be confusing or missed entirely for people using an IUD, especially a hormonal IUD, as these devices often cause lighter or absent menstrual periods. Any change in typical bleeding patterns, new pelvic pain, or other common signs such as nausea or breast tenderness should prompt a pregnancy test. Confirmation of pregnancy typically begins with a blood test to measure human chorionic gonadotropin (hCG) hormone levels.
A positive pregnancy test requires an immediate ultrasound. The primary goal of this early imaging is to rule out an ectopic pregnancy, a life-threatening condition where the fertilized egg implants outside the uterus, most often in a fallopian tube. IUDs are highly effective at preventing pregnancy inside the uterus, but they offer less protection against pregnancy outside the uterus.
If an IUD failure occurs, a disproportionately high number of those pregnancies will be ectopic. Approximately half of pregnancies occurring with a hormonal IUD may be ectopic. With a copper IUD, the risk is lower but still elevated, with studies showing around 15% of failures resulting in an ectopic pregnancy. An untreated ectopic pregnancy can lead to rupture and severe internal bleeding, making immediate location assessment essential. The ultrasound also confirms the location of the IUD within the uterus or determines if it has been expelled or perforated the uterine wall.
Management Decisions Regarding the IUD Device
Once an intrauterine pregnancy is confirmed, the immediate management decision centers on the IUD itself: whether to remove it or leave it in place. This choice is highly individualized and involves careful counseling about the associated risks. The IUD should be removed as early as possible if the patient chooses to continue the pregnancy, as this action significantly reduces the risk of adverse outcomes.
The removal protocol is attempted when the IUD strings are visible protruding from the cervix. If the strings are visible, the device can often be removed by a healthcare provider using gentle traction. While removal carries a small, immediate risk of miscarriage, the long-term risk of later miscarriage and infection is much higher if the IUD is left in place. The removal procedure is performed without the need for antibiotic coverage when done in the first trimester.
If the IUD strings are not visible, the device is considered retained, and its removal becomes significantly more complex. In this situation, the IUD is usually left in place if the pregnancy is advanced beyond the first trimester. If the IUD cannot be safely removed, it will be pushed to the side of the uterus as the pregnancy grows. In rare cases where the strings are not visible, specialized procedures like ultrasound-guided retrieval or hysteroscopic removal may be considered.
Risks to the Fetus and Pregnancy Outcomes
The decision to retain or remove the IUD profoundly affects the potential risks to both the patient and the pregnancy. Even after successful IUD removal, the risk of a late-term miscarriage or preterm delivery remains higher compared to a pregnancy conceived without an IUD. Studies indicate that the rate of spontaneous abortion after IUD removal in early pregnancy is around 20%.
The most severe risk associated with IUD retention is the potential for infection, specifically pelvic inflammatory disease or a septic miscarriage. The IUD acts as a foreign body, and its presence can introduce bacteria into the uterus, increasing the risk of infection, particularly during the second trimester. This type of infection can be life-threatening and may manifest with symptoms such as fever, abnormal vaginal discharge, or worsening abdominal pain, necessitating immediate medical attention.
A pregnancy that continues with a retained IUD is associated with an increased chance of preterm birth, defined as delivery before 37 weeks of gestation. The retained IUD is linked to a higher prevalence of placental inflammation and infection, which can trigger preterm labor or premature rupture of membranes. Increased prenatal surveillance is recommended for any continuing pregnancy. This often includes more frequent ultrasounds to monitor fetal growth, assess the IUD’s location relative to the placenta, and check for signs of infection or other complications.