Intrauterine devices (IUDs) are recognized as a highly effective, long-acting form of reversible contraception, with a failure rate of less than one percent per year. Despite this strong efficacy, a pregnancy can rarely occur when an IUD is in place within the uterus. The simultaneous presence of an IUD and an intrauterine pregnancy is a serious medical situation that immediately elevates the risk of complications for the developing pregnancy. Confirming a pregnancy in this context necessitates prompt medical evaluation and a careful discussion of the heightened risks involved. This unique circumstance requires immediate attention from a healthcare provider to determine the best course of management.
Understanding the Elevated Miscarriage Risk
The presence of an IUD significantly increases the likelihood of a spontaneous abortion, or miscarriage, compared to pregnancies conceived without one. For a pregnancy with a retained IUD, the risk of miscarriage is substantially higher, with some systematic reviews reporting rates between 48% and 77%. This compares drastically to the general population’s spontaneous miscarriage rate, which is estimated to be around 10% to 20% of clinically recognized pregnancies.
This elevated risk is primarily attributed to two distinct mechanisms depending on the IUD type. All IUDs, whether hormonal or copper, function as a foreign body inside the uterus, which can trigger an inflammatory response that may destabilize the pregnancy. The IUD device and its strings can also provide a pathway for bacteria to ascend from the vagina into the uterus, creating a localized infection.
In pregnancies involving a copper IUD, the inflammatory reaction and the potential for ascending infection are the main concerns leading to pregnancy loss. Hormonal IUDs, which release progestin, may also carry a theoretical concern of fetal exposure to the hormone. Regardless of the IUD type, the presence of the device in the uterine cavity poses a mechanical and infectious threat to the gestation.
Immediate Medical Management Upon Confirmation
The first and most important step upon confirming a pregnancy in an IUD user is to definitively rule out an ectopic pregnancy, where the fertilized egg implants outside the uterus. If a pregnancy does occur, the chance of it being ectopic is proportionally higher than in the general population. Once an intrauterine pregnancy is confirmed, the healthcare provider must assess the visibility and accessibility of the IUD strings.
If the IUD strings are visible extending through the cervix, immediate removal of the device is generally recommended. Removing the IUD early in the pregnancy significantly reduces the risk of miscarriage and severe infection compared to leaving it in place. While the removal procedure itself carries a small risk of inducing a miscarriage, the risk of spontaneous abortion is drastically reduced from over 50% with a retained IUD to approximately 20% after successful removal.
If the IUD strings are not visible, an ultrasound examination is necessary to confirm the device’s location within the uterus. If the IUD is positioned high in the uterine cavity, attempts at removal may be avoided due to the increased risk of disturbing the pregnancy. In this scenario, the healthcare provider will counsel the patient on the substantially increased risks of continuing the pregnancy and implement a plan for close monitoring.
Risks Associated with Keeping the IUD
If the IUD cannot be safely removed—either because the strings are not accessible or the removal attempt is deemed too risky—the pregnancy is monitored with the IUD retained in the uterus, which introduces several serious complications. One grave concern is the significantly increased risk of developing a septic abortion, which is a life-threatening infection of the uterus. This infection can quickly progress to maternal sepsis, a systemic infection that can be fatal for the mother.
Beyond infection, retaining the IUD dramatically increases the risk of preterm delivery, with rates reported to be as high as 25% in some studies. The persistent irritation and inflammatory state caused by the IUD can lead to complications like preterm premature rupture of membranes and early onset of labor. Pregnancies with a retained IUD are also associated with an elevated risk of placental complications, including placental abruption, where the placenta separates from the inner wall of the uterus before birth.
The decision to continue a pregnancy with a retained IUD requires a clear understanding of these outcomes. Patients must be advised to seek immediate medical attention if they experience any signs of infection, such as fever, chills, abnormal vaginal discharge, or increased cramping. Close surveillance throughout the entire gestation is necessary to manage these compounding risks.