Intrauterine devices, commonly known as IUDs, offer a highly effective method of birth control. These small, T-shaped devices are placed inside the uterus to prevent pregnancy for several years. While IUDs are highly effective, pregnancy can still occur in rare instances. Understanding these uncommon circumstances is important.
Understanding IUD Effectiveness
IUDs are among the most effective reversible birth control methods available, demonstrating a success rate exceeding 99%. This high level of protection applies to both hormonal and copper IUDs, though their mechanisms of action differ.
Hormonal IUDs, such as Mirena, Skyla, Liletta, and Kyleena, release a continuous, low dose of progestin hormone into the uterus. This hormone primarily works by thickening the cervical mucus, which blocks sperm from reaching the egg. It also thins the uterine lining, making it less hospitable for a fertilized egg to implant, and can sometimes suppress ovulation.
Conversely, copper IUDs, like Paragard, do not use hormones. Instead, they create an inflammatory reaction within the uterus. The copper ions released produce an inflammatory response that is toxic to sperm and eggs, preventing fertilization. This reaction also alters the uterine lining, making it unfavorable for implantation.
How IUD Pregnancies Occur
Despite their high effectiveness, IUDs can fail, leading to pregnancy under specific, infrequent circumstances. One such scenario involves the partial or complete expulsion of the device from the uterus. If an IUD is expelled, it no longer provides contraceptive protection.
An IUD may also become displaced, meaning it moves out of its optimal position within the uterine cavity. Even if not fully expelled, a displaced IUD may not prevent pregnancy effectively because its protective mechanisms are compromised. This can occur without a person’s knowledge, as symptoms might be subtle or absent.
Pregnancy can also occur if the IUD was not inserted correctly by a healthcare provider, preventing it from functioning as intended. Additionally, there is a short period immediately after insertion when the IUD might not be fully effective. For some IUD types, backup birth control is recommended for the first seven days following insertion.
Recognizing Pregnancy and Medical Considerations
If pregnancy is suspected while an IUD is in place, recognize common signs, including a missed period, breast tenderness, nausea, or fatigue. These symptoms warrant immediate medical consultation to confirm the pregnancy and assess the situation.
Upon confirmation of pregnancy, a healthcare provider will typically perform an ultrasound to determine the IUD’s position and to check if the pregnancy is located within the uterus. There is an increased likelihood of ectopic pregnancy, where the fertilized egg implants outside the uterus, if conception occurs with an IUD. Ectopic pregnancies are serious medical emergencies requiring immediate intervention.
If the pregnancy is confirmed to be intrauterine, meaning it is in the uterus, the healthcare provider will discuss options regarding the IUD. If the IUD strings are visible, the device is usually removed to reduce the risks of miscarriage, infection, or preterm labor. However, removing the IUD can also increase the risk of miscarriage.
If the IUD cannot be easily removed or if the strings are not visible, leaving the device in place may be considered. This carries a higher risk of complications such as miscarriage or premature birth. A thorough discussion with a healthcare provider is necessary to understand all potential risks and benefits associated with IUD removal versus retention during pregnancy, to guide the best course of action.