Uterine fibroids are common growths that develop within or on the uterus. Many individuals are concerned about how these growths might affect pregnancy, particularly regarding the risk of miscarriage. This article aims to clarify the relationship between uterine fibroids and pregnancy outcomes, exploring how fibroids can influence the course of a pregnancy and what management strategies are available.
Understanding Uterine Fibroids
Uterine fibroids, also known as leiomyomas or myomas, are muscular and connective tissue growths that form in or on the wall of the uterus. These growths are not cancerous. Fibroids are common, with many women developing them by age 50.
Fibroids can vary significantly in size, ranging from microscopic growths to large masses that can fill the entire uterus. Their location within the uterus is a key factor in how they might affect a woman’s health.
The Link Between Fibroids and Miscarriage
The presence of uterine fibroids can increase the risk of miscarriage, though the extent of this risk depends largely on the fibroid’s location, size, and number.
Fibroids that bulge into the uterine cavity, known as submucosal fibroids, pose the highest risk of miscarriage. These fibroids can interfere with the implantation of a fertilized egg into the uterine lining, or they can disrupt the blood supply to the developing placenta.
Intramural fibroids, which grow within the muscular wall of the uterus, can also contribute to miscarriage risk, especially if they are large or numerous. These fibroids may distort the shape of the uterine cavity, limit space for the embryo, or affect blood flow to the uterine lining and placenta. In contrast, subserosal fibroids, located on the outer surface of the uterus, generally present little to no direct risk of miscarriage because they do not typically impact the uterine cavity or implantation site.
Larger fibroids, particularly those over 5 centimeters, or multiple fibroids, can exert greater pressure on the uterine cavity and compromise blood flow, affecting the developing pregnancy.
Other Potential Pregnancy Complications
Beyond the risk of miscarriage, uterine fibroids can lead to several other complications during pregnancy. Pain is a common symptom, particularly with larger fibroids (over 5 cm) or if a fibroid undergoes degeneration, a process where it outgrows its blood supply. This pain often occurs in the second and third trimesters.
Fibroids have been linked to an increased likelihood of preterm labor and delivery. Additionally, fibroids can increase the risk of placental abruption, where the placenta separates from the uterine wall too early, or placenta previa, where the placenta covers the cervix.
Fetal growth restriction, where the baby does not grow as expected, can sometimes occur with large fibroids that reduce space in the womb or compromise nutrient supply. Fibroids can also increase the likelihood of needing a cesarean section (C-section) for delivery. This may happen if a large fibroid blocks the birth canal, if the fibroids prevent the uterus from contracting effectively during labor, or if they lead to an abnormal fetal position.
Managing Fibroids During Pregnancy
When fibroids are present during pregnancy, management typically focuses on monitoring and symptom relief. Most fibroids do not require active treatment during pregnancy.
Healthcare providers usually monitor the fibroids’ size and location through regular ultrasounds. For common symptoms like pain, conservative measures are often recommended. Rest, hydration, and over-the-counter pain relievers such as acetaminophen are generally used. Non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen are generally avoided, especially later in pregnancy, due to potential risks to the fetus. In rare instances of severe, unmanageable pain, stronger pain medication or temporary hospitalization for monitoring might be necessary.
Surgical removal of fibroids, known as myomectomy, during pregnancy is rare due to the increased risks of bleeding and potential complications, including miscarriage. However, in very specific and rare circumstances, such as intractable pain from a degenerating fibroid or a fibroid obstructing the birth canal, surgery might be considered. It is important for individuals with diagnosed fibroids to inform their healthcare provider when they become pregnant. This allows for appropriate monitoring and management throughout the pregnancy, especially if severe pain, bleeding, or signs of preterm labor occur.