Uterine fibroids are common, non-cancerous growths that develop in or on the uterus. While many individuals with fibroids experience uncomplicated pregnancies, their presence can introduce considerations for both the pregnant person and the developing fetus. Understanding how fibroids interact with pregnancy helps manage potential concerns effectively.
Fibroids and Pregnancy
Uterine fibroids, also known as leiomyomas, are benign muscle and tissue growths that can form within the uterus. These growths are highly influenced by hormones like estrogen and progesterone, which are elevated during pregnancy. Due to these hormonal changes, fibroids can sometimes increase in size during pregnancy, particularly in the first trimester. However, many fibroids do not change significantly in size, and some may even shrink after delivery.
Fibroids are classified based on their location within the uterus. Intramural fibroids grow within the muscular wall. Subserosal fibroids develop on the outer surface, sometimes extending into the pelvis. Submucosal fibroids grow just beneath the inner lining and can protrude into the uterine cavity. Pedunculated fibroids are attached to the uterus by a stalk.
Assessing Risk Factors
Determining the potential risk of fibroids during pregnancy involves more than just their size; location, number, and type are often more significant factors. While a specific “dangerous” size is not universally defined, fibroids over 5 cm are more likely to grow during pregnancy and may cause pain or complications.
The location of a fibroid can profoundly influence pregnancy outcomes. For instance, fibroids near the cervix or in the lower uterine segment can obstruct the birth canal, potentially necessitating a cesarean delivery. Submucosal fibroids or those impinging on the placenta’s implantation site or fetal development space may pose higher risks. Multiple fibroids can also increase the likelihood of complications.
Common Pregnancy Complications
Fibroids can lead to several complications during pregnancy, although most individuals with fibroids have uneventful pregnancies. Pain is a frequent symptom, often occurring in the second and third trimesters, especially with larger fibroids. This pain can sometimes be due to “red degeneration,” where the fibroid outgrows its blood supply, leading to tissue changes and severe discomfort.
Fibroids may increase the risk of miscarriage, particularly if they are submucosal or distort the uterine cavity. Preterm labor and delivery are also more common in pregnancies with fibroids. Additionally, fibroids can be associated with placental abruption, where the placenta separates from the uterine wall prematurely.
Complications can extend to labor and delivery. Fibroids may contribute to fetal malpresentation, such as a breech position. They can also obstruct the birth canal, impede uterine contractions, or cause labor to not progress, increasing the likelihood of a cesarean delivery. Postpartum hemorrhage, excessive bleeding after delivery, has also been linked to fibroids.
Care and Monitoring
Management of fibroids during pregnancy typically involves close monitoring rather than active treatment. Regular ultrasound examinations track the size and location of fibroids and assess their impact on the pregnancy. Most fibroid-related pain can be managed conservatively with rest, hydration, and over-the-counter pain relievers like acetaminophen. Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen are generally avoided in late pregnancy due to potential risks to the fetus.
Surgical removal of fibroids (myomectomy) during pregnancy is rare due to the increased risk of complications such as bleeding and preterm labor. Such interventions are typically considered only in severe cases of unrelenting pain or if a fibroid actively obstructs the birth canal.
Delivery planning considers the fibroids’ characteristics, and healthcare providers determine the safest method of delivery based on individual circumstances. Individuals with fibroids should maintain open communication with their healthcare team throughout pregnancy.