Uterine fibroids are common, non-cancerous growths in the uterus, especially among women during their childbearing years. For those who become pregnant, a key concern is how these growths might behave. This article discusses whether fibroids grow during pregnancy and their potential impact on both pregnancy and delivery.
Understanding Fibroid Growth During Pregnancy
Fibroids can grow during pregnancy, often due to hormonal shifts, particularly elevated estrogen and progesterone. These hormones, which surge to support pregnancy, can stimulate fibroid growth. While some studies suggest fibroids can dramatically enlarge, even doubling in size within the first two months, about two-thirds may not change significantly. If growth occurs, it is often rapid and typically happens in the first trimester.
Fibroid growth varies; some shrink, some remain unchanged, and others expand. Fibroids larger than 5 cm are more prone to growth, though small fibroids detected early can also grow throughout the term. A common cause of pain is “red degeneration,” which occurs when a fibroid outgrows its blood supply, leading to tissue breakdown.
Potential Effects on Pregnancy and Delivery
Fibroids can lead to various considerations for pregnancy and delivery. Pain is common, especially with fibroids larger than 5 centimeters, often in later trimesters. Bleeding can also occur, particularly if the fibroid is near the placenta. Between 10% and 30% of women with fibroids may experience complications during pregnancy.
Complications include an increased risk of miscarriage, with some studies indicating a doubled chance, particularly with multiple fibroids or those in the uterine body. Preterm labor and delivery are also concerns, possibly due to uterine irritability. Fibroids can sometimes lead to placental abruption, where the placenta detaches from the uterine wall before delivery, reducing oxygen and nutrient supply to the fetus.
While rare, large fibroids might restrict fetal growth by taking up space or affecting blood supply. Fibroids can also influence fetal positioning, leading to malpresentation, such as a breech position. This can increase the likelihood of a Cesarean section, with women with fibroids being up to six times more likely to require one. Additionally, there is potential for increased blood loss after delivery, known as postpartum hemorrhage.
Monitoring and Managing Fibroids During Pregnancy
Monitoring fibroids during pregnancy involves regular ultrasounds to track their size, location, and fetal development. Healthcare providers also monitor for symptoms like pelvic pain, vaginal bleeding, or contractions. Management of fibroids during pregnancy is conservative, focusing on alleviating symptoms.
Pain management often includes bed rest, hydration, and safe pain relievers such as acetaminophen. In some instances, hospitalization might be required for severe pain, bleeding, or signs of preterm labor. Surgical intervention, known as myomectomy, to remove fibroids during pregnancy is rare due to risks like bleeding and further complications. Such surgery is considered only for severe complications that cannot be managed otherwise. If a myomectomy is performed during pregnancy, a Cesarean birth may be necessary afterward.
Fibroids After Childbirth
After delivery, fibroid behavior changes as the body undergoes significant hormonal shifts. Most fibroids tend to shrink in the postpartum period, primarily due to the rapid decrease in pregnancy hormones like estrogen and progesterone. Studies show over 70% of women experience a significant reduction in fibroid size, often by more than 50%, within three to six months after giving birth.
This shrinkage is also influenced by uterine involution, where the uterus contracts and returns to its pre-pregnancy size. While many fibroids shrink considerably, they may not disappear entirely. Some women find their fibroid symptoms improve after childbirth, though others might experience worsening symptoms due to fluctuating hormone levels. Future management for fibroids might be considered if symptoms persist or new pregnancies are planned.