Most fibroids during pregnancy are managed conservatively with rest, hydration, and safe pain relief. Surgery is rarely needed. About 11% of pregnant women have fibroids detected on ultrasound, and the majority carry to term without serious complications. The key is understanding what to expect at each stage and knowing which symptoms need attention.
How Fibroids Change During Pregnancy
One of the biggest worries is that fibroids will balloon in size as pregnancy hormones rise. The reality is more reassuring. A large NIH-funded study tracking fibroid growth throughout pregnancy found that total fibroid volume actually decreased by about 1% per week on average. The number of visible fibroids also dropped by roughly 1.2% per week as smaller ones became too small to detect on ultrasound.
Size at the start matters. Small fibroids tended to grow modestly, increasing about 2% per week. Medium fibroids stayed roughly stable. Large fibroids shrank the most, declining about 2.2% per week. So if you’ve been told you have a large fibroid, it may actually get smaller as your pregnancy progresses, not larger.
Risks Are Lower Than You Might Think
Older medical literature painted a concerning picture of fibroids and pregnancy, linking them to miscarriage and preterm birth. More recent, larger studies tell a different story. A Vanderbilt University study of over 5,500 pregnant women found that the miscarriage rate was 11% regardless of whether fibroids were present. A separate large prospective study from the same research group found no association between fibroids and any subtype of preterm birth.
Postpartum hemorrhage, placental abruption, and restricted fetal growth also showed no significant increase in women with a fibroid diagnosis, according to a cohort study published in BMJ Open. This doesn’t mean fibroids never cause problems, but it does mean the baseline risk is much lower than many people fear.
When Fibroids Do Cause Problems
The most common issue is pain, particularly from something called red degeneration. This happens when a fibroid outgrows its blood supply and the tissue inside begins to break down. It typically causes localized tenderness over the fibroid, sometimes with mild fever and elevated inflammation markers on blood tests. There’s usually no vaginal bleeding. On MRI, the affected fibroid shows characteristic bright areas where degeneration is occurring.
Red degeneration can be intensely painful and may require multiple hospital visits. In one well-documented case published in The Lancet, a woman needed three separate admissions over 20 weeks for pain management. Despite the severity, these episodes are managed without surgery in the vast majority of cases.
Fibroid location also matters more than size in some situations. Fibroids in the lower part of the uterus or those that press against the placenta are more likely to cause positioning problems for the baby. Breech presentation occurred in about 17% of deliveries complicated by fibroids in one study, and submucosal fibroids (those growing into the uterine cavity) or those sitting behind the placenta carry the highest risk of malpresentation.
Managing Pain Safely
Pain management is the cornerstone of dealing with fibroids during pregnancy, and your options shift depending on how far along you are. Acetaminophen is considered the go-to pain reliever throughout pregnancy. For more severe pain, a medical team may add other medications or use structured pain management plans, especially during degeneration episodes.
Anti-inflammatory drugs like ibuprofen and naproxen are a different story. The FDA warns against using these from 20 weeks onward because they can cause kidney problems in the developing baby, leading to dangerously low amniotic fluid levels. Before 20 weeks, short courses at the lowest effective dose may sometimes be considered, but this is a conversation to have with your care team. After 20 weeks, they’re essentially off the table.
Beyond medication, the standard approach includes rest, staying well hydrated, and close monitoring. Heat packs applied to the painful area can also help. If you’re having repeated pain episodes, your provider may schedule more frequent ultrasounds to track the fibroid and the baby’s growth.
Surgery During Pregnancy Is Rare
Removing fibroids during pregnancy (myomectomy) was historically considered a last resort, and it still is. Surgery carries a risk of significant bleeding in a pregnant uterus, so it’s only considered when conservative treatment completely fails. Specific scenarios that might warrant it include a pedunculated fibroid (one attached by a stalk) that twists, persistent severe pain that doesn’t respond to any pain management, compression of nearby organs, or a fibroid larger than 5 cm sitting in the lower uterine segment where it could block delivery.
Rapid growth raising concern about malignancy is another rare but recognized reason for surgical evaluation. In most cases, though, even large or painful fibroids are managed with rest, hydration, and pain relief until delivery.
When a cesarean delivery is planned for other reasons, some surgeons will remove accessible fibroids at the same time. This decision depends on the fibroid’s location, size, and how much additional bleeding it might cause.
How Fibroids Affect Delivery
Fibroids raise the likelihood of a cesarean delivery. Studies show cesarean rates of 39% to 86% in women with fibroids compared to about 17% in the general population. The wide range reflects differences in fibroid size, number, and location across study populations.
The biggest factor is where the fibroid sits. A fibroid in the lower uterine segment or near the cervix can physically obstruct the birth canal, making vaginal delivery difficult or impossible. Large fibroids over 5 cm in this location typically lead to a planned cesarean around 38 weeks. Fibroids high on the uterus or on its outer surface are much less likely to interfere with labor.
If your fibroids are small, located away from the cervix, and the baby is in a head-down position, vaginal delivery remains a realistic goal. Your provider will likely monitor the baby’s position more closely in the third trimester and discuss delivery options based on how things look as your due date approaches.
What You Can Do Right Now
If you know you have fibroids and you’re pregnant or planning to be, the most practical steps are straightforward. Make sure your provider knows the number, size, and location of your fibroids from early ultrasounds. This baseline helps track any changes and plan for delivery. Ask specifically whether any fibroids are in the lower uterine segment, since that’s the location most likely to affect your delivery options.
Stay ahead of pain rather than waiting for it to become severe. If you start feeling localized tenderness over a known fibroid, especially in the second trimester when degeneration most commonly occurs, contact your provider early. Prompt management with rest and acetaminophen can sometimes prevent the kind of escalation that leads to hospitalization.
Keep in mind that most pregnancies with fibroids end with healthy deliveries. The path may involve more monitoring, more ultrasounds, and possibly more discomfort than a fibroid-free pregnancy, but the outcomes are overwhelmingly positive.