What is a fibroid during pregnancy

Uterine fibroids can be life-altering for some women, and they don’t magically go away when you get pregnant. If you have a history with fibroids, it’s understandable to wonder how they’ll impact your pregnancy and what kind of treatment, if any, may be available to you. Ditto if you suddenly develop fibroid-like symptoms while expecting. If you suspect you have uterine fibroids during pregnancy, talk to your doctor. In the meantime, here’s the lowdown on uterine fibroids and pregnancy.

What Are Uterine Fibroids?

Uterine fibroids are tumors—almost always benign—that grow in the muscular tissue of the uterus. According to the US Office on Women’s Health (OWH), fibroids can grow as just one tumor or there can be many of them in the uterus, and they can range in size from as small as an apple seed to as large as a grapefruit. A fibroid may stay very small for a long time and then grow rapidly, or grow slowly over a period of years. They can prompt abdominal pain and other symptoms, but other times a woman may not even know she has uterine fibroids until they’re revealed during a pelvic exam or prenatal ultrasound.

Types of uterine fibroids

Uterine fibroids are generally classified into three categories, explains Gloria Bachmann, MD, professor in the department of obstetrics, gynecology and reproductive sciences and associate dean of women’s health at Rutgers Robert Wood Johnson Medical School. They are:

  • Intramural fibroids, which grow within the walls of the uterus but stay outside of the uterine cavity.

  • Submucosal fibroids, which push into the uterine cavity.

  • Subserosal fibroids, which grow on the outside of the uterus.

Are uterine fibroids cancerous?

Fibroids are almost always not cancerous, says Michael Cackovic, MD, a maternal-fetal medicine physician at The Ohio State University Wexner Medical Center.

In very rare cases, someone may experience a cancerous fibroid called a leiomyosarcoma, but according to the OWH, it’s not thought that they form from an existing fibroid. Having uterine fibroids also does not increase your risk of developing a cancerous fibroid or your risk of uterine cancers.

What Causes Uterine Fibroids?

It’s not entirely clear what prompts uterine fibroids to develop, but the OWH says researchers suspect that factors like hormones—specifically estrogen and progesterone levels—and genes could play a role. According to the OWH, up to 80 percent of women develop fibroids by the time they reach 50, and they’re most common in women in their 40s and early 50s.

Fibroids are more common in Black women than white women, and also seem to happen at a younger age and grow more quickly in Black women. The reason isn’t entirely clear, “except we do understand that there’s a genetic predisposition to fibroids,” says Angela Chaudhari, MD, associate professor in the department of obstetrics and gynecology at the Northwestern University Feinberg School of Medicine. “There’s a lot of ongoing research on why that is,” she adds.

Do Uterine Fibroids Affect Pregnancy?

Most women who have uterine fibroids have normal pregnancies, the OWH says, although the presence of these growths increase your risk of complications during pregnancy and delivery. Fibroids have historically been linked to miscarriage and pre-term birth, but Cackovic says that the research has generally been “flawed,” noting that there are so many other factors that go into these outcomes that it’s difficult to say for sure if fibroids are a cause. Worth noting: A 2017 study published in the American Journal of Epidemiology found that there was no link between uterine fibroids and miscarriage.

In rare cases, fibroids may cause infertility, but the American College of Obstetricians and Gynecologists (ACOG) says women will often be able to become pregnant after they’re treated for the condition. If you have a known history of fibroids, Chaudhari recommends talking to your doctor about having any fibroids that are in the cavity of your uterus removed before trying to conceive.

Overall, Cackovic says that pregnant women with fibroids shouldn’t stress about the condition. “Uterine fibroids tend to breed anxiety amongst patients, when the truth of the matter is that they aren’t usually going to have any problems in pregnancy,” Cackovic says. “Sometimes patients don’t even know they have them and we’ll see them on ultrasound.”

Signs of Uterine Fibroids During Pregnancy

Fibroids can be “masked” during pregnancy, Chaudhari says—meaning, the signs of uterine fibroids can be easily confused with common pregnancy symptoms. The following can be symptoms of uterine fibroids during pregnancy:

  • Pelvic pressure or pain
  • Lower back pain
  • Pain during sex
  • Spotting or bleeding
  • Frequent urination
  • Constipation
  • Abdominal heaviness or swelling

However, some women with fibroids have no symptoms at all.

How to diagnose uterine fibroids

There are several tests that can diagnose uterine fibroids when you’re not pregnant. But during pregnancy, Cackovic says they’re often detected on ultrasound.

How to Treat Uterine Fibroids During Pregnancy

Typically, Chaudhari says, your prenatal care won’t change simply because you have uterine fibroids. Rather, your doctor will keep an eye on your fibroids as baby grows. “It wouldn’t change our management of their delivery or prenatal care,” she says.

How to Safely Manage Uterine Fibroids Pain

Uterine fibroids can cause pain during pregnancy. While it’s usually “short-lived,” Chaudhari says, it can cause “pretty significant pain for a week to 10 days.” The reason, she says, is that as baby grows, blood supply can be shuttled from the fibroids to the growing fetus, causing the tumors to die off.

If you’re in pain from fibroids during your pregnancy, Chaudhari recommends talking to your doctor. As a uterine fibroid treatment, they may suggest anti-inflammatory medications to control the pain or potentially stronger pain medication. If you’re having uterine fibroid pain during your pregnancy, don’t just assume you have to soldier through it. “Seek immediate care,” Bachmann says.

Gloria Bachmann, MD, is a professor in the department of obstetrics, gynecology and reproductive sciences. She also serves as associate dean of women’s health at Rutgers Robert Wood Johnson Medical School and director of the Rutger’s RWJMS Women’s Health Institute.

Michael Cackovic, MD, is an ob-gyn specializing in maternal fetal medicine at the Ohio State University Wexner Medical Center in Columbus. He earned his medical degree from Hahnemann University College of Medicine in 1997.

Angela Chaudhari, MD, is an associate professor in the department of obstetrics and gynecology at the Northwestern University Feinberg School of Medicine. She earned her medical degree from Northeast Ohio Medical University College of Medicine in 2000.

Please note: The Bump and the materials and information it contains are not intended to, and do not constitute, medical or other health advice or diagnosis and should not be used as such. You should always consult with a qualified physician or health professional about your specific circumstances.

1. Day Baird D, Dunson DB, Hill MC, et al. High cumulative incidence of uterine leiomyoma in black and white women: ultrasound evidence. Am J Obstet Gynecol. 2003;188:100–107. [PubMed] [Google Scholar]

2. Muram D, Gillieson M, Walters JH. Myomas of the uterus in pregnancy: ultrasonographic follow-up. Am J Obstet Gynecol. 1980;138:16–19. [PubMed] [Google Scholar]

3. Burton CA, Grimes DA, March CM. Surgical management of leiomyomata during pregnancy. Obstet Gynecol. 1989;74:707–709. [PubMed] [Google Scholar]

4. Rice JP, Kay HH, Mahony BS. The clinical significance of uterine leiomyomas in pregnancy. Am J Obstet Gynecol. 1989;160:1212–1216. [PubMed] [Google Scholar]

5. Qidwai GI, Caughey AB, Jacoby AF. Obstetric outcomes in women with sonographically identified uterine leiomyomata. Obstet Gynecol. 2006;107:376–382. [PubMed] [Google Scholar]

6. Cooper NP, Okolo S. Fibroids in pregnancycommon but poorly understood. Obstet Gynecol Surv. 2005;60:132–138. [PubMed] [Google Scholar]

7. Klatsky PC, Tran ND, Caughey AB, Fujimoto VY. Fibroids and reproductive outcomes: a systematic literature review from conception to delivery. Am J Obstet Gynecol. 2008;198:357–366. [PubMed] [Google Scholar]

8. Aharoni A, Reiter A, Golan D, et al. Patterns of growth of uterine leiomyomas during pregnancy. A prospective longitudinal study. Br J Obstet Gynaecol. 1988;95:510–513. [PubMed] [Google Scholar]

9. Rosati P, Exacoustòs C, Mancuso S. Longitudinal evaluation of uterine myoma growth during pregnancy. A sonographic study. J Ultrasound Med. 1992;11:511–515. [PubMed] [Google Scholar]

10. Lev-Toaff AS, Coleman BG, Arger PH, et al. Leiomyomas in pregnancy: sonographic study. Radiology. 1987;164:375–380. [PubMed] [Google Scholar]

11. Katz VL, Dotters DJ, Droegemueller W. Complications of uterine leiomyomas in pregnancy. Obstet Gynecol. 1989;73:593–596. [PubMed] [Google Scholar]

12. De Carolis S, Fatigante G, Ferrazzani S, et al. Uterine myomectomy in pregnant women. Fetal Diagn Ther. 2001;16:116–119. [PubMed] [Google Scholar]

13. Parker WH. Etiology, symptomatology, and diagnosis of uterine myomas. Fertil Steril. 2007;87:725–736. [PubMed] [Google Scholar]

14. Benson CB, Chow JS, Chang-Lee W, et al. Outcome of pregnancies in women with uterine leiomyomas identified by sonography in the first trimester. J Clin Ultrasound. 2001;29:261–264. [PubMed] [Google Scholar]

15. Goldenberg M, Sivan E, Sharabi Z, et al. Outcome of hysteroscopic resection of submucous myomas for infertility. Fertil Steril. 1995;64:714–716. [PubMed] [Google Scholar]

16. Casini ML, Rossi F, Agostini R, Unfer V. Effects of the position of fibroids on fertility. Gynecol Endocrinol. 2006;22:106–109. [PubMed] [Google Scholar]

17. Bernard G, Darai E, Poncelet C, et al. Fertility after hysteroscopic myomectomy: effect of intramural myomas associated. Eur J Obstet Gynecol Reprod Biol. 2000;88:85–90. [PubMed] [Google Scholar]

18. Wallach EE, Vu KK. Myomata uteri and infertility. Obstet Gynecol Clin North Am. 1995;22:791–799. [PubMed] [Google Scholar]

19. Winer-Muram HT, Muram D, Gillieson MS. Uterine myomas in pregnancy. J Can Assoc Radiol. 1984;35:168–170. [PubMed] [Google Scholar]

20. Exacoustòs C, Rosati P. Ultrasound diagnosis of uterine myomas and complications in pregnancy. Obstet Gynecol. 1993;82:97–101. [PubMed] [Google Scholar]

21. Vergani P, Locatelli A, Ghidini A, et al. Large uterine leiomyomata and risk of cesarean delivery. Obstet Gynecol. 2007;109:410–414. [PubMed] [Google Scholar]

22. Coronado GD, Marshall LM, Schwartz SM. Complications in pregnancy, labor, and delivery with uterine leiomyomas: a population-based study. Obstet Gynecol. 2000;95:764–769. [PubMed] [Google Scholar]

23. Chuang J, Tsai HW, Hwang JL. Fetal compression syndrome caused by myoma in pregnancy: a case report. Acta Obstet Gynecol Scand. 2001;80:472–473. [PubMed] [Google Scholar]

24. Graham JM , Jr, Miller ME, Stephan MJ, Smith DW. Limb reduction anomalies and early in utero limb compression. J Pediatr. 1980;96:1052–1056. [PubMed] [Google Scholar]

25. Romero R, Chervenak FA, DeVore G, et al. Fetal head deformation and congenital torticollis associated with a uterine tumor. Am J Obstet Gynecol. 1981;141:839–840. [PubMed] [Google Scholar]

26. Phelan JP. Myomas and pregnancy. Obstet Gynecol Clin North Am. 1995;22:801–805. [PubMed] [Google Scholar]

27. Vergani P, Ghidini A, Strobelt N, et al. Do uterine leiomyomas influence pregnancy outcome? Am J Perinatol. 1994;11:356–358. [PubMed] [Google Scholar]

28. Aydeniz B, Wallwiener D, Kocer C, et al. Significance of myoma-induced complications in pregnancy. A comparative analysis of pregnancy course with and without myoma involvement [Article in German] Z Geburtshilfe Neonatol. 1998;202:154–158. [PubMed] [Google Scholar]

29. Donnez J, Pirard C, Smets M, et al. Unusual growth of a myoma during pregnancy. Fertil Steril. 2002;78:632–633. [PubMed] [Google Scholar]

30. Roberts WE, Fulp KS, Morrison JC, Martin JN., Jr The impact of leiomyomas on pregnancy. Aust N Z J Obstet Gynaecol. 1999;39:43–47. [PubMed] [Google Scholar]

31. Hasan F, Arumugam K, Sivanesaratnam V. Uterine leiomyomata in pregnancy. Int J Gynaecol Obstet. 1991;34:45–48. [PubMed] [Google Scholar]

32. Ohkuchi A, Onagawa T, Usui R, et al. Effect of maternal age on blood loss during parturition: a retrospective multivariate analysis of 10,053 cases. J Perinat Med. 2003;31:209–215. [PubMed] [Google Scholar]

33. Szamatowicz J, Laudanski T, Bulkszas B, Akerlund M. Fibromyomas and uterine contractions. Acta Obstet Gynecol Scand. 1997;76:973–976. [PubMed] [Google Scholar]

34. Palerme GR, Friedman EA. Rupture of the gravid uterus in the third trimester. Am J Obstet Gynecol. 1966;94:571–576. [PubMed] [Google Scholar]

35. Miller CE. Myomectomy. Comparison of open and laparoscopic techniques. Obstet Gynecol Clin North Am. 2000;27:407–420. [PubMed] [Google Scholar]

36. Brown AB, Chamberlain R, Te Linde RW. Myomectomy. Am J Obstet Gynecol. 1956;71:759–763. [PubMed] [Google Scholar]

37. Levine D, Hulka CA, Ludmir J, et al. Placenta accreta: evaluation with color Doppler US, power Doppler US, and MR imaging. Radiology. 1997;205:773–776. [PubMed] [Google Scholar]

38. Harris WJ. Uterine dehiscence following laparoscopic myomectomy. Obstet Gynecol. 1992;80:545–546. [PubMed] [Google Scholar]

39. Dubuisson JB, Chavet X, Chapron C, et al. Uterine rupture during pregnancy after laparoscopic myomectomy. Hum Reprod. 1995;10:1475–1477. [PubMed] [Google Scholar]

40. Dubuisson JB, Fauconnier A, Deffarges JV, et al. Pregnancy outcome and deliveries following laparoscopic myomectomy. Hum Reprod. 2000;15:869–873. [PubMed] [Google Scholar]

41. Dubuisson JB, Fauconnier A, Babaki-Fard K, Chapron C. Laparoscopic myomectomy: a current view. Hum Reprod Update. 2000;6:588–594. [PubMed] [Google Scholar]

42. Asakura H, Oda T, Tsunoda Y, et al. A case report: change in fetal heart rate pattern on spontaneous uterine rupture at 35 weeks gestation after laparoscopically assisted myomectomy. J Nippon Med Sch. 2004;71:69–72. [PubMed] [Google Scholar]

43. Lieng M, Istre O, Langebrekke A. Uterine rupture after laparoscopic myomectomy. J Am Assoc Gynecol Laparosc. 2004;11:92–93. [PubMed] [Google Scholar]

44. Banas T, Klimek M, Fugiel A, Skotniczny K. Spontaneous uterine rupture at 35 weeks’ gestation, 3 years after laparoscopic myomectomy, without signs of fetal distress. J Obstet Gynaecol Res. 2005;31:527–530. [PubMed] [Google Scholar]

45. Grande N, Catalano GF, Ferrari S, Marana R. Spontaneous uterine rupture at 27 weeks of pregnancy after laparoscopic myomectomy. J Minim Invasive Gynecol. 2005;12:301. [PubMed] [Google Scholar]

46. Norton ME, Merril J, Cooper BA, et al. Neonatal complications after administration of indomethacin for preterm labor. N Engl J Med. 1993;329:1602–1607. [PubMed] [Google Scholar]

47. Seki H, Takizawa Y, Sodemoto T. Epidural analgesia for painful myomas refractory to medical therapy during pregnancy. Int J Gynaecol Obstet. 2003;83:303–304. [PubMed] [Google Scholar]

48. Wittich AC, Salminen ER, Yancey MK, Markenson GR. Myomectomy during early pregnancy. Mil Med. 2000;165:162–164. [PubMed] [Google Scholar]

49. Li TC, Mortimer R, Cooke ID. Myomectomy: a retrospective study to examine reproductive performance before and after surgery. Hum Reprod. 1999;14:1735–1740. [PubMed] [Google Scholar]

50. Surrey ES, Minjarez DA, Stevens JM, Schoolcraft WB. Effect of myomectomy on the outcome of assisted reproductive technologies. Fertil Steril. 2005;83:1473–1479. [PubMed] [Google Scholar]

51. Glavind K, Palvio DH, Lauritsen JG. Uterine myoma in pregnancy. Acta Obstet Gynecol Scand. 1990;69:617–619. [PubMed] [Google Scholar]

52. Michalas SP, Oreopoulou FV, Papageorgiou JS. Myomectomy during pregnancy and caesarean section. Hum Reprod. 1995;10:1869–1870. [PubMed] [Google Scholar]

53. Mollica G, Pittini L, Minganti E, et al. Elective uterine myomectomy in pregnant women. Clin Exp Obstet Gynecol. 1996;23:168–172. [PubMed] [Google Scholar]

54. Febo G, Tessarolo M, Leo L, et al. Surgical management of leiomyomata in pregnancy. Clin Exp Obstet Gynecol. 1997;24:76–78. [PubMed] [Google Scholar]

55. Celik C, Acar A, Ciçek N, et al. Can myomectomy be performed during pregnancy? Gynecol Obstet Invest. 2002;53:79–83. [PubMed] [Google Scholar]

56. Brown D, Fletcher HM, Myrie MO, Reid M. Caesarean myomectomy-a safe procedure. A retrospective case controlled study. J Obstet Gynaecol. 1999;19:139–141. [PubMed] [Google Scholar]

57. Kwawukume EY. Caesarean myomectomy. Afr J Reprod Health. 2002;6:38–43. [PubMed] [Google Scholar]

58. Ehigiegba AE, Ande AB, Ojobo SI. Myomectomy during cesarean section. Int J Gynaecol Obstet. 2001;75:21–25. [PubMed] [Google Scholar]

59. Buttram VC , Jr, Reiter RC. Uterine leiomyomata: etiology, symptomatology, and management. Fertil Steril. 1981;36:433–445. [PubMed] [Google Scholar]

60. Liu WM, Wang PH, Tang WL, et al. Uterine artery ligation for treatment of pregnant women with uterine leiomyomas who are undergoing cesarean section. Fertil Steril. 2006;86:423–428. [PubMed] [Google Scholar]

61. Pron G, Mocarski E, Bennett J, et al. Pregnancy after uterine artery embolization for leiomyomata: the Ontario multicenter trial. Obstet Gynecol. 2005;105:67–76. [PubMed] [Google Scholar]

62. Walker WJ, McDowell SJ. Pregnancy after uterine artery embolization for leiomyomata: a series of 56 completed pregnancies. Am J Obstet Gynecol. 2006;195:1266–1271. [PubMed] [Google Scholar]

63. Goldberg J, Pereira L, Berghella V, et al. Pregnancy outcomes after treatment for fibromyomata: uterine artery embolization versus laparoscopic myomectomy. Am J Obstet Gynecol. 2004;191:18–21. [PubMed] [Google Scholar]


Page 2

Cumulative Risk of Adverse Obstetric Outcomes in Pregnant Women With Fibroids

FibroidsNo FibroidsP ValueUnadjusted OR (95% CI)
Cesarean delivery48.8% (2098/4322)13.3% (22,989/173,052)<.0013.7 (3.5–3.9)
Malpresentation13.0% (466/3585)4.5% (5864/130,932)<.0012.9 (2.6–3.2)
Labor dystocia7.5% (260/3471)3.1% (4703/148,778)<.0012.4 (2.1–2.7)
Postpartum hemorrhage2.5% (87/3535)1.4% (2130/153,631)<.0011.8 (1.4–2.2)
Peripartum hysterectomy3.3% (18/554)0.2% (27/18,000)<.00113.4 (9.3–19.3)
Retained placenta1.4% (15/1069)0.6% (839/134,685).0012.3 (1.3–3.7)
Chorio or endometriosis8.7% (78/893)8.2% (2149/26,090).631.06 (0.8–1.3)
IUGR11.2% (112/961)8.6% (3575/41,630)<.0011.4 (1.1–1.7)
Preterm labor16.1% (116/721)8.7% (1577/18,187)<.0011.9 (1.5–2.3)
Preterm delivery16.0% (183/1145)10.8% (3433/31,770)<.0011.5 (1.3–1.7)
Placenta previa1.4% (50/3608)0.6% (924/154,334)<.0012.3 (1.7–3.1)
First-trimester bleeding4.7% (120/2550)7.6% (1193/15,732)<.0010.6 (0.5–0.7)
Abruption3.0% (115/4159)0.9% (517/60,474)<.0013.2 (2.6–4.0)
PPROM9.9% (123/1247)13.0% (7319/56,418).0030.8 (0.6–0.9)
PPROM or PROM6.2% (217/3512)12.2% (7425/60.661)<.0010.5 (0.4–0.6)