You’re having a baby—and you have fibroids. With the endless amount of information you’re absorbing in preparation for your little one, you may now also be wondering how fibroids could affect your pregnancy.
Fibroids have been reported in approximately 0.1%-11% of all pregnancies and become more common in women 35 years and older, those who’ve never had children, and among African Americans.1
Although the majority of women with fibroids will have a smooth pregnancy, 10%-40% of women will experience complications.1 Facing this reality, it’s important to build awareness around the possible effects these benign tumors can have on a pregnancy in order to receive appropriate care.
Nearly 75% of fibroids increase in size during the first and second trimesters and 66% between the second and third trimesters.1 “The increased estrogen and progesterone during pregnancy can result in increased [fibroid] growth, which can become problematic in about five percent of pregnant women with fibroids,” says Mark Perloe, MD, infertility specialist and medical director at Georgia Reproductive Specialists in Atlanta, GA.
And although fibroids are seen to reduce in size for the majority of women by 50% after giving birth, until this occurs, they can be painful and cause pressure on the uterus.1
“Most physicians look at fibroids during pregnancy as a pressure effect,” explains Dr. Perloe. “If the fibroid is cutting down on the blood supply to the uterus by pressing on arteries, or causing engorgement in the uterine lining because it’s pressing on the veins that return blood to the uterine lining, this could potentially bring about a miscarriage. Also, larger fibroids may impair the blood supply to the fetus so that growth is retarded or delayed, and you have a smaller baby as a result.”
Other complications can include premature labor, postpartum bleeding, the baby being in the wrong position at birth—as seen with breech births—and an increased need for cesarean section.1
According to a small study published in the American Journal of Obstetrics & Gynecology, factors like fibroid number, location, and size can increase risk of complications and miscarriage.2 Researchers observed 121 women with fibroids between 2002 and 2012. Through ultrasound exam, the size, location, and number of fibroids were noted in each woman. They then compared this information to a total of 179 pregnancy outcomes verified through the women’s medical records.
Results indicated that complications like preterm delivery were more common among women with multiple fibroids.2 What’s more, fibroids located in the lower part of the uterus were associated with the need for cesarean section. In addition to location, researchers found that larger fibroids were consistent with postpartum bleeding.
Further research has shown the risk of preterm birth increases if the placenta is positioned next to or on top of a fibroid.1 Fibroids specifically growing under the lining of the uterine cavity or within the uterine wall—but not outside the uterus—have been connected to higher rates of miscarriage.1
Since having fibroids is associated with pregnancy complications, it’s important to see your gynecologist to learn more about your fibroids before conceiving and also throughout your pregnancy—especially monitoring where they are in relation to the placenta and cervix.1 Doing so could help assess the pregnancy and any potential risks. “Each person’s fibroids offer a unique situation,” Dr. Perloe stresses. “This baby is going to be around for a lifetime, and you want to make sure you’re doing everything to give the baby the best life.”
ABOUT THE AUTHOR Alicia Armeli is a freelance writer and editor, registered dietitian nutritionist, and certified holistic life coach. She has master’s degrees in English education and nutrition. Through her writing, she empowers readers to live optimally by building awareness surrounding issues that impact health and well-being. She is a paid consultant of Merit Medical.
ABOUT THE DOCTOR Mark Perloe, MD, is an infertility specialist and medical director at Georgia Reproductive Specialists. Dr. Perloe has extensive experience treating conditions related to infertility, including menstrual disorders, uterine fibroids, endocrine and other reproductive health problems. He presently serves on the advisory board of the journal, Fertility and Sterility.
- Guo, X. C., & Segars, J. H. (2012). The impact and management of fibroids for fertility: An evidence-based approach. Obstet Gynecol Clin North Am, Dec;39(4):521-533.
- Lam, S. J., Best, S., & Kumar, S. (2014). The impact of fibroid characteristics on pregnancy. Am J Obstet Gynecol, Oct;211(4):395.e1-5.