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Uterine Fibroids in Pregnancy

by Devin Garza, MD F.A.C.O.G., Renaissance Women’s Group

Uterine fibroids (leiomyomas) are commonly occurring benign smooth muscle tumors of the uterus. The effect of these tumors on pregnancy, and the effect of the pregnancy on these tumors is a topic of clinical concern. Although it is estimated that up to approximately 60% of  women have fibroids, the incidence of fibroids in pregnancy varies between 1.6 and 10.7 %. This prevalence increases with age and is greater in African-American women.

Symptoms and clinical manifestations of fibroids either in the non-pregnant state, or during pregnancy depend on three main factors-size, number and location. Fibroids within the uterine cavity itself (submucosal) have been implicated with an increased risk for pregnancy loss especially if they are 3cm or greater, or multiple 1-3cm fibroids are present possibly due to a distortion of the cavity, altered blood flow and implantation site disruption. Growth of fibroids occurs in approximately one third of patients, and it is impossible to predict which fibroids in which patients will grow in size. Growth of fibroids in pregnancy may lead to an increase in clinical complications, most notably, pain. Pain is most commonly experienced in the late first and second trimesters as rapid growth of the uterus occurs. With this rapid growth, fibroids especially 5cm or greater in diameter may undergo an alteration and resultant lack of blood flow that cannot keep up with the rate of growth of the tumor which produces ischemia-related pain. This mechanism is much like pain associated with a heart attack.

The incidence of preterm labor, preterm premature rupture of membranes and placental abruption are increased only slightly, but the risk increases depending on the fibroid’s relation to the placenta. Implantation (placental site) overlying a fibroid being the biggest risk factor. With implantation being completely random, it is also completely unpredictable which pregnancies will be at risk. Large fibroids distort the normal uterine contour and contractility of the uterine muscle. If located within the cavity itself, a large fibroid can cause fetal deformations due to spatial restrictions, but this is not common. Fibroids can lead to dysfunctional labor with decrease in contractile force. This in itself can increase risk for cesarean delivery, and fibroids located in the lower segment of the uterus are associated with mal-presentation of the fetus, which frequently leads to cesarean delivery. With all of these potential risks, what is the treatment of fibroids in pregnancy?

It has been generally accepted with good support that surgical removal (myomectomy) during pregnancy is to be avoided with rare exception. Although the risk of cesarean section is increased, MOST women will have an uneventful pregnancy and vaginal delivery. Myomectomy during pregnancy or at cesarean section is associated with significant hemorrhage. Pain related to fibroids is managed conservatively with analgesic medications and narcotics as needed. PRE-conception myomectomy should be discussed and considered given a patient’s unique pregnancy history and symptoms and clinical manifestations of fibroids in the non-pregnant state. Myomectomy is the treatment of choice for large intra-cavity fibroids and is typically managed via a hysteroscopic resection. Large intra-muscular (intramural) fibroids can be managed via laparotomy or laparoscopy with newer surgical advances in robotic daVinci techniques with improved  laparoscopic suturing. As always, consult with your physician, and seek advice from trusted publications and sites to determine what is best for your unique situation.

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