Introduction:
A pregnant woman faces many challenges. One of them is uterine fibroids, also called leiomyomas. Fibroids are benign tumors that can affect a woman's fertility and outcomes during childbirth. They occur in approximately 80 percent of women of reproductive age. The majority of the fibroid tumors do not exhibit any change in volume. However, about ten to 30 percent of women with fibroid tumors develop complications during pregnancy. Fibroid volume assessment can be done by two or three-dimensional ultrasonographic techniques and magnetic resonance imaging (MRI).
What Are the Effects of Pregnancy on Fibroid Volume?
Studies have reported an uncertain relationship between pregnancy and fibroid volume. Fibroid growth is influenced by estrogen. Also, estrogen levels increase in pregnancy, which may lead to an increased fibroid volume.
Some researchers suggest that the fibroids that were present before a pregnancy decreased in size after delivery. Two main mechanisms are reported for an increase in fibroid volume: decreased uterine distensibility and mechanical obstruction. Following are the effects of pregnancy on fibroid volume.
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Early Pregnancy: The first trimester of pregnancy is a crucial period for the development of baby’s organs. Many complications can arise during this time.
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Miscarriage: An increase in fibroid volume is implicated in miscarriages. However, multiple fibroids may increase the miscarriage rate. Early miscarriage is more common in women with fibroids in the uterine body as compared to the lower uterus. Increased uterine irritability and the compressive effect of fibroids can compromise the blood supply of the developing placenta and fetus.
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Bleeding: In pregnancy, there is an increased blood supply to the uterus.
The placenta provides nutrition to the developing baby. It attaches to the uterine wall. Significant bleeding in early pregnancy is seen if the placenta forms close to the fibroid.
2. Late Pregnancy: Late pregnancy is an important time due to organ maturation of the baby. The effects of late pregnancy in relation to fibroid volume are:
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Preterm Labor and Premature Rupture of Membranes (PROM): Pregnant women with increased fibroid volume are more likely to develop preterm labor. PROM is the early rupture of membranes surrounding the baby. However, PROM and fibroids are a controversial topic. It is because some studies suggest that fibroids are associated with lesser risk of PROM.
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Placental Abruption: Placental abruption is the placental detachment from the uterine wall.The placenta developed in close proximity to the fibroid is three times more susceptible to abruption. A possible mechanism of placental abruption can be reduced blood flow to the fibroid and the surrounding tissues. As a result, it results in partial ischemia and death of the placental tissues adjacent to the fibroid.
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Placenta Previa (PP): PP is a problem during pregnancy. In PP, the placenta grows in the lowest part of the uterus and partially or completely covers the cervix (opening to the vagina). Placenta previa has a two fold increase in fibroid patients.
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Fetal Growth Restriction: Some studies depict that women with fibroids are at a slightly higher risk of delivering a growth-restricted baby. This is because a fibroid with increased volume can sometimes compress and distort the uterine cavity leading to fetal deformities.
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Fetal Anomalies: Large submucosal fibroids can lead to fetal anomalies, including dolichocephaly (lateral compression of the skull), torticollis (abnormal twisting of the neck), and limb defects.
What Are the Risks for Pregnant Women During Delivery With Increased Fibroid Volume?
An increased fibroid volume can lead to delivery complications such as:
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Cesarean Delivery: Increased cases of fetal malpresentation (abnormal fetal position) are reported with increased fibroid volume. Crowding in the lower uterus due to bulky fibroids can block the vaginal opening. Obstruction from fibroids in this area can increase the risk of a C-section.
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Postpartum Hemorrhage: Severe bleeding after childbirth is called postpartum hemorrhage. Data suggest that postpartum hemorrhage is more likely to occur in women with fibroids. Fibroids distort the uterine structure and interfere with uterine contractions. Therefore, it leads to loss of uterine tone and causes postpartum hemorrhage.
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Retained Placenta: The placenta sheds after delivery of a child. However, failure of the same leads to a retained placenta. It can be a life-threatening condition. Retained placenta can occur in women with placenta near the lower portion of the uterus.
What Are the Treatment Modalities to Reduce Fibroid Volume or Remove Fibroids?
Some of the treatment options to manage fibroids are:
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Medications: Progestins, oral contraceptives (OCPs), nonsteroidal anti-inflammatory drugs (NSAIDs), tranexamic acid, and gonadotropin-releasing hormone agonists (GnRHa) are some available medications to reduce fibroids. However, a few drugs work to decrease the fibroid volume.
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GnRH: It is important for the production of estrogen and testosterone (sex hormones). However, GnRHa works like the hormone for a certain time period, followed by decreased uterine bleeding. It also leads to fibroid shrinkage. GnRHa are shown to reduce the fibroid volume by about 65 percent. The menstrual bleeding also decreased by about 97 percent after six months. Long-term treatment is not advised due to side effects such as estrogen decline in the body.
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Mifepristone: It blocks progesterone hormone. It is helpful in decreasing fibroid volume by 50 percent and also decreases heavy uterine bleeding. However, the side effects include endometrial thickening (thickened uterine lining).
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Selective Progesterone Receptor Modulators: It is a new drug category that works at the progesterone receptor level. These also work to reduce fibroid volume and uterine bleeding.
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Aromatase Inhibitors: Aromatase is an important enzyme in estrogen production. Aromatase inhibitors such as letrozole reduce fibroid volume to about 45 percent.
2. Myomectomy: Myomectomy removes the uterine fibroids and reconstructs the uterus. Nowadays, minimally invasive myomectomy is done. Furthermore, myomectomy does not affect a future pregnancy.
3. Uterine Artery Embolization (UAE): In this procedure, tiny agents are sent through the blood vessels to the uterus which leads to fibroid shrinkage. The UAE is successful in about 85 percent of the cases.
4. Hysterectomy: It involves uterus removal. However, a woman cannot become pregnant after a hysterectomy. It can be done via conventional surgery or with the assistance of a robot.
Conclusion:
Uterine fibroids are very frequently detected in pregnant women. About one-third may increase in size in the first trimester. Many treatment options are available for fibroid tumors. However, each patient's treatment depends on their age and desire to retain the uterus. Clinicians must weigh the risk-benefit ratio for each treatment option. This is because designing personal management plans will ensure positive consequences and maximal patient satisfaction.
