Pregnancy Complications. Myomas are associated with several complications that include preterm labor, placental abruption, fetal malpresentation, obstructed labor, cesarean delivery, and postpartum hemorrhage. In a review of pregnancy outcomes in 2065 women with leiomyomas, Coronado and colleagues (2000) reported that placental abruption and breech presentation were each increased fourfold; irst-trimester bleeding and dysfunctional labor, twofold; and cesarean delivery, sixfold. Salvador and associates (2002) reported an eightfold higher second-trimester abortion risk in these women.
Factors most important in determining morbidity in pregnancy are leiomyoma number, size, and location (Ciavattini, 2015; Jenabi, 2018; Lam, 2014). If the placenta is adjacent to or implanted over a leiomyoma, rates of abortion, preterm labor, placental abruption, and postpartum hemorrhage are all increased. Retroplacental myomas are also associated with fetal-growth restriction (Knight, 2016) . Tumors in the cervix or lower uterine segment may obstruct labor, as did the one shown in Figure 63-5. Despite these complications, Qidwai and associates (2006) reported a 70-percent vaginal delivery rate in women in whom myomas measured : 10 cm. hese data argue against empirical cesarean delivery for leiomyomas, and we allow a trial of labor unless myomas clearly obstruct the birth canal. If cesarean delivery is indicated, uterine malrotation should be excluded prior to hysterotomy. Myomas are generally let alone unless they cause recalcitrant bleeding. n important caveat is that cesarean hysterectomy may be technically diicult because of lateral ureteral displacement by the masses.
Bleeding due to myomas may develop during pregnancy from any of several factors. Especially common is bleeding with miscarriage, preterm labor, placenta previa, and placental abruption. Much less often, bleeding may result from a submucous myoma that has prolapsed from the uterus and into the cervix or vagina. In this unusual circumstance, although heavy or persistent bleeding may require earlier intervention, the stalk, if accessible, can be ligated vaginally near term to avoid tumor avulsion during delivery.
FIGURE 63-5 Cesarean delivery performed because of a large leiomyoma in the lower uterine segment. A classical vertical uterine incision, seen to the left of the myoma, was required for delivery of the fetus.
Fortunately, myomas rarely become infected (Genta, 2001).
When infection develops, it usually is postpartum, especially if the tumor is located immediately adjacent to the implantation site (Lin, 2002). hey also may become infected with an associated septic abortion and myoma perforation by a sound, dilator, or curette.
Fertility Considerations. Despite the relatively high prevalence of myomas in young women, it is not clear whether they diminish fertility, other than by possibly causing miscarriage. In a review of 11 studies, Pritts (2001) concluded that submucous myomas did signiicantly afect fertility. He also found that hysteroscopic myomectomy improved infertility and early miscarriage rates in these women. If truly implicated in infertility, myomas in other locations may require laparoscopy or laparotomy for excision.
Some of these methods of treatment for infertility may afect subsequent pregnancies. For example, after myomectomy, the gravid uterus can rupture either before or during labor (American College of Obstetricians and Gynecologists, 20 16a). Management is individualized, and review of the prior operative report is prudent. If resection resulted in a defect into or immediately adjacent to the endometrial cavity, then cesarean delivery is usually done before labor begins.