In some cases, uterine involution is hindered because of infection, retained placental fragments, or other causes. Such subinvolution is accompanied by varied intervals of prolonged lochia as well as irregular or excessive uterine bleeding. During bimanual examination, the uterus is larger and soter than would be expected. With bleeding, pelvic sonography may help exclude retained placenta or, less-commonly, vascular malformations as the source (lraha, 2017). Methylergonovine (Methergine), 0.2 mg orally every 3 to 4 hours for 24 to 48 hours, is recommended by many, but its eicacy is questionable. If there is infection, antimicrobial therapy usually leads to a good response. In an earlier study, Wager and coworkers (1980) reported that a third of these late cases of postpartum metritis are caused by Chamydia trachomatis. For mild infection, empirical therapy with azithromycin or doxycycline usually prompts resolution regardless of bacterial etiology. At our institution, common oral options taken for 7 to 10 days include doxycycline, 100 mg twice daily; azithromycin, 500 mg twice daily; or ampicillin-clavulanate (Augmentin), 875 mg twice daily. Serious metritis is treated with intravenous broad-spectrum antibiotics listed in Table 37-2.
Another cause of subinvolution is incompletely remodeled uteroplacental arteries (Andrew, 1989; Kavalar, 2012). hese noninvoluted vessels are illed with thromboses and lack an endothelial lining. Perivascular trophoblasts are also identiied in the vessel walls, which suggests an aberrant interaction between uterine cells and trophoblasts.
Seconday pospartum hemorrhage is deined as bleeding 24 hours to 12 weeks ater delivery. Clinically worrisome uterine hemorrhage develops within 1 to 2 weeks in perhaps 1 percent of women. Such bleeding most oten is the result of abnormal involution of the placental site. It occasionally is caused by retention of a placental fragment or by a uterine artery pseudoaneurysm. Usually, retained products undergo necrosis with ibrin deposi tion and may eventually form a so-called placental poyp. As the eschar of the polyp detaches from the myometrium, hemorrhage may be brisk. As discussed in Chapter 56 (p. 1090), delayed postpartum hemorrhage may also be caused by von Willebrand disease or other inherited coagulopathies (Lipe, 2011).
In our experiences, few women with delayed hemorrhage are found to have retained placental fragments. hus, we and others do not routinely perform curettage (Lee, 1981). Another concern is that curettage may worsen bleeding by avulsing part of the implantation site. Thus, in a stable patient, if sonographic examination shows an empty cavity, then oxytocin, methylergonovine, or a prostaglandin analogue is given. Suitable dosing is found in Table 20-2 (p. 392). Antimicrobials are added if uterine infection is suspected. If large clots are seen in the uterine cavity with sonography, then gentle suction curettage is considered. Otherwise curettage is carried out only if appreciable bleeding persists or recurs after medical management.