Methods used to diagnose ruptured membranes are detailed in Chapter 22 (p. 435). A history of vaginal leakage of luid, either as a continuous stream or a gush, should prompt a speculum examination to visualize gross vaginal pooling ofamnionic fluid, clear fluid from the cervical canal, or both. Conirmation of PPROM is usually accompanied by sonographic examina tion to assess amnionic fluid volume, to identiY the presenting part, and if not previously determined, to estimate gestational age. Once PPROM is identified, the general scheme shown in
Table 42-9 can guide management.
Cox and associates (1988) describedpregnancy outcomes of298 consecutive womenwho gave birth following spontaneously ruptured membranes between 24 and 34 weeks' gestation at Parkland Hospital. Although this complication was identified in only 1.7 percent of pregnancies, it contributed to 20 percent of all perinatal deaths. By the time they presented, 76 percent of the women were already in labor, and 5 percent were delivered for other complications. Thus, only 19 percent initially were permitted expectant management. Ultimately, deliverywas delayed 48 hours or more ater membrane rupture in only 7 percent of the total study cohort. There was beneit noted from delayed delivery, however, as none of the neonates died in this group. This contrasted with a neonatal death rate of 80 per 1000 in preterm newborns delivered within 48 hours ofmembrane rupture. Nelson and colleagues later (1994) reported similar results.
The time from PPROM to delivery is inversely proportional to the gestational age when rupture occurs (Carroll, 1995). s shown in Figure 42-9, very few days are gained when membranes ruptured during the third trimester compared with midpregnancy.
Most clinicians hospitalize women with ruptured membranes. Concerns regarding the costs oflengthy hospitalizations are usually moot, because most women enter labor within a week or less after membrane rupture. Carlan and coworkers (1993) randomly assigned 67 women with ruptured membranes ro home or hospital management. No benefitswere found for hospitalization, and maternal hospital stays were reduced by 50 percent in those sent home-14 versus 7 days. Importantly, the investigators emphasized that this study was too small to conclude that home management was safe in regard to umbilical cord prolapse.
Before the mid-1970s, labor was usually induced in women with preterm ruptured membranes because of fear of sepsis. Maternal infection risk and fetal prematurity risk vary according to the gestational age at membrane rupture, and management decisions hinge on this balance. With regard ro periviable pregnancy, 110rales (1993b) expectantly managed 94 singleton pregnancies with ruptured membranes before 25 weeks. he average time gained was 11 days. Although 41 percent ofinfants survived to age 1 year, only 2 percent of the original cohort were neurologically normal. Similar results were reported by Farooqi (1998) and Winn (2000) and their colleagues. Management of these early pregnancies is discussed on page 807.
For PPROM in general, two randomized trials in the 1990s compared labor induction with expectant management (Cox, 1995; Mercer, 1993). In both of these studies, the balance of risk and beneit was diicult to ascertain, as neither immediate • •I I . .•.,. . .• I · .......
FIGURE 42-9 Relationship of time between preterm membrane rupture and delivery in 172 singleton pregnancies. (Reproduced with permission from Carroll SG, Blott M, Nicolaides KH: of membranes before 37 weeks' gesPreterm prelabor amniorrhexis: Outcome of live births, Obstet Gynecol 1995 Jul;86(1 ):18-25.) tation without contraindications to