Clinical significance of oligohydramnios in patients with preterm labor and intact membranes*,**

Abstract

OBJECTIVE To determine the frequency and clinical significance of oligohydramnios in patients with preterm labor and intact membranes. STUDY DESIGN An amniotic fluid index (AFI) was determined before amniocentesis (<24hrs) in 272 patients with preterm labor and intact membranes (<35 weeks of gestation). Amniotic fluid (AF) was cultured for aerobic and anaerobic bacteria and genital mycoplasmas, and assayed for matrix metalloproteinase-8 (MMP-8). Nonparametric statistical techniques and survival analysis were used. RESULTS 1) The overall prevalence of oligohydramnios (AFI of ≤5cm) in patients with preterm labor and intact membranes was 2.6% (7/272); 2) patients with oligohydramnios had a higher frequency of AF infection and/or inflammation than those without oligohydramnios (85.7% [6/7] vs. 32.8% [87/265]; p<.01); 3) Patients with oligohydramnios had a higher median AF MMP-8 concentration than those without oligohydramnios (median 664.2 [range 16.6 – 3424.7] ng/ml vs. median 2.3 [range <0.3 – 6142.6] ng/ml; p<.01); 4) women with preterm labor and oligohydramnios had a shorter interval to delivery than those without oligohydramnios (median 18 hrs [range 0-74 hrs] vs. median 311 hrs [range 0-3228 hrs]; p<.01), and this difference remained significant after adjusting for gestational age and the presence or absence of AF infection/inflammation CONCLUSION Patients with preterm labor and oligohydramnios are at increased risk for impending preterm delivery and intra-amniotic inflammation and, therefore, may benefit from careful surveillance.

Midtrimester amniotic fluid concentrations of interleukin-6 and interferon-gamma-inducible protein-10: evidence for heterogeneity of intra-amniotic inflammation and associations with spontaneous early (<32 weeks) and late (>32 weeks) preterm delivery

“…Some have reported sterile amniotic fluid [26, 42] while others have found the presence of microorganisms in an unexpectedly high number of cases [13, 65, 104]. The presence of microorganisms in the amniotic cavity elicits, in some cases, an inflammatory response that can be detected by demonstration of an elevation of the amniotic fluid white blood cell count [18, 43, 161, 171], a decrease in amniotic fluid glucose [28, 45, 46, 66, 90, 157, 171], or an elevation in proinflammatory cytokines, such as interleukin-6 (IL-6) [9, 29, 79, 82, 136, 156, 167, 170, 171, 177, 178, 200, 201], MCP-1 [20, 27, 40, 75], and matrix metalloproteinases (MMPs) such as MMP-8 [40, 85, 88, 89, 95, 96, 112, 123, 126, 132, 134, 135]. …”

“…Until recently, the standard definition of intra-amniotic inflammation relied on the demonstration of an elevation of amniotic fluid white blood cell count (largely neutrophils) [161, 171], or proinflammatory cytokines, such as IL-6 [9, 29, 79, 82, 102, 136, 156, 167, 170, 171, 177, 178, 201], IL-1 beta [10, 72, 122, 148, 152, 155, 158, 160, 164, 168, 203], TNF [108, 153, 166, 174, 177, 200 – 202], chemokines [21, 40, 68, 121, 125, 201], or MMP-8 [79, 84, 85, 88, 89, 95, 96, 112, 113, 123, 126, 132, 134, 135]. We have recently identified a different form of intra-amniotic inflammation characterized by an elevation of T-cell chemokines [87, 99, 100, 127, 196], and demonstrated that such inflammatory process is associated with chronic chorioamnionitis, a lesion characterized by the infiltration of maternal lymphocytes into the amnion and chorion [48, 49, 77, 87].…”

Volume de líquido amniótico e os desfechos maternos em gestantes com ruptura prematura das membranas pré-termo

“…O estudo de Kim et al 21 observou que as gestantes com oligo-hidrâmnio em trabalho de parto prematuro, mesmo sem ruptura das membranas, têm uma frequência maior de infecção intramniótica quando comparadas às gestantes sem oligo-hidrâmnio. Porém, em nosso estudo, observamos uma associação grave entre a infecção intramniótica e o oligo-hidrâmnio.…”

The frequency and clinical significance of intra-amniotic inflammation in women with preterm uterine contractility but without cervical change: do the diagnostic criteria for preterm labor need to be changed?

“…Table IV displays the prevalence of microbial invasion observed in different obstetrical syndromes [86,101,106-192]. It is noteworthy that, among patients with preterm labor and intact membranes, the mean frequency of microbial invasion at the time of admission is approximately 12%.…”