Term labor is associated with global thinning of the myometrium. We hypothesized that a thickened myometrium at the time of preterm premature rupture of membranes (PPROM) predicts less myometrial wall stress and, consequently, a longer latency interval.
Myometrial thickness was measured prospectively in 76 pregnant women enrolled in the following groups: PPROM (n=28, mean [range], gestational age [GA]: 29.5 weeks [w] [21.0 w-33.0 w]), preterm nonlabor control group (P-CTR), (n=21, GA: 27.5 w [23.0 w-32.0 w]) and term nonlabor control (T-CTR) (n=27, GA: 38.6 w [37.0 w-41.6 w]). All PPROM women had oligohydramnios (AFI: 1.4 cm [0.0 cm-5.1 cm]). MT was measured ultrasonographically at the midanterior, fundal, posterior, and lower uterine segment wall in cases and controls with an intraoperator variability <10%.
Women in the PPROM group displayed uniform thickness of the uterine body (mean +/- SEM, anterior: 10.6 +/- 0.6 mm, fundal: 10.7 +/- 0.7 mm, posterior: 8.9 +/- 0.5 mm, P=.078). At midanterior site the myometrium of the PPROM group was thicker compared to both P-CTR (P < .001) and T-CTR (P=.025) groups. This difference was preserved at the fundus (PPROM vs P-CTR, P < .001; PPROM vs T-CTR, P=.015). There was a positive correlation between fundal MT and latency period (r=0.43, P=0.02) that persisted after adjusting for GA (P=.04). A fundal MT less than 12.1 mm was 93.7% sensitive and 63.6% specific for the identification of women whose latency period was less than 120 hours.
Significant thickening of the anterior and fundal walls of the uterus follows PPROM. A thick myometrium in nonlaboring patients with PPROM is associated with longer latency interval. Sonographic evaluation of MT may represent an alternative clinical tool for the prediction of a short latency interval in women with PPROM.
[Show abstract][Hide abstract] ABSTRACT: Spontaneous rupture of membranes (ROM) is a normal component of labor and delivery. Premature ROM (PROM) refers to rupture of the fetal membranes prior to the onset of labor irrespective of gestational age. Once the membranes rupture, delivery is recommended when the risk of ascending infection outweighs the risk of prematurity. When PROM occurs at term, labor typically ensues spontaneously or is induced within 12 to 24 hours. The management of pregnancies complicated by preterm PROM (defined as PROM occurring prior to 37 weeks of gestation) is more challenging. Preterm PROM complicates 2% to 20% of all deliveries and is associated with 18% to 20% of perinatal deaths. Management options include admission to hospital, amniocentesis to exclude intra-amniotic infection, and administration of antenatal corticosteroids and broad-spectrum antibiotics, if indicated. This article reviews in detail the contemporary diagnosis and management of preterm PROM.
Reviews in obstetrics and gynecology 02/2008; 1(1):11-22.
[Show abstract][Hide abstract] ABSTRACT: The objective of the study was to evaluate longitudinally the in vivo changes in myometrial thickness (MT) during gestation in patients carrying twin gestations in relation to pregnancy outcome.
Serial abdominal ultrasounds were performed prospectively in 92 patients carrying twin gestations through each trimester. Ninety-seven patients pregnant with singletons served as controls. For twins, the primary endpoint was spontaneous delivery at less than 35 weeks' gestational age (GA). The myometrium was defined sonographically as the echohomogeneous layer between the serosa and the decidua and was measured at the anterior, fundal, and lower uterine segment (LUS) walls. The estimated fetal weight, maximum vertical pocket of amniotic fluid, and placental thickness were also assessed ultrasonographically at the same time as the MT and served as estimates for the contribution of each to the uterine volume. In twins, cervical length measurements were performed transvaginally, as clinically indicated. Data analysis included 2-way analysis of variance and linear, nonlinear, and multivariate regression.
A total of 41.3% of twin pregnancies (38 of 92) delivered preterm (< 35 weeks). There were no significant changes in measurements at the anterior and fundal site over time throughout pregnancy and no differences in these sites between twin and singleton gestations. Conversely, in both twins and singletons, there was a significant and gradual thinning of the LUS myometrium during gestation. In the absence of uterine contractions or symptoms of preterm labor, twins that delivered preterm had a significantly thinner LUS at an earlier gestation, compared with twins that delivered at term (P < .001), suggesting that LUS thinning occurred earlier in these cases. There was a significant correlation between cervical length and LUS thinning during gestation in twins that delivered 35 weeks GA or later (r = 0.352; P < .001) but not in those that delivered preterm (< 35 weeks GA; r = 0.125; P = .326).
Twin pregnancy is characterized by a significant, selective, and gradual thinning of the LUS during gestation, which does not occur in the anterior and fundal myometrium. Thinning of the LUS occurs earlier in twin pregnancies destined to deliver preterm. These observations suggest that similar to the cervix, the LUS changes dynamically during twin pregnancy and that this too may be assessed through ultrasound imaging.
American journal of obstetrics and gynecology 05/2008; 198(5):530.e1-10. DOI:10.1016/j.ajog.2007.11.022 · 4.70 Impact Factor
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