Prediction of spontaneous preterm delivery in women with threatened preterm labour: a prospective cohort study of multiple proteins in maternal serum.

OBJECTIVE: To analyse whether specific proteins in maternal serum and cervical length, alone or in combination, can predict the likelihood that women with intact membranes with threatened preterm labour will deliver spontaneously within 7 days of sampling. DESIGN: Cohort study. SETTING: Sahlgrenska University Hospital, Gothenburg, Sweden. POPULATION: Women at between 22 and 33 weeks of gestation with threatened preterm labour (n = 142) admitted to the Sahlgrenska University Hospital, Gothenburg, Sweden, in 1995-2005. METHODS: Maternal serum was tested for 27 proteins using multiplex xMAP technology. Individual levels of each protein were compared, and calculations were performed to investigate potential associations between different proteins, cervical length and spontaneous preterm delivery. Receiver operating characteristic curves were used to find the best cut-off values for continuous variables in relation to spontaneous preterm delivery within 7 days of sampling. Prediction models were created based on a stepwise logistic regression using binary variables. MAIN OUTCOME MEASURE: Spontaneous preterm delivery within 7 days. RESULTS: In order to determine the best prediction model, we analysed models of serum proteins alone, cervical length alone, and the combination of serum proteins and cervical length. We found one multivariable combined model through the data analysis that more accurately predicted spontaneous preterm delivery within 7 days. This model was based on serum interleukin-10 (IL-10) levels, serum RANTES levels and cervical length (sensitivity 74%, specificity 87%, positive predictive value 76%, negative predictive value 86%, likelihood ratio 5.8 and area under the curve 0.88). CONCLUSIONS: A combination of maternal serum proteins and cervical length constituted the best prediction model, and would help determine whether women with threatened preterm labour are likely to deliver within 7 days of measurement.

Prediction of microbial invasion of the amniotic cavity in women with preterm labour: analysis of multiple proteins in amniotic and cervical fluids.

OBJECTIVE: Microbial invasion of the amniotic cavity is a major cause of preterm delivery and the diagnosis is dependent on invasive amniocentesis. The objective was to determine whether specific proteins in amniotic and cervical fluids alone, or in combination, could identify bacterial invasion. DESIGN: A prospective follow-up study. POPULATION: Women with singleton pregnancies presenting with preterm labour between 22 and 33 weeks of gestation (n = 89). SETTING: Sahlgrenska University Hospital, Gothenburg, Sweden. METHODS: Amniotic and cervical fluid was analysed with polymerase chain reaction for Mycoplasmas, and was cultured for aerobic and anaerobic bacteria. Twenty-seven proteins were analysed using multiplex technology. Individual levels of each protein were compared in order to find associations between different proteins and microbial invasion of the amniotic cavity. Predictive models based on multiple proteins were created using stepwise binary logistic regression. MAIN OUTCOME MEASURE: The main outcome measure was microbial invasion of the amniotic cavity. RESULTS: Microbial invasion of the amniotic cavity was present in 17% (15/89) of the women. Concentration levels of several amniotic and cervical proteins were significantly higher in women with microbial invasion of the amniotic cavity. Three multivariate predictive models were found. The predictive power of the non-invasive model (73% sensitivity, 88% specificity, 55% positive predictive value, 94% negative predictive value) was as good as the invasive models. Area under the receiver operating characteristic (ROC) curve and likelihood ratio were 0.87 and 6.0, respectively. CONCLUSIONS: Prediction of intra-amniotic infection using selected cervical proteins was equally good as prediction using the same proteins collected from amniotic fluid, or a combination of cervical and amniotic proteins.

Cervical length in women in preterm labor with intact membranes: relationship to intra-amniotic inflammation/microbial invasion, cervical inflammation and preterm delivery.

OBJECTIVE: Intra-amniotic infection, diagnosed by microbial invasion of the amniotic cavity (MIAC) and/or the presence of intra-amniotic inflammation (IAI), is related to adverse perinatal outcome in women with preterm labor. Due to the subclinical nature of IAI, a correct diagnosis depends on amniocentesis, which is an invasive method not performed as a clinical routine. The aim of this study was to evaluate if cervical length measured by transvaginal sonography could assist in the identification of women at high risk for IAI. METHODS: Cervical length was assessed by transvaginal sonography in 87 women with singleton pregnancies in preterm labor (<34 weeks of gestation). Cervical (n=87) and amniotic (n=55) fluids were collected. Polymerase chain reactions for Ureaplasma urealyticum and Mycoplasma hominis, and culture for aerobic and anaerobic bacteria, were performed. Interleukin (IL)-6 and IL-8 were analyzed by enzyme-linked immunosorbent assay. RESULTS: IAI was present in 25/55 (45%) of the patients presenting with preterm labor who underwent amniocentesis. Women with IAI had a significantly shorter cervical length (median, 10 (range, 0-34) mm) than had those without IAI (median, 21 (range, 11-43) mm) (P<0.0001). Receiver-operating characteristics curve analysis showed that a cervical length (cut-off of 15 mm) predicted IAI (relative risk, 3.6; CI, 1.9-10.0) with a sensitivity of 72%, specificity of 83%, positive predictive value of 78% and negative predictive value of 78%. Cervical length was also significantly associated with preterm birth up to 7 days from sampling and at