Prediction Of Spontaneous Preterm Delivery Research Articles

146: Prediction of spontaneous preterm delivery in women with preterm labor: analysis of multiple proteins in maternal serum

delivery in women with preterm labor: analysis of multiple proteins in maternal serum Panagiotis Tsiartas, Rose-Marie Holst, Ulla-Britt Wennerholm, Henrik Hagberg, David Hougaard, Kristin Skogstrand, Brad Pearce, Marian Kacerovsky, Bo Jacobsson Papageorgiou University Hospital of Thessaloniki, Obstetrics and Gynecology, Thessaloniki, Greece, Sahlgrenska University Hospital, Department of Obstetrics and Gynecology, Gothenburg, Sweden, Sahlgrenska University Hospital, East, Obstetrics and Gynecology, Gothenburg, Sweden, Queen Charlottes and Chelsea Hospital, Institute of Reproductive and Developmental Biology, London, United Kingdom, Statens Serum Institut, Department of Clinical Biochemistry and Immunology, Copenhagen, Denmark, Statens Serum Institut, 3Department of Clinical Biochemistry and Immunology, Copenhagen, Denmark, Rollins School of Public Health, Epidemiology, Atlanta, GA, Univerzita Karlova Praha, Porodnicka a gynekologicka klinika FN Hradec Kralova, Praha, Czech Republic OBJECTIVE: To analyze whether specific proteins in maternal serum and the cervical length, alone or in combination, can identify the likelihood that women in preterm labor with intact membranes will deliver spontaneously within 7 days of sampling. STUDY DESIGN: We used in our study two independent cohorts of women, an exploratory cohort from 1995-2005 and a confirmatory cohort from 2008-2010 admitted to the Sahlgrenska University Hospital, Gothenburg, Sweden in preterm labor. In the exploratory cohort of 142 women in preterm labor between 22 and 33 weeks of gestation, maternal serum was collected and tested for twenty-seven proteins using multiplex xMAP technology. The women in the study provided serum samples at admission to the hospital for xMAP analysis. Individual levels of each protein were compared and calculations performed to find associations among different proteins, cervical length, and spontaneous preterm delivery within 7 days of sampling. Prediction models were created based on stepwise logistic regression. We have in a second stage applied our multivariable model in order to confirm its predictive capacity to an independent confirmatory cohort of 42 women between 23 and 33 weeks of gestation, who were admitted to the hospital in preterm labor and provided serum samples for xMAP analysis. RESULTS: We found one multivariable model through the data analysis of the exploratory cohort of women that predicts spontaneous preterm delivery within 7 days. This model was based on serum IL-10, RANTES and cervical length (sensitivity 73.8%, specificity 87.3%, positive predictive value 75.6%, negative predictive value 86.3%, likelihood ratio 5.8 and area under the curve 0.89). From the application of the multivariable model to the confirmatory cohort we found that the model had a sensitivity of 66.6%, specificity 66.6%, positive predictive value 35.3%, negative predictive value 88%, likelihood ratio 2 and area under the curve 0.66. CONCLUSION: A combination of maternal serum proteins and cervical length might help to determine whether women with preterm labor will deliver within 7 days.

501: Prediction of spontaneous preterm delivery based on sonographic cervical length and gestational age at cervical length measurement in asymptomatic women with twin pregnancies

To estimate the risk of spontaneous preterm delivery within 14 and 28 days based on sonographic cervical length and gestational age at which cervical length was measured in asymptomatic women with twin pregnancies.

Serum markers for prediction of spontaneous preterm delivery in preterm labour

Simple, more sensitive markers to predict spontaneous preterm delivery in preterm labour are needed. The aim of this study is to compare the clinical effectiveness of various serum inflammatory markers and cervix length for prediction of spontaneous preterm delivery. We retrospectively reviewed medical records of 175 patients hospitalized for preterm labour (102 with preterm delivery and 73 with term delivery). For all study subjects, haematological markers and cervix length were recorded on admission. Because neutrophil to lymphocyte ratio (NLR) showed the potential as a diagnostic marker, we designed a combined marker by dividing cervix length by NLR. The diagnostic and prognostic accuracy of the combined marker was analysed using multivariate analyses. The levels of combined marker (P < 0·001), neutrophil (P < 0·001), lymphocyte (P = 0·02), NLR (P < 0·001), C-reactive protein (P = 0·016) and the cervix length (P < 0·001) in preterm delivery group were significantly different from those of term delivery group. Compared to cervix length or systemic inflammatory markers alone, combined marker showed higher sensitivity (64·2%) and specificity (88·3%) for prediction of preterm delivery. On Cox multivariate analysis, combined marker positive (< 0·29) and short cervix length (< 1·7 cm) were independent poor prognostic factors and combined marker positive was the most powerful prognostic marker for spontaneous preterm delivery (hazard ratio = 5·60, P < 0·001). Combined marker could be used as a simple and sensitive parameter for identifying women at risk of spontaneous preterm delivery.

478: Should we repeat the cervical ultrasound assessment to predict preterm birth? (COLIBRI study)

Even if transvaginal ultrasound exam (TVUS) is the best predictive factor for spontaneous preterm birth (sPTB), only a proportion of patients with short cervix deliver prematurely. We hypothesized that pathologic modifications of cervix increase the accuracy to predict sPTB. The objective was to determine if we have to repeat transvaginal ultrasound exam to improve prediction of spontaneous preterm delivery.

Prediction of spontaneous preterm delivery from maternal factors, obstetric history and placental perfusion and function at 11–13 weeks

To develop a model for prediction of spontaneous delivery before 34 weeks based on maternal factors, placental perfusion and function at 11-13 weeks' gestation. Two groups of studies: first, screening study of maternal characteristics, serum pregnancy-associated plasma protein-A (PAPP-A), free β-human chorionic gonadotrophin (β-hCG) and uterine artery pulsatility index (PI). Second, case-control studies of maternal serum or plasma concentration of placental growth factor (PlGF), placental protein 13 (PP13), a disintegrin and metalloprotease 12 (ADAM12), inhibin-A and activin-A. Regression analysis was used to develop a model for the prediction of spontaneous early delivery. Spontaneous early delivery occurred in 365 (1.1%) of the 34 025 pregnancies. A model based on maternal factors could detect 38.2% of the preterm deliveries in women with previous pregnancies at or beyond 16 weeks and 18.4% in those without, at a false positive rate (FPR) of 10%. In the preterm delivery group, compared with unaffected pregnancies there were no significant differences in the markers of placental perfusion or function, except for PAPP-A which was reduced. Patient-specific risk of preterm delivery is provided by maternal factors and obstetric history. Placental perfusion and function at 11-13 weeks are not altered in pregnancies resulting in spontaneous early delivery.

Prediction of spontaneous preterm delivery from endocervical length at 11 to 13 weeks

To define the potential value of endocervical length at 11 to 13 weeks' gestation in the prediction of spontaneous early delivery. The lengths of the endocervix and cervico-isthmic complex were measured by transvaginal ultrasound at 11 to 13 weeks in singleton pregnancies, including 1492 that subsequently delivered after 34 weeks and 16 (1.1%) who had spontaneous delivery before 34 weeks. In 1320 of the cases, the measurements were repeated at 20 to 24 weeks. There were significant associations in the length of the endocervix and cervico-isthmic complex between 11 to 13 and 20 to 24 weeks (r = 0.548, p < 0.0001 and r = 0.194, p < 0.0001), and the respective median lengths were 32.4 and 32.2 mm for the endocervix and 45.3 and 40.4 mm for the cervico-isthmic complex. At 11 to 13 weeks in the early delivery group, compared to unaffected pregnancies, the median endocervical length was shorter (27.5 vs 32.5 mm, p < 0.0001), but there was no significant difference in the length of the cervico-isthmic complex (41.4 vs 45.4 mm, p = 0.054). In the measurement of cervical length, the endocervix should be distinguished from the isthmus. The endocervical length at 11 to 13 weeks is shorter in pregnancies resulting in spontaneous delivery before 34 weeks than in those delivering after 34 weeks.

Phosphorylated insulin‐like growth factor binding protein‐1 and cervical measurement in women with threatening preterm birth

To assess the efficacy of the cervical phosphorylated insulin-like growth factor binding protein-1 (pIGFBP-1) in combination with cervical length measurement for the prediction of preterm delivery. Observational prospective study. University Hospital, Spain. A total of 276 women between 24 and 34 weeks gestational age complaining of uterine contractions and intact membranes. Transvaginal scan to assess cervical length and cervical swabs for pIGFBP-1 detection. Prevalence of preterm delivery within 48 hours and 7 days, delivery at < 32, < 34 weeks, admission-to-delivery interval by cervical length and the presence of pIGFBP-1. Results. The prevalence of preterm delivery at < 34 weeks was 14.1% (39/276) and 7.6% (21/276) at < 32 weeks. Cervical pIGFBP-1 was positive in 38.7% (107/276), whereas cervical length < 15 mm was present in 7.2% (20/276) and was > 30 mm for 64.8% (179/276) of the women. The presence of a positive pIGFBP-1 appeared useful for prediction of delivery before 32 (likelihood ratio (LR) = 2.21, confidence interval (CI): 1.63-3.00) and 34 weeks (LR = 1.76, CI: 1.25-2.41), respectively. Receiver operating characteristic curves were significant for cervical length and pIGFBP-1 for prediction of delivery at < 34 weeks, < 32 weeks, < 48 hours and < 7 days. Combining pIGFBP-1 and cervical length had a median interval that was shorter when both were positive as compared to only one positive or both negative, but the CIs overlapped. Both cervical length measurement and pIGFBP-1 are useful for prediction of spontaneous preterm delivery. A pIGFBP-1 positive result associated with cervical length does not improve preterm delivery prediction rates.

Two-stage transvaginal cervical length screening for preterm birth in twin pregnancies

To compare cervical length (CL) at 18-21 and 22-25 weeks' gestation in twin pregnancies in prediction of spontaneous preterm delivery and to examine cervical shortening. Retrospective cohort study of CL measured at 18-21 and 22-25 weeks' gestation in twin pregnancies. Receiver operating characteristics (ROC) curve revealed area of 0.64 (95% CI 0.53-0.75) and 0.80 (95% CI 0.72-0.88) for measurements at 18-21 and 22-25 weeks, respectively (P<or=0.001). Sensitivities of 33.3% and 23% and negative predicting value (NPV) of 97.3% and 86.8% for delivery at <28 and <34 weeks gestation were reached for measurements at 18-21 weeks. Sensitivities of 71.4% and 38.2% and NPV of 99.1% and 91.4% for delivery at <28 and <34 weeks' gestation were reached for measurements at 22-25 weeks. Cervical length shortening analysis showed an area under ROC curve of 0.81 (95% CI 0.73-0.89) and best cut-off was at >or=2 mm/week. Sensitivities of 80% and 60.8% and NPV of 98.9% and 90.6% for delivery at <28 and <34 weeks gestation were reached. In twin gestations, assessment of CL at 22-25 weeks is better than assessment at 18-21 weeks to predict preterm delivery before 34 weeks. Cervical shortening at a rate of >or=2 mm/weeks between 18 and 25 weeks gestation was a good predictor of spontaneous preterm birth in this high-risk population.

526: Fetal fibronectin as a predictor of spontaneous preterm delivery in multiple gestations: a systematic review and meta-analysis

526: Fetal fibronectin as a predictor of spontaneous preterm delivery in multiple gestations: a systematic review and meta-analysis

Phosphorylated insulin‐like growth factor binding protein‐1 in cervical secretions and sonographic cervical length in the prediction of spontaneous preterm delivery

The aim of this study was to evaluate the efficacy of the test for the decidual phosphorylated isoform of insulin-like growth factor binding protein-1 (phIGFBP-1) in endocervical secretions in predicting preterm delivery in women with uterine contractions. The study included 210 women with a singleton pregnancy with documented uterine contractions and intact membranes at between 24 and 34 weeks' gestation who underwent the cervicovaginal phIGFBP-1 test and transvaginal sonographic measurement of cervical length. A receiver-operating characteristics (ROC) curve was used to determine the most useful cut-off point for cervical length. A multivariate logistic regression model was used in order to analyze the combination of significant predictive variables for preterm delivery following univariate analysis. ROC curves indicated that 26 mm was the optimal cut-off value for cervical length in predicting preterm delivery. A cervical length of < 26 mm and the presence of phIGFBP-1 were statistically significant in univariate logistic regression analyses (P < 0.0001) with odds ratios of 16.18 and 9.29 for preterm delivery, respectively. Multivariate analysis of cervical length and phIGFBP-1 showed that they were independent and therefore useful in combination for predicting preterm delivery. Cervical length and the phIGFBP-1 test are independent variables that can be used together to predict preterm delivery in women with uterine contractions. A sonographically measured cervical length of > 26 mm with a negative phIGFBP-1 test in a patient with regular uterine contractions before 37 weeks' gestation seems to indicate a low risk of preterm delivery and may therefore allow avoidance of unnecessary therapies.

Prediction of Spontaneous Preterm Delivery in Women With Preterm Labor

To analyze whether specific proteins in amniotic and cervical fluids, alone or in combination with risk factors, can identify women in preterm labor with intact membranes who will deliver spontaneously within 7 days of sampling. In a cohort of 89 women in preterm labor, amniotic and cervical fluids were collected between 22 and 33 weeks of gestation. Twenty-seven proteins were analyzed simultaneously using multiplex technology. Individual levels of each protein were compared and calculations performed to find associations among different proteins, background variables, and spontaneous preterm delivery within 7 days of sampling. The area under the curve (AUC) was calculated using receiver operating characteristic curve analysis, and prediction models were created based on stepwise logistic regression. We found two multivariable models that predicted spontaneous preterm delivery better than any single variable. One combined multivariable prediction model was based on amniotic macrophage inflammatory protein-1beta, cervical interferon-gamma, and monocyte chemotactic protein-1. This model predicted outcome with 91% sensitivity, 84% specificity, 78% positive predictive value, and 94% negative predictive value, with a likelihood ratio of 5.6 and AUC of 0.91. An alternative, noninvasive model based on cervical length, cervical interferon-gamma, interleukin-6, and monocyte chemotactic protein-1 predicted delivery within 7 days with 85% sensitivity, 82% specificity, 74% positive predictive value, and 90% negative predictive value, with a likelihood ratio of 4.7 and AUC of 0.91. A combination of proteins from amniotic fluid and cervical fluid or cervical length can help determine which women will deliver preterm. II.

Mid‐trimester amniotic fluid C‐reactive protein, ferritin and lactate dehydrogenase concentrations and subsequent risk of spontaneous preterm labour

Preterm delivery is a serious problem in obstetrics. A pre-existing inflammation in the first half of gestation has been proposed as a possible condition that leads to preterm delivery. Our aim was to compare C-reactive protein (CRP), ferritin and lactate dehydrogenase (LDH) concentrations in mid-trimester amniotic fluid of patients with preterm and term deliveries and to found out their predictive values for preterm delivery. The study was conducted on 90 pregnant women who underwent genetic amniocentesis between the 15th and the 20th weeks of gestation. The samples were carried immediately to the laboratory for cytogenetic and biochemical examination. Non-parametric tests and receiver-operating characteristic curve analysis were used for statistical purpose. This study showed women with preterm delivery at < 37 weeks (n = 17) had a higher median of amniotic fluid LDH concentration than those women who delivered at term (n = 73) (P = 0.003). Amniotic fluid LDH concentration of > 120 IU/L had a sensitivity of 59% and a specificity of 81% in the prediction of spontaneous preterm delivery at < 37 weeks. Maternal serum alpha-fetoprotein levels were higher in patients delivered preterm compared with term deliveries (P = 0.036). Mid-trimester LDH is found to be quite effective in the prediction of preterm delivery. Pre-existing intrauterine inflammatory process early in gestation may be an important risk factor for preterm delivery.

Prediction of Spontaneous Preterm Delivery in Twin Pregnancies By Cervical Length at Mid-Gestation

The objective of our study was to evaluate the correlation of the cervical length at 20-25 weeks of gestation with the incidence of spontaneous preterm delivery in twins in a country with a high incidence of preterm delivery compared to other European countries. Cervical length was measured in 262 consecutive patients. Previous preterm delivery before 34 weeks of gestation, chorionicity, maternal age, body-mass-index, smoking habit and parity were recorded as risk factors for preterm delivery. Women who were symptomatic at 20-25 weeks and who delivered because of other reasons than spontaneous labour and preterm rupture of membranes or at term were excluded. The primary outcome was incidence of preterm birth before 34 weeks. Two hundred and twenty-three patients were analyzed. Thirty-two (14%) delivered before 34 weeks. There was a significant correlation between cervical length of less than 25 mm and spontaneous delivery before 34 weeks (50% vs. 13%, p = .007). In addition, logistic regression analysis found cervical length to be the only significant predictor of spontaneous delivery before 34 weeks (OR 1.084; 95% CI 1.015; 1.159; p = .017). We conclude that the risk of severe preterm delivery in twins is high. Cervical length at mid-gestation was the only predictor of delivery before 34 weeks.

Preterm Prediction Study

To prospectively compare digital cervical score with Bishop score as a predictor of spontaneous preterm delivery before 35 weeks of gestation. Data from a cohort of 2,916 singleton pregnancies enrolled in a multicenter preterm prediction study were available. Patients underwent digital cervical examinations at 22-24 and 26-29 weeks of gestation for calculation of Bishop score and cervical score. Relationships between Bishop score, cervical score, and spontaneous preterm delivery were assessed with multivariable logistic regression analysis, McNemar test, and receiver operating characteristic (ROC) curves to identify appropriate diagnostic thresholds and predictive capability. One hundred twenty-seven of 2,916 patients (4.4%) undergoing cervical examination at 22-24 weeks had a spontaneous preterm delivery before 35 weeks. Eighty-four of the 2,538 (3.3%) reexamined at 26-29 weeks also had spontaneous preterm delivery. Receiver operating characteristic curves indicated that optimal diagnostic thresholds for Bishop score were at least 4 at 22-24 weeks, at least 5 at 26-29 weeks, and less than 1.5 at both examinations for cervical score. At 22-24 weeks, areas under the ROC curve favored Bishop score. At 26-29 weeks, there was no significant difference in areas under the ROC curve; however, a cervical score less than 1.5 (sensitivity 35.7%, false positive rate 4.8%) was superior to a Bishop score of 5 or more (P<.001). Both cervical evaluations are associated with spontaneous preterm delivery in a singleton population; however, predictive capabilities for spontaneous preterm delivery were modest among women with low event prevalence. Although Bishop score performed better in the mid trimester, by 26-29 weeks a cervical score less than 1.5 was a better predictor of spontaneous preterm delivery before 35 weeks than a Bishop score of at least 5.

OC141: Prediction of spontaneous preterm delivery in twin pregnancies by cervical length at mid‐gestation

OC141: Prediction of spontaneous preterm delivery in twin pregnancies by cervical length at mid‐gestation

P11.03: Comparison of ecographic cervical length at two different cut‐off points and two biochemical markers as predictors of spontaneous preterm delivery in women admitted because of preterm labor

P11.03: Comparison of ecographic cervical length at two different cut‐off points and two biochemical markers as predictors of spontaneous preterm delivery in women admitted because of preterm labor

A sonographic short cervix as the only clinical manifestation of intra-amniotic infection

A sonographically short cervix is a powerful predictor of spontaneous preterm delivery. However, the etiology and optimal management of a patient with a short cervix in the mid-trimester of pregnancy remain uncertain. Microbial invasion of the amniotic cavity (MIAC) and intra-amniotic inflammation are frequently present in patients with spontaneous preterm labor or acute cervical insufficiency. This study was conducted to determine the rate of MIAC and intra-amniotic inflammation in patients with a cervical length < 25 mm in the mid-trimester. A retrospective cohort study was conducted of patients referred to our high risk clinic because of a sonographic short cervix or a history of a previous preterm birth. Amniocenteses were performed for the evaluation of MIAC and for karyotype analysis in patients with a short cervix. Fluid was cultured for aerobic and anaerobic bacteria, as well as genital mycoplasmas. Patients with MIAC were treated with antibiotics selected by their physician. Of 152 patients with a short cervix at 14-24 weeks, 57 had amniotic fluid analysis. The prevalence of MIAC was 9% (5/57). Among these patients, the rate of preterm delivery (< 32 weeks) was 40% (2/5). Microorganisms isolated from amniotic fluid included Ureaplasma urealyticum (n=4) and Fusobacterium nucleatum (n=1). Patients with a positive culture for Ureaplasma urealyticum received intravenous Azithromycin. Three patients with Ureaplasma urealyticum had a sterile amniotic fluid culture after treatment, and subsequently delivered at term. The patient with Fusobacterium nucleatum developed clinical chorioamnionitis and was induced. (1) Sub-clinical MIAC was detected in 9% of patients with a sonographically short cervix (< 25 mm); and (2) maternal parenteral treatment with antibiotics can eradicate MIAC caused by Ureaplasma urealyticum. This was associated with delivery at term in the three patients whose successful treatment was documented by microbiologic studies.

Prediction of preterm delivery using changes in serum relaxin in low risk pregnancies

Objective To examine serum relaxin as a predictor of spontaneous preterm delivery. Study design A prospective study of 2846 women with singleton pregnancies, from which a matched case–control study (84 cases of spontaneous preterm delivery before 37 weeks gestation and 175 controls) and a cohort (84 preterm and 399 term deliveries) were extracted. Results In the women with a subsequent preterm delivery the relaxin level decreased by 0.9% per week as compared to 1.9% per week ( t-test, p = 0.004) in the women with term deliveries. From the cohort the course of S-relaxin during pregnancy in both preterm and term deliveries were fitted and graphed. S-relaxin level was raised in women who were hormonally stimulated to obtain pregnancy ( p = 0.0001), and lower in women with pre-pregnancy overweight (BMI ≥ 25, p = 0.01) as well as in women, who had previously been pregnant ( p = 0.008). A longitudinal adjusted model for the prediction of preterm delivery based on the change in S-relaxin was established. Conclusions S-relaxin levels decrease less rapidly in women who subsequently deliver preterm; this results in elevated S-relaxin levels in the second and the third trimesters.

Evaluation and validation of a new risk score (CLEOPATRA score) to predict the probability of premature delivery for patients with threatened preterm labor

To develop a clinically useful tool to predict the probability of preterm delivery in patients with threatened preterm labor. One hundred and seventy patients with preterm labor between 24 and 34 weeks of gestation were included. Preterm delivery < 37 weeks of gestation was the main endpoint of the study. The data were randomized and split into an evaluation set (n = 85) and a validation set (n = 85). The evaluation set was subjected to stepwise backward logistic regression analysis to quantify the relative impact of four potential risk factors, including individual patient factors, results of a rapid fetal fibronectin assay, and sonographic measurement of cervical length. Using the constant of the logistic regression analysis and the beta-coefficients for the identified risk factors the individual probability of preterm delivery for each woman of the validation dataset was calculated. The area under a receiver-operating characteristics curve (AUC) was used to evaluate the discriminating power of the score. The overall rate of preterm delivery was 27.1%. The logistic regression analysis was performed for the potential predictors of spontaneous preterm delivery, identified by univariate analysis. These were positive fetal fibronectin, cervical length, previous preterm delivery and maternal age. Two risk factors were independent predictors of preterm delivery and were included in the CLEOPATRA I (clinical evaluation of preterm delivery and theoretical risk assessment) score: cervical length measurement and previous preterm delivery were associated with a higher risk of preterm delivery (odds ratio, 7.65 and 6.74, respectively). Since fetal fibronectin assay is not available at all institutions worldwide, it was excluded from the initial model. In the CLEOPATRA II model the risk factors fetal fibronectin and previous preterm delivery were associated with higher risk of preterm delivery, with odds ratios of 17.9 and 4.56, respectively. The discrimination power (AUC) obtained from the models were: CLEOPATRA I, 0.69 (95% CI, 0.56-0.82); CLEOPATRA II, 0.81 (95% CI, 0.69-0.93). In symptomatic women the risk for preterm delivery can be predicted best with the CLEOPATRA II score based on fetal fibronectin and previous preterm delivery.

Cervical length at 18–22 weeks of gestation for prediction of spontaneous preterm delivery in Hong Kong Chinese women

To assess the value of a single cervical length measurement by transvaginal sonography (TVS) at the time of mid-trimester anomaly scan for predicting spontaneous preterm delivery (SPD) among Chinese women. A prospective observational study was carried out involving 2880 subjects with singleton pregnancies and confirmed gestational age. Cervical length was measured at 18-22 weeks of gestation. The incidence of SPD < 34 weeks and < 37 weeks were 0.7% and 3.7%, respectively. Women with SPD < 34 weeks and SPD < 37 weeks had shorter median cervical lengths (32.6 mm and 36.2 mm, respectively) than those with term deliveries (37.6 mm) (P = 0.006 and 0.025, respectively). The predictive performance of cervical length was better for SPD < 34 weeks compared with < 37 weeks. A cervical length < or = 27 mm, which corresponded to the 4th centile, occurred in 36.8%, 62.5% and 100% of those with SPD < 34, < 30 and < 26 weeks, respectively. The positive likelihood ratio (LR) of a cervical length < or = 27 mm in predicting SPD < 34 weeks was 9.8. Using logistic regression, both short cervix and funneling were independent predictors for SPD < 34 weeks of gestation. The coexistence of funneling and a cervical length < or = 27 mm gave a positive predictive value (PPV) and LR of SPD < 34 weeks of 14.7% and 26.0, respectively. Mid-trimester cervical length is predictive of SPD in Chinese women. However, given the low PPV of a short cervical length, its clinical utility is still limited in low-risk populations.