Assessing reVITALize: Should the Definition of Postpartum Hemorrhage Differ by Mode of Delivery?

Background Obstetrical hemorrhage is a leading cause of morbidity and mortality, yet is inconsistently defined. In 2014, the American Congress of Obstetricians and Gynecologists (ACOG) reVITALize program redefined postpartum hemorrhage (PPH) as greater than 1,000 mL blood loss regardless of the mode of delivery (MOD). Objective We sought to assess the reVITALize definition's validity by understanding whether the definition of PPH should, as proposed by ACOG, be one value regardless of MOD. Study Design This is a retrospective study of all women who delivered at the hospital of the University of Pennsylvania from October 15, 2013 through December 15, 2013. Results A total of 592 of the 626 (95%) women were included. The average reported estimated blood loss (EBL) for vaginal delivery (VD) was significantly lower than for cesarean delivery (CD) ([350 ±170 mL) and [880 ± 360 mL]; p < 0.001). The average hemoglobin (Hb) drop was only slightly lower for VD compared with CD ([1.4 ± 1.0 g/dL {11.5% drop}] and [1.9 ± 1.2 g/dL {16.2% drop}], respectively, p < 0.001). The association between EBL and observed Hb drop differed in accuracy by MOD. Conclusion Likely based on historic perceptions, obstetric providers estimate blood loss for VD as less than half that of CD. However, using objective measures, blood loss is more similar than perceived between VD and CD, supporting the ACOG reVITALize single definition of PPH regardless of MOD.

The Effect of Early Excessive Weight Gain on the Development of Hypertension in Pregnancy.

Background Previous studies have shown an association between total excessive gestational weight gain and hypertension in pregnancy. However, this may be a reflection of excessive water retention associated with the pathophysiology of hypertensive disorders of pregnancy. Early excessive weight gain, prior to the third trimester, results in greater maternal fat deposition and inflammation, which has also been associated with the development of hypertension. By focusing on early excessive weight gain, the association between maternal weight gain and the future development of hypertension can be examined. Objective To evaluate the association between early excessive maternal weight gain and the development of hypertension during pregnancy. Study Design This was a secondary analysis of a longitudinal cohort study of 1,441 women without chronic hypertension who were enrolled in a prospective study evaluating maternal angiogenic factors and the prediction of preeclampsia. Initial body mass index (BMI) was calculated by weight and height at the first study visit. Early excessive maternal weight gain was defined as weight gain by 28 weeks that exceeded the Institute of Medicine (IOM) guidelines and was calculated utilizing the maximum amount of weight gain per week recommended by the IOM based on the patient's starting BMI (normal: 0.45 kg; overweight: 0.32 kg; obese: 0.27 kg). Hypertension was defined as a sustained systolic blood pressure of ≥140 mm Hg or a diastolic blood pressure of ≥90 mm Hg. Logistic regression was used to determine the association between early excessive weight gain, initial BMI, and the development of hypertension, including gestational hypertension and preeclampsia, during pregnancy. Results Of 1,441 women, 767 (53.2%) had weight gain that exceeded the IOM guidelines in the first 28 weeks and 154 (10.8%) developed hypertension during pregnancy. Women whose weight gain exceeded the IOM guidelines were more likely to develop hypertension even after adjusting for relevant confounders (12.5 vs. 8.6%; p = 0.02; adjusted odds ratio [OR] = 1.70; 95% confidence interval [CI]: 1.18-2.44; p < 0.01). Obese women had a 2.4-fold increased risk of developing hypertension, even after controlling for excessive weight gain (adjusted OR = 2.44; 95% CI: 1.66-3.59; p < 0.01) Conclusions Early excessive maternal weight gain and initial BMI are independently associated with the diagnosis of a hypertensive disorder of pregnancy. Women should be counseled regarding the benefits of achieving a normal BMI prior to pregnancy and appropriate weight gain during pregnancy, as well as the potential harms of excessive weight gain related to perinatal outcomes.

Second-Trimester Sonographic Thymus Measurements Are Not Associated With Preterm Birth and Other Adverse Obstetric Outcomes.

OBJECTIVES: Previous studies have demonstrated an association between adverse obstetric outcomes, such as preterm birth, and in utero inflammation. The fetal thymus, which can be visualized in the anterior mediastinum on obstetric sonography, may involute in response to such inflammation and thus may identify pregnancies at increased risk for these outcomes. We therefore sought to determine whether second-trimester fetal thymus measurements are associated with preterm birth. METHODS: Transabdominal fetal thymus measurements were prospectively obtained in singleton pregnancies at gestational ages of 18 weeks to 23 weeks 6 days during a 5-month period. The transverse and anterorposterior thymus diameters and the thymic-thoracic ratio were measured. Delivery outcomes were collected from our clinical database. The primary outcome was preterm birth, which we defined as delivery between 24 weeks and 36 weeks 6 days. Small for gestational age (SGA) and pregnancy-related hypertension, which are adverse obstetric outcomes that may also be associated with in utero inflammation, were included as secondary outcomes. RESULTS: We included 520 patients with thymus measurements and obstetric outcome data. The prevalence of preterm birth was 12.3% (n = 64). None of the thymus measurements were associated with preterm birth. Similarly, there was no association between thymus measurements and SGA or pregnancy-related hypertension. CONCLUSIONS: Sonographic assessment of the second-trimester fetal thymus did not identify patients at increased risk for preterm birth, SGA, and pregnancy-related hypertension. Routine thymus measurements during the second-trimester anatomic scan are not clinically useful for prediction of preterm birth and other adverse outcomes.

Evaluating the Obstetrical Implications of Antenatal Testing for Women with Morbid Obesity: Maternal and Fetal Outcomes of Increased Surveillance.

Objectives Despite limited data, antenatal testing has been initiated in many institutions for women with morbid obesity given their increased risk of stillbirth. Therefore, our objective was to evaluate the obstetrical implications of antenatal testing in the morbidly obese population. Study Design We performed a retrospective cohort study of women undergoing antenatal testing from January 2011 through December 2012 who delivered at our institution. The exposed group was women undergoing antenatal testing with morbid obesity (body mass index [BMI] ≥ 40 kg/m(2)). This group was subdivided into two groups: group 1, which included women undergoing testing for morbid obesity alone, and group 2, which included women undergoing testing for morbid obesity with an additional medical comorbidity. The unexposed group (group 3) comprised nonmorbidly obese women (BMI < 35 kg/m(2)) undergoing antenatal testing for similar medical comorbidities. Our primary outcomes were induction of labor and gestational age at delivery. Results A total of 512 women met inclusion criteria. Group 1 had a lower induction rate as compared with groups 2 and 3 (22.2, 32.5, and 37.6%, respectively; p = 0.003). Additionally, women delivered at a later gestational age in group 1 (39.3 weeks [38.4-40.2]) compared with groups 2 (38.5 weeks [36.1-40.3]) or 3 (37.1 weeks [37.0-38.2]), p = 0.04. There were no significant differences in our secondary outcomes including rate of cesarean delivery (p = 0.11) or rate of nonreactive nonstress test (p = 0.4). Conclusions While it remains unknown whether antenatal testing decreases the stillbirth risk in morbidly obese women, this population does not appear to be at increased risk of induction of labor or delivery prior to 39 weeks secondary to testing. Future studies should evaluate neonatal implications and cost-effectiveness of antenatal testing in this group.

Cell-free DNA fetal fraction and preterm birth.

BACKGROUND: Cell-free deoxyribonucleic acid (DNA) is increasingly being used to screen for fetal aneuploidy. The majority of fetal cell-free DNA in the maternal blood results from release from the syncytiotrophoblast as a result of cellular apoptosis and necrosis. Elevated levels of fetal cell-free DNA may be indicative of underlying placental dysfunction, which has been associated with preterm birth. Preliminary studies have demonstrated that fetal cell-free DNA is increased in pregnancies complicated by spontaneous preterm birth. There are limited data on the association between fetal cell-free DNA levels and fetal fraction and preterm birth in asymptomatic women in the first and second trimesters. Preliminary studies have failed to find an association between first-trimester cell-free DNA levels and preterm birth, whereas there is conflicting evidence as to whether elevated second-trimester cell-free DNA is associated with a subsequent spontaneous preterm birth clinical event. OBJECTIVE: The objective of the study was to evaluate the association between first- and second-trimester cell-free DNA fetal fraction and preterm birth. STUDY DESIGN: This was a retrospective cohort study of women with singleton pregnancies at increased risk for aneuploidy who had cell-free DNA testing at 10-20 weeks' gestation between October 2011 and May 2014. The cohort was subdivided by gestational age at the time of cell-free DNA testing (10-14 weeks or 14.1-20 weeks). The primary outcome was preterm birth less than 37 weeks' gestation, and the secondary outcomes were preterm birth at less than 34 weeks' gestation and spontaneous preterm birth at less than 37 and 34 weeks' gestation. RESULTS: Among 1349 pregnancies meeting inclusion criteria 119 (8.8 %) had a preterm birth prior to 37 weeks with 49 cases (3.6 %) delivering prior to 34 weeks. Whereas there was no significant association between fetal fraction and the preterm birth outcomes for those who underwent cell-free DNA testing at 10-14 weeks' gestation, there were significant associations among those screened at 14.1-20.0 weeks' gestation. Fetal fraction greater than or equal to the 95th percentile at 14.1-20.0 weeks' gestation was associated with an increased risk for preterm birth less than 37 and 34 weeks' gestation (adjusted odds ratio, 4.59; 95% confidence interval, 1.39-15.2; adjusted odds ratio, 22.0; 95% confidence interval, 5.02-96.9). CONCLUSION: Elevated fetal fraction levels at 14.1-20.0 weeks' gestation were significantly associated with an increased incidence of preterm birth. Our findings warrant future exploration including validation in a larger, general population and investigation of the potential mechanisms that may be responsible for the initiation of preterm labor associated with increased fetal cell-free DNA.

Patient characteristics associated with 17-alpha hydroxyprogesterone caproate use among a high-risk cohort.

BACKGROUND: Preterm birth (PTB) remains a significant cause of neonatal morbidity and mortality. Women with a prior PTB are at risk for recurrent PTB. Treatment with 17-alpha hydroxyprogesterone caproate (17OHP-C) has become standard of care for women with prior PTB to help reduce this risk. Factors that affect a woman's decision to use this medication are largely unknown. OBJECTIVE: The objective of our study was to investigate patient-level barriers to 17OHP-C. We studied a cohort of women eligible for 17OHP-C with the hypothesis that 17OHP-C is underutilized and certain patient characteristics, such as obstetrical history, influence its use. STUDY DESIGN: A cross-sectional study of all women seen at a specialty prematurity clinic from 2009 through 2013 was performed. Women with a singleton pregnancy were included if they had a prior spontaneous PTB (sPTB). The χ(2) tests were performed for univariate analyses. Multivariable logistic regression was used to control for confounders. RESULTS: In all, 243 women had 17OHP-C recommended to them based on obstetrical history. There were 218 women with a pregnancy during our study period that were included in our analysis. A total of 163 (74.7%) had documented 17OHP-C use. Women were more likely to accept 17OHP-C if they had a history of a second-trimester loss only (odds ratio [OR], 2.32; 95% confidence interval [CI], 1.17-4.58) or received recommendation for cerclage due to a short cervical length (OR, 4.12; 95% CI, 1.55-10.99). Women with a prior full-term birth were less likely to accept 17OHP-C (OR, 0.48; 95% CI, 0.26-0.89), especially when the prior full-term birth was subsequent rather than prior to the PTB (OR, 0.19; 95% CI, 0.08-0.47). Race, obesity, and insurance status did not impact 17OHP-C use. There was no difference in the rate of sPTB between those who used and did not use 17OHP-C (37.2 vs 34.0%, P = .7). CONCLUSION: Obstetric history impacted 17OHP-C use. This study identifies biases regarding 17OHP-C at the patient level and can be used to develop strategies to increase its use. However, the similarity in the sPTB rate between users and nonusers highlights the importance of identifying specific populations where 17OHP-C is and is not effective in preventing PTB.

A prediction score to assess the risk of delivering a large for gestational age infant among obese women.

OBJECTIVE: To create a prediction score incorporating both maternal clinical characteristics and sonographic measurements in an effort to more accurately determine the risk of a large for gestational age (LGA) infant in the obese gravida. METHODS: We performed a retrospective cohort study of obese women with singleton pregnancies who had a fetal ultrasound performed between 32 and 36 weeks from 1/2008 to 12/2011. LGA was defined as birth weight (BW) ≥ 90%. Clinical characteristics associated with fetal overgrowth were included in a multivariable logistic model and stepwise backwards regression was performed to identify which risk factors generated the most parsimonious predictive model. Adjusted odds ratios of covariates in the final model were used to estimate weights for each risk factor that were summed to generate a predictive score. RESULTS: Six-hundred and sixty-nine obese women were included. The incidence of LGA infants was 11.8%. Ultrasound estimation of fetal weight alone accurately predicted LGA in 17.7 % of cases (AUC = 0.58). The most parsimonious model to accurately predict LGA at birth included 3rd trimester ultrasound EFW >90th percentile, interval from scan to delivery, and maternal history of diabetes mellitus (DM) (AUC = 0.74). A positive prediction score test result was associated with 92% specificity and 89% negative predictive value. CONCLUSIONS: A clinical prediction rule was developed and internally validated to predict the risk of an LGA infant among obese women. The ability to calculate a prediction score at the time of delivery is appealing to the clinician in order to accurately counsel women regarding the risks surrounding the delivery.

Women with preterm birth have a distinct cervicovaginal metabolome.

OBJECTIVE: Metabolomics has the potential to reveal novel pathways involved in the pathogenesis of preterm birth (PTB). The objective of this study was to investigate whether the cervicovaginal (CV) metabolome was different in asymptomatic women destined to have a PTB compared with term birth. STUDY DESIGN: A nested case-control study was performed using CV fluid collected from a larger prospective cohort. The CV fluid was collected between 20-24 weeks (V1) and 24-28 weeks (V2). The metabolome was compared between women with a spontaneous PTB (n = 10) to women who delivered at term (n = 10). Samples were extracted and prepared for analysis using a standard extraction solvent method. Global biochemical profiles were determined using gas chromatography/mass spectrometry and ultra-performance liquid chromatography/tandem mass spectrometry. An ANOVA was used to detect differences in biochemical compounds between the groups. A false discovery rate was estimated to account for multiple comparisons. RESULTS: A total of 313 biochemicals were identified in CV fluid. Eighty-two biochemicals were different in the CV fluid at V1 in those destined to have a PTB compared with term birth, whereas 48 were different at V2. Amino acid, carbohydrate, and peptide metabolites were distinct between women with and without PTB. CONCLUSION: These data suggest that the CV space is metabolically active during pregnancy. Changes in the CV metabolome may be observed weeks, if not months, prior to any clinical symptoms. Understanding the CV metabolome may hold promise for unraveling the pathogenesis of PTB and may provide novel biomarkers to identify women most at risk.

Unintended clinical consequences of the implementation of a checklist-based, low-dose oxytocin protocol.

OBJECTIVE: Standardized oxytocin protocols have been used to improve the safety and quality of obstetric care. We examined rates of chorioamnionitis and labor dystocia requiring cesarean delivery as unintended consequences of the implementation of a low-dose, checklist-based oxytocin protocol. STUDY DESIGN: We performed a retrospective cohort study of live singleton deliveries that underwent a trial of labor in two 15-month periods, comparing outcomes in those who delivered before to after protocol implementation. Patients and outcomes were identified using a combination of electronic medical records and International Classification of Diseases, 9th Revision, Clinical Modification codes. Time trend analysis was performed to evaluate for secular trends. RESULTS: A total of 8,717 women were included; 5,077 received oxytocin. Despite an unchanged rate of cesarean deliveries from before to after initiation of the protocol (15.15 vs. 14.75%, p = 0.60), deliveries after protocol implementation were generally characterized by higher rates of chorioamnionitis (7.48 vs. 5.97%, p < 0.001), longer median time from admission to delivery (524 vs. 462 minutes, p < 0.001), more cesarean deliveries performed for labor dystocia (50.62 vs. 40.92%, p < 0.001), and fewer cesarean deliveries performed for fetal distress (32.52 vs. 38.67%, p = 0.02). CONCLUSION: Low-dose oxytocin protocols are intended to increase safety, but they may have unintended consequences related to prolonged labor, and should be studied before widespread use.

Environmental variables as potential modifiable risk factors of preterm birth in Philadelphia, PA.

OBJECTIVE: To examine whether variation in neighborhood context is associated with preterm birth (PTB) outcomes and gestational age (GA) at delivery in Philadelphia, and to determine whether these associations might persist when considering relevant individual-level variables. STUDY DESIGN: We analyzed individual-level data collected for a prospective cohort study of singleton pregnancies with preterm labor. We merged block-group level data to each individual's home address. Unadjusted analyses were performed to determine the association between block-group variables and individual-level outcomes. Block-group variables identified as potential risk factors were incorporated into multivariable individual-level models to determine significance. RESULTS: We analyzed data for 817 women. The prevalence of PTB <37 weeks was 41.5%. Although in unadjusted analyses several block-group variables were associated with PTB and GA at delivery, none retained significance in individual-level multivariable models. CONCLUSION: Block-group level data were not associated with PTB outcomes or GA at delivery in Philadelphia.

Does a maternal-fetal medicine-centered labor and delivery coverage model put the 'M' back in MFM?

OBJECTIVE: Maternal morbidity is increasing in the United States. Our objectives were to examine whether a labor and delivery (L&D) provider model with regular maternal-fetal medicine (MFM) coverage decreases the rates of maternal morbidity during delivery hospitalizations and has an impact on obstetrician-gynecologist residents' perceptions of safety and education. STUDY DESIGN: We performed a retrospective cohort study to compare the rates of maternal morbidity before and after the implementation of an MFM-centered coverage model on L&D. Outcomes were identified using International Classification of Diseases, ninth revision, codes. The primary outcome was a composite of severe maternal morbidity. Additionally, obstetrician-gynecologist residents completed an anonymous survey asking them to compare coverage models, and their Council on Resident Education in Obstetrics and Gynecology examination scores were compared. RESULTS: Data from 4715 deliveries were included. There were no differences in composite morbidity or individual adverse outcomes. Most residents (81.3%) preferred the new provider model, with median 5-point Likert scores indicating perceived increases in safety and education. Mean Council on Resident Education in Obstetrics and Gynecology scores improved in the 18 residents exposed to both models. CONCLUSION: Although the MFM-centered provider model appears to have had a positive impact on residents' perceptions of safety and education, it was not associated with significant changes in severe maternal morbidity.

Isolated abdominal circumference < 5% or estimated fetal weight 10 to 19% as predictors of small for gestational age infants.

OBJECTIVES: To determine whether (1) isolated fetal abdominal circumference < 5% (AC5) in absence of growth restriction (estimated fetal weight < 10% [EFW10]) or (2) borderline fetal growth 10 to 19% (EFW10-19) predicts subsequent fetal and/or neonatal growth restriction. STUDY DESIGN: The authors performed a retrospective cohort study (January 2008 to December 2011) of women with singleton pregnancies between 26 and 36 weeks who had ≥ 1 growth ultrasound. Univariable and multivariable analyses were performed to determine the association between isolated AC5 or EFW10-19 with both subsequent sonographic diagnosis of EFW10 and neonatal diagnosis of small for gestational age (SGA). Test characteristics were calculated. RESULTS: Out of the 10,642 pregnancies, prevalence of isolated AC5, EFW10-19, EFW10, and SGA were as follows: AC5, 5.31%; EFW10-19, 13.30%; EFW10, 7.95%; and SGA, 17.63%. While screening for SGA using EFW10 alone would miss 68.34% of SGA neonates, using isolated AC5 would identify an additional 16.15% of SGA neonates with a 3.7% false positive rate. Using EFW10-19 would identify an additional 40.20% of SGA neonates with a 9.0% false positive rate. CONCLUSION: Fetuses with isolated AC5 or EFW10-19 are at an increased risk of growth restriction. Using isolated AC5 or composite EFW10-19 would identify SGA neonates that are missed using conventional sonographic definitions of growth restriction alone.

The Association between Early Artificial Amniotomy and Chorioamnionitis in Nulliparous Induction of Labor.

Objectives. To investigate whether early artificial amniotomy (AROM) <4 cm in nulliparous women admitted for induction of labor was associated with an increased rate of chorioamnionitis and cesarean section or a decreased time to vaginal delivery. Study Design. A retrospective cohort study was performed on nulliparous women with a term, singleton gestation and intact membranes who presented for induction of labor (January 2008 to December 2011). Chorioamnionitis was defined using ICD9 codes. Results. 1,567 women were enrolled; 25.4% underwent early AROM. Overall, the prevalence of chorioamnionitis was 12.4%, the rate of cesarean section was 32.2%, and the time from 4 cm cervical dilation to vaginal delivery was 413 min. Compared to women without AROM < 4 cm, early AROM did not affect overall chorioamnionitis rates (10.2 versus 13.2%, P = 0.12) but was associated with an increased cesarean section rate (40.2 versus 29.5%, P < 0.001). However, among those who delivered vaginally, AROM < 4 cm decreased the rate of chorioamnionitis (8.4 versus 14.6%, P = 0.01), which persisted when controlling for potential confounders (OR 0.55, 95% CI 0.33-0.92), and decreased the time from 4 cm dilation to vaginal delivery (329 versus 472 min, P < 0.001). Conclusions. Our findings do not suggest that early AROM is associated with an increased rate of clinical chorioamnionitis.

Prenatal inflammation is associated with adverse neonatal outcomes.

OBJECTIVE: The purpose of this study was to determine whether prenatal inflammation (as assessed by clinical chorioamnionitis, maternal temperature >38°C, or histologic chorioamnionitis) is associated with a composite adverse neonatal outcome. STUDY DESIGN: We performed a prospective cohort study of women at 22 weeks to 33 weeks 6 days' gestation with symptoms of labor (April 2009 to March 2012). Relevant maternal and neonatal exposures and outcomes were recorded. Multivariable logistic regression was performed to determine the association between prenatal inflammation and neonatal outcomes that were controlled for potential confounders. RESULTS: We analyzed 871 mother-infant pairs. The preterm birth rate was 42.0%. When we controlled for infant sex and modified the data by gestational age at delivery, prenatal inflammation remains a significant risk factor for adverse neonatal outcomes, despite advancing gestational age: clinical chorioamnionitis at 32 weeks' gestation (odds ratio [OR], 3.12; 95% confidence interval [CI], 1.02-9.52], at 36 weeks' gestation (OR, 8.88; 95% CI, 4.32-18.25), and at 40 weeks' gestation (OR, 25.30; 95% CI, 9.25-69.19); maternal temperature >38°C at 32 weeks' gestation (OR, 3.18; 95% CI, 0.66-15.42), at 36 weeks gestation (OR, 8.40; 95% CI, 3.60-19.61), and at 40 weeks gestation (OR, 22.19; 95% CI, 8.15-60.44); histologic chorioamnionitis at 32 weeks gestation (OR, 1.25; 95% CI, 0.64-2.46), at 36 weeks gestation (OR, 2.56; 95% CI, 1.54-4.23), and at 40 weeks gestation (OR, 5.23; 95% CI, 1.95-13.99). CONCLUSION: The protective association with advancing gestational age is diminished when prenatal inflammation is present.

Biomarkers and cervical length to predict spontaneous preterm birth in asymptomatic high-risk women.

OBJECTIVE: To investigate whether biomarkers from different pathways of spontaneous preterm birth (cervical membrane degradation [fetal fibronectin], cervical remodeling [soluble E-cadherin], and inflammation (elafin, surfactant protein-D, interleukin-6 [IL-6]) were superior to one biomarker alone in predicting preterm birth. Our secondary objective was to examine the association of these biomarkers with cervical length in predicting preterm birth. METHODS: We performed a single-center, prospective cohort study from August 2011 to November 2012 of asymptomatic women at risk for spontaneous preterm birth as a result of obstetric and gynecologic history. Cervicovaginal fluid and cervical length measurements were collected at two time points (20-23 6/7 weeks and 24-27 6/7 weeks of gestation). RESULTS: Among the 104 women with complete data, the preterm birth rate was 24.5%. Prior preterm birth (P=.006) and cervical length at visit 1 (P=.003) were significantly associated with preterm birth, whereas fetal fibronectin and median biomarker levels (elafin, soluble E-cadherin, IL-6) were not. Median surfactant protein-D levels at visit 1 by preterm birth status were statistically but not clinically different (0.44 ng/mL compared with 0.40 ng/mL, P<.001). Analyses of biomarkers from more than one pathway were not superior to single biomarker analyses in predicting prematurity. Neither inclusion of biomarkers nor fetal fibronectin improved the predictive ability of cervical length alone. CONCLUSION: Cervical length assessment and obstetric history but not fetal fibronectin or biomarkers were useful in the risk stratification of women identified to be at greatest risk for spontaneous preterm birth. LEVEL OF EVIDENCE: II.

Can transabdominal ultrasound identify women at high risk for short cervical length?

OBJECTIVE: To determine whether transabdominal cervical length screening could identify women at high risk for having a short cervix on transvaginal ultrasound. DESIGN: Retrospective cohort study. SETTING: Tertiary referral center. POPULATION: A total of 703 patients with a singleton pregnancy at 18 to 23(+6) weeks of gestation who underwent transabdominal and transvaginal cervical length assessment during anatomy ultrasound at a single institution between January 2007 and October 2011. METHODS: Electronic medical records were reviewed to identify women who met the study criteria. MAIN OUTCOME MEASURES: The primary outcome was the number of women with a short transabdominal cervical length (defined as ≤ 30 mm) who needed to undergo transvaginal ultrasound to detect one woman with a short transvaginal cervical length of ≤ 20 mm. RESULTS: In all, 703 patients were included in the primary analysis; 3.42 women with transabdominal cervical length ≤ 30 mm needed to undergo transvaginal ultrasound to detect one woman with transvaginal ultrasound cervical length ≤ 20 mm. Of women with short transvaginal cervical length ≤ 20 mm, 89.8% had a transabdominal measurement ≤ 30 mm and 96.7% had a transabdominal measurement ≤ 33 mm. CONCLUSIONS: Screening of transabdominal cervical length may represent a useful strategy for detecting women with short cervix on transvaginal ultrasound.

The role and challenges of biomarkers in spontaneous preterm birth and preeclampsia.

Biomarkers associated with spontaneous preterm birth and preeclampsia have been discovered in patients who experience these adverse obstetrical outcomes. The identification of such biomarkers holds promise in both facilitating the early identification of those patients at greatest risk and enhancing our understanding of these disease processes to determine therapeutic interventions. To that end, our objective was to review the existing literature to determine the utility of biomarkers in the risk stratification of spontaneous preterm birth and preeclampsia. We found that despite the promise of some biomarkers in identifying patients at increased risk for spontaneous preterm birth and/or preeclampsia, the use of biomarkers in clinical practice to predict adverse obstetrical outcome remains challenging. Although data from small discovery studies may be encouraging, progress with biomarker research remains limited by the lack of validation of these discovered biomarkers. Furthermore, owing to the heterogeneity of existing studies, generalizable conclusions are difficult to understand, meta-analyses are challenging to perform, and agreement on cut-point standardization is difficult. The identification of an abnormal biomarker level does not guarantee whether or when an adverse clinical event might occur. Our lack of understanding of the true etiologies of these disease processes leaves us without definitive interventions to prevent spontaneous preterm birth and preeclampsia from occurring.

Can vibroacoustic stimulation improve the efficiency of a tertiary care antenatal testing unit?

OBJECTIVE: Our primary objective was to determine whether vibroacoustic stimulation (VAS) decreases time to fetal reactivity in the antenatal testing unit (ATU) of a tertiary care center. METHODS: We performed a prospective, quality assurance initiative to determine whether VAS could increase the efficiency of our ATU. On pre-specified "VAS days," VAS was applied for 3 s, if the non-stress test was non-reactive in the first 10 min. Generalized estimating equations models were used to account for within subject correlation due to multiple appointments per patient. RESULTS: VAS use was associated with a 3.76-min reduction in time to reactivity (21.79 vs 25.55, p = 0.011) and a 56% reduction in the need for a biophysical profile (OR: 0.44, 95% CI: 0.21-0.90). Overall, however, we found no significant decrease in time spent on the monitor or in the ATU. CONCLUSION: Compliance with a strict VAS protocol may improve the efficiency of increasingly busy ATUs.

Examining the correlation between placental and serum placenta growth factor in preeclampsia.

OBJECTIVE: Decreased levels of serum placenta growth factor (PlGF) are associated with preeclampsia. We sought to determine whether serum and placental levels of PlGF (sPlGF and pPlGF) are associated with preeclampsia and whether there is a correlation between serum and placental PlGF levels. STUDY DESIGN: These analyses were part of a larger, prospective, case-control study. Cases were women with preeclampsia. Controls were women without preeclampsia who delivered at term. Analyses included nonparametric tests to compare medians, logistic regression to estimate odds, and calculation of correlation coefficients. RESULTS: Twenty-four cases (10 preterm, 14 term) were compared with 14 controls. Median levels of PlGF were significantly lower in cases than controls (pPlGF: 232.6 vs 363.4 pg/mL, P = .02; sPlGF: 85.5 vs 274.4 pg/mL, P < .001). Serum and placental PlGF were correlated (overall: 39%, P = .006; cases with preterm preeclampsia and growth restriction: 87%, P = .02). CONCLUSION: Serum and placental PlGF are independently associated with preeclampsia and correlated with each other.

Clinical prediction rules for preterm birth in patients presenting with preterm labor.

OBJECTIVE: To develop prediction rules to identify which women with preterm labor are at greatest risk for delivery within 10 days and before 37 weeks of gestation using demographic and clinical risk factors alone. METHODS: We analyzed data collected for a prospective cohort study of singleton pregnancies at 22-33 6/7 weeks of gestation with preterm labor. Potential risk factors were included in multivariable logistic models for each outcome. Using backwards regression, we identified combinations of risk factors that generated the most parsimonious yet predictive models. Adjusted odds ratios of covariates in the final models were used to estimate weights for each risk factor and were summed to generate a predictive score. The score associated with the highest negative predictive value was defined as a positive test result for each outcome. Bootstrapping techniques internally validated the scoring systems. RESULTS: We include data from 583 women. The risk of delivery within 10 days was 15.4% (n=90) and before 37 weeks of gestation it was 35.0% (n=204). The final model for delivery within 10 days included initial cervical dilatation, no prenatal care, and tobacco use (area under curve=0.75), and for delivery before 37 weeks of gestation it included initial cervical dilatation, obstetric history, and tobacco use (area under the curve=0.73). A positive test result was associated with 84% sensitivity, 51% specificity, 24% positive predictive value, and 95% negative predictive value in predicting delivery within 10 days and 79% sensitivity, 50% specificity, 46% positive predictive value, and 82% negative predictive value in predicting delivery before 37 weeks of gestation. CONCLUSION: Based on their strong negative predictive values, these prediction rules could identify patients who do not require intensive monitoring when they present with preterm labor. LEVEL OF EVIDENCE: II.