Discussion: 'Predicting spontaneous preterm birth' by Esplin et al.

In the roundtable that follows, clinicians discuss a study published in this issue of the Journal in light of its methodology, relevance to practice, and implications for future research. Article discussed: Esplin MS, Merrell K, Goldenberg R, et al; the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units. Proteomic identification of serum peptides predicting subsequent spontaneous preterm birth.

The relationship between maternal body mass index and tobacco use on small-for-gestational-age infants.

We sought to estimate the association between prepregnancy body mass index (BMI) and small-for-gestational-age (SGA) neonates and to determine if there is a synergistic effect of tobacco use on SGA across all BMI strata. We performed a retrospective cohort study of 65,104 patients seen for second-trimester ultrasound. BMI was categorized into underweight, normal weight, overweight, and obese.

First-trimester prediction of preeclampsia using metabolomic biomarkers: a discovery phase study.

Objective: We tested the hypothesis that first-trimester metabolic biomarkers offered a unique profile in women with preeclampsia (PE) in the second half of pregnancy, compared with controls.

Method: We conducted a nested case-control study within a prospective cohort of pregnant women followed from the first-trimester to delivery. Cases were those who developed PE at any gestational age, and these were compared with a control group without adverse pregnancy outcome, matched for gestational age within 3 days.

First-trimester placental protein 13, PAPP-A, uterine artery Doppler and maternal characteristics in the prediction of pre-eclampsia.

Objective: To test the hypothesis that a combination of PP13, PAPP-A and first-trimester uterine artery Doppler would improve the prediction of pre-eclampsia.

Methods: This is a prospective cohort study of pregnant women followed from the first-trimester to delivery. PP13 and PAPP-A were determined by immunoassay of maternal serum at 11-14 weeks', when uterine artery Doppler measurements were assessed.

Echogenic bowel on second-trimester ultrasonography: evaluating the risk of adverse pregnancy outcome.

Objective: To estimate if echogenic bowel diagnosed on second-trimester ultrasonography has an independent risk association with intrauterine growth restriction (IUGR) and intrauterine fetal demise.

Methods: This is a retrospective cohort study of all patients with singleton gestations who presented to our institution for second-trimester ultrasonography between 1990 and 2008. Study groups were defined by the presence or absence of echogenic bowel.

Comparative efficiency of measures of early fetal growth restriction for predicting adverse perinatal outcomes.

Objective: To estimate the comparative efficiency of first-trimester fetal growth restriction, second-trimester fetal growth restriction, and first-to-second-trimester growth lag for predicting adverse perinatal outcomes.

Methods: This is a retrospective cohort study of pregnancies with reliable dating based on last menstrual periods and first-trimester ultrasound examinations. Pregnancies with multiple fetuses, aneuploidy, and major structural anomalies were excluded.

Diagnosis and management of fetal growth restriction.

Fetal growth restriction (FGR) remains a leading contributor to perinatal mortality and morbidity and metabolic syndrome in later life. Recent advances in ultrasound and Doppler have elucidated several mechanisms in the evolution of the disease. However, consistent classification and characterization regarding the severity of FGR is lacking.

Prediction of intrauterine fetal death in small-for-gestational-age fetuses: impact of including ultrasound biometry in customized models.

Objective: Customized growth charts derived from maternal demographic characteristics alone have been shown to improve the prediction of pregnancy complications compared to population growth curves. We sought to estimate the impact of adding ultrasound biometric parameters to the customized chart for the prediction of intrauterine fetal death (IUFD).

Methods: A retrospective cohort study was undertaken using an ultrasound database including singleton pregnancies followed between 16 and 20 weeks' gestation.

Perinatal outcomes in women with subchorionic hematoma: a systematic review and meta-analysis.

Objective: To estimate the association between subchorionic hematoma and adverse perinatal outcomes.

Data Sources: MEDLINE, EMBASE, and the Cochrane Library.

Methods Of Study Selection: We searched English language publications from January 1981 to August 2010 for cohort and case-control studies evaluating subchorionic hematoma and perinatal outcomes.

The genetic sonogram: comparing the use of likelihood ratios versus logistic regression coefficients for Down syndrome screening.

Objectives: The purpose of this study was to compare the screening efficiency for Down syndrome using likelihood ratios versus logistic regression coefficients.

Methods: We conducted a retrospective study of women at increased risk for Down syndrome referred for a second-trimester genetic sonogram. Likelihood ratios were calculated by multiplying the risk ratio from maternal serum screening by the likelihood ratios of sonographic markers.

Revisiting the risk for aneuploidy in fetuses with isolated pyelectasis.

Objective: Previous studies are contradictory with regard to the association of isolated pyelectasis and aneuploidy. Our objective was to test the hypothesis that isolated pyelectasis is associated with aneuploidy and calculate likelihood ratios using a large ultrasound database.

Methods: A retrospective cohort study of pregnancies presenting to our prenatal ultrasound unit at 16 to 22 weeks was conducted.

Perinatal outcomes in women with preeclampsia and superimposed preeclampsia: do they differ?

Objective: The purpose of this study was to determine whether superimposed preeclampsia results in worse perinatal outcomes than preeclampsia.

Study Design: We conducted a retrospective cohort study using our perinatal database (1990-2008). Perinatal outcomes among women with chronic hypertension (n = 1032), superimposed preeclampsia (n = 489), and preeclampsia (n = 4217) were compared with outcomes of control subjects (n = 57,103).

Assessing the optimal definition of oligohydramnios associated with adverse neonatal outcomes.

Objectives: The purpose of this study was to compare the use of an amniotic fluid index (AFI) less than 5 cm to the use of an AFI less than the fifth percentile for gestational age in predicting adverse perinatal outcomes.

Methods: This was a retrospective cohort study from 1998 to 2008. Patients with an AFI less than 5 cm and those with an AFI less than the fifth percentile were compared to patients with a normal AFI.

The role of serum markers and uterine artery Doppler in identifying at-risk pregnancies.

Measures of placental dysfunction, including maternal serum analytes and Doppler studies, have been linked to adverse pregnancy outcomes, although the predictive ability of any single one is poor. Improved knowledge of the multifactorial nature of many of the adverse outcomes of pregnancy has sparked interest in the use of multi-parameter models that combine maternal serum analytes with measures of placental structure and blood flow. The combination of various first-trimester and second-trimester analytes and uterine artery Doppler screening show promise as potential screening tools, but large prospective studies are needed to further define their role in clinical practice.

Staples compared with subcuticular suture for skin closure after cesarean delivery: a systematic review and meta-analysis.

Objective: To estimate whether staples or subcuticular suture closure is associated with a higher risk of wound complications when used for transverse skin incisions after cesarean delivery.

Data Sources: A systematic review and meta-analysis were performed through electronic database searches (MEDLINE, Cochrane, and Trial Registries).

Methods Of Study Selection: We searched electronic databases from 1966 to September 2010 for randomized controlled trials (RCTs) and prospective cohort studies comparing staples to subcuticular sutures after cesarean delivery.

First-trimester serum analytes, biophysical tests and the association with pathological morphometry in the placenta of pregnancies with preeclampsia and fetal growth restriction.

Objective: We test the hypothesis that first-trimester serum analytes, 4-D power Doppler placental vascular indices and uterine artery Doppler (UAD) predicts abnormal placental morphometry in pregnancies with preeclampsia (PE) and fetal growth restriction (FGR).

Study Design: Maternal serum analytes (PAPP-A, hCG, ADAM12s, and PP13), bilateral UADs, and placental vascular indices were measured at 11-14 weeks in a nested-case control study within a prospective cohort of women followed from the first-trimester to delivery. Vascularization index (VI), flow index (FI), and vascularization flow index (VFI) were obtained from 4-D power Doppler histograms.

Placental volume and vascular flow assessed by 3D power Doppler and adverse pregnancy outcomes.

Objective: To estimate the utility of first-trimester 3D-placental volume and vascular flow indices in the prediction of adverse pregnancy outcomes.

Methods: A prospective cohort study including women with singleton pregnancies seen between 11 and 14 weeks as part of a screening program for aneuploidy. Placental volume and vascularization indices were obtained using 3D power Doppler imaging and the VOCAL technique.

Vaginal birth after cesarean for cephalopelvic disproportion: effect of birth weight difference on success.

Objective: To estimate the effect of birth weight difference between the current and index pregnancy on vaginal birth after cesarean (VBAC) failure in patients whose prior cesarean was for cephalopelvic disproportion (CPD).

Methods: This was a retrospective cohort study of women with one cesarean for CPD, comparing the rate of VBAC failure in women whose infant was smaller, the same, or larger in the VBAC attempt compared with cesarean. The primary outcome was VBAC attempt failure, defined as a patient who attempted VBAC but subsequently required a cesarean delivery for any indication.

Discussion: 'Testing for biomarkers after ASC-US Pap smears' by Lin et al.

In the roundtable that follows, clinicians discuss a study published in this issue of the Journal in light of its methodology, relevance to practice, and implications for future research. Article discussed: Lin CJ, Lai H-C, Wang KH, et al. Testing for methylated PCDH10 or WT1 is superior to the HPV test in detecting severe neoplasms (CIN3 or greater) in the triage of ASC-US smear results.