Tensile Mechanical Properties and Dynamic Collagen Fiber Re-Alignment of the Murine Cervix are Dramatically Altered Throughout Pregnancy

The cervix is a unique organ able to dramatically change its shape and function by serving as a physical barrier for the growing fetus and then undergoing dramatic dilation allowing for delivery of a term infant. As a result, the cervix endures changing mechanical forces from the growing fetus. There is an emerging concept that the cervix may change or remodel "early" in many cases of spontaneous preterm birth (sPTB). However, the mechanical role of the cervix in both normal and preterm birth remains unclear. Therefore, the primary objective of this study was to determine the mechanical and structural responses of murine cervical tissue throughout a normal gestational time course. In this study, both tissue structural and material properties were determined via a quasi-static tensile load-to-failure test, while simultaneously obtaining dynamic collagen fiber re-alignment via cross-polarization imaging. This study demonstrated that the majority of the mechanical properties evaluated decreased at midgestation and not just at term, while collagen fiber re-alignment occurred earlier in the loading curve for cervices at term. This suggests that although structural changes in the cervix occur throughout gestation, the differences in material properties function in combination with collagen fiber re-alignment as mechanical precursors to regulate term gestation. This work lays a foundation for investigating cervical biomechanics and the role of the cervix in preterm birth.

Role of early second-trimester uterine artery Doppler screening to predict small-for-gestational-age babies in nulliparous women

BACKGROUND

Trophoblastic invasion of the uterine spiral arteries substantially increases compliance to accommodate increased blood flow to the placenta. Failure of this process impedes uterine artery blood flow, and this may be detected by uterine artery Doppler flow studies. However, the clinical utility of uterine artery Doppler flow studies in the prediction of adverse pregnancy outcomes in a general population remains largely unknown.

OBJECTIVE

We sought to determine the utility of early second-trimester uterine artery Doppler studies as a predictor of small-for-gestational-age neonates.

STUDY DESIGN

Nulliparous women with a viable singleton pregnancy were recruited during their first trimester into an observational prospective cohort study at 8 institutions across the United States. Participants were seen at 3 study visits during pregnancy and again at delivery. Three indices of uterine artery Doppler flow (resistance index, pulsatility index, and diastolic notching) were measured in the right and left uterine arteries between 16 weeks 0 days' and 22 weeks 6 days' gestation. Test characteristics for varying thresholds in the prediction of small for gestational age (defined as birthweight <5th percentile for gestational age [Alexander growth curve]) were evaluated.

RESULTS

Uterine artery Doppler indices, birthweight, and gestational age at birth were available for 8024 women. Birthweight <5th percentile for gestational age occurred in 358 (4.5%) births. Typical thresholds for the uterine artery Doppler indices were all associated with birthweight <5th percentile for gestational age (P < .0001 for each), but the positive predictive values for these cutoffs were all <15% and areas under receiver operating characteristic curves ranged from 0.50-0.60. Across the continuous scales for these measures, the areas under receiver operating characteristic curves ranged from 0.56-0.62. Incorporating maternal age, early pregnancy body mass index, race/ethnicity, smoking status prior to pregnancy, chronic hypertension, and pregestational diabetes in the prediction model resulted in only modest improvements in the areas under receiver operating characteristic curves ranging from 0.63-0.66.

CONCLUSION

In this large prospective cohort, early second-trimester uterine artery Doppler studies were not a clinically useful test for predicting small-for-gestational-age babies.

Exposure to intrauterine inflammation alters metabolomic profiles in the amniotic fluid, fetal and neonatal brain in the mouse

INTRODUCTION

Exposure to prenatal inflammation is associated with diverse adverse neurobehavioral outcomes in exposed offspring. The mechanism by which inflammation negatively impacts the developing brain is poorly understood. Metabolomic profiling provides an opportunity to identify specific metabolites, and novel pathways, which may reveal mechanisms by which exposure to intrauterine inflammation promotes fetal and neonatal brain injury. Therefore, we investigated whether exposure to intrauterine inflammation altered the metabolome of the amniotic fluid, fetal and neonatal brain. Additionally, we explored whether changes in the metabolomic profile from exposure to prenatal inflammation occurs in a sex-specific manner in the neonatal brain.

METHODS

CD-1, timed pregnant mice received an intrauterine injection of lipopolysaccharide (50 μg/dam) or saline on embryonic day 15. Six and 48 hours later mice were sacrificed and amniotic fluid, and fetal brains were collected (n = 8/group). Postnatal brains were collected on day of life 1 (n = 6/group/sex). Global biochemical profiles were determined using ultra performance liquid chromatography/tandem mass spectrometry (Metabolon Inc.). Statistical analyses were performed by comparing samples from lipopolysaccharide and saline treated animals at each time point. For the P1 brains, analyses were stratified by sex.

RESULTS/CONCLUSIONS

Exposure to intrauterine inflammation induced unique, temporally regulated changes in the metabolic profiles of amniotic fluid, fetal brain and postnatal brain. Six hours after exposure to intrauterine inflammation, the amniotic fluid and the fetal brain metabolomes were dramatically altered with significant enhancements of amino acid and purine metabolites. The amniotic fluid had enhanced levels of several members of the (hypo) xanthine pathway and this compound was validated as a potential biomarker. By 48 hours, the number of altered biochemicals in both the fetal brain and the amniotic fluid had declined, yet unique profiles existed. Neonatal pups exposed to intrauterine inflammation have significant alterations in their lipid metabolites, in particular, fatty acids. These sex-specific metabolic changes within the newborn brain offer an explanation regarding the sexual dimorphism of certain psychiatric and neurobehavioral disorders associated with exposure to prenatal inflammation.

A Social Media Peer Group for Mothers To Prevent Obesity from Infancy: The Grow2Gether Randomized Trial

BACKGROUND

Few studies have addressed obesity prevention among low-income families whose infants are at increased obesity risk. We tested a Facebook peer-group intervention for low-income mothers to foster behaviors promoting healthy infant growth.

METHODS

In this randomized controlled trial, 87 pregnant women (Medicaid insured, BMI ≥25 kg/m2) were randomized to the Grow2Gether intervention or text message appointment reminders. Grow2Gether participants joined a private Facebook group of 9-13 women from 2 months before delivery until infant age 9 months. A psychologist facilitated groups featuring a curriculum of weekly videos addressing feeding, sleep, parenting, and maternal well-being. Feasibility was assessed using the frequency and content of participation, and acceptability using surveys. Maternal beliefs and behaviors and infant growth were assessed at birth, 2, 4, 6, and 9 months. Differences in infant growth between study arms were explored. We conducted intention-to-treat analyses using quasi-least-squares regression.

RESULTS

Eighty-eight percent (75/85) of intervention participants (42% (36/85) food insecure, 88% (75/85) black) reported the group was helpful. Participants posted 30 times/group/week on average. At 9 months, the intervention group had significant improvement in feeding behaviors (Infant Feeding Style Questionnaire) compared to the control group (p = 0.01, effect size = 0.45). Intervention group mothers were significantly less likely to pressure infants to finish food and, at age 6 months, give cereal in the bottle. Differences were not observed for other outcomes, including maternal feeding beliefs or infant weight-for-length.

CONCLUSIONS

A social media peer-group intervention was engaging and significantly impacted certain feeding behaviors in families with infants at high risk of obesity.

Women with Symptomatic Preterm Birth Have a Distinct Cervicovaginal Metabolome

Objective The objective was to determine if women with symptoms of preterm labor who ultimately have a spontaneous preterm birth (sPTB) have a distinct cervicovaginal (CV) metabolome compared with women who deliver at term.

Study Design A nested case–control study of women presenting with symptoms of preterm labor was performed. CV fluid was collected from women between 22 and 336/7 weeks' gestation. The CV metabolome was compared between women with sPTB (n = 20) and women who delivered at term (n = 30). Global biochemical profiles were determined using ultraperformance liquid chromatography/tandem mass spectrometry. Welch's two-sample t-test was used to identify metabolites that differed significantly. Level of significance was defined as p ≤ 0.05.

Results Eighty-eight percent of women were African-American and none had a prior history of sPTB. A total of 301 metabolites were identified in CV fluid. Thirty metabolites were significantly different in women with preterm birth compared with term birth. Two metabolites (mannitol and methyl phosphate) were significantly upregulated, and the remaining 28 metabolites were significantly downregulated and consisted of medium chain-fatty acids and collagen degradation markers.

Conclusion The CV metabolome is significantly altered among women who present with preterm labor symptoms and ultimately have a sPTB.

Obesity and the association with maternal mental health symptoms

OBJECTIVE

To evaluate the association between maternal obesity and mood disorders including depression, anxiety, stress, and pregnancy-specific stress during pregnancy.

STUDY DESIGN

This was a planned secondary analysis of a prospective cohort study investigating factors associated with preterm delivery. The cohort included women who initiated prenatal care before 20 weeks with a singleton pregnancy. Maternal mental health was assessed using four standard psychosocial behavioral measures to screen for depression, pregnancy-specific stress, anxiety, and stress. Screen positive scores for each tool were established based on previously published "high" scores.

RESULTS

Of the 1010 women included in the cohort, 355 (35.1%) were obese. There was no significant difference in the number of obese women with stress (64.2% versus 68.4%, p = 0.18), pregnancy-specific stress (26.2% versus 22.1%, p = 0.15), or anxiety (38.6% versus 41.2%, p = 0.42); however, a greater number of obese women did report symptoms consistent with major depression when compared to women with BMIs <30 (30.4% versus 21.2%, p < 0.01).

CONCLUSION

Obese women had higher rates of depression in early pregnancy compared to nonobese women. As many of the health behavior interventions for obese women during pregnancy have proven ineffective, incorporating depression screening and treatment into prenatal care may improve perinatal outcomes.

Predictive Accuracy of Serial Transvaginal Cervical Lengths and Quantitative Vaginal Fetal Fibronectin Levels for Spontaneous Preterm Birth Among Nulliparous Women

Importance

Spontaneous preterm birth is a leading cause of infant mortality. Prediction, largely based on prior pregnancy outcomes, is not possible in women pregnant for the first time.

Objective

To assess the accuracy of universal screening to predict spontaneous preterm birth in nulliparous women using serial measurements of vaginal fetal fibronectin levels and cervical length.

Design, Settings, and Participants

A prospective observational cohort study of nulliparous women with singleton pregnancies, from 8 clinical sites across the United States between October 2010 and May 2014. Women and clinicians were blinded to results unless cervical shortening less than 15 mm was identified.

Exposures

Transvaginal cervical length and quantitative vaginal fetal fibronectin levels were reviewed at 2 study visits 4 or more weeks apart.

Main Outcomes and Measures

Spontaneous preterm birth at less than 37 weeks was the primary outcome. Cervical length and quantitative fetal fibronectin were considered independently and together at each visit. Measurement distributions were compared for spontaneous preterm birth vs all other births. Spontaneous preterm birth before 32 weeks was a secondary outcome.

Results

The study included 9410 women (median age, 27.0 [interquartile range, 9.0] years; 60.7% non-Hispanic white, 13.8% non-Hispanic black, 16.5% Hispanic, 4.0% Asian, and 5.1% other), of whom 474 (5.0%) had spontaneous preterm births, 335 (3.6%) had medically indicated preterm births, and 8601 (91.4%) had term births. Among women with spontaneous preterm birth, cervical length of 25 mm or less occurred in 35 of 439 (8.0%) at 16 to 22 weeks' gestation and in 94 of 403 (23.3%) at 22 to 30 weeks' gestation. Fetal fibronectin levels of 50 ng/mL or greater at 16 to 22 weeks identified 30 of 410 women (7.3%) with spontaneous preterm birth and 31 of 384 (8.1%) at 22 to 30 weeks. The area under the receiver operating characteristic curve for screening between 22 and 30 weeks for fetal fibronectin level alone was 0.59 (95% CI, 0.56-0.62), for transvaginal cervical length alone was 0.67 (95% CI, 0.64-0.70), and for the combination as continuous variables was 0.67 (95% CI, 0.64-0.70).

Conclusions and Relevance

Among nulliparous women with singleton pregnancies, quantitative vaginal fetal fibronectin and serial transvaginal ultrasound cervical length had low predictive accuracy for spontaneous preterm birth. These findings do not support routine use of these tests in such women.

Psychometric properties of stress and anxiety measures among nulliparous women

OBJECTIVE

To examine the psychometric properties of three measures, the perceived stress scale (PSS), pregnancy experience scale (PES), and state trait anxiety inventory (STAI), for assessing stress and anxiety during pregnancy among a large sample of nulliparous women.

METHODS

The sample included 10,002 pregnant women participating in the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be (nMoM2b). Internal consistency reliability was assessed with Cronbach's alpha and factorial validity with confirmatory factor analyses. Intraclass correlations (ICCs) were calculated to determine stability of PSS scales over time. Psychometric properties were examined for the overall sample, as well as subgroups based on maternal age, race/ethnicity and language.

RESULTS

All three scales demonstrated good internal consistency reliability. Confirmatory factor analyses supported the factor structures of the PSS and the PES. However, a one-factor solution of the trait-anxiety subscale from the STAI did not fit well; a two-factor solution, splitting the items into factors based on direction of item wording (positive versus negative) provided a better fit. Scores on the PSS were generally stable over time (ICC = 0.60). Subgroup analyses revealed a few items that did not perform well on Spanish versions of the scales.

CONCLUSION

Overall, the scales performed well, suggesting they could be useful tools for identifying women experiencing high levels of stress and anxiety during pregnancy and allowing for the implementation of interventions to help reduce maternal stress and anxiety.

Mechanical and Pharmacologic Methods of Labor Induction: A Randomized Controlled Trial

OBJECTIVE

To evaluate the effectiveness of four commonly used induction methods.

METHODS

This randomized trial compared four induction methods: misoprostol alone, Foley alone, misoprostol-cervical Foley concurrently, and Foley-oxytocin concurrently. Women undergoing labor induction with full-term (37 weeks of gestation or greater), singleton, vertex-presenting gestations, with no contraindication to vaginal delivery, intact membranes, Bishop score 6 or less, and cervical dilation 2 cm or less were included. Women were enrolled only once during the study period. Our primary outcome was time to delivery. Neither patients nor health care providers were blinded to assigned treatment group because examinations are required for placement of all methods; however, research personnel were blinded during data abstraction. A sample size of 123 per group (n=492) was planned to compare the four groups pairwise (P≤.008) with a 4-hour reduction in delivery time considered clinically meaningful.

RESULTS

From May 2013 through June 2015, 997 women were screened and 491 were randomized and analyzed. Demographic and clinical characteristics were similar among the four treatment groups. When comparing all induction method groups, combination methods achieved a faster median time to delivery than single-agent methods (misoprostol-Foley: 13.1 hours, Foley-oxytocin: 14.5 hours, misoprostol: 17.6 hours, Foley: 17.7 hours, P<.001). When censored for cesarean delivery and adjusting for parity, women who received misoprostol-Foley were almost twice as likely to deliver before women who received misoprostol alone (hazard ratio 1.92, 95% confidence interval [CI] 1.42-2.59) or Foley alone (hazard ratio 1.87, 95% CI 1.87 1.39-2.52), whereas Foley-oxytocin was not statistically different from single-agent methods.

CONCLUSION

After censoring for cesarean delivery and adjusting for parity, misoprostol-cervical Foley resulted in twice the chance of delivering before either single-agent method.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, https://clinicaltrials.gov, NCT01916681.

Placental microRNA Expression Is Not Altered by Maternal Obesity and Fetal Overgrowth

Objective The epigenetic mechanisms underlying fetal metabolic programming are poorly understood. We studied whether obesity is associated with alterations in placental miRNA expression. Study Design A cross-sectional study was performed, including (1) normal-weight women (BMI 20-24.9 kg/m²) and normal-birth-weight (BW) infants (2,700-3,500 g) (n = 20), (2) normal-weight and macrosomic infants (BW ≥ 4,000 g) (n = 10), (3) obese (BMI ≥ 35 kg/m²) and normal BW infants (n = 16), and (4) obese and macrosomic infants (n = 10). All had term deliveries (37-41 weeks) and normal glucose tolerance (1 hour GCT < 7.2 mmol/L [130 mg/dL]). The expression of 5,639 placental miRNAs was assessed using miRNA microarray. Differential miRNA expression was determined using two-way ANOVA and pairwise contrasts, with the Benjamini-Hochberg (BH) correction. MiRNAs with Z-scores ≥ 2 and false discovery rate (FDR) < 20% were considered significant. Results Principal components analysis demonstrated similar global miRNA expression profiles among groups. Of 5,639 miRNAs, only 5 were significantly different between obese and controls, which were not validated by quantitative polymerase reaction. Conclusion There was no difference in placental miRNA expression associated with obesity or overgrowth. Aberrant placental miRNA expression is an unlikely mechanism underlying fetal metabolic programming related to maternal obesity.

Induction, labor length and mode of delivery: the impact on preeclampsia-related adverse maternal outcomes

OBJECTIVE

The objectives were to evaluate whether induction, specifically prolonged labor, was associated with adverse maternal outcomes related to preeclampsia with severe features (PEC-S) and whether cesarean affected the rate.

STUDY DESIGN

This was a retrospective cohort study of women with PEC-S ⩾34 weeks who were diagnosed either before planned cesarean or before induction/latent labor. The primary outcome was a composite adverse maternal outcome related to PEC-S.

RESULTS

The final cohort comprised 193 women (n=172 with labor and n=21 with planned cesarean). The prevalence of the outcome was 15.5%. Women exposed to labor did not have a higher rate compared with planned cesarean (16.3% vs 9.5%, P=0.4). Adjusting for confounders, women with a cesarean after prolonged labor had a 10-fold higher adverse outcome risk compared with women with a planned cesarean (adjusted odds ratio (aOR) 9.7 (1.2 to 78.6), P=0.03) or with a vaginal delivery <24 h (aOR 9.7 (1.4 to 67.4), P=0.02).

CONCLUSION

Prolonged labor and cesarean in labor were both associated with an increase in our outcome.

Ultrasound Measurement of the Fetal Adrenal Gland as a Predictor of Spontaneous Preterm Birth

OBJECTIVE

To estimate whether ultrasound measurement of the fetal adrenal gland remote from delivery in asymptomatic women can accurately predict spontaneous preterm birth.

METHODS

We conducted a prospective multicenter observational nested cohort study of asymptomatic nulliparous women with a singleton pregnancy to study adverse pregnancy outcomes. Between 22 0/7 and 30 6/7 weeks of gestation, credentialed ultrasonographers measured the width (width), length (length), and, when able, depth (depth) of the "fetal zone" of the fetal adrenal gland as well as the width (Width), length (Length), and depth (Depth) of the total gland. We used the ratios of each measurement (width/Width, length/Length, and depth/Depth) to control for variation in adrenal size by gestational age. The accuracy of each ratio measurement in predicting spontaneous preterm birth at less than 37 0/7 weeks of gestation and spontaneous preterm birth at less than 34 0/7 weeks of gestation was assessed by receiver operating characteristic curves using area under the curve.

RESULTS

Pregnancy outcomes were available for 1,697 women with one or more fetal adrenal gland measurements. Spontaneous preterm birth at less than 37 0/7 weeks of gestation and spontaneous preterm birth at less than 34 0/7 weeks of gestation occurred in 82 (4.8%) and six women (0.4%), respectively. None of the fetal adrenal gland measurements distinguished spontaneous preterm birth from term birth. The areas under the curve (95% confidence intervals) for spontaneous preterm birth at less than 37 0/7 weeks of gestation were 0.51 (0.45-0.58), 0.50 (0.44-0.56), and 0.52 (0.41-0.63) for width/Width, length/Length, and depth/Depth ratios, respectively. The areas under the curve for spontaneous preterm birth at less than 34 0/7 weeks of gestation were 0.52 (0.25-0.79) and 0.55 (0.31-0.79) for width/Width and length/Length ratios, respectively. Additionally, none of the means of the gland measurements were statistically different between those delivering at term and spontaneous at preterm (P>.05).

CONCLUSION

Fetal adrenal size, as measured by ultrasonography between 22 0/7 and 30 6/7 weeks of gestation, is not predictive of spontaneous preterm birth in asymptomatic nulliparous women.

Comparison of placenta samples with contamination controls does not provide evidence for a distinct placenta microbiota

BACKGROUND

Recent studies have suggested that bacteria associated with the placenta-a "placental microbiome"-may be important in reproductive health and disease. However, a challenge in working with specimens with low bacterial biomass, such as placental samples, is that some or all of the bacterial DNA may derive from contamination in dust or commercial reagents. To investigate this, we compared placental samples from healthy deliveries to a matched set of contamination controls, as well as to oral and vaginal samples from the same women.

RESULTS

We quantified total 16S rRNA gene copies using quantitative PCR and found that placental samples and negative controls contained low and indistinguishable copy numbers. Oral and vaginal swab samples, in contrast, showed higher copy numbers. We carried out 16S rRNA gene sequencing and community analysis and found no separation between communities from placental samples and contamination controls, though oral and vaginal samples showed characteristic, distinctive composition. Two different DNA purification methods were compared with similar conclusions, though the composition of the contamination background differed. Authentically present microbiota should yield mostly similar results regardless of the purification method used-this was seen for oral samples, but no placental bacterial lineages were (1) shared between extraction methods, (2) present at >1 % of the total, and (3) present at greater abundance in placental samples than contamination controls.

CONCLUSIONS

We conclude that for this sample set, using the methods described, we could not distinguish between placental samples and contamination introduced during DNA purification.