Approximately one-third of medically indicated late preterm births are complicated by fetal growth restriction

Maternal Blood Angiogenic Factors and the Prediction of Critical Adverse Perinatal Outcomes Among Small-for-Gestational-Age Pregnancies

OBJECTIVE

Our objective was to determine whether maternal blood angiogenic factors in suspected-small-for-gestational-age (sSGA) fetuses can predict critical adverse perinatal outcomes (CAPO) and improve risk assessment.

METHODS

Women with singleton pregnancies diagnosed with sSGA, between 24 and 356/7 weeks' gestation, were included. Clinical and sonographic comprehensive evaluations were performed at enrolment. Plasma angiogenic factors, soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF), were obtained at diagnosis. In parallel, three attending maternal-fetal-medicine specialists predicted the risk (1-5 scale) of these pregnancies to develop CAPO, based on the clinical presentation. CAPOs were defined as prolonged neonatal intensive care unit hospitalization, fetal or neonatal death, and major neonatal morbidity. Statistical analysis included sensitivity, specificity, positive and negative predictive values, and receiver-operating characteristic (ROC) curve analyses.

RESULTS

Of the 79 cases included, 32 were complicated by CAPO (40.5%). In SGA fetuses with CAPO, the sFlt-1/PlGF ratio was higher (p < 0.001) and PlGF was lower (p < 0.001) as compared with uncomplicated pregnancies. The areas under the ROC curves for specialists were 0.913, 0.824, and 0.811 and for PlGF and sFlt-1/PlGF ratio 0.926 and 0.900, respectively. CAPO was more common in pregnancies with absent end-diastolic flow or reversed end-diastolic flow (AEDF or REDF) in the umbilical artery upon enrolment (91.6%). Yet, 65.6% of cases involving CAPO occurred in patients without AEDF or REDF, and 66.6% of these cases were not identified by one or more of the experts. The sFlt-1/PlGF ratio identified 92.9% of the experts' errors in this group and 100% of the errors in cases with AEDF or REDF.

CONCLUSION

Among sSGA pregnancies prior to 36 weeks' gestation, angiogenic factors testing can identify most cases later complicated with CAPO. Our data demonstrate for the first time that these markers can reduce clinician judgment errors. Incorporation of these measures into decision-making algorithms could potentially improve management, outcomes, and even health care costs.

KEY POINTS

· Angiogenic factors at diagnosis of sSGA can be used to predict CAPO.. · The sFlt-1/PlGF ratio can flag sSGA pregnancies at increased risk.. · The sFlt-1/PlGF ratio at admission of sSGA adds to clinical assessment..

Prediction of preterm birth in women with fetal growth restriction - Is the weekly change in sFlt-1/PlGF ratio or PlGF levels useful?

INTRODUCTION

To assess the rate of change in soluble fms-like tyrosine kinase-1/placental growth factor (sFlt-1/PlGF) ratio and PlGF levels per week compared to a single sFlt-1/PlGF ratio or PlGF level to predict preterm birth for pregnancies complicated by fetal growth restriction.

MATERIAL AND METHODS

A prospective cohort study of pregnancies complicated by isolated fetal growth restriction. Maternal serum PlGF levels and the sFlt-1/PlGF ratio were measured at 4-weekly intervals from recruitment to delivery. We investigated the utility of PlGF levels, sFlt-1/PlGF ratio, change in PlGF levels per week or sFlt-1/PlGF ratio per week. Cox-proportional hazard models and Harrell's C concordance statistic were used to evaluate the effect of biomarkers on time to preterm birth.

RESULTS

The total study cohort was 158 pregnancies comprising 91 (57.6%) with fetal growth restriction and 67 (42.4%) with appropriate for gestational age controls. In the fetal growth restriction cohort, sFlt-1/PlGF ratio and PlGF levels significantly affected time to preterm birth (Harrell's C: 0.85-0.76). The rate of increase per week of the sFlt-1/PlGF ratio (hazard ratio [HR] 3.91, 95% confidence interval [CI]: 1.39-10.99, p = 0.01, Harrell's C: 0.74) was positively associated with preterm birth but change in PlGF levels per week was not (HR 0.65, 95% CI: 0.25-1.67, p = 0.37, Harrell's C: 0.68).

CONCLUSIONS

Both a high sFlt-1/PlGF ratio and low PlGF levels are predictive of preterm birth in women with fetal growth restriction. Although the rate of increase of the sFlt-1/PlGF ratio predicts preterm birth, it is not superior to either a single elevated sFlt-1/PlGF ratio or low PlGF level.

The medullary serotonergic centres involved in cardiorespiratory control are disrupted by fetal growth restriction

Fetal growth restriction (FGR) is associated with cardiovascular and respiratory complications after birth and beyond. Despite research showing a range of neurological changes following FGR, little is known about how FGR affects the brainstem cardiorespiratory control centres. The primary neurons that release serotonin reside in the brainstem cardiorespiratory control centres and may be affected by FGR. At two time points in the last trimester of sheep brain development, 110 and 127 days of gestation (0.74 and 0.86 of gestation), we assessed histopathological alterations in the brainstem cardiorespiratory control centres of the pons and medulla in early-onset FGR versus control fetal sheep. The FGR cohort were hypoxaemic and asymmetrically growth restricted. Compared to the controls, the brainstem of FGR fetuses exhibited signs of neuropathology, including elevated cell death and reduced cell proliferation, grey and white matter deficits, and evidence of oxidative stress and neuroinflammation. FGR brainstem pathology was predominantly observed in the medullary raphé nuclei, hypoglossal nucleus, nucleus ambiguous, solitary tract and nucleus of the solitary tract. The FGR groups showed imbalanced brainstem serotonin and serotonin 1A receptor abundance in the medullary raphé nuclei, despite evidence of increased serotonin staining within vascular regions of placentomes collected from FGR fetuses. Our findings demonstrate both early and adaptive brainstem neuropathology in response to placental insufficiency. KEY POINTS: Early-onset fetal growth restriction (FGR) was induced in fetal sheep, resulting in chronic fetal hypoxaemia. Growth-restricted fetuses exhibit persistent neuropathology in brainstem nuclei, characterised by disrupted cell proliferation and reduced neuronal cell number within critical centres responsible for the regulation of cardiovascular and respiratory functions. Elevated brainstem inflammation and oxidative stress suggest potential mechanisms contributing to the observed neuropathological changes. Both placental and brainstem levels of 5-HT were found to be impaired following FGR.

Intracranial ultrasound abnormalities and mortality in preterm infants with and without fetal growth restriction stratified by fetal Doppler study results

OBJECTIVE

To evaluate whether fetal growth restriction (FGR) with or without abnormal Dopplers is associated with intracranial abnormalities and death in premature infants.

STUDY DESIGN

Premature infants with and without FGR born between 2016 and 2019 were included. Primary outcome was death, severe intraventricular hemorrhage (IVH) or periventricular leukomalacia (PVL). Groups were compared using standard bivariate testing and multivariable regression.

RESULTS

Among 168 FGR and 560 non-FGR infants, FGR infants with abnormal Dopplers had an increased incidence of death, severe IVH or PVL compared to non-FGR infants (13% (16/123) vs. 7% (41/560); p = 0.03) while FGR infants with normal Dopplers had a nonsignificant decrease. In a logistic regression model, FGR with abnormal Dopplers was associated with more than three times higher odds of death, severe IVH or PVL (OR 3.2, 95% CI 1.54,6.49; p < 0.001).

CONCLUSIONS

Growth-restricted infants with abnormal Dopplers had an increased risk of death, intracranial abnormalities, and prematurity-related morbidities.

Abnormal Fetal Growth: Small for Gestational Age, Fetal Growth Restriction, Large for Gestational Age: Definitions and Epidemiology

Abnormal fetal growth (growth restriction and overgrowth) is associated with perinatal morbidity, mortality, and lifelong risks to health. To describe abnormal growth, "small for gestational age" and "large for gestational age" are commonly used terms. However, both are statistical definitions of fetal size below or above a certain threshold related to a reference population, rather than referring to an abnormal condition. Fetuses can be constitutionally small or large and thus healthy, whereas fetuses with seemingly normal size can be growth restricted or overgrown. Although golden standards to detect abnormal growth are lacking, understanding of both pathologic conditions has improved significantly.

Earlier preterm birth is associated with a worse neurocognitive outcome in a rabbit model

Background

Preterm birth (PTB) and particularly late preterm PTB has become a research focus for obstetricians, perinatologists, neonatologists, pediatricians and policy makers alike. Translational models are useful tools to expedite and guide clinical but presently no model exists that contextualizes the late PTB scenario. Herein we aimed to develop a rabbit model that echo’s the clinical neurocognitive phenotypes of early and late PTB.

Methods

Time mated rabbit does underwent caesarean delivery at a postconceptional age (PCA) of either 28 (n = 6), 29 (n = 5), 30 (n = 4) or 31 (n = 4) days, term = 31 d. Newborn rabbits were mixed and randomly allocated to be raised by cross fostering and underwent short term neurobehavioral testing on corrected post-natal day 1. Open field (OFT), spontaneous alteration (TMT) and novel object recognition (NORT) tests were subsequently performed at 4 and 8 weeks of age.

Results

PTB was associated with a significant gradient of short-term mortality and morbidity inversely related to the PCA. On postnatal day 1 PTB was associated with a significant sensory deficit in all groups but a clear motor insult was only noted in the PCA 29d and PCA 28d groups. Furthermore, PCA 29d and PCA 28d rabbits had a persistent neurobehavioral deficit with less exploration and hyperanxious state in the OFT, less alternation in TMT and lower discriminatory index in the NORT. While PCA 30d rabbits had some anxiety behavior and lower spontaneous alteration at 4 weeks, however at 8 weeks only mild anxiety driven behavior was observed in some of these rabbits.

Conclusions

In this rabbit model, delivery at PCA 29d and PCA 28d mimics the clinical phenotype of early PTB while delivery at PCA 30d resembles that of late PTB. This could serve as a model to investigate perinatal insults during the early and late preterm period.

Use of birth weight- vs. ultrasound-derived fetal weight classification methods: implications for detection of abnormal umbilical artery Doppler

Objectives To compare a birth weight-derived (Brenner) and multiple ultrasound-derived [Hadlock, National Institute of Child Health and Human Development (NICHD), International Fetal and Newborn Growth Consortium (INTERGROWTH)] classification systems' frequency of assigning an antenatal estimated fetal weight (EFW) <10% and subsequent detection rate for abnormal umbilical artery Doppler (UAD). Methods We analyzed 569 consecutive non-anomalous singleton gestations identified by ultrasound with either an abdominal circumference (AC) <3% or EFW <10% at a tertiary medical center between 1/2012 and 12/2016. The biometric measurements were exported for all serial ultrasounds and the sensitivity, specificity, positive and negative predictive values, and area under the curve (AUC) were calculated for the diagnosis of any abnormal UAD, absent or reversed end-diastolic flow (AREDF), and small for gestational age (SGA) for each classification method. Results Brenner classified less patients with EFW <10% (49.7%) vs. the comparison methods (range: 84.2-85.0%; P < 0.001). The sensitivity was highest using Hadlock for detection of any abnormal UAD [96.6%; confidence interval (CI) 92.8-98.8%], AREDF (100%; CI 95.1-100%), and SGA (89.0%; CI 85.4-91.6%). However, there was minimal variation between the Hadlock, NICHD, and INTERGROWTH methods for detection of the studied outcomes. The AUCs for any abnormal UAD, AREDF, and SGA were highest for the Brenner method, but there were a substantial number of false-negative results with lower overall detection rates. Conclusions Use of a birth weight-derived method to assign a fetal weight <10% as the threshold to initiate UAD surveillance has a lower detection rate for abnormal UAD when compared to ultrasound-derived methods. Despite substantial methodological differences in the creation of the Hadlock, NICHD, and INTERGROWTH methods, there were no differences in the detection rates of abnormal UAD.

Effect of levothyroxine supplementation on pregnancy loss and preterm birth in women with subclinical hypothyroidism and thyroid autoimmunity: a systematic review and meta-analysis

BACKGROUND

Subclinical hypothyroidism (SCH) and thyroid autoimmunity (TAI) are associated with adverse pregnancy outcomes such as pregnancy loss and preterm birth. However, the ability of levothyroxine (LT4) supplementation to attenuate the risks of these outcomes remains controversial.

OBJECTIVE AND RATIONALE

This systematic review and meta-analysis was conducted to determine the effect of LT4 supplementation on pregnancy loss rate (PLR) and preterm birth rate (PBR) among pregnant women with SCH and TAI.

SEARCH METHODS

A systematic literature search of the PubMed, EMBASE, Web of Science and Cochrane Controlled Trials Register databases and Clinicaltrials.gov was performed to identify all relevant English studies published up to April 2018. The following terms were used for the search: [subclinical hypothyroidism OR thyroid autoimmunity OR thyroperoxidase antibody (TPO-Ab) OR thyroglobulin antibodies (Tg-Ab)] AND (levothyroxine OR euthyrox) AND [pregnancy outcome OR miscarriage OR abortion OR pregnancy loss OR preterm birth OR premature delivery OR early labo(u)r]. The reference lists of the relevant publications were also manually searched for related studies. Published manuscripts were included if they reported data on pregnancy loss, preterm birth or both. We separately analysed the pooled effects of LT4 supplementation on PLR and PBR in women with SCH and TAI.

OUTCOMES

Overall, 13 eligible studies including 7970 women were included in the meta-analysis. Eight and five of these studies were randomized controlled trials (RCTs) and retrospective studies, respectively. The pooled results indicated that LT4 supplementation significantly decreased the PLR [relative risk (RR) = 0.56, 95% confidence interval (CI): 0.42-0.75, I2 = 1%, 12 studies] and PBR (RR = 0.68, 95% CI: 0.51-0.91, I2 = 21%, eight studies) in women with SCH and/or TAI. We further found that LT4 supplementation significantly decreased the risk of pregnancy loss (RR = 0.43, 95% CI: 0.26-0.72, P = 0.001, I2 = 0%) but not of preterm birth (RR = 0.67, 95% CI: 0.41-1.12, P = 0.13, I2 = 0%) in women with SCH. Furthermore, LT4 supplementation significantly decreased the risks of both pregnancy loss (RR = 0.63, 95% CI: 0.45-0.89, P = 0.009, I2 = 0%) and preterm birth (RR = 0.68 95% CI: 0.48-0.98, P = 0.04, I2 = 46%) in women with TAI. These results were consistent when only RCTs were included in the analysis. Further, in women with SCH, LT4 supplementation reduced the risk of pregnancy loss in pregnancies achieved by assisted reproduction (RR = 0.27, 95% CI: 0.14-0.52, P < 0.001, I2 = 14%) but not in naturally conceived pregnancies (RR = 0.60, 95% CI: 0.28-1.30, P = 0.13, I2 = 0%). By contrast, in women with TAI, LT4 supplementation reduced the risks of both pregnancy loss (RR = 0.61, 95% CI: 0.39-0.96, P = 0.03, I2 = 0%) and preterm birth (RR = 0.49, 95% CI: 0.30-0.79, P = 0.003, I2 = 0%) in naturally conceived pregnancies but not in pregnancies achieved by assisted reproduction (RR = 0.68, 95% CI: 0.40-1.15, P = 0.15, I2 = 0% for pregnancy loss and RR = 1.20, 95% CI: 0.68-2.13, P = 0.53, I2 not applicable for preterm birth).

WIDER IMPLICATIONS

This meta-analysis confirmed the beneficial effects of LT4 supplementation, namely the reduced risks of pregnancy loss and preterm birth, among pregnant women with SCH and/or TAI. The different effects of LT4 supplementation on naturally conceived pregnancies and pregnancies achieved by assisted reproduction in women with SCH and/or TAI suggest that these women should be managed separately. Due to the limited number of studies included in this meta-analysis, especially in the subgroup analysis, further large RCTs and fundamental studies are warranted to confirm the conclusions and better clarify the molecular mechanism underlying these associations.

Missed opportunities for optimal antenatal corticosteroid timing in medically indicated preterm births

OBJECTIVE

Although delivery timing is physician dictated in indicated preterm births, suboptimal antenatal corticosteroids (ACS) administration occurs in most cases. We aimed to characterize the patterns of use of ACS in indicated preterm births and identify missed opportunities of optimal ACS administration.

METHODS

We reviewed the records of women who received ACS and were delivered due to maternal or fetal indications at 24-34 weeks of gestation during 2015-2017 at a university hospital. Optimal ACS timing was defined as delivery ≥24 h ≤7 d from the previous ACS course.

RESULTS

Overall, 188 pregnancies were included. The median gestational age at delivery was 32 weeks. Considering only the initial ACS course, the rate of optimal timing was 32.4%. Of 105 (55.8%) women eligible (delivery >7 d since the initial ACS course), only a third (n = 38) received a rescue ACS course. Among women who did not receive rescue ACS course despite their eligibility (n = 67), the decision-to-delivery was ≥3 h in 36 (53.7%), and ≥24 h in 20 (29.9%), representing 19.1 and 10.6% of the entire cohort, respectively. The urgency of the decision to deliver (i.e. in the upcoming 24 h and later) and allowing a trial of labor, were both positively associated with decision-to-delivery interval ≥3 h and ≥24 h. The rate of delivery within any optimal window (either initial or rescue course) was 40.4%, with gestational hypertensive disorders (OR [95% CI]: 2.40 (1.23, 4.72), p = .01) and decision to deliver made at first hospitalization (OR [95% CI]: 2.27 (1.04, 4.76), p = .04) as independent positive predictors of optimal ACS timing. The rate of composite adverse neonatal outcome was significantly lower in those with optimal ACS administration as compared to those with suboptimal timing (32.9 versus 50.9%, OR [95% CI]: 0.47 (0.26, 0.87), p = .02).

CONCLUSIONS

Suboptimal ACS administration occurred in most indicated preterm births. Underutilization of rescue ACS course and a substantial rate of missed opportunities for optimal ACS administration were identified as potentially modifiable contributors to improve ACS timing.

Postnatal length and weight growth velocities according to Fenton reference and their associated perinatal factors in healthy late preterm infants during birth to term-corrected age: an observational study

Background

Optimum early postnatal growth is critical for early and later health of preterm infants. Postnatal length and weight growth velocities and their associated perinatal factors in healthy late preterm infants without restriction of neonatal complications and nutritional problems have not been widely studied.

Methods

As part of ongoing longitudinal follow-up study of growth and development of preterm infants in Shandong Qianfoshan Hospital in China, 599 healthy late preterm infants without neonatal complications and nutritional problems were sampled from 795 preterm infants born in January 2014 to April 2017. Perinatal factors, growth parameters, growth velocities(ΔLengthZ and ΔWeightZ: Z-score changes of length and weight) during birth and term-corrected age were documented. Associated variables of growth velocities were analyzed by bivariate and multivariate regression analyses. Adjusted ΔLengthZ and ΔWeightZ were compared between/among subgroups of associated variables using analysis of covariance. Catch-up growth were defined as ΔLengthZ or ΔWeightZ > 0.67.

Results

The mean ΔLengthZ and ΔWeightZ were 0.28, 0.65, respectively. Catch-up growth of length and weight was ubiquitous(30.7, 46.2%, respectively). Faster length growth velocity was associated with male, larger postmenstrual age(PMA) at birth, younger mother and larger PMA at visit; Faster weight growth velocity was associated with male, unfavorable intrauterine growth status defined by birth weight percentile(Small-for-Gestational-Age(<P10), Appropriate-for-Gestational-Age(P10–90), Large-for-Gestational-Age(>P90)), twin and larger PMA at visit. When adjusted for associated co-variables, weight catch-up growth existed in subgroups of 36 weeks PMA at birth, male, twin and SGA, while AGA almost reached this standard with mean adjusted ΔWeightZ as 0.66. Although none of these subgroups got length catch-up growth standard, infants of 36 weeks PMA at birth had statistically rapider length growth velocity than 34 and 35 weeks PMA at birth subgroups(mean adjusted ΔLengthZs of 34, 35 and 36 weeks subgroups: 0.10, 0.22, 0.38, respectively).

Conclusions

Postnatal length and weight growth velocities of healthy late preterm infants from birth to term-corrected age were much superior than that of Fenton reference, especially for weight, with ubiquitous catch-up growth. Different associated factors for length and weight growth signified the necessity of constructing more detailed growth standards by specific stratification for associated factors.

An epigenetic association of malformations, adverse reproductive outcomes, and fetal origins hypothesis related effects

VACTERL, the prototype for associated congenital anomalies, also has connections with functional issues such as pregnancy losses, prematurity, growth delays, perinatal difficulties, and parental subfertility. This segues into a broader association with similar connections even in the absence of malformations. DNA methylation disturbances in the ovum are a likely cause, with epigenetic links to individual components and to folate effects before conception, explaining diverse fetal and placental findings and providing a link to fetal origin hypothesis-related effects. The association encompasses the following: (1) Pre- and periconceptual effects, with frequent fertility issues and occasional imprinting disorders. (2) Early malformations. (3) Adverse pregnancy outcomes (APOs), as above. (4) Developmental destabilization that resolves soon after birth. This potentiates other causes of association findings, introducing multiple confounders. (5) Long-term fetal origins hypothesis-related risks. The other findings are exceptional when the same malformations have Mendelian origins, supporting a distinct pathogenesis. Expressions are facilitated by one-carbon metabolic issues, maternal and fetal stress, and decreased embryo size. This may be one of the commonest causes of adverse reproductive outcomes, but multifactorial findings, variable onsets and phenotypes, and interactions with multiple confounders make recognition difficult. This association supports VACTERL as a continuum that includes isolated malformations, extends the fetal origins hypothesis, explains adverse effects linked to maternal obesity, and suggests possible interventions.

Diagnosis and surveillance of late-onset fetal growth restriction

By consensus, late fetal growth restriction is that diagnosed >32 weeks. This condition is mildly associated with a higher risk of perinatal hypoxic events and suboptimal neurodevelopment. Histologically, it is characterized by the presence of uteroplacental vascular lesions (especially infarcts), although the incidence of such lesions is lower than in preterm fetal growth restriction. Screening procedures for fetal growth restriction need to identify small babies and then differentiate between those who are healthy and those who are pathologically small. First- or second-trimester screening strategies provide detection rates for late smallness for gestational age <50% for 10% of false positives. Compared to clinically indicated ultrasonography in the third trimester, universal screening triples the detection rate of late smallness for gestational age. As opposed to early third-trimester ultrasound, scanning late in pregnancy (around 37 weeks) increases the detection rate for birthweight <3rd centile. Contrary to early fetal growth restriction, umbilical artery Doppler velocimetry alone does not provide good differentiation between late smallness for gestational age and fetal growth restriction. A combination of biometric parameters (with severe smallness usually defined as estimated fetal weight or abdominal circumference <3rd centile) with Doppler criteria of placental insufficiency (either in the maternal [uterine Doppler] or fetal [cerebroplacental ratio] compartments) offers a classification tool that correlates with the risk for adverse perinatal outcome. There is no evidence that induction of late fetal growth restriction at term improves perinatal outcomes nor is it a cost-effective strategy, and it may increase neonatal admission when performed <38 weeks.

Customized vs population-based growth charts to identify neonates at risk of adverse outcome: systematic review and Bayesian meta-analysis of observational studies

OBJECTIVE

To compare the effectiveness of customized vs population-based growth charts for the prediction of adverse pregnancy outcomes.

METHODS

MEDLINE, ClinicalTrials.gov and The Cochrane Library were searched up to 31 May 2016 to identify interventional and observational studies comparing adverse outcomes among large- (LGA) and small- (SGA) for-gestational-age neonates, when classified according to customized vs population-based growth charts. Perinatal mortality and admission to the neonatal intensive care unit (NICU) of both SGA and LGA neonates, intrauterine fetal demise (IUFD) and neonatal mortality of SGA neonates, and neonatal shoulder dystocia and hypoglycemia as well as maternal third- and fourth-degree perineal lacerations in LGA pregnancies were evaluated.

RESULTS

The electronic search identified 237 records that were examined based on title and abstract, of which 27 full-text articles were examined for eligibility. After excluding seven articles, 20 observational studies were included in a Bayesian meta-analysis. Neonates classified as SGA according to customized growth charts had higher risks of IUFD (odds ratio (OR), 7.8 (95% CI, 4.2-12.3)), neonatal death (OR, 3.5 (95% CI, 1.1-8.0)), perinatal death (OR, 5.8 (95% CI, 3.8-7.8)) and NICU admission (OR, 3.6 (95% CI, 2.0-5.5)) than did non-SGA cases. Neonates classified as SGA according to population-based growth charts also had increased risk for adverse outcomes, albeit the point estimates of the pooled ORs were smaller: IUFD (OR, 3.3 (95% CI, 1.9-5.0)), neonatal death (OR, 2.9 (95% CI, 1.2-4.5)), perinatal death (OR, 4.0 (95% CI, 2.8-5.1)) and NICU admission (OR, 2.4 (95% CI, 1.7-3.2)). For LGA vs non-LGA, there were no differences in pooled ORs for perinatal death, NICU admission, hypoglycemia and maternal third- and fourth-degree perineal lacerations when classified according to either the customized or the population-based approach. In contrast, both approaches indicated that LGA neonates are at increased risk for shoulder dystocia than are non-LGA ones (OR, 7.4 (95% CI, 4.9-9.8) using customized charts; OR, 8.0 (95% CI, 5.3-10.1) using population-based charts).

CONCLUSIONS

Both customized and population-based growth charts can identify SGA neonates at risk for adverse outcomes. Although the point estimates of the pooled ORs may differ for some outcomes, the overlapping CIs and lack of direct comparisons prevent conclusions from being drawn on the superiority of one method. Future clinical trials should compare directly the two approaches in the management of fetuses of abnormal size. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

The clinical significance of an estimated fetal weight below the 10th percentile: a comparison of outcomes of <5th vs 5th-9th percentile

BACKGROUND

The association between small-for-gestational-age (birthweight <10th percentile for gestational age) and neonatal morbidity is well established. Yet, there is a paucity of data on the relationship between suspected small for gestational age (sonographic-estimated fetal weight <10th percentile) at 2 thresholds and subsequent neonatal morbidity.

OBJECTIVE

The objective of this study was to determine the relationship between sonographic-estimated fetal weight <5th percentile vs 5-9th percentile and neonatal morbidity.

STUDY DESIGN

This retrospective study involved 5 centers and included nonanomalous, singletons with sonographic-estimated fetal weight <10th percentile for gestational age who delivered from 2009-2012. Composite neonatal morbidity included respiratory distress syndrome, proven sepsis, intraventricular hemorrhage grade III or IV, necrotizing enterocolitis, thrombocytopenia, seizures, or death. Odd ratios were adjusted for center, maternal age, race, body mass index at first visit, smoking status, use of alcohol, use of drugs, and neonatal gender.

RESULTS

Of 834 women with suspected small-for-gestational-age fetuses, 513 (62%) had sonographic-estimated fetal weight <5th percentile, and 321 (38%) had sonographic-estimated fetal weight of 5-9th percentile for gestational age. At delivery, 81% of women with a suspected small-for-gestational-age fetus had a confirmed small-for-gestational-age fetus. In the group with a sonographic-estimated fetal weight <5th percentile, 59% of neonates had birthweight <5th percentile; in the group with a sonographic-estimated fetal weight 5-9th percentile, 41% had birthweight <5th percentile, and 36% had birthweight at 5-9th percentile. Neonatal intensive care unit admission differed significantly for those fetuses at <5th percentile (29%) compared with those fetuses at 5-9th percentile (15%; P<.001). The composite neonatal morbidity among the sonographic-estimated fetal weight <5th percentile group was higher than the sonographic-estimated fetal weight of 5-9th percentile group (31% vs 13%; adjusted odds ratio, 2.41; 95% confidence interval, 1.53-3.80). Similar findings were noted when the analysis was limited to sonographic-estimated fetal weight within 28 days of delivery (adjusted odds ratio, 2.22; 95% confidence interval, 1.34-3.67).

CONCLUSION

Eight of 10 suspected small-for-gestational-age fetuses had birthweight <10th percentile for gestational age; the prediction of actual birthweight was more accurate in the <5th percentile group. Neonates with sonographic-estimated fetal weight of <5th percentile were more likely to be admitted to the neonatal intensive care unit and have complications than were those neonates with sonographic-estimated fetal weight of 5-9th percentile.

DNA Methylation Patterns in Cord Blood of Neonates Across Gestational Age: Association With Cell-Type Proportions

Background

A statistical methodology is available to estimate the proportion of cell types (cellular heterogeneity) in adult whole blood specimens used in epigenome-wide association studies (EWAS). However, there is no methodology to estimate the proportion of cell types in umbilical cord blood (also a heterogeneous tissue) used in EWAS.

Objectives

The objectives of this study were to determine whether differences in DNA methylation (DNAm) patterns in umbilical cord blood are the result of blood cell type proportion changes that typically occur across gestational age and to demonstrate the effect of cell type proportion confounding by comparing preterm infants exposed and not exposed to antenatal steroids.

Methods

We obtained DNAm profiles of cord blood using the Illumina HumanMethylation27k BeadChip array for 385 neonates from the Boston Birth Cohort. We estimated cell type proportions for six cell types using the deconvolution method developed by Houseman et al. (2012).

Results

The cell type proportion estimates segregated into two groups that were significantly different by gestational age, indicating that gestational age was associated with cell type proportion. Among infants exposed to antenatal steroids, the number of differentially methylated CpGs dropped from 127 to 1 after controlling for cell type proportion.

Discussion

EWAS utilizing cord blood are confounded by cell type proportion. Careful study design including correction for cell type proportion and interpretation of results of EWAS using cord blood are critical.

Alarmin high mobility group box-1 in maternal serum as a potential biomarker of chorioamnionitis-associated preterm birth

Chorioamnionitis is associated with an increased risk of spontaneous preterm birth. The aim of this study was to investigate the serum levels of high mobility group box-1 (HMGB1) in pregnancies with histological chorioamnionitis (HCA)-associated preterm labor (PTL) with intact membranes or preterm premature rupture of membranes (PPROM), and to access the role of serum HMGB1 in HCA and HCA-associated PTL. A total of 190 pregnant women were enrolled in this study: PLT patients with (n = 28) or without HCA (n = 36), PPROM patients with (n = 26) or without HCA (n = 65), and non-HCA PTL controls (n = 35). Maternal serum levels of HMGB1 were measured by enzyme-linked immunosorbent assay. Serum HMGB1 levels were significantly higher in PTL or PPROM patients than in control group (p < 0.01, respectively). The PPROM patients also exhibited higher serum HMGB1 levels compared to PTL patients (p = 0.015). HCA patients were characterized by significantly increased levels of serum HMGB1 when compared with non-HCA patients (p < 0.01). Therefore, maternal serum HMGB1 may become a potential biomarker of HCA and HCA-associated PTL.

The use of angiogenic biomarkers in maternal blood to identify which SGA fetuses will require a preterm delivery and mothers who will develop pre-eclampsia

OBJECTIVE

To determine (1) whether maternal plasma concentrations of angiogenic and anti-angiogenic factors can predict which mothers diagnosed with "suspected small for gestational age fetuses (sSGA)" will develop pre-eclampsia (PE) or require an indicated early preterm delivery (≤ 34 weeks of gestation); and (2) whether risk assessment performance is improved using these proteins in addition to clinical factors and Doppler parameters.

METHODS

This prospective cohort study included women with singleton pregnancies diagnosed with sSGA (estimated fetal weight <10th percentile) between 24 and 34 weeks of gestation (n = 314). Plasma concentrations of soluble vascular endothelial growth factor receptor-1 (sVEGFR-1), soluble endoglin (sEng) and placental growth factor (PlGF) were determined in maternal blood obtained at the time of diagnosis. Doppler velocimetry of the umbilical (Umb) and uterine (UT) arteries was performed. The outcomes were (1) subsequent development of PE; and (2) indicated preterm delivery at ≤ 34 weeks of gestation (excluding deliveries as a result of spontaneous preterm labor, preterm pre-labor rupture of membranes or chorioamnionitis).

RESULTS

(1) The prevalence of PE and indicated preterm delivery was 9.2% (n = 29/314) and 7.3% (n = 23/314), respectively; (2) the area under the receiver operating characteristic curve (AUC) for the identification of patients who developed PE and/or required indicated preterm delivery was greater than 80% for the UT artery pulsatility index (PI) z-score and each biochemical marker (including their ratios) except sVEGFR-1 MoM; (3) using cutoffs at a false positive rate of 15%, women with abnormal plasma concentrations of angiogenic/anti-angiogenic factors were 7-13 times more likely to develop PE, and 12-22 times more likely to require preterm delivery than those with normal plasma MoM concentrations of these factors; (4) sEng, PlGF, PIGF/sEng and PIGF/sVEGFR-1 ratios MoM, each contributed significant information about the risk of PE beyond that provided by clinical factors and/or Doppler parameters: women who had low MoM values for these biomarkers were at 5-9 times greater risk of developing PE than women who had normal values, adjusting for clinical factors and Doppler parameters (adjusted odds ratio for PlGF: 9.1, PlGF/sEng: 5.6); (5) the concentrations of sVEGFR-1 and PlGF/sVEGFR-1 ratio MoM, each contributed significant information about the risk of indicated preterm delivery beyond that provided by clinical factors and/or Doppler parameters: women who had abnormal values were at 8-9 times greater risk for indicated preterm delivery, adjusting for clinical factors and Doppler parameters; and (6) for a two-stage risk assessment (Umb artery Doppler followed by Ut artery Doppler plus biochemical markers), among women who had normal Umb artery Doppler velocimetry (n = 279), 21 (7.5%) developed PE and 11 (52%) of these women were identified by an abnormal UT artery Doppler mean PI z-score (>2SD): a combination of PlGF/sEng ratio MoM concentration and abnormal UT artery Doppler velocimetry increased the sensitivity of abnormal UT artery Doppler velocimetry to 76% (16/21) at a fixed false-positive rate of 10% (p = 0.06).

CONCLUSION

Angiogenic and anti-angiogenic factors measured in maternal blood between 24 and 34 weeks of gestation can identify the majority of mothers diagnosed with "suspected SGA" who subsequently developed PE or those who later required preterm delivery ≤ 34 weeks of gestation. Moreover, incorporation of these biochemical markers significantly improves risk assessment performance for these outcomes beyond that of clinical factors and uterine and umbilical artery Doppler velocimetry.

Fetal Growth and the Risk of Spontaneous Preterm Birth in a Prospective Cohort Study of Nulliparous Women

Previous studies have suggested an association between fetal growth restriction and the risk of spontaneous preterm birth (sPTB). However, addressing this association is methodologically challenging. We conducted a prospective cohort study of nulliparous women with a singleton pregnancy in Cambridge, United Kingdom (2008-2012). Ultrasonic fetal biometry was performed at 20 weeks of gestation as per routine clinical care. Participants also had blinded research ultrasonography performed at approximately 28 weeks. Biometric measurements were expressed as gestational-age-adjusted z scores. Fetal growth velocity was quantified by change in z score between 20 weeks and 28 weeks. Risk of sPTB, defined as delivery at ≥28 weeks and <37 weeks associated with labor in the absence of induction, was analyzed using cause-specific Cox regression. Of 3,892 women, 98 (2.5%) had sPTB. When compared with the other decile groups, the lowest decile of growth velocity of the fetal femur between 20 and 28 weeks was associated with increased risk of sPTB (hazard ratio = 2.37, 95% confidence interval: 1.43, 3.93; P < 0.001). Adjustment for maternal characteristics had no material effect (hazard ratio = 2.50, 95% confidence interval: 1.50, 4.14; P < 0.001). There were no significant associations between other fetal measurements and risk of sPTB. To conclude, slow growth velocity of the fetal femur is associated with an increased risk of sPTB.

The timing of administration of antenatal corticosteroids in women with indicated preterm birth

OBJECTIVE

We sought to determine the timing of administration of antenatal corticosteroids (AS) for indicated preterm births and to identify which indications are associated with the most optimal timing of administration.

STUDY DESIGN

This was a retrospective cohort of patients who received AS in anticipation of indicated preterm birth from 2009 through 2012 at Winthrop University Hospital, Mineola, NY. Medical records of patients who received AS, as identified through the hospital pharmacy database, were reviewed. Patients were included if they had a singleton or twin gestation and they received AS for maternal or fetal indications. Women were excluded if they received AS for spontaneous preterm labor or preterm rupture of membranes. Maternal demographic and obstetrical characteristics were compared between those who received AS≤7 days vs >7 days from delivery using parametric and nonparametric tests with relative risks and 95% confidence intervals. P<.05 was considered significant.

RESULTS

In all, 193 patients were included in this study. Median latency from AS administration to delivery was 9 days (range, 0-83); 93 patients (48%) received AS within 7 days of delivery. There were no significant differences between the 2 groups with regards to baseline maternal characteristics. Those delivering within 7 days of AS administration were more likely to have maternal vs fetal indications (84% vs 16%).

CONCLUSION

Only 48% of patients with an indication for preterm birth received AS within 7 days of its administration. AS appear to be more optimally timed in the presence of maternal rather than fetal indications.

Practice variation in late-preterm deliveries: a physician survey

OBJECTIVE

Late-preterm (LPT) neonates account for over 70% of all preterm births in the US. Approximately 60% of LPT births are the result of non-spontaneous deliveries. The optimal timing of delivery for many obstetric conditions at LPT gestations is unclear, likely resulting in obstetric practice variation. The purpose of this study is to identify variation in the obstetrical management of LPT pregnancies.

STUDY DESIGN

We surveyed obstetrical providers in North Carolina identified from North Carolina Medical Board and North Carolina Obstetrical and Gynecological Society membership lists. Participants answered demographic questions and six multiple-choice vignettes on management of LPT pregnancies.

RESULT

We obtained 215/859 (29%) completed surveys which are as follows: 167 (78%) from obstetrics/gynecology, 27 (13%) from maternal-fetal medicine, and 21 (10%) from family medicine physicians. Overall, we found more agreement on respondents' management of chorioamnionitis (97% would proceed with delivery), mild pre-eclampsia (84% would delay delivery/expectantly manage) and fetal growth restriction (FGR) (80% would delay delivery/expectantly manage). We found less agreement on the management of severe preeclampsia (71% would proceed with delivery), premature preterm rupture of membranes (69% would proceed with delivery) and placenta previa (67% would delay delivery/expectantly manage). Management of LPT pregnancies complicated by preterm premature rupture of membranes, FGR and placenta previa vary by specialty.

CONCLUSION

Obstetrical providers report practice variation in the management of LPT pregnancies. Variation might be influenced by provider specialty. The absence of widespread agreement on best practice might be a source of modifiable LPT birth.

Subtypes of preterm birth and the risk of postneonatal death

OBJECTIVE

To examine the differences in postneonatal death risk among 3 clinical subtypes of preterm birth: preterm premature rupture of membranes (PROM), indicated preterm birth, and spontaneous preterm labor.

STUDY DESIGN

We analyzed the 2001-2005 US linked birth/infant death (birth cohort) datasets. The preterm birth subtypes were classified using information on the birth certificate: reported PROM, induction of labor, cesarean section, and complications of pregnancy and labor. Cox proportional hazard models were used to estimate covariate-adjusted hazard ratios and 95% CIs for postneonatal death (from days 28 to 365). Estimation was given for preterm birth subtypes in a week-by-week analysis. Causes of death were analyzed by preterm birth subtype and then separately at 24-27, 28-31, and 32-36 weeks of gestation.

RESULTS

For the total of 1895350 singleton preterm births who survived the neonatal period, the postneonatal mortality rate was 1.11% for preterm PROM, 0.78% for indicated preterm birth, and 0.53% for spontaneous preterm labor. Preterm PROM was associated with significantly higher risk of postneonatal death compared with spontaneous preterm labor in infants born at 27 weeks gestation or later. Similarly, indicated preterm birth was associated with a significantly higher risk of postneonatal death than spontaneous preterm labor in infants born at 25 weeks gestation or later. Preterm PROM and indicated preterm birth were associated with greater risk of death in the postneonatal period compared with spontaneous preterm labor, irrespective of the cause of death.

CONCLUSION

Subtypes of preterm birth carry different risks of postneonatal mortality. Prevention of preterm-related postneonatal death may require more research into the root causes of preterm birth subtypes.

Is short first-trimester crown-rump length associated with spontaneous preterm birth?

OBJECTIVE

To assess the association between first-trimester crown-rump length (CRL) and the risk of spontaneous preterm birth before 32 weeks' gestation.

METHODS

We performed a matched case-control study of 129 women with spontaneous preterm birth at < 32 weeks' gestation (cases) and 129 women with term deliveries (controls) using data stored in the ultrasound and obstetric databases of our tertiary referral center. Cases and controls were individually matched based on maternal age, parity, history of preterm birth and medical indication for antenatal care. Fetal CRL measured between 8 + 0 and 13 + 6 weeks was expressed as multiples of the median (MoM) expected CRL, based on last menstrual period. We investigated the association between CRL-MoM and spontaneous preterm birth using logistic regression analysis.

RESULTS

CRL-MoM was not associated with spontaneous preterm birth: odds ratio (OR) 1.10 (95% CI, 0.89-1.36) per 0.10 MoM increase in CRL. Timing of measurement did not influence the model (P = 0.59). This was confirmed when restricting the analysis to the 93 pairs with CRL measurements made between 10 + 0 and 13 + 6 weeks: OR for preterm birth 1.07 (95% CI, 0.83-1.37) per 0.10 MoM increase in CRL.

CONCLUSION

A short CRL in the first trimester is not associated with spontaneous preterm birth before 32 weeks' gestation, thus short CRL cannot be used to identify women at increased risk of preterm birth.

Customized estimated fetal weight: a novel antenatal tool to diagnose abnormal fetal growth

OBJECTIVE

We sought to apply customized standards to ultrasound-derived estimated fetal weight (EFW), and assess the frequency of abnormal growth when compared to population-based standards. We also evaluated association with adverse perinatal outcomes.

STUDY DESIGN

This was a historical cohort using prenatal ultrasound examination data at ≥24 weeks over a 1-year period. Ultrasound-derived EFW and growth percentile (population-based EFW [popEFW]) were reported and compared to a customized EFW (custEFW).

RESULTS

In all, 782 women met inclusion criteria. More fetuses were identified as small for gestational age (SGA) (15.1% vs 3.8%; P < .0001) and large for gestational age (LGA) (6.8% vs 1.7%; P < .0001) using custEFW, and adverse perinatal outcomes were more frequent among those identified by the custEFW compared to the popEFW. Both SGA and LGA diagnosed by custEFW were predictive of a neonatal SGA (positive likelihood ratio, 8.64) and LGA (positive likelihood ratio, 15.4).

CONCLUSION

CustEFW was a better predictor of abnormal birthweight and adverse outcomes compared to traditional popEFW standards.

Late preterm birth: a review of medical and neuropsychological childhood outcomes

Late preterm (LP) birth (34 0/7 - 36 6/7 weeks' gestation) accounts for nearly three-fourths of all preterm births, making this population a sizeable public health concern. The immature fetal development associated with LP delivery increases the risk of mortality and short-term medical complications. Which combination of maternal, fetal, or neonatal risk factors may be most critical has only recently begun to be addressed, and whether LP birth's disruptive impact on brain development will exert adverse effects on neuropsychological functioning in childhood and adolescence has been understudied. Early data have shown a graded response, with LP children often functioning better than very preterm children but worse than term children, and with subtle intellectual and neuropsychological deficits in LP children compared with healthy children born at term gestational age. Further characterization of the neuropsychological profile is required and would be best accomplished through prospective longitudinal studies. Moreover, since moderate and LP births result in disparate medical and psychological outcomes, the common methodology of combining these participants into a single research cohort to assess risk and outcome should be reconsidered. The rapidly growing LP outcomes literature reinforces a critical principle: fetal development occurs along a dynamic maturational continuum from conception to birth, with each successive gestational day likely to improve overall outcome.

NEONATAL OUTCOMES FOLLOWING LATE PRETERM BIRTH

It is well recognised that birth before 32 weeks of gestation is associated with substantial neonatal morbidity and mortality and these risks have been extensively reported. The focus of perinatal research for many years has therefore been very preterm and extremely preterm delivery, since the likelihood and severity of adverse neonatal outcomes are highest within this group. In contrast, until recently, more mature preterm infants have been understudied and indeed, almost ignored by researchers.

Late-preterm birth by delivery circumstance and its association with parent-reported attention problems in childhood

OBJECTIVE

Late-preterm birth (LPB, 34-36 wk) has been associated with an increased risk of attention problems in childhood relative to full-term birth (FTB, ≥37 wk), but little is known about factors contributing to this risk. The authors investigated the contributions of clinical circumstances surrounding delivery using follow-up data from the Pregnancy Outcomes and Community Health (POUCH) Study.

METHODS

Women who delivered late preterm or full term and completed the sex- and age-referenced Conners' Parent Rating Scales-Short Form: Revised were included in the present analysis (N = 762; children's age, 3-9 y). The Conners' Parent Rating Scales-Short Form: Revised measures dimensions of behavior linked to attention problems, including oppositionality, inattention, hyperactivity, and a global attention problem index. Using general linear models, the authors evaluated whether LPB subtype (medically indicated [MI] or spontaneous) was associated with these dimensions relative to FTB.

RESULTS

After adjustment for parity, sociodemographics, child age, and maternal symptoms of depression and serious mental illness during pregnancy and at the child survey, only MI LPB was associated with higher hyperactivity and global index scores (mean difference from FTB = 3.8 [95% confidence interval {CI}: 0.5, 7.0] and 3.1 [95% CI 0.0, 6.2]). These findings were largely driven by children between 6 and 9 years. Removal of women with hypertensive disorders during pregnancy (N = 85) or placental findings related to hypertensive conditions (obstruction, decreased maternal spiral artery conversion; N = 134) reduced the differences below significance thresholds.

CONCLUSIONS

Among LPBs, only MI LPB was associated with higher levels of parent-reported childhood attention problems, suggesting that complications motivating medical intervention during the late-preterm period mark increased risk for such problems. Hypertensive disorders seem to play a role in these associations.