Intrauterine growth restriction: how to manage and when to deliver

Neonatal and Long-Term Prognosis of Monochorionic Diamniotic Pregnancies Complicated by Selective Growth Restriction

Background: There are few data concerning the neonatal and long-term prognosis of monochorionic biamniotic twin pregnancies (MCBA) complicated by selective intrauterine growth restriction (sIUGR). The aim of the study is to assess the neurological outcomes at two years of age of these newborns and compares these outcomes to those of newborns resulting from intrauterine growth restriction (IUGR) pregnancies. Methods: The study focuses on a cross-sectional prospective cohort of patients treated between 2012 and 2019 in Marseille, France. The primary endpoint is the overall score of the Ages and Stages questionnaires (ASQ) at two years, which assesses the global neurodevelopment. The secondary endpoint is the assessment of neonatal morbi-mortality for both groups (composite endpoint). Results: In total, 251 patients were included in the analysis: 67 in the sIUGR group and 184 in the IUGR group. There was no statistically significant difference in the overall ASQ score at two years but there was the finest motor skills impairment in the IUGR group. The areas most often impaired were communication and fine motor skills. There were no significant differences between the neonatal morbi-mortality of the two groups (adjusted OR = 0.95, p = 0.9). Conclusions: Newborns from MCBA pregnancies with sIUGR appear to have similar overall neurological development to IUGR. Notably, IUGR seems to have the most moderate neurobehavioral disorder (fine motor) as a consequence of impaired antenatal brain development due to placenta insufficiency leading to chronic hypoxia.

Selective intrauterine growth restriction of monochorionic diamniotic twin pregnancies: What is the neonatal prognosis?

OBJECTIVE

This study compares the neonatal morbidity and mortality of the smallest twins of monochorionic diamniotic (MCDA) pregnancies complicated with selective intrauterine growth restriction (sIUGR) with newborns from singleton pregnancies with intrauterine growth restriction (IUGR).

METHODS

We conducted a retrospective cohort study of patients managed at the prenatal diagnosis center in a single tertiary care hospital between 2012 and 2019. MCDA twin pregnancies complicated with sIUGR (sIUGR group) were compared with singleton pregnancies with IUGR (IUGR group). The primary outcome was the comparison in neonatal morbidity and mortality between the two groups.

RESULTS

The analysis included 251 patients: 67 in the sIUGR group and 184 in the IUGR group. The two groups were comparable in gestational age and birth weight (p > 0.05). Multivariate analysis controlling for factors that may influence neonatal status showed no significant difference between the two groups in any of the neonatal morbidity criteria or the composite morbidity-mortality endpoint (adjusted OR = 0.946 [95% CI = 0.317-2.827]; p = 0.921).

CONCLUSION

Despite supposedly different pathophysiological mechanisms, neonates from MCDA pregnancies complicated with sIUGR and those from singleton pregnancies with IUGR appear to have identical neonatal morbidity and mortality .

Sleep Apnea and Fetal Growth Restriction (SAFER) study: protocol for a pragmatic randomised clinical trial of positive airway pressure as an antenatal therapy for fetal growth restriction in maternal obstructive sleep apnoea

INTRODUCTION

Fetal growth restriction (FGR) is a major contributor to fetal and neonatal morbidity and mortality with intrauterine, neonatal and lifelong complications. This study explores maternal obstructive sleep apnoea (OSA) as a potentially modifiable risk factor for FGR. We hypothesise that, in pregnancies complicated by FGR, treating mothers who have OSA using positive airway pressure (PAP) will improve birth weight and neonatal outcomes.

METHODS AND ANALYSIS

The Sleep Apnea and Fetal Growth Restriction study is a prospective, block-randomised, single-blinded, multicentre, pragmatic controlled trial. We enrol pregnant women aged 18-50, between 22 and 31 weeks of gestation, with established FGR based on second trimester ultrasound, who do not have other prespecified known causes of FGR (such as congenital anomalies or intrauterine infection). In stage 1, participants are screened by questionnaire for OSA risk. If OSA risk is identified, participants proceed to stage 2, where they undergo home sleep apnoea testing. Participants are determined to have OSA if they have an apnoea-hypopnoea index (AHI) ≥5 (if the oxygen desaturation index (ODI) is also ≥5) or if they have an AHI ≥10 (even if the ODI is <5). These participants proceed to stage 3, where they are randomised to nightly treatment with PAP or no PAP (standard care control), which is maintained until delivery. The primary outcome is unadjusted birth weight; secondary outcomes include fetal growth velocity on ultrasound, enrolment-to-delivery interval, gestational age at delivery, birth weight corrected for gestational age, stillbirth, Apgar score, rate of admission to higher levels of care (neonatal intensive care unit or special care nursery) and length of neonatal stay. These outcomes are compared between PAP and control using intention-to-treat analysis.

ETHICS AND DISSEMINATION

This study has been approved by the Institutional Review Boards at Washington University in St Louis, Missouri; Hadassah Hebrew University Medical Center, Jerusalem; and the University of Rochester, New York. Recruitment began in Washington University in November 2019 but stopped from March to November 2020 due to COVID-19. Recruitment began in Hadassah Hebrew University in March 2021, and in the University of Rochester in May 2021. Dissemination plans include presentations at scientific conferences and scientific publications.

TRIAL REGISTRATION NUMBER

NCT04084990.

Sleep Disordered Breathing, a Novel, Modifiable Risk Factor for Hypertensive Disorders of Pregnancy

PURPOSE OF REVIEW

Pathophysiology of hypertensive disorders of pregnancy (HDP), especially preeclampsia, has not been fully elucidated. Most trials aimed at the prevention of preeclampsia have failed to show significant benefit and investigation of novel, modifiable risk factors is sorely needed. Sleep disordered breathing (SDB), a group of disorders for which treatments are available, meets these criteria. SDB impacts about a third of all pregnancies and is associated with hypertension in the general non-pregnant population.

RECENT FINDINGS

Recent studies have shown a high prevalence of SDB, especially in complicated pregnancies. Several studies have shown that pregnant women with SDB have a higher risk for developing HDP, and these two disorders are associated with similar maternal long-term cardiovascular outcomes. Based on limited animal models of gestational intermittent hypoxia and human studies, SDB and HDP share similar risk factors and some pathophysiological mechanisms. However, there is paucity of studies addressing causality of this association and identifying therapeutic targets for intervention. Maternal SDB represents a novel and modifiable risk factor of HDP. Further studies are needed in order to establish the exact mechanisms underlying this association and to identify specific areas for clinical interventions.

Heparin therapy in placental insufficiency: Systematic review and meta-analysis

INTRODUCTION

The objective of this study was to establish whether heparin improves the neonatal outcome of fetuses with suspected placental insufficiency.

MATERIAL AND METHODS

Before data extraction, the project was registered in the PROSPERO International Prospective Register of Systematic Reviews (registration number: CRD42019117627). A systematic search was performed to identify relevant studies, using PubMed, SCOPUS, ISI Web of Knowledge, and PROSPERO database for meta-analysis. Suspected placental insufficiency was defined as either an estimated fetal weight or abdominal circumference below the 10th centile or when at least 2 of the following criteria were met: (1) abnormal biochemical markers, (2) sonographic evidence of abnormal placental morphology, or (3) abnormal uterine artery Doppler. Heparin in any commercial presentation was defined as the intervention. Mean difference (MD) by random effects model was used. Heterogeneity between studies was assessed using Cochran's Q, H, and I² statistics.

RESULTS

From 1159 assessed studies, two were retained for analysis. The results showed a significantly higher birthweight (MD 365; 95% CI 236 to 494; P < 0.001) and a significant increase of gestational age at birth by 1 week in those women treated with heparin (MD 0.806; 95% CI 0.354 to 1.258; P < 0.001). However, there were no significant differences in Apgar scores, neonatal admission, neonatal mortality, or composite neonatal morbidity.

CONCLUSIONS

In women with very high suspicion of placental insufficiency, heparin may increase fetal growth and prolong pregnancy. There is no evidence for a beneficial effect of heparin in reducing neonatal adverse outcomes.

Risk of fetal death in growth-restricted fetuses with umbilical and/or ductus venosus absent or reversed end-diastolic velocities before 34 weeks of gestation: a systematic review and meta-analysis

OBJECTIVE

The objective of the study was to establish the risk of fetal death in early-onset growth-restricted fetuses with absent or reversed end-diastolic velocities in the umbilical artery or ductus venosus.

DATA SOURCES

A systematic search was performed to identify relevant studies published in English, Spanish, French, Italian, or German using the databases PubMed, ISI Web of Science, and SCOPUS, without publication time restrictions.

STUDY ELIGIBILITY CRITERIA

The study criteria included observational cohort studies and randomized controlled trials of early-onset growth-restricted fetuses (diagnosed before 34 weeks of gestation), with information on the rate of fetal death occurring before 34 weeks of gestation and absent or reversed end-diastolic velocities in the umbilical artery and/or ductus venosus.

STUDY APPRAISAL AND SYNTHESIS METHODS

For quality assessment, 2 reviewers independently assessed the risk of bias using the Newcastle-Ottawa Scale for observational studies and the Cochrane Collaboration's tool for randomized trials. For the meta-analysis, odds ratio for both fixed and random-effects models (weighting by inverse of variance) were used. Heterogeneity between studies was assessed using tau², χ2 (Cochrane Q), and I² statistics. Publication bias was assessed by a funnel plot for meta-analyses and quantified by the Egger method.

RESULTS

A total of 31 studies were included in this meta-analysis. The odds ratios for fetal death (random-effects models) were 3.59 (95% confidence interval, 2.3-5.6), 7.27 (95% confidence interval, 4.6-11.4), and 11.6 (95% confidence interval, 6.3-19.7) for growth-restricted fetuses with umbilical artery absent end-diastolic velocities, umbilical artery reversed end-diastolic velocities, and ductus venosus absent or reversed end-diastolic velocities, respectively. There was no substantial heterogeneity among studies for any of the analyses.

CONCLUSION

Early-onset growth-restricted fetuses with either umbilical artery or ductus venosus absent or reserved end-diastolic velocities are at a substantially increased risk for fetal death.

N-carbamylglutamate and L-arginine improved maternal and placental development in underfed ewes

The objectives of this study were to determine how dietary supplementation ofN-carbamylglutamate (NCG) and rumen-protected L-arginine (RP-Arg) in nutrient-restricted pregnant Hu sheep would affect (1) maternal endocrine status; (2) maternal, fetal, and placental antioxidation capability; and (3) placental development. From day 35 to day 110 of gestation, 32 Hu ewes carrying twin fetuses were allocated randomly into four groups: 100% of NRC-recommended nutrient requirements, 50% of NRC recommendations, 50% of NRC recommendations supplemented with 20g/day RP-Arg, and 50% of NRC recommendations supplemented with 5g/day NCG product. The results showed that in maternal and fetal plasma and placentomes, the activities of total antioxidant capacity and superoxide dismutase were increased (P<0.05); however, the activity of glutathione peroxidase and the concentration of maleic dialdehyde were decreased (P<0.05) in both NCG- and RP-Arg-treated underfed ewes. The mRNA expression of vascular endothelial growth factor and Fms-like tyrosine kinase 1 was increased (P<0.05) in 50% NRC ewes than in 100% NRC ewes, and had no effect (P>0.05) in both NCG- and RP-Arg-treated underfed ewes. A supplement of RP-Arg and NCG reduced (P<0.05) the concentrations of progesterone, cortisol, and estradiol-17β; had no effect on T4/T3; and improved (P<0.05) the concentrations of leptin, insulin-like growth factor 1, tri-iodothyronine (T3), and thyroxine (T4) in serum from underfed ewes. These results indicate that dietary supplementation of NCG and RP-Arg in underfed ewes could influence maternal endocrine status, improve the maternal–fetal–placental antioxidation capability, and promote fetal and placental development during early-to-late gestation.

Gestational nanomaterial exposures: microvascular implications during pregnancy, fetal development and adulthood

Air pollution particulate matter and engineered nanomaterials are encompassed in the broad definition of xenobiotic particles. While the effects of perinatal air pollution exposure have been investigated, elucidation of outcomes associated with nanomaterial exposure, the focus of this review, is still in its infancy. As the potential uses of nanomaterials, and therefore exposures, increase exponentially so does the need for thorough evaluation. Up to this point, the majority of research in the field of cardiovascular nanotoxicology has focused on the coronary and vascular reactions to pulmonary exposures in young adult, healthy, male models; however, as intentional and unintentional contacts persist, the non-pulmonary risks to under-represented populations become a critical concern. Development of the maternal-fetal circulation during successful mammalian gestation is one of the most unusual complex, dynamic, and acutely demanding physiological systems. Fetal development in a hostile gestational environment can lead to systemic alterations, which may encourage adult disease. Therefore, the purpose of this review is to highlight the few knowns associated with gestational engineered nanomaterial exposure segmented by physiological periods of development or systemic targets: preconception and maternal, gestational, fetal and progeny (Abstract figure). Overall, the limited studies currently available provide compelling evidence of maternal, fetal and offspring dysfunctions after engineered nanomaterial exposure. Understanding the mechanisms associated with these multigenerational effects may allow pregnant women to safely reap the benefits of nanotechnology-enabled products and assist in the implementation of exposure controls to protect the mother and fetus allowing for development of safety by design for engineered nanomaterials.

Pregnancy morbidity in antiphospholipid syndrome: what is the impact of treatment?

Women with persistently circulating antiphospholipid antibodies (aPL) have a higher incidence of recurrent abortions, fetal losses, pre-eclampsia, and placental insufficiency. Current treatment of patients with antiphospholipid syndrome (APS) during pregnancy with heparin and aspirin can act by preventing clot formation and improving live birth rates, but other obstetric morbidities remain high, especially in patients with a history of thrombotic events. In addition to the classical thrombotic placental events, other factors involving inflammation and complement activation seem to play a role in certain complications. In this article, we will review how medications interfere in the pathogenic mechanisms of APS, discuss the impact of current recommended treatment on pregnancy morbidity, and analyze new promising therapies.

Effect of l-Arginine on Nitric Oxide Levels in Intrauterine Growth Restriction and its Correlation with Fetal Outcome

The current management of intrauterine growth restriction (IUGR) being empirical and aimed at selecting a safe time for delivery. Acknowledging the beneficial effects of l-arginine on endothelial vasculature the present study was designed to evaluate efficacy of l-arginine on bioavailability of nitric oxide (NO) with respect to fetal outcome. With l-arginine supplementation, mean NO levels were significantly increased and a significant mild reduction in systolic/end-diastolic velocity ratio (S/D ratio) was observed on doppler blood flow study, also neonatal outcome improved and incidences of complications were lowered. A deficiency in NO may play an important role in the causation of asymmetric fetal growth restriction. l-Arginine can be used to increase maternal NO levels, enhancing birth weight and decreasing neonatal morbidity. The ideal candidate for arginine therapy according to our study would be IUGR cases with S/D ratio less than 4.96 ± 0.49 and NO levels below 33 μmol/L with minimum of 3 weeks duration of arginine supplementation.

Snoring during pregnancy and delivery outcomes: a cohort study

STUDY OBJECTIVE

This cohort study examined the impact of maternal snoring on key delivery outcomes such as mode of delivery, infant birth centile, and small-for-gestational age.

DESIGN

Cohort study.

SETTING

A large tertiary medical center.

PATIENTS OR PARTICIPANTS

Pregnant women in their third trimester were recruited between March 2007 and December 2010.

MEASUREMENTS AND RESULTS

Women were screened for habitual snoring, as a known marker for sleep disordered breathing. Outcome data were obtained from medical records following delivery and birth centiles were calculated. Of 1,673 women, a total of 35% reported habitual snoring (26% with pregnancy-onset snoring and 9% with chronic snoring). After adjusting for confounders, chronic snoring was associated with small-forgestational age (OR 1.65, 95%CI 1.02-2.66, P = 0.041) and elective cesarean delivery (OR 2.25, 95%CI 1.22-4.18, P = 0.008). Pregnancy-onset snoring was associated with emergency cesarean delivery (OR 1.68, 95%CI 1.22-2.30, P = 0.001).

CONCLUSION

Maternal snoring during pregnancy is a risk factor for adverse delivery outcomes including cesarean delivery and small-for-gestational age. Screening pregnant women for symptoms of SDB may provide an early opportunity to identify women at risk of poor delivery outcomes.

CLINICAL TRIALS REGISTRATION

IDENTIFIER: NCT01030003.

In vivo function and evolution of the eutherian-specific pluripotency marker UTF1

Embryogenesis in placental mammals is sustained by exquisite interplay between the embryo proper and placenta. UTF1 is a developmentally regulated gene expressed in both cell lineages. Here, we analyzed the consequence of loss of the UTF1 gene during mouse development. We found that homozygous UTF1 mutant newborn mice were significantly smaller than wild-type or heterozygous mutant mice, suggesting that placental insufficiency caused by the loss of UTF1 expression in extra-embryonic ectodermal cells at least in part contributed to this phenotype. We also found that the effects of loss of UTF1 expression in embryonic stem cells on their pluripotency were very subtle. Genome structure and sequence comparisons revealed that the UTF1 gene exists only in placental mammals. Our analyses of a family of genes with homology to UTF1 revealed a possible mechanism by which placental mammals have evolved the UTF1 genes.

Identification and analysis of multi-protein complexes in placenta

Placental malfunction induces pregnancy disorders which contribute to life-threatening complications for both the mother and the fetus. Identification and characterization of placental multi-protein complexes is an important step to integratedly understand the protein-protein interaction networks in placenta which determine placental function. In this study, blue native/sodium dodecyl sulfate polyacrylamide gel electrophoresis (BN/SDS-PAGE) and Liquid chromatography-tandem mass spectrometry (LC-MS/MS) were used to screen the multi-protein complexes in placenta. 733 unique proteins and 34 known and novel heterooligomeric multi-protein complexes including mitochondrial respiratory chain complexes, integrin complexes, proteasome complexes, histone complex, and heat shock protein complexes were identified. A novel protein complex, which involves clathrin and small conductance calcium-activated potassium (SK) channel protein 2, was identified and validated by antibody based gel shift assay, co-immunoprecipitation and immunofluorescence staining. These results suggest that BN/SDS-PAGE, when integrated with LC-MS/MS, is a very powerful and versatile tool for the investigation of placental protein complexes. This work paves the way for deeper functional characterization of the placental protein complexes associated with pregnancy disorders.

Can maternal serum placental growth factor estimation in early second trimester predict the occurrence of early onset preeclampsia and/or early onset intrauterine growth restriction? A prospective cohort study

AIM

To determine whether maternal serum placental growth factor (PlGF) estimation in early second trimester (20-22 weeks of gestation) can predict the occurrence of early onset preeclampsia and/or early onset intrauterine growth restriction (IUGR).

MATERIAL AND METHODS

A prospective cohort study was conducted on 722 women with singleton pregnancies, screened from the antenatal clinic, and serum PlGF levels were estimated at 20-22 weeks of gestation. A cut-off value of <155 pg/mL for serum PlGF was determined by receiver operating characteristic (ROC) curve analysis for identifying pregnant women at risk of developing early onset preeclampsia and/or early onset IUGR. Preeclampsia and IUGR were classified as early onset when diagnosed by 32 weeks of gestation. Univariate logistic regression analysis was used to analyze the association between serum PlGF level <155 pg/mL and the two outcome measures (i.e. early onset preeclampsia and early onset IUGR) and odds ratio (OR) was computed. P-value < 0.05 was considered statistically significant.

RESULTS

Maternal serum PlGF level <155 pg/mL at 20-22 weeks of gestation had a strong association with early onset preeclampsia (OR 8.35; 95% CI 1.79-18.94; P = 0.007) and with early onset IUGR (OR 10.73; 95% CI 4.08-20.23; P = 0.000). The sensitivity of serum PlGF < 155 pg/mL for predicting early onset preeclampsia and early onset IUGR were 82 and 84, respectively.

CONCLUSION

Maternal serum PlGF level estimation in early second trimester (20-22 weeks of gestation) may be useful in predicting the occurrence of early onset preeclampsia and/or early onset IUGR.

Cervical cancer and risk for delivery of small-for-gestational age neonates

OBJECTIVE

To determine if cervical intraepithelial neoplasia grade 3 (CIN-3) and cervical cancer are associated with adverse obstetrical outcomes.

METHODS

Women with diagnoses of CIN-3 and cervical cancer were first identified from the University of Pittsburgh Medical Center (UPMC) Network Cancer Registry by using respective ICD-3 codes. Identified records were then linked to the Magee Obstetrical Maternal and Infant (MOMI) database to identify women who subsequently delivered pregnancies at Magee-Womens Hospital. Women with cervical disease were compared with women without known disease to determine the impact of cervical disease on various maternal and neonatal outcomes. The latter group consisted of those women who delivered singleton pregnancies at our institution, as determined by the MOMI database, but who did not have any matching records in the UPMC Cancer Registry. Statistical significance was defined by a p value <0.05.

RESULTS

We identified CIN-3 (n = 52) and cervical cancer patients (n = 83) who later had documented pregnancies delivered at Magee-Womens Hospital between 1989 and 2006. Women with cervical cancer and CIN-3 were at greater risk to deliver small-for-gestational age (SGA) neonates compared with women without known cervical disease (RR 1.54, 95% confidence interval [CI] 1.0-2.46). A secondary analysis of risk factors for SGA neonates demonstrated a significant association with cervical cancer (p = 0.04). After accounting for variables known to be risk factors for SGA, cervical cancer was associated with a 1.9-fold increased risk of a SGA delivery (OR 1.9, 95% CI 1.1-3.4).

CONCLUSIONS

Cervical cancer is a risk factor for delivery of an SGA neonate in a subsequent pregnancy.

Brain metabolism in fetal intrauterine growth restriction: a proton magnetic resonance spectroscopy study

OBJECTIVE

The purpose of this study was to investigate alterations in brain metabolism in fetuses with intrauterine growth restriction (IUGR) and evidence of cerebral redistribution of blood flow.

STUDY DESIGN

Biometry and Doppler assessment of blood flow was assessed with ultrasound in 28 fetuses with IUGR and cerebral redistribution and in 41 appropriately grown control subjects. Proton magnetic resonance spectroscopy of the fetal brain was then performed to determine the presence of choline (Cho), creatine (Cr), N-acetylaspartate (NAA), and lactate and to generate ratios for NAA:Cho, NAA:Cr, and Cho:Cr.

RESULTS

Sixty-five percent of spectra were interpretable: N-acetylaspartate, choline, and creatine peaks were identified in all these spectra; lactate was present in 5 IUGR fetuses and in 3 appropriately grown fetuses. NAA:Cr and NAA:Cho ratios were significantly lower in IUGR fetuses with cerebral redistribution.

CONCLUSION

Cerebral redistribution is associated with altered brain metabolism that is evidenced by a reduction in NAA:Cho and NAA:Cr ratios.

Hypomethylation along with increased H19 expression in placentas from pregnancies complicated with fetal growth restriction

The expression of imprinted genes is regulated by epigenetic modifications, such as DNA methylation. Many imprinted genes are expressed in the placenta and affect nutrient transfer capacity of the placental exchange barrier. The H19 gene is abundantly expressed by the human placenta and is implicated in the pathogenesis of congenital growth disorders such as Beckwith-Wiedemann (BWS) and Silver-Russell (SRS) syndromes. The aim of this study was to investigate the role of DNA methylation on H19 transcription and imprinting, in the pathophysiology of fetal growth restriction (FGR). Thirty one and 17 placentas from FGR-complicated and normal pregnancies were collected, respectively. We studied gene transcription, genotyping and methylation analysis of the AluI H19 on exon 5 polymorphism. Placental expression levels of H19 were significantly increased in the FGR group. The H19 mRNA levels were similar between normal placental samples that demonstrated loss and maintenance of imprinting. Placentas from growth-restricted pregnancies had lower methylation levels compared to normals, in the H19 promoter region. We have demonstrated an increased H19 transcription in the FGR group of placentas. The hypomethylation of the H19 promoters is compatible with the aberrant expression. The association of these two findings is reported for the first time in placental tissues, however, its significance remains unknown. Whether the results of this study represent an adaptation of the placenta to hypoperfusion, or they are part of FGR pathophysiology has to be further investigated.

Obstetrical intervention and the singleton preterm birth rate in the United States from 1991-2006

OBJECTIVES

We examined the relationship between obstetrical intervention and preterm birth in the United States between 1991 and 2006.

METHODS

We assessed changes in preterm birth, cesarean delivery, labor induction, and associated risks. Logistic regression modeled the odds of preterm obstetrical intervention after risk adjustment.

RESULTS

From 1991 to 2006, the percentage of singleton preterm births increased 13%. The cesarean delivery rate for singleton preterm births increased 47%, and the rate of induced labor doubled. In 2006, 51% of singleton preterm births were spontaneous vaginal deliveries, compared with 69% in 1991. After adjustment for demographic and medical risks, the mother of a preterm infant was 88% (95% confidence interval [CI] = 1.87, 1.90) more likely to have an obstetrical intervention in 2006 than in 1991. Using new birth certificate data from 19 states, we estimated that 42% of singleton preterm infants were delivered via induction or cesarean birth without spontaneous onset of labor.

CONCLUSIONS

Obstetrical interventions were related to the increase in the US preterm birth rate between 1991 and 2006. The public health community can play a central role in reducing medically unnecessary interventions.

Feto-maternal interaction: a mathematical model simulating placental response in hypertensive disorders of pregnancy

Elevated maternal blood pressure (BP) is common in pregnancies complicated by hypertensive disorders. In response, increased production and accumulation of elastin occurs in the feto-placental blood vessels. This results in increased vascular wall stiffness that increases the resistance to flow. To study the interaction between the stiffness of the fetoplacental blood vessels, fetoplacental blood flow and BP, a mathematical model of the fetoplacental vascular tree was developed. The model describes an elastic structure exposed to external pressure. Model results indicate that increased vascular stiffness in the fetal blood vessels may contribute to optimizing fetoplacental blood flow in hypertensive pregnancies. According to model predictions, uncontrolled lowering of BP following vascular adaptation may adversely affect fetoplacental blood flow.

Parenteral administration of L-arginine prevents fetal growth restriction in undernourished ewes

Intrauterine growth restriction (IUGR) is a major health problem worldwide that currently lacks an effective therapeutic solution. This study was conducted with an ovine IUGR model to test the hypothesis that parenteral administration of l-arginine (Arg) is effective in enhancing fetal growth. Beginning on d 28 of gestation, ewes were fed a diet providing 100% (control-fed) or 50% (underfed) of NRC-recommended nutrient requirements. Between d 60 of gestation and parturition, underfed ewes received i.v. infusions of saline or 155 micromol Arg-HCl/kg body weight 3 times daily, whereas control-fed ewes received only saline. The birth weights of lambs from saline-infused underfed ewes were 23% lower (P < 0.01) than those of lambs from control-fed dams. Administration of Arg to underfed ewes increased (P < 0.01) concentrations of Arg (69%), ornithine (55%), proline (29%), methionine (37%), leucine (36%), isoleucine (35%), cysteine (19%), and FFA (43%) in maternal serum, decreased maternal circulating levels of ammonia (18%) and triglycerides (32%), and enhanced birth weights of lambs by 21% compared with saline-infused underfed ewes. There was no difference in birth weights of lambs between the control-fed and the Arg-infused underfed ewes. These novel results indicate that parenteral administration of Arg to underfed ewes prevented fetal growth restriction and provide support for its clinical use to ameliorate IUGR in humans. The findings also lay a new framework for studying cellular and molecular mechanisms responsible for the beneficial effects of Arg in regulating conceptus growth and development.

Placental vascular lesion differences in pregnancy-induced hypertension and normotensive fetal growth restriction

OBJECTIVE

Pregnancy-induced hypertension/preeclampsia (PIH) and fetal growth restriction (FGR) share a common placental origin. The pathologic classification that divides placental lesions to maternal or fetal origin was compared between these disorders.

STUDY DESIGN

Placentas from pregnancies that were complicated by PIH, normotensive FGR, or by both (combined) were analyzed, and lesions were classified as those consistent with maternal under-perfusion and with fetal thromboocclusive disease.

RESULTS

Maternal vascular lesions were more common in the PIH group and combined group (61% and 59%, respectively), compared with the FGR group (16.2%; P < .001), and villous lesions were more common in the combined group, compared with the FGR and PIH groups (79.5%, 53.5%, and 46.9%, respectively; P = .004). Fetal villous changes were observed in 16.2% in the FGR group, compared with 3.1% in the PIH group (P = .03), and chronic villitis was 15.2% in the FGR group vs 1.6% in the PIH group (P = .004).

CONCLUSION

Placental lesions correspond with different clinical presentations.

Perinatal outcome of recurrent pre-eclampsia versus pre-eclampsia in nulliparas

AIM

The aim of the study was to compare the perinatal outcome of recurrent pre-eclampsia in multiparas with that of pre-eclampsia in nulliparas.

METHODS

This retrospective study was performed by collecting maternal and perinatal data from records of women with pre-eclampsia who delivered at Mackay Memorial Hospital over a 10-year period. Fifty women with recurrent pre-eclampsia were compared with 207 women who developed pre-eclampsia as nulliparas. In the 50 multiparas, the outcome of recurrent pre-eclampsia was also compared with that of their earlier episodes of pre-eclampsia. Maternal and fetal variables compared included maternal blood pressure, serum biochemistry, rate of preterm delivery, rate of abruptio placentae and neonatal outcome.

RESULTS

Compared with nulliparous women with pre-eclampsia (n = 50), women with recurrent pre-eclampsia (n = 207) had a smaller increase in mean maternal blood pressure (27.0 +/- 18.9 mmHg vs 34.3 +/- 19.3 mmHg, P = 0.021), less dipstick proteinuria (>or=++; 36.0 vs 58.5%, P = 0.004), and bore children with a heavier mean birthweight (2909.1 +/- 895.5 g vs 2551.1 +/- 933.0 g, P = 0.017). No significant statistical difference was found in the gestational age of delivery, maternal serum biochemical levels and rate of abruptio placentae or preterm delivery. Within the multiparous group (n = 50), recurrent disease was associated with a lower mean maternal blood pressure and dipstick proteinuria and with higher birthweight than in their previous pre-eclamptic pregnancies.

CONCLUSION

Recurrent pre-eclampsia appears to be less severe and to have a better perinatal outcome than pre-eclampsia in nulliparas.

Placental MRI in intrauterine fetal growth restriction

OBJECTIVE

Our objectives were to determine if MR imaging of the placenta could demonstrate a specific placental phenotype in small for gestational age fetuses with increasing severity of fetal growth restriction, and if MRI findings at the time of scan could be used to predict fetal or neonatal mortality.

METHOD

We included singleton growth restricted fetuses with increasing severity of fetal growth restriction secondary to placental insufficiency. 20 growth restricted fetuses and 28 normal fetuses were scanned once during pregnancy at varying gestations. MRI scans were performed on a 1.5T system using ssFSE sequences through the uterus. Data was collected on the severity of fetal growth restriction and pregnancy outcome, including clinical neonatal details, perinatal mortality, and birthweight and centile. Placental volume, maximal placental thickness, the placental thickness to volume ratio, the placenta to amniotic fluid signal intensity ratio, and the presence of abnormal signal intensity consistent with placental pathology were noted. In a subset of patients, histopathological diagnosis was compared with the MRI appearance of the placenta.

RESULTS

There was a significant increase in the placental volume affected by pathology in growth restricted fetuses (p < 0.001). The placental appearance was also thickened and globular, with an increase in the placental thickness to volume ratio (p < 0.001). Although placental volume increased with increasing gestation, it remained reduced in the growth restricted fetuses (p = 0.003). There was a significant correlation between the severity of fetal growth restriction and the placental volume affected by pathology, the placental thickness to volume ratio, and the placental volume. ROC analysis showed that fetal or neonatal death was predicted by the percentage of abnormal signal intensity consistent with placental pathology (p = 0.002). The presence of a thickened, globular placenta and a maximal placental thickness to volume ratio above the 95% confidence limit for gestation was significantly associated with an increased incidence of fetal or neonatal mortality (relative risk = 1.615, p = 0.001 and relative risk = 7, p < 0.001).

CONCLUSIONS

The MRI appearance of the placenta provides an indication of the severity and underlying disease process in fetal growth restriction. In units where MRI imaging of the growth restricted fetus occurs, we suggest that the assessment of the placenta should also occur as it may contribute to management decisions in cases at the threshold of viability. It may have a role to play in monitoring disease severity, and the effect of future interventions designed to improve placental function.

Maternal hemoglobin level and fetal outcome at low and high altitudes

Both, low (<7 g/dl) and high (>14.5 g/dl), maternal hemoglobin (Hb) levels have been related to poor fetal outcome. Most studies have been done at low altitude (LA). Here, we have sought to determine whether this relationship exists at both high and low altitude, and also whether there is an adverse effect of high altitude (HA) on fetal outcome independent of level of maternal hemoglobin. The study is based on a retrospective multicenter analysis of 35,449 pregnancies at LA and six other cities above 3000 meters. In analyses of all women at both LA and HA, those with Hb <9 g/dl had odds ratios (ORs) and 95% confidence intervals (CI) of 4.4 (CI: 2.8-6.7), 2.5 (CI: 1.9-3.2), and 1.4 (CI: 1.1-1.9) for stillbirths, preterm, and small for gestational age (SGA) births, respectively, compared with women with 11-12.9 g/dl of Hb, after adjustment for confounders. These risks by hemoglobin level differed little between women at LA and HA, suggesting that no correction of the definition of anemia is necessary for women at HA. Women living at high altitude with hemoglobin >15.5 g/dl had higher risks for stillbirths (OR: 1.3; CI: 1.05-1.3), preterm (OR: 1.5; CI 1.3-1.8), and SGA births (OR: 2.1, CI 1.8-2.3). There was also a significant adverse effect of living at HA, independent of hemoglobin level for all three outcomes (OR: 3.9, 1.7, and 2.3; CI: 2.8-5.2, 1.5-1.9, and 2.1-2.5) for stillbirths, preterms, and SGA respectively, after adjusting for hemoglobin level. Both, high and low maternal hemoglobin levels were related to poor pregnancy outcome, with similar effect of low hemoglobin in both LA and HA. Our data suggest, that maternal hemoglobin above 11 g/dl but below 13 g/dl is the area of minimal risk of poor adverse outcomes. Living at HA had an adverse effect independent of hemoglobin level.

Low pregnancy weight gain and small for gestational age: a comparison of the association using 3 different measures of small for gestational age

OBJECTIVE

The purpose of this study was to assess associations between pregnancy weight gain (PWG) and small for gestational age (SGA) defined by birthweight < 10th percentile and 2 more restrictive definitions and to assess the proportion of SGA attributed to low PWG.

STUDY DESIGN

This was a retrospective cohort study of 104,980 singleton, term births from the 2000-2005 Pregnancy Risk Assessment Monitoring System (PRAMS).

RESULTS

Compared with women who gained 15-25 lbs during pregnancy, women who gained 1-14 lbs had 1.5 greater odds (95% confidence interval, 1.2-1.8) of SGA for the most restrictive definition and 1.2 greater odds (95% confidence interval, 1.1-1.4) for the least restrictive definition, after adjustments for confounders. Depending upon the definition used, PWG below current Institute of Medicine recommendations contributed to 10-15% of SGA, representing 0.8-1.2% of all singleton term infants.

CONCLUSION

Associations between low PWG and SGA varied little by definition of SGA and contributed to only a small proportion of term SGA infants.

Comparative systems biology of human and mouse as a tool to guide the modeling of human placental pathology

Placental abnormalities are associated with two of the most common and serious complications of human pregnancy, maternal preeclampsia (PE) and fetal intrauterine growth restriction (IUGR), each disorder affecting ∼5% of all pregnancies. An important question for the use of the mouse as a model for studying human disease is the degree of functional conservation of genetic control pathways from human to mouse. The human and mouse placenta show structural similarities, but there have been no systematic attempts to assess their molecular similarities or differences. We collected protein and mRNA expression data through shot-gun proteomics and microarray expression analysis of the highly vascular exchange region, microdissected from the human and mouse near-term placenta. Over 7000 ortholog genes were detected with 70% co-expressed in both species. Close to 90% agreement was found between our human proteomic results and 1649 genes assayed by immunohistochemistry for expression in the human placenta in the Human Protein Atlas. Interestingly, over 80% of genes known to cause placental phenotypes in mouse are co-expressed in human. Several of these phenotype-associated proteins form a tight protein–protein interaction network involving 15 known and 34 novel candidate proteins also likely important in placental structure and/or function. The entire data are available as a web-accessible database to guide the informed development of mouse models to study human disease.

Doppler ultrasonography in obstetrics: from the diagnosis of fetal anemia to the treatment of intrauterine growth-restricted fetuses

After the adoption of the use of umbilical artery and middle cerebral artery peak systolic velocity in high-risk pregnancies and in pregnancies that are at risk of having an anemic fetus, the main focus of Doppler ultrasonography in obstetrics today is intrauterine growth-restricted fetuses. What is most needed at this time are (1) training of sonographers and sonologists on how to perform a Doppler study, (2) an international classification of intrauterine growth-restricted fetuses, and (3) a study of the natural history of intrauterine growth-restricted fetuses that might contribute to a better understanding of the intrauterine growth-restriction process and to standard treatment of intrauterine growth-restricted fetuses. Future investigations, which would include randomized studies, could be designed from the results of such studies.

Fetal Doppler: umbilical artery, middle cerebral artery, and venous system

One of the most important applications of Doppler ultrasonography in obstetrics is the detection of fetal anemia in pregnancies complicated by either red-cell alloimmunization or by other causes of fetal anemia. Doppler of the umbilical artery also has prognostic value in pregnancies affected by twin-twin transfusion syndrome undergoing in-utero intervention. Another potential major application is the use of Doppler ultrasound in the management of intrauterine-growth-restricted fetuses. At the present time, there is no single test that appears superior to the other available tests for timing the delivery of the growth-restricted fetus. Therefore, the decision to deliver a fetus, especially at <32 weeks, remains mostly based on empirical management. Doppler may provide a more reliable and systematic basis for timing these deliveries. This review emphasizes the three following concepts: (a) normal and abnormal Doppler of the umbilical artery, middle cerebral artery, mitral and tricuspid valves, umbilical vein, and ductus venosus; (b) some clinical applications of Doppler sonography in obstetrics; and (c) potential future research of Doppler in obstetrics.

Doppler vascular changes in intrauterine growth restriction

Intrauterine growth restriction (IUGR) secondary to placental insufficiency is a major cause of perinatal morbidity and mortality in the United States. Historically, Doppler changes occurring in IUGR fetuses play an important role in the diagnosis and management of these fetuses, and now, based on these changes, we have proposed a staging system for IUGR fetuses that demonstrates prognostic value. This manuscript also summarizes a practical classification for IUGR fetuses. We believe that future studies should differentiate among the different types of IUGR fetuses.

Immune function in pregnancy: the role of corticotropin-releasing hormone

Pregnancy represents a major challenge to the maternal immune system since it has to tolerate the semi-allograft fetus. Indeed, the success of pregnancy requires an appropriate immunological interaction between the mother and the fetus. Furthermore, evidence suggests that some pregnancy complications, such as spontaneous abortions, preeclampsia and intrauterine growth restriction, are associated with abnormal maternal-fetal immune responses. Corticotropin-releasing hormone (CRH), a 41-amino acid peptide originally found in the hypothalamus, appears to have a fundamental role in the mechanisms responsible for the implantation and maintenance of human pregnancy. Reproductive CRH is a form of tissue CRH (CRH found in peripheral tissues), analogous to the immune CRH detected in peripheral inflammatory sites. Reproductive CRH has been identified in the endometrial glands, the decidualized endometrial stroma and the placental trophoblast, synctiotrophoblast and decidua. Reproductive CRH participates in various reproductive functions with an inflammatory component, where it serves as an autocrine/paracrine modulator. The immunological mechanisms contributing to the establishment and maintenance of pregnancy are not fully understood. The present article focuses on the potential roles of CRH on the physiology and pathophysiology of pregnancy and highlights its participation in implantation, early fetal immunotolerance and parturition.

Staging of intrauterine growth-restricted fetuses

OBJECTIVE

The purpose of this study was to evaluate the value of cardiovascular, ultrasonographic, and clinical parameters for developing a staging classification of intrauterine growth-restricted (IUGR) fetuses delivered at 32 weeks or earlier.

METHODS

Intrauterine growth restriction was defined as the presence of an estimated fetal weight below the 10th percentile. Intrauterine growth-restricted fetuses were staged according to the following parameters, with the presence of any 1 parameter in a stage placing the fetus in that stage: stage I, an abnormal umbilical artery or middle cerebral artery pulsatility index; stage II, an abnormal middle cerebral artery peak systolic velocity, umbilical artery absent/reversed diastolic flow, umbilical vein pulsation and an abnormal ductus venosus pulsatility index; and stage III, reversed flow at the ductus venosus or reversed flow at the umbilical vein, an abnormal tricuspid E wave (early ventricular filling)/A wave (late ventricular filling) ratio, and tricuspid regurgitation. Each stage was divided into A (amniotic fluid index [AFI] <5 cm) and B (AFI >5 cm). The presence of maternal abnormalities was also reported.

RESULTS

Seventy-four IUGR fetuses delivered at 32 weeks or earlier were included. Gestational age at delivery was greater in stage I fetuses compared with the other stages. Birth weight decreased with advancing stages. Stage III fetuses had the lowest AFI. There was a direct correlation between the severity of staging and both perinatal mortality and mortality occurring between 20 weeks' gestation and before the neonates were discharged from the hospital (P < .05).

CONCLUSIONS

The staging system proposed here may allow comparison of outcome data for IUGR fetuses and may be valuable in determining more timely delivery for these high-risk fetuses.