Enhancement of amniotic cyclooxygenase type 2 activity in women with preterm delivery associated with twins or polyhydramnios

Idiopathic Polyhydramnios and Neonatal Morbidity at Term

OBJECTIVE

Idiopathic polyhydramnios is among the most common etiologies of polyhydramnios. However, conflicting evidence exists regarding the relationship between polyhydramnios and neonatal morbidity. We investigated the association between pregnancies with and without idiopathic polyhydramnios and neonatal morbidity at term.

STUDY DESIGN

This is a retrospective cohort study of singleton, term (i.e., ≥370/7 weeks) pregnancies from 2014 to 2018. Pregnancies complicated by fetal anomalies, pregestational diabetes, and multifetal gestation were excluded. Pregnancies complicated by idiopathic polyhydramnios were defined by the deepest vertical pocket (DVP) ≥8 cm or amniotic fluid index (AFI) ≥24 cm after 20 weeks' gestation and were compared with women without polyhydramnios at time of delivery. These groups were matched 1:2 by gestational age within 7 days at delivery and maternal race. The primary outcome was a composite neonatal morbidity (neonatal death, respiratory morbidity, hypoxic-ischemic encephalopathy, therapeutic hypothermia, seizures, and umbilical artery pH < 7.10). Outcomes were compared between pregnancies with and without idiopathic polyhydramnios. Unadjusted and adjusted risk ratios were estimated using multivariable logistic regression.

RESULTS

Idiopathic polyhydramnios was diagnosed in 192 pregnancies and were matched to 384 pregnancies without polyhydramnios. After adjustment for obesity, women with pregnancies complicated by idiopathic polyhydramnios had an increased risk of composite neonatal morbidity 21.4 versus 5.5% (adjusted risk ratio [aRR] = 4.0, 95% confidence interval [CI]: 2.3-6.7). Term neonatal respiratory morbidity was the primary driver 20.3 versus 4.2%, (aRR = 4.8, 95% CI: 2.7-8.7) and included higher use of continuous positive airway pressure 19.8 versus 3.4%, p <0.01 and the need for supplemental oxygen at >12 hours of newborn life 6.8 versus 1.8%, p <0.01.

CONCLUSION

Idiopathic polyhydramnios is associated with term neonatal respiratory morbidity at delivery and during the subsequent hours of newborn life, compared with pregnancies without idiopathic polyhydramnios. Further studies are needed to minimize neonatal morbidity at term.

KEY POINTS

· Idiopathic polyhydramnios is associated with increased risk of neonatal morbidity at term.. · Increasing idiopathic polyhydramnios severity was associated with a trend toward worsening morbidity at term.. · Idiopathic polyhydramnios at term requires respiratory support at delivery and during neonatal care..

Spontaneous preterm birth: Involvement of multiple feto-maternal tissues and organ systems, differing mechanisms, and pathways

Survivors of preterm birth struggle with multitudes of disabilities due to improper in utero programming of various tissues and organ systems contributing to adult-onset diseases at a very early stage of their lives. Therefore, the persistent rates of low birth weight (birth weight < 2,500 grams), as well as rates of neonatal and maternal morbidities and mortalities, need to be addressed. Active research throughout the years has provided us with multiple theories regarding the risk factors, initiators, biomarkers, and clinical manifestations of spontaneous preterm birth. Fetal organs, like the placenta and fetal membranes, and maternal tissues and organs, like the decidua, myometrium, and cervix, have all been shown to uniquely respond to specific exogenous or endogenous risk factors. These uniquely contribute to dynamic changes at the molecular and cellular levels to effect preterm labor pathways leading to delivery. Multiple intervention targets in these different tissues and organs have been successfully tested in preclinical trials to reduce the individual impacts on promoting preterm birth. However, these preclinical trial data have not been effectively translated into developing biomarkers of high-risk individuals for an early diagnosis of the disease. This becomes more evident when examining the current global rate of preterm birth, which remains staggeringly high despite years of research. We postulate that studying each tissue and organ in silos, as how the majority of research has been conducted in the past years, is unlikely to address the network interaction between various systems leading to a synchronized activity during either term or preterm labor and delivery. To address current limitations, this review proposes an integrated approach to studying various tissues and organs involved in the maintenance of normal pregnancy, promotion of normal parturition, and more importantly, contributions towards preterm birth. We also stress the need for biological models that allows for concomitant observation and analysis of interactions, rather than focusing on these tissues and organ in silos.

The role of the obstetrician in the prevention of retinopathy of prematurity

This review underlines the important role that obstetricians play in the prevention of retinopathy of prematurity. Efforts predominately focus on predicting which pregnant women are at highest risk of preterm birth, instigating treatments to prevent pre-eclampsia, fetal growth restriction and maternal infection which could lead to iatrogenic or spontaneous preterm birth, and optimizing care when preterm birth is inevitable. More broadly, optimizing maternal health pre-conception through stopping smoking, improving diet, reducing obesity with its associated gestational diabetes, and treating hypertension may reduce preterm birth and other pregnancy complications. This is a message that all healthcare professionals including obstetricians, neonatologists and GPs, nursing and midwifery staff need to communicate all women and men who are contemplating having a baby.

Cyclooxygenase inhibitors for treating preterm labour: What is the molecular evidence? 1

Preterm birth (<37 weeks of gestation) significantly increases the risk of neonatal mortality and morbidity. As many as half of all preterm births occur following spontaneous preterm labour. Since in such cases there are no known reasons for the initiation of labour, treatment of preterm labour (tocolysis) has sought to stop labour contractions and delay delivery. Despite some success, the use of cyclooxygenase (COX) inhibitors is associated with maternal/fetal side effects, and possibly increased risk of preterm birth. Clinical use of these drugs predates the collection of molecular and biochemical evidence in vitro, examining the expression and activity of COX enzymes in pregnant uterine tissues with and without labour. Such evidence is important to the rationale that COX enzymes are, or are not, appropriate targets for the tocolysis. The current study systematically searched existing scientific evidence to address the hypothesis that COX expression/activity is increased with the onset of human labour, in an effort to determine whether there is a rationale for the use of COX inhibitors as tocolytics. Our review identified 44 studies, but determined that there is insufficient evidence to support or refute a role of COX-1/-2 in the onset of preterm labour that supports COX-targeted tocolysis.

Short-term outcome for term and near-term singleton infants with intrapartum polyhydramnios

OBJECTIVE

To evaluate rates of early short-term neonatal complications among term and near-term newborn infants with polyhydramnios.

METHODS

Retrospective data were collected on 788 term infants with prenatal diagnosis of polyhydramnios and 1,576 matched controls, including information on maternal condition and on infant perinatal complications.

RESULTS

The total rate of major congenital malformations among infants born to mothers with polyhydramnios was 2.3% compared to 0.13% for those with normal amniotic fluid index (p < 0.001). Infants in the study group were more likely to be born to diabetic mothers, were heavier and large for gestational age and were more likely to be delivered by cesarean section. Infants with polyhydramnios, but no major congenital malformations, are at increased risk for minor congenital malformations (4.2%) as well as for postnatal complications, such as respiratory distress (5.7%), cardiovascular manifestations (mainly delayed closure of the ductus arteriosus; 3.1%) and hypoglycemia (7%) compared to controls. Multivariate logistic regression revealed that polyhydramnios was associated only with postnatal respiratory distress and hypoglycemia. The severity of polyhydramnios was not associated with an increased rate of neonatal complications.

CONCLUSION

Although infants with polyhydramnios, but no major congenital malformations, were found to have increased rates of respiratory distress and hypoglycemia, these clinical manifestations were mild and had little effect on the babies' well-being and length of hospital stay.

Treatment of abnormal vaginal flora in early pregnancy with clindamycin for the prevention of spontaneous preterm birth: a systematic review and metaanalysis

The purpose of this study was to determine whether the administration of clindamycin to women with abnormal vaginal flora at <22 weeks of gestation reduces the risk of preterm birth and late miscarriage. We conducted a systematic review and metaanalysis of randomized controlled trials of the early administration of clindamycin to women with abnormal vaginal flora at <22 weeks of gestation. Five trials that comprised 2346 women were included. Clindamycin that was administered at <22 weeks of gestation was associated with a significantly reduced risk of preterm birth at <37 weeks of gestation and late miscarriage. There were no overall differences in the risk of preterm birth at <33 weeks of gestation, low birthweight, very low birthweight, admission to neonatal intensive care unit, stillbirth, peripartum infection, and adverse effects. Clindamycin in early pregnancy in women with abnormal vaginal flora reduces the risk of spontaneous preterm birth at <37 weeks of gestation and late miscarriage. There is evidence to justify further randomized controlled trials of clindamycin for the prevention of preterm birth. However, a deeper understanding of the vaginal microbiome, mucosal immunity, and the biology of BV will be needed to inform the design of such trials.

Metabolomics in premature labor: a novel approach to identify patients at risk for preterm delivery

OBJECTIVE

Biomarkers for preterm labor (PTL) and delivery can be discovered through the analysis of the transcriptome (transcriptomics) and protein composition (proteomics). Characterization of the global changes in low-molecular weight compounds which constitute the 'metabolic network' of cells (metabolome) is now possible by using a 'metabolomics' approach. Metabolomic profiling has special advantages over transcriptomics and proteomics since the metabolic network is downstream from gene expression and protein synthesis, and thus more closely reflects cell activity at a functional level. This study was conducted to determine if metabolomic profiling of the amniotic fluid can identify women with spontaneous PTL at risk for preterm delivery, regardless of the presence or absence of intraamniotic infection/inflammation (IAI).

STUDY DESIGN

Two retrospective cross-sectional studies were conducted, including three groups of pregnant women with spontaneous PTL and intact membranes: (1) PTL who delivered at term; (2) PTL without IAI who delivered preterm; and (3) PTL with IAI who delivered preterm. The first was an exploratory study that included 16, 19, and 20 patients in groups 1, 2, and 3, respectively. The second study included 40, 33, and 40 patients in groups 1, 2, and 3, respectively. Amniotic fluid metabolic profiling was performed by combining chemical separation (with gas and liquid chromatography) and mass spectrometry. Compounds were identified using authentic standards. The data were analyzed using discriminant analysis for the first study and Random Forest for the second.

RESULTS

(1) In the first study, metabolomic profiling of the amniotic fluid was able to identify patients as belonging to the correct clinical group with an overall 96.3% (53/55) accuracy; 15 of 16 patients with PTL who delivered at term were correctly classified; all patients with PTL without IAI who delivered preterm neonates were correctly identified as such (19/19), while 19/20 patients with PTL and IAI were correctly classified. (2) In the second study, metabolomic profiling was able to identify patients as belonging to the correct clinical group with an accuracy of 88.5% (100/113); 39 of 40 patients with PTL who delivered at term were correctly classified; 29 of 33 patients with PTL without IAI who delivered preterm neonates were correctly classified. Among patients with PTL and IAI, 32/40 were correctly classified. The metabolites responsible for the classification of patients in different clinical groups were identified. A preliminary draft of the human amniotic fluid metabolome was generated and found to contain products of the intermediate metabolism of mammalian cells and xenobiotic compounds (e.g. bacterial products and Salicylamide).

CONCLUSION

Among patients with spontaneous PTL with intact membranes, metabolic profiling of the amniotic fluid can be used to assess the risk of preterm delivery in the presence or absence of infection/inflammation.

Prostaglandin treatment is associated with a withdrawal of progesterone and androgen at the receptor level in the uterine cervix

Treatment with prostaglandin(PG)-E2 is clinically efficient for cervical priming. The aim of this study was to evaluate the impact of PG-E2 on the expression of the progesterone (PR), androgen (AR) and glucocorticoid (GR) receptors in human uterine cervix in prolonged pregnancy. The study groups were postterm nulliparous women with unripe cervices undergoing cervical priming with PG-E2 before labor induction. Responders (n = 12) who delivered vaginally were compared with non-responders (n = 10), who underwent cesarean section due to failure to progress to the active phase of labor. Controls (n = 18) with vaginal partus at a normal gestational age served as a reference group. Cervical levels of PR-A and PR- B isoforms, AR and GR, serum levels of their ligands and sex hormone-binding globulin (SHBG) were quantified. The responder group displayed lower total PR-AB and AR protein levels as compared to non-responders, and lower PR-B and AR protein levels as compared to controls. In addition, the PR mRNA level was lower in responders as compared to non-responders. The GR protein level did not differ between the groups. We conclude that successful PG-E2 priming was followed by a progesterone and androgen withdrawal at the receptor level in the uterine cervix.

Chronic stretching of amniotic epithelial cells increases pre-B cell colony-enhancing factor (PBEF/visfatin) expression and protects them from apoptosis

In normal pregnancy, the fetal membranes become increasingly distended towards term and in multifetal gestations they become over-distended. Apoptosis of the amniotic epithelium increases with advancing gestation and may contribute to fetal membrane weakening and rupture. The effects of chronic static stretching for 36h have been investigated using primary amniotic epithelial cells. Pre-B cell colony-enhancing factor (PBEF) is a stretch-responsive cytokine and expression of its gene, intracellular and secreted protein were all significantly increased by 4h and its secretion sustained over 36h, contrasting with the rapid increase and decline in expression of IL-8. Increased expression of SIRT1 and decreased p53 paralleled the changes in PBEF, are known to be responsive to PBEF, and contribute to cell survival. Distension had no effects on proliferation or necrosis but protected the cells from apoptosis, knocking-down PBEF with antisense probes abrogated this protective effect. There was increased immunostaining of PBEF in the compact layer of the amnion in multifetal tissues and significantly fewer apoptotic amniotic epithelial cells. These results show that chronic stretching of the amniotic epithelial cells increases PBEF expression, which protects them from apoptosis.

Prostaglandins and the myometrium and cervix

Prostaglandins have long been thought to play important roles in the mechanism of parturition. Here we review the involvement of prostaglandins in myometrial and cervical functions with emphasis on human labor and birth. In addition, the cellular sources of prostaglandins as well as their interactions with various other endocrine, paracrine and physical factors, such as oxytocin, corticotropin releasing hormone, nitric oxide, platelet activating factor, cytokines, endothelin and stretch are also addressed together with their potential role in the molecular reorganization of cervical structure associated with labor and delivery. Finally, the premier role of progesterone in pregnancy maintenance and parturition is juxtaposed with the proposed "fine-tuning", modulatory role of prostaglandins and the above listed factors in the regulation of parturition.

A prospective randomized safety trial of celecoxib for treatment of preterm labor

OBJECTIVE

We compared the safety of celecoxib, a selective cyclo-oxygenase-2 inhibitor, with the safety of the nonselective cyclo-oxygenase inhibitor indomethacin, when it was administered for treatment of preterm labor.

STUDY DESIGN

In a randomized, double-blind, placebo-controlled trial, 24 pregnant women in preterm labor at 24 to 34 weeks of gestation received either indomethacin or celecoxib for 48 hours. Clinical assessment, fetal sonography, and Doppler blood flow studies of the fetal ductus arteriosus were performed daily.

RESULTS

Mean maximum ductal flow velocity was significantly elevated over baseline (82.9 +/- 4.6 cm/s vs 111.14 +/- 14.3 cm/s; P =.02) after 24 hours of indomethacin, but not celecoxib. Both medications were associated with a transient decrease in amniotic fluid volume, with a greater effect by indomethacin. The medications were equally effective in the maintenance of tocolysis. There were no significant maternal or neonatal adverse events.

CONCLUSION

In this initial evaluation, the safety of short-term celecoxib in women with preterm labor was superior to that of indomethacin.

Preterm labour

Studies in the past year have clarified the roles of inflammatory mediators in preterm labour. Exploration of possible genetic predisposition is just beginning. Ultrasound measurement of cervical length has the potential to predict women at risk of preterm delivery several weeks before it occurs. Biochemical testing such as fetal fibronectin can possibly increase its predictive value and differentiate true preterm labour from more innocent preterm contractions. The use of antibiotics for preterm premature rupture of membranes has been clarified with the ORACLE I trial, which shows health benefits for the neonate with the use of erythromycin, whereas antibiotics do not seem to play a beneficial role in spontaneous preterm labour without evidence of clinical infection. There have been further studies suggesting that agents other than beta-agonists are preferable for acute tocolysis and that repeated doses of corticosteroids should be used with caution.