Risk factors for the development of preterm premature rupture of the membranes after arrest of preterm labor

Novel First-Trimester Prediction Model for Any Type of Preterm Birth Occurring before 37 Gestational Weeks in the Absence of Other Pregnancy-Related Complications Based on Cardiovascular Disease-Associated MicroRNAs and Basic Maternal Clinical Characteristics

The goal of the study was to establish an efficient first-trimester predictive model for any type of preterm birth before 37 gestational weeks (spontaneous preterm birth (PTB) or preterm prelabor rupture of membranes (PPROM)) in the absence of other pregnancy-related complications, such as gestational hypertension, preeclampsia, fetal growth restriction, or small for gestational age. The retrospective study was performed in the period from 11/2012 to 3/2020. Peripheral blood samples were collected from 6440 Caucasian individuals involving 41 PTB and 65 PPROM singleton pregnancies. A control group with 80 singleton term pregnancies was selected on the basis of equal sample-storage time. A combination of only six microRNAs (miR-16-5p, miR-21-5p, miR-24-3p, miR-133a-3p, miR-155-5p, and miR-210-3p; AUC 0.812, p < 0.001, 70.75% sensitivity, 78.75% specificity, cut-off > 0.652) could predict preterm delivery before 37 gestational weeks in early stages of gestation in 52.83% of pregnancies with a 10.0% FPR. This predictive model for preterm birth based on aberrant microRNA expression profile was further improved via implementation of maternal clinical characteristics (maternal age and BMI at early stages of gestation, infertility treatment with assisted reproductive technology, occurrence of preterm delivery before 37 gestational weeks in previous pregnancy(ies), and presence of any kind of autoimmune disease (rheumatoid arthritis, systemic lupus erythematosus, antiphospholipid syndrome, type 1 diabetes mellitus, or other autoimmune disease)). With this model, 69.81% of pregnancies destined to deliver before 37 gestational weeks were identified with a 10.0% FPR at early stages of gestation. When other clinical variables as well as those mentioned above—such as positive first-trimester screening for early preeclampsia with onset before 34 gestational weeks and/or fetal growth restriction with onset before 37 gestational weeks using the Fetal Medicine Foundation algorithm, as well as positive first-trimester screening for spontaneous preterm birth with onset before 34 gestational weeks using the Fetal Medicine Foundation algorithm—were added to the predictive model for preterm birth, the predictive power was even slightly increased to 71.70% with a 10.0% FPR. Nevertheless, we prefer to keep the first-trimester screening for any type of preterm birth occurring before 37 gestational weeks in the absence of other pregnancy-related complications as simple as possible.

The role of the placenta in spontaneous preterm labor and delivery with intact membranes

OBJECTIVES

To determine whether placental vascular pathology and impaired placental exchange due to maturational defects are involved in the etiology of spontaneous preterm labor and delivery in cases without histologic acute chorioamnionitis.

METHODS

This was a retrospective, observational study. Cases included pregnancies that resulted in spontaneous preterm labor and delivery (<37 weeks), whereas uncomplicated pregnancies that delivered fetuses at term (≥37-42 weeks of gestation) were selected as controls. Placental histological diagnoses were classified into three groups: lesions of maternal vascular malperfusion, lesions of fetal vascular malperfusion, and placental microvasculopathy, and the frequency of each type of lesion in cases and controls was compared. Moreover, we specifically searched for villous maturational abnormalities in cases and controls. Doppler velocimetry of the umbilical and uterine arteries were performed in a subset of patients.

RESULTS

There were 184 cases and 2471 controls, of which 95 and 1178 had Doppler studies, respectively. The frequency of lesions of maternal vascular malperfusion was greater in the placentas of patients with preterm labor than in the control group [14.1% (26/184) vs. 8.8% (217/2471) (p=0.023)]. Disorders of villous maturation were more frequent in the group with preterm labor than in the control group: 41.1% (39/95) [delayed villous maturation in 31.6% (30/95) vs. 2.5% (13/519) in controls and accelerated villous maturation in 9.5% (9/95) vs. none in controls].

CONCLUSIONS

Maturational defects of placental villi were associated with approximately 41% of cases of unexplained spontaneous preterm labor and delivery without acute inflammatory lesions of the placenta and with delivery of appropriate-for-gestational-age fetuses.

First Trimester Prediction of Preterm Delivery in the Absence of Other Pregnancy-Related Complications Using Cardiovascular-Disease Associated MicroRNA Biomarkers

The aim of the study was to determine if aberrant expression profile of cardiovascular disease associated microRNAs would be able to predict within 10 to 13 weeks of gestation preterm delivery such as spontaneous preterm birth (PTB) or preterm prelabor rupture of membranes (PPROM) in the absence of other pregnancy-related complications (gestational hypertension, preeclampsia, fetal growth restriction, or small for gestational age). In addition, we assessed if aberrant expression profile of cardiovascular disease associated microRNAs would be able to predict preterm delivery before and after 34 weeks of gestation. The retrospective study was performed within the period November 2012 to March 2020. Whole peripheral blood samples were collected from 6440 Caucasian individuals involving 41 PTB and 65 PPROM singleton pregnancies. A control group, 80 singleton term pregnancies, was selected on the base of equal sample storage time. Gene expression of 29 selected cardiovascular disease associated microRNAs was studied using real-time RT-PCR. Downregulation of miR-16-5p, miR-20b-5p, miR-21-5p, miR-24-3p, miR-26a-5p, miR-92a-3p, miR-126-3p, miR-133a-3p, miR-145-5p, miR-146a-5p, miR-155-5p, miR-210-3p, miR-221-3p and miR-342-3p was observed in pregnancies with preterm delivery before 37 (≤36 + 6/7) weeks of gestation. Majority of downregulated microRNAs (miR-16-5p, miR-24-3p, miR-26a-5p, miR-92a-3p, miR-133a-3p, miR-145-5p, miR-146a-5p, miR-155-5p, miR-210-3p, and miR-342-3p) was associated with preterm delivery occurring before 37 (≤36 + 6/7) weeks of gestation. The only miR-210-3p was downregulated in pregnancies with preterm delivery before 34 (≤33 + 6/7) weeks of gestation. The type of preterm delivery also had impact on microRNA gene expression profile. Downregulation of miR-24-3p, miR-92a-3p, miR-155-5p, and miR-210-3p was a common feature of PTB and PPROM pregnancies. Downregulation of miR-16-5p, miR-20b-5p, miR-26a-5p, miR-126-3p, miR-133a-3p, miR-146a-5p, miR-221-3p, and miR-342-3p appeared just in PTB pregnancies. No microRNA was uniquely dysregulated in PPROM pregnancies. The combination of 12 microRNAs (miR-16-5p, miR-20b-5p, miR-21-5p, miR-24-3p, miR-26a-5p, miR-92a-3p, miR-133a-3p, miR-145-5p, miR-146a-5p, miR-155-5p, miR-210-3p, and miR-342-3p, AUC 0.818, p < 0.001, 74.53% sensitivity, 75.00% specificity, cut off > 0.634) equally as the combination of 6 microRNAs (miR-16-5p, miR-21-5p, miR-24-3p, miR-133a-3p, miR-155-5p, and miR-210-3p, AUC 0.812, p < 0.001, 70.75% sensitivity, 78.75% specificity, cut off > 0.652) can predict preterm delivery before 37 weeks of gestation in early stages of gestation in 52.83% pregnancies at 10.0% FPR. Cardiovascular disease associated microRNAs represent promising biomarkers with very good diagnostical potential to be implemented into the current routine first trimester screening programme to predict preterm delivery.

Nonovert disseminated intravascular coagulation (DIC) in pregnancy: a new scoring system for the identification of patients at risk for obstetrical hemorrhage requiring blood product transfusion

BACKGROUND

Nonovert disseminated intravascular coagulation (DIC) is a subclinical hemostatic dysfunction that has not yet reached the decompensation stage. The detection of pregnant patients at this stage may assist in the identification of those who will develop severe obstetrical hemorrhage, as it is one of the leading causes for preventable maternal mortality. Currently, nonovert DIC is diagnosed by a scoring system based on nonpregnant patients, originally generated by the International Society on Thrombosis and Hemostasis (ISTH), which does not address the physiologic changes of the hemostatic system during pregnancy.

OBJECTIVES

(1) To develop a pregnancy-specific nonovert DIC score, (2) to determine the diagnostic performance of this score in detecting women at risk for obstetrical hemorrhage requiring blood product transfusion, and (3) to compare it to the existing ISTH nonovert DIC score.

STUDY DESIGN

This retrospective study has longitudinal and cross-sectional components and includes three steps: (1) characterization of the longitudinal changes in the components of modified ISTH nonovert DIC scores, including these parameters - fibrinogen, antithrombin III, protein C, prothrombin time (PT), platelets, thrombin-antithrombin (TAT) complex, and D-dimer - during gestation in a group of normal pregnancies (n = 50); (2) development of a pregnancy-specific nonovert DIC score in a cross-sectional design of high-risk (n = 152) and control (n = 50) pregnancies, based on the predictive performance of each analyte for the detection of women at risk for obstetrical hemorrhage requiring blood product transfusion and a logistic regression model; and (3) comparison between the diagnostic performance of the pregnancy-specific nonovert DIC score and the modified ISTH nonovert DIC score to detect, upon admission, women who are at increased risk for subsequent development of obstetrical hemorrhage requiring blood product transfusion.

RESULTS

(1) The study cohort included 202 patients, of which 21 (10%) had obstetrical hemorrhage that required blood product transfusion and were considered to have nonovert DIC; (2) using the nonpregnant ISTH nonovert DIC score, 92% of the patients had a D-dimer concentration above the 0.5 mg/L threshold, and only 2% were identified to have a low fibrinogen concentration (<100 mg/dL); thus, this scoring system was unable to identify any of the patients with nonovert DIC based on the suggested cutoff of a score of ≥5; (3) the parameters included in the pregnancy-specific nonovert DIC score were selected based on their contribution to the performance of the model for the prediction of women at risk for obstetrical hemorrhage requiring blood product transfusion; as a result, we excluded the PT difference parameter from the score and the TAT complex concentration was added; and (4) a pregnancy-specific nonovert DIC score of ≥3 had a sensitivity of 71.4% and a specificity of 77.9% to identify patients at risk for obstetrical hemorrhage requiring blood product transfusion.

CONCLUSION

We propose (1) a pregnancy-specific nonovert DIC score adjusted for the physiologic changes in the hemostatic system during gestation; and (2) that the pregnancy-specific nonovert DIC score can be a useful tool for the identification of patients at risk for obstetrical hemorrhage requiring blood product transfusion.

Proteomic profiling of human amnion for preterm birth biomarker discovery

Spontaneous preterm birth (PTB) complicates about 12% of pregnancies worldwide, remaining the main cause of neonatal morbidity and mortality. Spontaneous preterm birth PTBs is often caused by microbial-induced preterm labor, mediated by an inflammatory process threatening both maternal and newborn health. In search for novel predictive biomarkers of PTB and preterm prelabor rupture of the membranes (pPROM), and to improve understanding of infection related PTB, we performed an untargeted mass spectrometry discovery study on 51 bioptic mid zone amnion samples from premature babies. A total of 6352 proteins were identified. Bioinformatics analyses revealed a ranked core of 159 proteins maximizing the discrimination between the selected clinical stratification groups allowing to distinguish conditions of absent (FIR 0) from maximal Fetal Inflammatory Response (FIR 3) stratified in function of Maternal Inflammatory Response (MIR) grade. Matrix metallopeptidase-9 (MMP-9) was the top differentially expressed protein. Gene Ontology enrichment analysis of the core proteins showed significant changes in the biological pathways associated to inflammation and regulation of immune and infection response. Data suggest that the conditions determining PTB would be a transversal event, secondary to the maternal inflammatory response causing a breakdown in fetal-maternal tolerance, with fetal inflammation being more severe than maternal one. We also highlight matrix metallopeptidase-9 as a potential predictive biomarker of PTB that can be assayed in the maternal serum, for future investigation.

Postnatal Expression Profile of MicroRNAs Associated with Cardiovascular Diseases in 3- to 11-Year-Old Preterm-Born Children

(1) Background: Preterm-born children have an increased cardiovascular risk with the first clinical manifestation during childhood and/or adolescence. (2) Methods: The occurrence of overweight/obesity, prehypertension/hypertension, valve problems or heart defects, and postnatal microRNA expression profiles were examined in preterm-born children at the age of 3 to 11 years descending from preterm prelabor rupture of membranes (PPROM) and spontaneous preterm birth (PTB) pregnancies. The whole peripheral blood gene expression of 29 selected microRNAs associated with cardiovascular diseases was the subject of our interest. (3) Results: Nearly one-third of preterm-born children (32.43%) had valve problems and/or heart defects. The occurrence of systolic and diastolic prehypertension/hypertension was also inconsiderable in a group of preterm-born children (27.03% and 18.92%). The vast majority of children descending from either PPROM (85.45%) or PTB pregnancies (85.71%) had also significantly altered microRNA expression profiles at 90.0% specificity. (4) Conclusions: Postnatal microRNA expression profiles were significantly influenced by antenatal and early postnatal factors (gestational age at delivery, birth weight of newborns, and condition of newborns at the moment of birth). These findings may contribute to the explanation of increased cardiovascular risk in preterm-born children. These findings strongly support the belief that preterm-born children should be dispensarized for a long time to have access to specialized medical care.

Crowdsourcing assessment of maternal blood multi-omics for predicting gestational age and preterm birth

Identification of pregnancies at risk of preterm birth (PTB), the leading cause of newborn deaths, remains challenging given the syndromic nature of the disease. We report a longitudinal multi-omics study coupled with a DREAM challenge to develop predictive models of PTB. The findings indicate that whole-blood gene expression predicts ultrasound-based gestational ages in normal and complicated pregnancies (r = 0.83) and, using data collected before 37 weeks of gestation, also predicts the delivery date in both normal pregnancies (r = 0.86) and those with spontaneous preterm birth (r = 0.75). Based on samples collected before 33 weeks in asymptomatic women, our analysis suggests that expression changes preceding preterm prelabor rupture of the membranes are consistent across time points and cohorts and involve leukocyte-mediated immunity. Models built from plasma proteomic data predict spontaneous preterm delivery with intact membranes with higher accuracy and earlier in pregnancy than transcriptomic models (AUROC = 0.76 versus AUROC = 0.6 at 27-33 weeks of gestation).

A History of Preterm Delivery Is Associated with Aberrant Postpartal MicroRNA Expression Profiles in Mothers with an Absence of Other Pregnancy-Related Complications

This prospective cross-sectional case-control study investigated the postpartal gene expression of microRNAs associated with diabetes/cardiovascular/cerebrovascular diseases in the peripheral white blood cells of women with anamnesis of preterm prelabor rupture of membranes (n = 58), spontaneous preterm birth (n = 55), and term delivery (n = 89) by a quantitative reverse transcription polymerase chain reaction. After pregnancies complicated by preterm prelabor rupture of membranes or spontaneous preterm birth, mothers showed diverse expression profiles for 25 out of 29 tested microRNAs (miR-1-3p, miR-16-5p, miR-17-5p, miR-20a-5p, miR-20b-5p, miR-21-5p, miR-23a-3p, miR-24-3p, miR-26a-5p, miR-29a-3p, miR-100-5p, miR-103a-3p, miR-125b-5p, miR-126-3p, miR-130b-3p, miR-133a-3p, miR-143-3p, miR-145-5p, miR-146a-5p, miR-181a-5p, miR-195-5p, miR-199a-5p, miR-221-3p, miR-499a-5p, and miR-574-3p). The earliest gestational ages at delivery and the lowest birth weights of newborns were associated with the highest postpartal levels of the previously mentioned microRNAs in maternal peripheral white blood cells. Administration of tocolytic drugs in order to prolong pregnancy, used in order to administer and complete a full course of antenatal corticosteroids, was associated with alterations in postpartal microRNA expression profiles to a lesser extent than in women with imminent delivery, where there was insufficient time for administration of tocolytics and antenatal corticosteroids. Overall, mothers who did not receive tocolytic therapy (miR-24-3p and miR-146a-5p) and mothers who did not receive corticosteroid therapy (miR-1-3p, miR-100-5p, and miR-143-3p) had increased or showed a trend toward increased postpartal microRNA expression when compared with mothers given tocolytic and corticosteroid therapy. In addition, mothers with serum C-reactive protein levels above 20 mg/L, who experienced preterm labour, showed a trend toward increased postpartal expression profiles of miR-143-3p and miR-199a-5p when compared with mothers with normal serum C-reactive protein levels. On the other hand, the occurrence of maternal leukocytosis, the presence of intra-amniotic inflammation (higher levels of interleukin 6 in the amniotic fluid), and the administration of antibiotics at the time of preterm delivery had no impact on postpartal microRNA expression profiles in mothers with a history of preterm delivery. Likewise, the condition of the newborns at the moment of birth, determined by Apgar scores at 5 and 10 min and the pH of cord arterial blood, had no influence on the postpartal expression profiles of mothers with a history of preterm delivery. These findings may contribute to explaining the increased cardiovascular risk in mothers with anamnesis of preterm delivery, and the greater increase of maternal cardiovascular risk with the decrease of gestational age at delivery. Women with preterm delivery in their anamnesis represent a high-risk group with special needs on a long-term basis, with a need to apply preventive and therapeutic interventions as early as possible.

Antibody microarray analysis of amniotic fluid proteins associated with subsequent ruptured membranes in women with threatened preterm labor

PROBLEM

We aimed to identify amniotic fluid (AF) proteins associated with the subsequent rupture of membranes (ROM) occurring in the absence of active labor in women with threatened preterm labor (PTL) using an antibody microarray.

METHOD OF THE STUDY

This retrospective cohort study included 183 singleton pregnant women with PTL (24-33 weeks) who underwent amniocentesis. A nested case-control study was conducted using AF samples from 20 women with subsequent ROM within 7 days of sampling (case subjects) and 20 gestational age-matched women with term delivery (TD) without ROM (control subjects), via protein-antibody microarray analysis. Seven candidate proteins of interest were validated via ELISA in the total cohort.

RESULTS

Seventeen proteins displayed significant intergroup differences. ELISA validation confirmed that the levels of EN-RAGE, Fas, IL-8, IP-10, MMP-8, and MMP-9 were significantly higher, whereas IGFBP-3 levels were significantly lower in the AF of women with subsequent ROM within 7 days of sampling than in that of women with TD without ROM. Moreover, the time interval from sampling to membrane rupture was significantly correlated with the expression levels of AF proteins, except for IL-10.

CONCLUSION

Using an antibody microarray, we identified various inflammatory, angiogenic, matrix-degrading, and apoptosis-related proteins in the AF that were associated with subsequent ROM occurring in the absence of active labor in women with threatened PTL. These findings provide novel insights into the molecular mechanisms underlying membrane rupture without active labor in threatened PTL.

Incidence and risk factors of preterm premature rupture of membranes in singleton pregnancies at Siriraj Hospital

AIM

To obtain the incidence of preterm premature rupture of membranes (PPROM) at Siriraj Hospital during 2012-2016 and to identify its possible risk factors in singleton pregnancies.

METHODS

This study was a retrospective case-control study. The institutional ethical committee has approved the study. The medical records of eligible cases were reviewed. To assess the risk factors of PPROM, the data of the cases with PPROM in 2016 were compared with the data of pregnant women who did not have PPROM and delivered at term. Fifteen variables of interest were studied.

RESULTS

During the 5-year period, there were 43 727 deliveries at Siriraj Hospital and 1280 (2.93%) cases had PPROM. In 2016, 252 pregnant women were diagnosed PPROM and data of 199 cases were compared with the data of 199 control cases. Mean latency period was 2 days and mean gestational age at birth was 34.7 weeks in PPROM group. Logistic regression analysis showed that diabetes mellitus, poor weight gain and history of previous preterm birth were the factors that significantly associated with PPROM, with adjusted odds ratio (OR) 3.22 (95% confidence interval [CI] 1.47-7.05), 2.58 (95% CI 1.63-4.07) and 8.81 (95% CI 2.81-28.69), respectively (P < 0.05), while multiparity decreased the risk of PPROM (adjusted OR = 0.36, 95% CI 0.23-0.57) (P < 0.001).

CONCLUSION

The incidence of PPROM during 5-year period was 2.93%. Diabetes mellitus, poor maternal weight gain and history of previous preterm birth significantly increased risk of PPROM while multigravida reduced the risk.

Expression profile of C19MC microRNAs in placental tissue of patients with preterm prelabor rupture of membranes and spontaneous preterm birth

The aim of the study was to demonstrate that preterm birth (PTB) is associated with altered C19MC microRNA expression profile in placental tissues. Gene expression of 15 placental specific microRNAs (miR-512-5p, miR-515-5p, miR-516-5p, miR-517-5p, miR-518b, miR-518f-5p, miR-519a, miR-519d, miR-519e-5p, miR-520a-5p, miR-520h, miR-524-5p, miR-525-5p, miR-526a and miR-526b-5p) was compared between groups: 34 spontaneous PTB, 108 preterm prelabor rupture of membranes (PPROM) and 20 term in labor pregnancies. Correlation between variables including relative microRNA quantification in placental tissues and the gestational age at delivery, white blood cell (WBC) count at admission and serum levels of C-reactive protein at admission in patients with PPROM and PTB was determined. Expression profile of microRNAs was different between PPROM and term in labor pregnancies, PTB and term in labor pregnancies, and between gestational age-matched PPROM and PTB groups. When compared with term in labor pregnancies, while C19MC microRNAs showed a downregulation in PPROM pregnancies (miR-525-5p), in PTB pregnancies C19MC microRNAs were upregulated (miR-515-5p, miR-516-5p, miR-518b, miR-518f-5p, miR-519a, miR-519e-5p, miR-520a-5p, miR-520h, and miR-526b-5p) or showed a trend to upregulation (miR-519d and miR-526a). In comparison to PTB pregnancies, the PPROM group demonstrated a significant portion of downregulated C19MC microRNAs (miR-516-5p, miR-517-5p, miR-518b, miR-518f-5p, miR-519a, miR-519d, miR-519e-5p, miR-520a-5p, miR-520h, miR-525-5p, miR-526a and miR-526b-5p). In the group of PPROM pregnancies, a weak negative correlation between the gestational age at delivery and microRNA gene expression in placental tissue for all examined C19MC microRNAs was observed. PTB pregnancies showed a positive correlation (miR-512-5p, miR-515-5p, miR-519e-5p) or a trend to positive correlation (miR-516-5p, miR-518b, miR-520h) between particular C19MC microRNAs and maternal WBC count at admission. Our study demonstrates that upregulation of C19MC microRNAs is a characteristic phenomenon of PTB. PPROM pregnancies have a tendency to produce lower levels of miR-525-5p. All examined C19MC microRNAs displayed decreased expression with advancing gestational age in PPROM group.

Transvaginal cervical length and amniotic fluid index: can it predict delivery latency following preterm premature rupture of membranes?

OBJECTIVE

We sought to determine whether transvaginal cervical length (TVCL), amniotic fluid index (AFI), or a combination of both can predict delivery latency within 7 days in women presenting with preterm premature rupture of membranes (PPROM).

STUDY DESIGN

This was a prospective observational study of TVCL measurements in 106 singleton pregnancies with PPROM between 23-33 weeks. Delivery latency was defined as the period (in days) from the initial TVCL after PPROM to delivery of the infant, with our primary outcome being delivery within 7 days of TVCL. The independent predictability of significant characteristics for delivery within 7 days was determined using multiple logistic regression. Sensitivity, specificity, and predictive values were used to examine whether the presence of a short TVCL, AFI, or a combination of both affected the risk of delivery within 7 days.

RESULTS

Delivery within 7 days occurred in 51/106 (48%) of pregnancies. Median duration (interquartile range) from PPROM to delivery and TVCL to delivery was 8 days (4.0-16.0) and 8 days (3.0-15.0), respectively. Using multiple regression TVCL as a continuous variable (odds ratio, 0.65; 95% confidence interval, 0.44-0.97; P < .05), AFI ≤5 cm (odds ratio, 4.69; 95% confidence interval, 1.58-13.93; P < .01) were determined to be independent predictors of delivery within 7 days. In all, 42 women (40%) had a TVCL ≤2 cm, while 62 (59%) had AFI ≤5 cm. A total of 26 women (25%) had a combination of both TVCL ≤2 cm and AFI ≤5 cm, while 28 women (27%) had neither characteristic. The predictive value of delivery within 7 days for a TVCL ≤2 cm was 62%, and for an AFI ≤5 cm was 58%. Having a combination of low TVCL and low AFI did not increase the predictive value of delivery within 7 days (58%). In contrast, only 3 of 27 women (11%) with neither characteristic delivered within 7 days. The predictive value of delivery >7 days for TVCL >2 cm alone was 61%. This predictive value changed when analyzed in conjunction with an AFI ≤5 cm and >5 cm at 42% and 89%, respectively.

CONCLUSION

A shorter TVCL and an AFI ≤5 cm independently predict delivery within 7 days in women presenting with PPROM. The combination of an AFI >5 cm and TVCL >2 cm greatly improved the potential to remain undelivered at 7 days following cervical length assessment. These findings may be helpful for counseling and optimizing maternal and neonatal care in women with PPROM.

Synergy and interactions among biological pathways leading to preterm premature rupture of membranes

Preterm premature rupture of membranes (PPROM) occurs in 1% to 2% of births. Impact of PPROM is greatest in low- and middle-income countries where prematurity-related deaths are most common. Recent investigations identify cytokine and matrix metalloproteinase activation, oxidative stress, and apoptosis as primary pathways to PPROM. These biological processes are initiated by heterogeneous etiologies including infection/inflammation, placental bleeding, uterine overdistention, and genetic polymorphisms. We hypothesize that pathways to PPROM overlap and act synergistically to weaken membranes. We focus our discussion on membrane composition and strength, pathways linking risk factors to membrane weakening, and future research directions to reduce the global burden of PPROM.

Prophylactic antibiotics for inhibiting preterm labour with intact membranes

BACKGROUND

The aetiology of preterm birth is complex and there is evidence that subclinical genital tract infection influences preterm labour in some women but the role of prophylactic antibiotic treatment in the management of preterm labour is controversial. Since rupture of the membranes is an important factor in the progression of preterm labour, it is important to see if the routine administration of antibiotics confers any benefit or causes harm, prior to membrane rupture.

OBJECTIVES

To assess the effects of prophylactic antibiotics administered to women in preterm labour with intact membranes, on maternal and neonatal outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 August 2013).

SELECTION CRITERIA

Randomised trials that compared antibiotic treatment with placebo or no treatment for women in preterm labour (between 20 and 36 weeks' gestation) with intact membranes.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial eligibility, and undertook quality assessment and data extraction. We contacted study authors for additional information. Results are presented using risk ratio (RR) for categorical data and mean difference (MD) for data measured on a continuous scale with their respective 95% confidence intervals (CI). The number needed to treat to benefit (NNTB) and the number needed to treat to harm (NNTH) was calculated where appropriate.

MAIN RESULTS

In this update (2013), with the addition of three trials (305 women), the large ORACLE II 2001 trial continues to dominate the results of this review. This review now includes a total of 14 studies randomising 7837 women. No significant difference was shown in perinatal or infant mortality for infants of women allocated to any prophylactic antibiotics compared with no antibiotics. However, an increase in neonatal deaths was shown for infants of women receiving any prophylactic antibiotics when compared with placebo (RR 1.57, 95% CI 1.03 to 2.40; NNTH 149, 95% CI 2500 to 61). No reduction in preterm birth or other clinically important short-term outcomes for the infant were shown.Long-term child outcomes to seven years of age were available for infants in the UK enrolled in the ORACLE II trial. Comparing any antibiotics with placebo, a marginally non-statistically significant increase was shown in any functional impairment (RR 1.10, 95% CI 0.99 to 1.23) and cerebral palsy (CP) (RR 1.82, 95% CI 0.99 to 3.34). In subgroup analysis, CP was statistically significantly increased for infants of women allocated to macrolide and beta-lactam antibiotics combined compared with placebo (RR 2.83, 95% CI 1.02 to 7.88; NNTH 35, 95% CI 333 to 9).Further, exposure to any macrolide antibiotics (including erythromycin alone or erythromycin plus co-amoxiclav) versus no macrolide antibiotics (including placebo and co-amoxiclav alone) was shown to increase neonatal death (RR 1.52, 95% CI 1.05 to 2.19; NNTH 139, 95% CI 1429 to 61), any functional impairment (RR 1.11, 95% CI 1.01 to 1.20; NNTH 24, 95% CI 263 to 13) and CP (RR 1.90, 95% CI 1.20 to 3.01; NNTH 64, 95% CI 286 to 29). Exposure to any beta-lactam (beta-lactam alone or in combination with macrolide antibiotics) versus no beta-lactam antibiotics resulted in more neonatal deaths (RR 1.51, 95% CI 1.06 to 2.15; NNTH 143, 95% CI 1250 to 63) and CP (RR 1.67, 95% CI 1.06 to 2.61; NNTH 79, 95% CI 909 to 33), however no difference was shown in functional impairment.Maternal infection was reduced with the use of any prophylactic antibiotics compared with placebo (RR 0.74, 95% CI 0.63 to 0.86; NNTB 34, 95% CI 24 to 63) and any beta-lactam compared with no beta-lactam antibiotics (RR 0.80, 95% CI 0.69 to 0.92; NNTB 47, 95% CI 31 to 119). However, caution should be exercised with this finding due to the possibility of bias shown by funnel plot asymmetry. Any beta-lactam compared with no beta-lactam antibiotics was associated with an increase in maternal adverse drug reaction (RR 1.61, 95% CI 1.02 to 2.54; NNTH 17, 95% CI 526 to 7).

AUTHORS' CONCLUSIONS

This review did not demonstrate any benefit in important neonatal outcomes with the use of prophylactic antibiotics for women in preterm labour with intact membranes, although maternal infection may be reduced. Of concern, is the finding of short- and longer-term harm for children of mothers exposed to antibiotics. The evidence supports not giving antibiotics routinely to women in preterm labour with intact membranes in the absence of overt signs of infection.Further research is required to develop sensitive markers of subclinical infection for women in preterm labour with intact membranes, as this is a group that might benefit from future novel interventions, including new modalities of antibiotic therapy. The results of this review demonstrate the need for future trials in the area of preterm birth to include assessment of long-term neurodevelopmental outcome.

Soluble ST2, a modulator of the inflammatory response, in preterm and term labor

OBJECTIVE

Intra-amniotic infection/inflammation (IAI) is causally linked with spontaneous preterm labor and delivery. The ST2L receptor and its soluble form (sST2) are capable of binding to interleukin (IL)-33, a member of the IL-1 superfamily. Members of this cytokine family have been implicated in the onset of spontaneous preterm labor in the context of infection. Soluble ST2 has anti-inflammatory properties, and plasma concentrations are elevated in systemic inflammation, such as sepsis, acute pyelonephritis in pregnancy and the fetal inflammatory response syndrome. The aims of this study were to examine: (1) whether amniotic fluid concentrations of sST2 change with IAI, preterm, and term parturition; and (2) if mRNA expression of ST2 in the chorioamniotic membranes changes with acute histologic chorioamnionitis in women who deliver preterm.

METHOD

A cross-sectional study was conducted to determine amniotic fluid concentrations of sST2 in: (1) women with preterm labor (PTL) who delivered at term (n=49); (2) women with PTL who delivered preterm without IAI (n=21); (3) women with PTL who delivered preterm with IAI (n=31); (4) term pregnancies not in labor (n=13); and (5) term pregnancies in labor (n=43). The amniotic fluid concentration of sST2 was determined by ELISA. The mRNA expression of ST2 in the chorioamniotic membranes of women who delivered preterm with (n=24), and without acute histologic chorioamnionitis (n=19) was determined by qRT-PCR.

RESULTS

(1) Patients with PTL who delivered preterm with IAI had a lower median amniotic fluid concentration of sST2 compared to those with PTL who delivered preterm without IAI [median 410 ng/mL, inter-quartile range (IQR) 152-699 ng/mL versus median 825 ng/mL, IQR 493-1216 ng/mL; p=0.0003] and those with PTL who delivered at term [median 410 ng/mL, IQR 152-699 ng/mL versus median 673 ng/mL, IQR 468-1045 ng/mL; p=0.0003]; (2) no significant differences in the median amniotic fluid concentration of sST2 were observed between patients with PTL who delivered at term and those who delivered preterm without IAI (p=0.4), and between women at term in labor and those at term not in labor (p=0.9); (3) the mean mRNA expression of ST2 was 4-fold lower in women who delivered preterm with acute histologic chorioamnionitis than in those without this lesion (p=0.008).

CONCLUSIONS

The median sST2 amniotic fluid concentration and mRNA expression of ST2 by chorioamniotic membranes is lower in PTL associated with IAI and acute histologic chorioamnionitis than in PTL without these conditions. Changes in the median amniotic fluid sST2 concentration are not observed in preterm and term parturition without IAI. Thus, amniotic fluid sST2 in the presence of IAI behaves differently when compared to sST2 in the plasma of individuals affected by fetal inflammatory response syndrome, acute pyelonephritis in pregnancy, and adult sepsis. Decreased concentrations of sST2 in IAI are likely to promote a pro-inflammatory response, which is important for parturition in the context of infection.

Intra-amniotic infection/inflammation as a risk factor for subsequent ruptured membranes after clinically indicated amniocentesis in preterm labor

The aim of this study was to determine whether intra-amniotic infection/inflammation (IAI) was associated with subsequent ruptured membranes in women with preterm labor and intact membranes who had a clinically indicated amniocentesis. This retrospective cohort study included 237 consecutive women with preterm labor (20-34.6 weeks) who underwent amniocentesis. The clinical and laboratory parameters evaluated included demographic variables, gestational age, C-reactive protein (CRP) and amniotic fluid (AF) white blood cell, interleukin-6 (IL-6) and culture results. IAI was defined as a positive AF culture and/or an elevated AF IL-6 level (>2.6 ng/mL). The primary outcome was ruptured membranes in the absence of active labor occurring within 48 hours of amniocentesis. Preterm premature rupture of membranes subsequently developed in 10 (4.2%) women within 48 hr of amniocentesis. Multivariate analysis demonstrated that only IAI was independently associated with the ruptured membranes occurring within 48 hr of amniocentesis. In the predictive model based on variables assessed before amniocentesis, only CRP level was retained. IAI is an independent risk factor for subsequent ruptured membranes after clinically indicated amniocentesis in preterm labor. Prior to amniocentesis, measurement of serum CRP level can provide a risk assessment for the subsequent development of ruptured membranes after the procedure.

Proteomic analysis of preterm premature rupture of membranes in placental tissue

OBJECTION

Preterm premature rupture of membranes (PPROM) is an obstetrics complication and is the leading cause of perinatal mortality and morbidity. PPROM results in critical care emergencies, and nearly all PPROM events are spontaneous and unpredictable. In addition, changes in the proteome in placental tissue during pregnancy that lead to PPROM are not clear.

METHODS

We utilize a proteomics approach to study the molecular mechanisms behind human PPROM. A better understanding of proteome alteration could lead to the identification of better diagnostic/prognostic markers. Human placental tissue was collected in clearly differentiated cases of PPROM and in a healthy term control. Two-dimensional gel polyacrylamide electrophoresis coupled with mass spectrometry and bioinformatics analysis was utilized to identify proteins with altered expression.

RESULTS

In this study, only the most important protein differences were selected for further analysis. Most of the identified proteins were structural/cytoskeletal components of the cell or involved in the regulation of energy metabolism and oxidative stress.

CONCLUSIONS

As a result, this approach has led to the identification of several proteins involved in the underlying pathophysiological mechanisms that can further serve as novel diagnostic tools and targets for rational drug intervention.

Endoglin in amniotic fluid as a risk factor for the subsequent development of bronchopulmonary dysplasia

OBJECTIVE

Cross-talk between inflammation and angiogenesis pathways has been recently reported. The objectives of this study were to: (i) examine whether amniotic fluid (AF) concentrations of soluble endoglin (sEng), a protein with anti-angiogenic properties, change during pregnancy, parturition, or intra-amniotic infection and/or inflammation (IAI); (ii) determine whether an increase in sEng in the AF of patients with preterm labor (PTL) and preterm prelabor rupture of membranes (PROM) is associated with adverse neonatal outcomes; and (iii) investigate potential sources of sEng in AF.

STUDY DESIGN

A cross-sectional study was conducted to include patients in the following groups: (i) mid-trimester (n = 20); (ii) PTL with term delivery (n = 95); (iii) PTL leading to preterm delivery with (n = 40) and without IAI (n = 46); (iv) preterm PROM with (n = 37) and without IAI (n = 37); (v) term in labor (n = 48) and not in labor (n = 44). AF concentrations of sEng were determined by enzyme-linked immunosorbent assay. Chorioamniotic membranes, umbilical cord blood, and AF macrophages were examined for the expression of endoglin.

RESULTS

(i) Patients with IAI had a higher median AF concentration of sEng than those without IAI (P = 0.02 for PTL and 0.06 for preterm PROM); (ii) AF concentrations of sEng in the 3rd and 4th quartiles were associated with IAI (OR 2.5 and 7.9, respectively); (iii) an AF sEng concentration ≥779.5 pg/mL was associated with bronchopulmonary dysplasia (BPD) (OR 7.9); (iv) endoglin was co-localized with CD14+ macrophages in AF pellets of patients with IAI by immunofluorescence and flow cytometry; and (v) the concentration of sEng in the supernatant was significantly increased after the treatment of macrophages with endotoxin or TNF-α.

CONCLUSIONS

Soluble endoglin participates in the host response against IAI. Activated macrophages may be a source of sEng concentrations in the AF of patients with IAI. An increase of sEng in the AF is associated with BPD and adverse neonatal outcomes.

Public Health Impact of Legal Termination of Pregnancy in the US: 40 Years Later

During the 40 years since the US Supreme Court decision in Doe versus Wade and Doe versus Bolton, restrictions on termination of pregnancy (TOP) were overturned nationwide. The use of TOP was much wider than predicted and a substantial fraction of reproductive age women in the U.S. have had one or more TOPs and that widespread uptake makes the downstream impact of any possible harms have broad public health implications. While short-term harms do not appear to be excessive, from a public perspective longer term harm is conceiving, and clearly more study of particular relevance concerns the associations of TOP with subsequent preterm birth and mental health problems. Clearly more research is needed to quantify the magnitude of risk and accurately inform women with the crisis of unintended pregnancy considering TOP. The current US data-gathering mechanisms are inadequate for this important task.

Role of the infections in recurrent spontaneous abortion

Embryo-fetal infections have been reported to cause recurrent spontaneous abortions (RSAs) at a rate lower than 4%. The possible mechanisms include production of toxic metabolic byproducts, fetal or placental infection, chronic endometrial infection, and chorio-amnionitis. Viruses appear to be the most frequently involved pathogens, since some of them can produce chronic or recurrent maternal infection. In particular, cytomegalovirus during pregnancy can reach the placenta by viremia, following both primary and recurrent infection, or by ascending route from the cervix, mostly following reactivation. Another herpesvirus, herpes simplex virus type 2, less frequently type 1, causes recurrent infections of the genital tract, which can involve the feto-placental unit. Parvoviruses have also been implicated in the development of repeated fetal loss. Among bacterial infections, Chlamydia trachomatis, Ureaplasma urealyticum,and Mycoplasma hominis have been mostly associated with occurrence of RSA. An increased risk of abortion among women with bacterial vaginosis (BV) during early pregnancy was also shown, but questions arise about the role of chronic BV in its occurrence. Although a definitive relationship between recurrently active infections and RSA is still lacking, mostly due to difficulties in demonstrating the pathogenic role of each individual isolated pathogen, diagnosis and therapy of RSA-related infections should be attempted. The diagnosis of infectious agents as a possible cause of RSA might lead to a therapeutic approach with antiviral drugs and antibiotics or using immunoglobulins, which can display both anti-infective neutralizing and immunomodulating properties.

The prognosis of pregnancy conceived despite the presence of an intrauterine device (IUD)

OBJECTIVE

Intrauterine devices (IUDs) are used for contraception worldwide; however, the management of pregnancies with an IUD poses a clinical challenge. The purpose of this study was to determine the outcome of pregnancy in patients with an IUD.

STUDY DESIGN

A retrospective cohort study (December 1997-June 2007) was conducted. The cohort consisted of 12,297 pregnancies, of which 196 had an IUD. Only singleton pregnancies were included. Logistic regression analysis was used to adjust for potential confounders between the groups.

RESULTS

1) Pregnancies with an IUD were associated with a higher rate of late miscarriage, preterm delivery, vaginal bleeding, clinical chorioamnionitis, and placental abruption than those without an IUD; 2) among patients with available histologic examination of the placenta, the rate of histologic chorioamnionitis and/or funisitis was higher in patients with an IUD than in those without an IUD (54.2% vs. 14.7%; P<0.001). Similarly, among patients who underwent an amniocentesis, the prevalence of microbial invasion of the amniotic cavity (MIAC) was also higher in pregnant women with an IUD than in those without an IUD (45.9% vs. 8.8%; P<0.001); and 3) intra-amniotic infection caused by Candida species was more frequently present in pregnancies with an IUD than in those without an IUD (31.1% vs. 6.3%; P<0.001).

CONCLUSION

Pregnant women with an IUD are at a very high risk for adverse pregnancy outcomes. This finding can be attributed, at least in part, to the high prevalence of intra-amniotic infection and placental inflammatory lesions observed in pregnancies with an IUD.

Racial, ethnic, and economic disparities in the prevalence of pregnancy complications

OBJECTIVES

Our objective was to use maternal self-reported data to estimate the prevalence of urinary tract infections, placenta disorders, and preterm rupture of the membranes (PROM) and to explore the association between these complications and race, ethnicity, and economic status.

METHODS

We used data for the years 2000-2002 from the Pregnancy Risk Assessment Monitoring System (PRAMS), an ongoing survey of women with a recent live birth, to examine the prevalence of and hospitalizations for self-reported urinary tract infections, placenta disorders, and PROM and to investigate differences by maternal race, Hispanic ethnicity, and economic status. Prevalence and hospitalizations were calculated as a percent of the represented population using SUDAAN to account for the sampling design.

RESULTS

Urinary tract infections were commonly reported, occurring in more than 17% of women during their pregnancy. Placenta disorders and PROM were each reported by approximately 6% of women. Poverty and race had independent effects on each of the pregnancy complications examined. Fewer than half of the women who experienced these pregnancy complications were hospitalized.

CONCLUSIONS

Pregnancy complications are common and not adequately measured by hospitalizations alone. Both more research and improved surveillance are needed to understand the effect of pregnancy complications on women's health and the reasons for the increased risk among poor or black women.

Acute and chronic respiratory diseases in pregnancy: associations with spontaneous premature rupture of membranes

OBJECTIVE

To examine whether acute and chronic respiratory diseases are associated with an increased risk of spontaneous premature rupture of the membranes (PROM).

METHODS

We used the 1993-2004 National Hospital Discharge Survey data of singleton deliveries in the USA (N = 41 250 539). The International Classification of Diseases Ninth Revision was utilized to identify acute (acute upper respiratory diseases, viral/bacterial pneumonia, and acute bronchitis/bronchiolitis) and chronic (chronic bronchitis and asthma) respiratory conditions and spontaneous PROM. All analyses were adjusted for potential confounders.

RESULTS

The incidence of PROM was 5%, and rates of acute and chronic respiratory conditions were 2.1 and 9.5 per 1000 pregnancies, respectively. Chronic bronchitis was associated with a reduced risk of PROM (RR 0.39, 95% CI 0.31, 0.48). Asthma was significantly associated with PROM at preterm (RR 1.15, 95% CI 1.14, 1.17) and term (RR 1.27, 95% CI 1.23, 1.30). Stratification by race showed that acute upper respiratory disease was associated with preterm PROM in whites (RR 1.90, 95% CI 1.71, 2.11) and blacks (RR 6.76, 95% CI 5.67, 8.07). Viral/bacterial pneumonia was associated with preterm PROM in blacks and term PROM in both races. Asthma was associated with term PROM in blacks but not whites.

CONCLUSIONS

Acute respiratory diseases and asthma during pregnancy are associated with spontaneous PROM, with substantially stronger association among blacks than whites. We speculate that timely diagnosis and treatment, coupled with closely mentoring of pregnant women may help reduce the rate of PROM and associated complications.

Recurrent preterm birth

Recurrent preterm birth is frequently defined as two or more deliveries before 37 completed weeks of gestation. The recurrence rate varies as a function of the antecedent for preterm birth: spontaneous versus indicated. Spontaneous preterm birth is the result of either preterm labor with intact membranes or preterm prelabor rupture of the membranes. This article reviews the body of literature describing the risk of recurrence of spontaneous and indicated preterm birth. Also discussed are the factors which modify the risk for recurrent spontaneous preterm birth (a short sonographic cervical length and a positive cervicovaginal fetal fibronectin test). Patients with a history of an indicated preterm birth are at risk not only for recurrence of this subtype, but also for spontaneous preterm birth. Individuals of black origin have a higher rate of recurrent preterm birth.

Intraventricular hemorrhage in the premature neonate

Intraventricular hemorrhage in the premature neonate has been and continues to be a cause of morbidity and mortality in NICUs around the globe. Much information is available concerning the etiology and preventative and treatment strategies to reduce the incidence of IVH in this patient population. As neonatal caregivers are struggling to care for and protect infants who are surviving despite extreme prematurity, this survival is complicated by the infant's cerebral vasculature, which is very susceptible to hemorrhage; by respiratory problems that require the use of lifesaving, but potentially harmful, ventilation interventions; and by the infant's compromised ability to self-regulate vascular responses to stress. The preventative treatments being explored and proposed may come with debilitating and potentially lethal sequelae. Research continues, however. New recommendations are being proffered, and perhaps, in the near future, the incidence of IVH and its associated morbidity and mortality will decline dramatically.

Prematurity at birth: trends, racial disparities, and epidemiology

While infant mortality rates have continued to decline in the U.S., low birth weight and preterm rates have dramatically increased. Although the combination of factors that underlies these trends has not been fully described, there is growing concern that an appreciable part of the rise in prematurity rates stems from efforts taken to improve the survival of these high-risk infants. While advancements in medical technology and practice, augmented by improvements in prenatal care use, may have adversely effected prematurity rates and played a role in broadening racial disparities in pregnancy outcomes, they have positively impacted infant survival. Although many risk factors for prematurity have been identified, there are presently few areas for effective prevention. Accordingly, there is little encouragement for a downturn in prematurity rates in the near future. The prospect of continuing growth in the annual number of surviving preterm infants in the U.S. highlights the need for early detection and treatment of developmental problems for these high-risk survivors, and emphasizes the importance of assuring that needed support services are available to these children and their families.

Periodontal therapy may reduce the risk of preterm low birth weight in women with periodontal disease: a randomized controlled trial

BACKGROUND

Recent studies have suggested that periodontal disease is a risk factor for preterm low birth weight (PLBW). A randomized controlled trial was undertaken to help further evaluate the proposed association between periodontal disease and PLBW.

METHODS

Four hundred pregnant women with periodontal disease, aged 18 to 35, were enrolled while receiving prenatal care in Santiago, Chile. Women were randomly assigned to either an experimental group (n = 200), which received periodontal treatment before 28 weeks of gestation or to a control group (n = 200) which received periodontal treatment after delivery. Previous and current pregnancies and known risk factors were obtained from patient medical records and interviews. The primary outcome assessed was the delivery at less than 37 weeks of gestation or an infant weighing less than 2,500 g.

RESULTS

Of the 400 women enrolled, 49 were excluded from the analyses for different reasons. The incidence of PLBW in the treatment group was 1.84% (3/163) and in the control group was 10.11% (19/188), (odds ratio [OR] 5.49, 95% confidence interval [CI] 1.65 to 18.22, P= 0.001). Multivariate logistic regression analysis showed that periodontal disease was the strongest factor related to PLBW (OR 4.70, 95% CI 1.29 to 17.13). Other factors significantly associated with such deliveries were: previous PLBW (OR 3.98, 95% CI 1.11 to 14.21), less than 6 prenatal visits (OR 3.70, 95% Cl 1.46 to 9.38), and maternal low weight gain (OR 3.42, 95% CI 1.16 to 10.03).

CONCLUSIONS

Periodontal disease appears to be an independent risk factor for PLBW. Periodontal therapy significantly reduces the rates of PLBW in this population of women with periodontal disease.

C-reactive protein: a serological marker for preterm delivery?

BACKGROUND

We studied the association between the C-reactive protein level in the maternal serum early in the second trimester with that in preterm delivery.

METHODS

The present study is a prospective nested case-control study including 84 singleton, preterm deliveries (cases) and 400 singleton, term deliveries (controls), based at the Odense University Hospital, Denmark. These cases were identified from a cohort of 2846 women, monitored from their first prenatal care visit until their delivery. All the participants were examined at enrollment (median 16.3 weeks of gestation). Conventional statistical methods were used for analyses.

RESULTS

We found statistically significant differences in the C-reactive protein levels measured in early pregnancy between the women delivering preterm and those delivering at term. Different statistically significant odds ratios of between 1.7 and 2.0 were calculated, depending on the C-reactive protein level's cut-off value, and ranged from 5.6 mg/l (75th percentile) to 16.4 mg/l (95th percentile). The highest level was achieved at the 85th percentile (7.6 mg/l); odds ratio 2.0 (95%CI, 1.2-3.5).

CONCLUSION

A high C-reactive protein level at the beginning of a pregnancy is associated with a nearly twofold increased risk of preterm delivery; however, the clinical value at this point is still limited.

Antenatal steroids are associated with a reduction in the incidence of cerebral white matter lesions in very low birthweight infants

AIMS

To investigate whether antenatal steroids reduce the incidence of cerebral white matter lesions in very low birthweight infants.

METHODS

A total of 224 newborn infants of < 31 weeks gestational age and weighing < 1500 g was studied between January 1998 and June 2000. Obstetric and neonatal information was obtained from the case notes. The study population was subdivided into two groups according to antenatal steroid exposure. A complete course of treatment consisted of two doses of 12 mg each of betamethasone given at an interval of 12-24 hours. Infants in group 1 were born to mothers who had not received betamethasone, or were delivered within 24 hours of receiving the first dose of steroid. Infants in group 2 were born to mothers who had received one or more complete courses of betamethasone and were delivered > 24 hours after receiving the first dose of steroid.

RESULTS

The two groups contained statistically similar proportions of boys and girls, and the infants had similar birth weights and survival rates. Those in group 2, compared with those in group 1, had a lower gestational age (p = 0.02) and a lower incidence of white matter lesions on cranial ultrasound scans (p = 0.03). Stepwise logistic regression analysis showed that gestational age (p = 0.0002) and a complete course of antenatal steroids (p = 0.02) had independent effects on cerebral white matter lesions.

CONCLUSIONS

These observations suggest that a complete course of antenatal steroids may have a protective effect against cerebral white matter lesions in very low birthweight infants.

Higher risk of preterm birth and low birth weight in women with periodontal disease

Pregnant women with periodontal disease (PD) may be at increased risk for having preterm low-birth-weight (PLBW) children. We investigated whether the maintenance of the mothers' periodontal health after 28 weeks' gestation reduces the risk of PLBW. Of the 639 women studied, 406 had gingivitis and received treatment before 28 weeks' gestation, and 233 had PD and were treated after delivery. Data about previous and current pregnancies and known risk factors were obtained from patients' medical records. Primary outcomes were delivery before 37 weeks' gestation or an infant with birth weight below 2500 g. The incidence of PLBW was 2.5% in periodontally healthy women, and 8.6% in women with PD (p = 0.0004, relative risk = 3.5, 95% CI, 1.7 to 7.3). Risk factors significantly associated with PLBW were previous PLBW, PD, fewer than 6 pre-natal visits, and low maternal weight gain. PD was associated with both preterm birth and low birth weight, independent of other risk factors.

The fetal inflammatory response syndrome and cerebral palsy: yet another challenge and dilemma for the obstetrician

There is increasing evidence demonstrating a relationship between intrauterine infection and the development of neonatal intraventricular haemorrhage and periventricular leukomalacia with the subsequent occurrence of cerebral palsy, which is thought to be mediated through the generation of pro-inflammatory cytokines by the fetus. In the light of this relationship, a review of the current management of intrapartum infection and the associated complications of intrauterine infection such as preterm labour and preterm premature rupture of the membranes would seem timely along with the development of potential strategies which might prevent or ameliorate the effects of the fetal inflammatory response syndrome. The suggested changes in the understanding and management of the fetal inflammatory response syndrome provide a challenge and pose a dilemma for the practising obstetrician.

Place of amniocentesis in the assessment of preterm labour

OBJECTIVE

To evaluate the benefits and indications for amniocentesis in cases of preterm labor with or without preterm rupture of membranes.

METHOD

A review of the literature on amniocentesis in cases of intra-amniotic infection.

RESULTS

Amniocentesis is an invasive method that allows the diagnosis of intra-amniotic infection. However, no randomized trials have been performed from which we can assess the benefits and complications of amniocentesis in preterm labor.

CONCLUSION

The published data do not justify the routine practice of amniocentesis in preterm labor. More data are needed to evaluate the benefits and complications of this practice. Only randomized trials of patients in preterm labor, comparing those who undergo amniocentesis with those who do not, will clarify the indications for this procedure.

Antibiotics for preterm labour with intact membranes

BACKGROUND

There may be a link between infection and preterm birth.

OBJECTIVES

Since rupture of the membranes is an important factor in the progression of preterm labour, it is important to see if antibiotics are of any benefit prior to membrane rupture. The objective of this review was to assess the effects of antibiotics administered to women in preterm labour with intact membranes, on maternal and neonatal outcomes.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register and reference lists of articles. We contacted experts in the field.

SELECTION CRITERIA

Randomised trials which compared antibiotic treatment with placebo or no treatment for women in preterm labour (between 20 and 36 weeks gestation) with intact membranes.

DATA COLLECTION AND ANALYSIS

Trial quality was assessed and data were extracted independently by two reviewers. Study authors were contacted for missing data.

MAIN RESULTS

Meta-analysis of the ten included trials demonstrated a statistically significant prolongation of pregnancy associated with the use of antibiotics (5. 4 days, 95% confidence interval (CI) 0.9- 9.8 days). Antibiotic treatment was also associated with a statistically significant reduction in maternal infection (odds ratio (OR) 0.59, 95% CI 0.36, 0.97) and neonatal necrotising enterocolitis (OR 0.33, 95% CI 0.13, 0.88). No statistically significant effect was detected on the neonatal outcomes of respiratory distress syndrome and neonatal sepsis, although there was a trend towards the latter (OR 0.67, 95% CI 0.42, 1.07). An increase in perinatal mortality was observed in the group receiving antibiotics (OR 3.36, 95% CI 1.21, 9.32).

REVIEWER'S CONCLUSIONS

Although a prolongation in time to delivery and a trend towards a reduction in neonatal sepsis was detected, this review fails to demonstrate a clear overall benefit from antibiotic treatment for preterm labour with intact membranes on neonatal outcomes and raises concerns about increased perinatal mortality for those who received antibiotics. This treatment cannot therefore be currently recommended for routine practice. Further research is required to identify a subgroup of women (and their babies) who are more likely to experience benefit from antibiotic treatment for preterm labour prior to membrane rupture, and to identify which antibiotic or combination of antibiotics is most effective. The results of the ongoing ORACLE trial should help resolve some of the uncertainties revealed by this review.

Maternal intrauterine infection, cytokines, and brain damage in the preterm newborn

To evaluate the hypothesis that the proinflammatory cytokines IL-1, IL-6, and tumor necrosis factor-alpha might be the link between prenatal intrauterine infection (IUI) and neonatal brain damage, the authors review the relevant epidemiologic and cytokine literature. Maternal IUI appears to increase the risk of preterm delivery, which in turn is associated with an increased risk of intraventricular hemorrhage, neonatal white matter damage, and subsequent cerebral palsy. IL-1, IL-6, and TNF-alpha have been found associated with IUI, preterm birth, neonatal infections. and neonatal brain damage. Unifying models not only postulate the presence of cytokines in the three relevant maternal/fetal compartments (uterus, fetal circulation, and fetal brain) and the ability of the cytokines to cross boundaries (placenta and blood-brain barrier) between these compartments, but also postulate how proinflammatory cytokines might lead to IVH and neonatal white matter damage during prenatal maternal infection. Interrupting the proinflammatory cytokine cascade might prevent later disability in those born near the end of the second trimester.

The pathobiology of premature rupture of membranes

Premature rupture of membranes arises from what are likely multifaceted and multistep pathogenic pathways. Pathophysiological processes may involve both endogenous and exogenous fetal and maternal factors. This article reviews and analyzes information regarding, first, the form and function of fetal membranes; second, how membranes physically fail (rupture) at term and preterm gestations; and third, evaluates if we can reduce risks of rupture using physiological understanding and evidence-based clinical studies.