Cervical pessaries for the prevention of preterm birth: a systematic review and meta-analysis

Objective: The objective of this study is to evaluate the effectiveness and safety of cervical pessaries for the prevention of preterm birth.

Methods: We searched PubMed, Embase, Web of Science, and other sources from inception to July 2016. This analysis referred to pregnant women with singleton/multiple viable fetus/fetuses, with or without cervical pessary placement.

Results: Six randomized control trials and five cohort studies involving 3911 participants were included. Overall, cervical pessary placement was slightly associated with the decrease of spontaneous delivery less than 34 weeks (relative risk 0.65 [95% CI: 0.44–0.96]) and increased gestational age at delivery (weighted mean difference 1.03 weeks [95% CI: 0.37–1.70]) in multiple pregnancies, but not with poor perinatal outcomes. Pessary placement in singleton pregnancies did not show any difference. A planned subgroup analysis showed multiple pregnancies with shorter cervical length (≤25?mm) had a longer prolongation of pregnancy (weighted mean difference 2.08 weeks [95% CI: 1.35–2.82]).

Conclusion: This meta-analysis suggested pessary placement could slightly reduce the rate of spontaneous preterm delivery before 34 weeks, and increase gestational age at delivery in multiple pregnancies, but not in singleton pregnancies. More studies of high quality with detailed records are urgent to confirm the efficacy of this procedure.     

Maternal BMI and preterm birth: A systematic review of the literature with meta-analysis

Objectives.?To examine the association between high prepregnancy maternal body mass index (BMI) and the risk of preterm birth (PTB).

Methods.?A systematic review of the literature. We included cohorts and case-control studies published since 1968 that examined the association between BMI and PTB of all types, spontaneous (s), elective and with ruptured membranes (PPROM) in three gestational age categories: general (<37 weeks), moderate (32–36 weeks) and very (<32 weeks) PTB.

Results.?20,401 citations were screened and 39 studies (1,788,633 women) were included. Preobese (BMI, 25–29.9) and obese I (BMI, 30–34.9) women have a reduced risk for sPTB: AOR?=?0.85 (95% CI: 0.80–0.92) and 0.83 (95% CI: 0.75–0.92), respectively. Their risk for moderate PTB was 1.20 (95% CI: 1.04–1.38) and 1.60 (95% CI: 1.32–1.94), respectively. Obese II women (BMI, 35–40) have an increased risk for PTB in general (AOR?=?1.33, 95% CI: 1.12–1.57) moderate (AOR?=?2.43, 95% CI: 1.46–4.05) and very PTB (AOR?=?1.96, 95% CI: 1.66–2.31). Obese III women (BMI?>?40) have an even higher risk for very PTB (AOR?=?2.27, 95%CI: 1.76–2.94). High BMI does not modify the risk for PPROM and increases the risk for elective PTB.

Conclusions.?High maternal BMI may have different effects on different types of PTB.     

Etiology and outcome of extremely low-birth-weight infants

OBJECTIVE: Our purpose was to determine whether the reason for delivery of extremely low-birth-weight infants influenced the immediate neonatal outcome. STUDY DESIGN: At a regional perinatal center a retrospective analysis of 111 neonates with birth weights between 500 and 800 gm and their respective mothers was performed. The mother-infant pairs were grouped according to the reason for delivery. Group 1 included those with idiopathic preterm labor. Group 2 included mothers with preterm premature rupture of membranes. Group 3 included those delivered for maternal or fetal indications. Group 4 included all multiple gestations. Maternal, intrapartum, and neonatal outcome variables were then evaluated for statistical significance by analysis of variance and χ² methods and a p value of 005. RESULTS: The neonatal outcome variables (survival and incidence of major intraventricular hemorrhage, hyaline membrane disease, and fetal sepsis) were not found to be significantly different among the four groups tested. CONCLUSION: The reason for the delivery of extremely low-birth-weight infants does not have an impact on the immediate neonatal outcome in these neonates. (Am J Obstet Gynecol 1996;174:1896-902.)     

Mid- and long-term outcome of extremely low birth weight (ELBW) infants: An analysis of prognostic factors

Objective. To evaluate morbidity and long-term neurological outcome in a group of extremely low birth weight infants (ELBW; <1000 g) and to correlate the neurological outcome in a small group of intrauterine growth retarded (IUGR) infants with Doppler indices in the umbilical artery.

Methods. One hundred and eighty-three live births with birth weight <1000 g and gestational age ≤34 weeks were included in the study. Neonatal mortality and morbidity were evaluated. At 24 months of corrected age an evaluation of the neurological development of the children was made by pediatric neuropsychiatrists. The children were classified as: normal, with minor neurological sequelae, and with major neurological sequelae. The evaluation of umbilical artery velocimetry was applied to 84 fetuses presenting with IUGR and the velocimetric patterns were correlated with neurological outcome.

Results. In the 183 infants discharged from the Department of Neonatology, respiratory distress syndrome (RDS) was the most frequent pathology (76.6%); less frequent were bronchopulmonary dysplasia (BPD; 19.5%), patent ductus arteriosus (PDA; 29.7%) and necrotizing enterocolitis (NEC; 5.5%). Retinopathy of prematurity (ROP) affected 34 children (26.6%), and 14.8% of the children developed intraventricular hemorrhage (IVH) and 14.1% periventricular leukomalacia (PVL). Out of the 183 infants included in the study, 107 had a neurological assessment at two years: 22 (20.6%) suffered from severe neurological sequelae, 20 (18.7%) from minor neurological sequelae, and 65 (60.7%) had a normal neurological development. In 84 IUGR fetuses a Doppler evaluation of the umbilical artery was performed: the incidence of neurologically normal children was 67% in the group with normal umbilical velocimetry, 93% in the group with increased umbilical resistances, and 59% in those with absent or reversed end-diastolic velocity (ARED).

Conclusions. This study, confirms that an extremely low birth weight implies a high risk of perinatal mortality and neonatal morbidity, but that the most significant variable that can be correlated to the long-term neurological outcome is the gestational age.     

Born too soon: the continuing challenge of preterm labor and birth in the United States

Prematurity is the single greatest cause of morbidity and mortality in obstetrics. Families, health care services, and education systems experience the impact of prematurity for the lifetime of the preterm-born child. Health care providers have tried to lower the preterm birth rate with prevention both before and during pregnancy and intervention for symptomatic women. The inability of the health care system to significantly decrease the incidence of preterm birth continues to be a challenge. To further complicate the situation, new data shows that infants born between 34 and 37 weeks' gestation who were thought to have minimal long-term effects of preterm birth may be more at risk than previously appreciated. This article reviews evidence-based risk identification, prevention, and management of women experiencing preterm labor and birth.     

Relationship of prenatal care and perinatal morbidity in low-birth-weight infants

OBJECTIVE: Lack of or no prenatal care (NPC) is associated with preterm birth (PTB) and low birth weight (LBW). Our purpose was to determine whether LBW infants delivered after NPC have worse outcomes than LBW infants with prenatal care (PC). STUDY DESIGN: Eight thousand sixty-five consecutive women delivered at six hospitals in Shelby County, Tenn, were evaluated regarding clinical characteristics and perinatal outcomes depending on the occurrence of PC. Infant and LBW infant outcomes were evaluated on the basis of the occurrence of PC. Multivariate analysis was performed for neonatal outcomes adjusting for race, plurality, antenatal steroids, amnionitis, and ponderal index. A P value less than .05 was considered significant. RESULTS: NPC women were more likely multiparous (80% vs 65%), African American (70% vs 61%), and uninsured (25% vs 4%), P<.0001 for each. PTB (36% vs 15%) and LBW (22% vs 12%) were more common with NPC, P<.0001 for each. Women with NPC had more advanced cervical dilation (ACD) greater than 4 cm (ACD: 63% vs 39%) and more amnionitis on admission (2% vs 1%), P相似文献   

Cervical pessary in the prevention of preterm births in multiple pregnancies with a short cervix: PRISMA compliant systematic review and meta-analysis

Background: Preterm births occur frequently in multiple pregnancies with a short cervix. The cervical pessary is a potential intervention for prevention of preterm births.

Objective: To assess the effectiveness of cervical pessary in the prevention of preterm births in multiple pregnancies with a short cervix (<25?mm).

Search strategy: Major databases from 2006 to 20th November 2016 were searched for relevant terms.

Selection criteria: We included randomized controlled trials that assessed the effectiveness of cervical pessary on pregnancy outcomes in multiple pregnancies with a short cervix.

Data collection and analysis: Risk ratio was used as the summary measure with random effects model. We assessed heterogeneity between studies using the I² index. Quality assessment was done based on Cochrane Handbook Method.

Main results: Pooled data showed no benefit of using cervical pessary in the prevention of preterm births, birth weights less than 1500?g, less than 2500?g, adverse neonatal events and fetal/neonatal deaths in twin pregnancies with a short cervix.

Conclusion: We are unable to show benefit of using cervical pessary in preventing preterm births in twin pregnancies with a short cervix. However, as cervical pessary is a reasonable intervention, there is a need for more randomized controlled trials in this area.     

Association between maternal periodontitis and preterm and/or low birth weight infants in normal pregnancies

Objective: To relate the periodontal condition with the presence of periodontal bacteria in pregnant that had babies with preterm delivery or/and low weight at birth (PTLBW).

Methods: We recruited 134 pregnant women without systemic diseases attending at the Gynaecology and Obstetrics Room, from Maternal Provincial Hospital, Córdoba, Argentine. Pregnant were grouped according to the International Classification for a System of Periodontal Disease. A sample from periodontal pocket was extracted to identify Porphyromonas gingivalis (Pg), Treponema denticola (Td), Tannerella forsythia (Tf) Prevotella intermedia (Pi) and Agreggatibacter actinomycemcomitans (Aa).

Results: We identified 7 (5%) cases of children born underweight or preterm of mothers diagnosed with Gingivitis, 6 (4%) in Mild Periodontitis and 4 (3%) in Moderate Periodontitis. We estimated that when Pi and/or Aa were not detected in the periodontal pockets of mothers, the infants had more than 129% chance of having normal birth weights (OR 3.47 for Pi and OR and 2.29 for Aa). The average age of the mothers who has PTLBW was 21?±?3.5. The age showed an association with PTLBW (p?<?0.0008).

Conclusions: The presences of periodontal pathogens in periodontal pockets from pregnant with different periodontal status would associate with PTLBW infants when the mothers are young, and the normal term and normal birth weight infant are associated with the absence of periodonto bacteria like Pi and Aa.     

Response of leukocytes and nucleated red blood cells in very low-birth weight preterm infants after exposure to intrauterine inflammation

Objectives.?To test the hypothesis if very immature preterm infants exposed to chorioamnionitis would exhibit increased numbers of leukocytes, neutrophils, and nucleated red blood cells (NRBC) in peripheral blood.

Study design.?Preterm infants with birth weight <1500?g were prospectively evaluated. Blood cells were counted within the first hour of life in infants exposed to histological chorioamnionitis and controls.

Results.?Birth weight, gestational age, and sex did not differ between the groups (n?=?71). Seventeen infants who were exposed to chorioamnionitis had significantly higher counts of leukocytes, neutrophils, and immature neutrophils after birth. However, there was no difference in the number of circulating NRBCs between both groups. In contrast, there was a tendency towards an increased NRBC count in the control group.

Conclusion.?Preterm infants exposed to chorioamnionitis elicited a strong inflammatory response as reflected by increased numbers of leukocytes and neutrophils. However, chorioamnionitis did not induce an increase in numbers of NRBC.     

Epigenetic modifications of human placenta associated with preterm birth: a systematic review

Objective: Preterm birth (PTB) is one of the leading causes of neonatal mortality and morbidity around the world. Epigenetic alterations of the human placenta may be involved in the causal chain of adverse pregnancy outcomes specifically PTB. In this systematic review, we investigated whether epigenetic dysregulation of the human placenta is associated with PTB.

Methods: We searched MEDLINE and EMBASE and systematically reviewed all relevant studies on epigenetic placental modifications in PTB. Two independent reviewers selected controlled human studies published in any language, evaluated their quality, and graded them using the Newcastle–Ottawa Quality Assessment Scale. We resolved disagreements by consensus with a third reviewer.

Results: Eleven observational studies of low to moderate quality met the eligibility criteria out of 60 unique studies. Most studies reported an association between placental epigenetic changes (methylation, mRNA and miRNA) and PTB, although research methods were highly heterogeneous.

Conclusions: Studies reported various associations between specific epigenetic findings and PTB, although methodological concerns limited results’ validity. Additional high quality studies are needed to assess the repeatability of these findings. The STROBE guidelines can be used to improve the quality of reporting.     

Maternal dyslipidemia during pregnancy may increase the risk of preterm birth: A meta-analysis

Epidemiological studies have reported an inconsistent relationship between maternal lipid levels and preterm birth (PTB). We performed this meta-analysis to evaluate the association between maternal dyslipidemia and PTB. Overall, three nested case-control studies and eight cohort studies were eligible. Effect estimates [odds ratio(OR)/relative risk] were pooled using a fixed-effects or a random-effects model. Subgroup and metaregression analyses were conducted to evaluate the sources of heterogeneity. Eleven studies involving 13,025 pregnant women were included. Compared with pregnant women with normal lipid levels, the women with elevated levels of lipids had an increased risk of PTB, and the pooled OR was 1.68 [95% confidence interval (CI): 1.25–2.26)]; meanwhile, women with lower levels of lipids also had a trend of an increased risk of PTB (OR = 1.52, 95% CI = 0.60–3.82). The pooled ORs for elevated levels of total cholesterol, triglycerides, low density lipoprotein-cholesterol, and lower levels of high density lipoprotein-cholesterol were 1.71 (95% CI: 1.05–2.79), 1.55 (95% CI: 1.13–2.12), 1.19 (95% CI: 0.95–1.48), and 1.33 (95% CI: 1.14–1.56), respectively. The present meta-analysis found that maternal dyslipidemia during pregnancy, either the elevated total cholesterol or triglycerides, was associated with an increased risk of PTB. These findings indicate that a normal level of maternal lipid during pregnancy may reduce the risk of PTB.     

Infantile survival and neurodevelopment at three years of age on delivery by the intended delivery mode in extremely preterm infants

ObjectiveTo elucidate the impact of the intended delivery mode on long-term outcomes among extremely preterm infants.Materials and methodsWomen who delivered singletons between 23 0/7 and 25 6/7 weeks of gestation from January 2010 to March 2014 and their infants were included in this study. The cases of fetal growth restriction and those with a chromosomal or major structural abnormality were excluded. The cases of fetal death that was diagnosed before labor onset and cases of non-reassuring fetal status, placental abruptions or umbilical cord prolapse that was diagnosed at labor onset were also excluded. The primary outcome was the incidence of composite adverse events, including death, cerebral palsy, or neurodevelopmental delay, at the age of three years. The composite adverse events, including death, grade III or IV intraventricular hemorrhage, cystic periventricular leukomalacia, necrotizing enterocolitis, focal intestinal perforation, and sepsis of neonatal period, were assessed as short-term outcomes. The association between the intended delivery mode and primary outcome, short-term outcome, and each component was analyzed using a multivariate logistic regression model.ResultsEighty cases were included in the analyses. Primary outcomes could be assessed in 72 cases. Infantile composite adverse events before discharge were observed in 19 cases (24%). The prevalence of primary outcomes was 40% (29 cases). The intended delivery mode was not associated with primary and short-term outcomes and each component complication.ConclusionAn advantage of intended cesarean delivery in terms of prognosis at three years of age in extremely preterm infants was not observed.     

High environmental temperature and preterm birth: A review of the evidence

Objective

to examine the evidence in relation to preterm birth and high environmental temperature.

Background

this review was conducted against a background of global warming and an escalation in the frequency and severity of hot weather together with a rising preterm birth rate.

Methods

electronic health databases such as: SCOPUS, MEDLINE, CINAHL, EMBASE and Maternity and Infant Care were searched for research articles, that examined preterm birth and high environmental temperature. Further searches were based on the reference lists of located articles. Keywords included a search term for preterm birth (preterm birth, preterm, premature, <37 weeks, gestation) and a search term for hot weather (heatwaves, heat-waves, global warming, climate change, extreme heat, hot weather, high temperature, ambient temperature). A total of 159 papers were retrieved in this way. Of these publications, eight met inclusion criteria.

Data extraction

data were extracted and organised under the following headings: study design; dataset and sample; gestational age and effect of environmental heat on preterm birth. Critical Appraisal Skills Programme (CASP) guidelines were used to appraise study quality.

Findings

in this review, the weight of evidence supported an association between high environmental temperature and preterm birth. However, the degree of association varied considerably, and it is not clear what factors influence this relationship. Differing definitions of preterm birth may also add to lack of clarity.

Key conclusions

preterm birth is an increasingly common and debilitating condition that affects a substantial portion of infants. Rates appear to be linked to high environmental temperature, and more especially heat stress, which may be experienced during extreme heat or following a sudden rise in temperature. When this happens, the body may be unable to adapt quickly to the change. As global warming continues, the incidence of high environmental temperature and dramatic temperature changes are also increasing. This situation makes it important that research effort is directed to understanding the degree of association and the mechanism by which high temperature and temperature increases impact on preterm birth. Research is also warranted into the development of more effective cooling practices to ameliorate the effects of heat stress. In the meantime, it is important that pregnant women are advised to take special precautions to avoid heat stress and to keep cool when there are sudden increases in temperature.