-
The Cochrane Database of Systematic... Aug 2016Chorioamnionitis is a leading cause of perinatal morbidity and mortality. Amnioinfusion aims at reducing the adverse effects of chorioamnionitis by dilution of the... (Review)
Review
BACKGROUND
Chorioamnionitis is a leading cause of perinatal morbidity and mortality. Amnioinfusion aims at reducing the adverse effects of chorioamnionitis by dilution of the infective organisms or by an anti-microbial effect of the fluid infused.
OBJECTIVES
The objective of this review was to determine the effect of amnioinfusion on clinical and sub-clinical chorioamnionitis, fetal well-being, fetal heart rate characteristics and perinatal and maternal morbidity and mortality.
SEARCH METHODS
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (6 July 2016), PubMed, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (6 July 2016) and reference lists of retrieved studies.
SELECTION CRITERIA
Randomised clinical trials (RCTs) of amnioinfusion (treatment group) versus no amnioinfusion in women with chorioamnionitis.We would have also considered trials comparing amnioinfusion with sham amnioinfusion; different types or volumes of amnioinfusion fluid but none were identified.Cluster-RCTs and quasi-RCTs were eligible for inclusion but none were identified. We identified one study published in abstract form but it did not contain any numerical data and has therefore been excluded. Studies using a cross-over design are not an appropriate study design and thus were not eligible for inclusion in this review.
DATA COLLECTION AND ANALYSIS
Two review authors independently assessed potential studies for inclusion and assessed trial quality. Both review authors independently extracted data and data were checked for accuracy.
MAIN RESULTS
We included one small trial (with data from 34 participants) comparing transcervical amnioinfusion with no amnioinfusion. The trial was considered to be at a high risk of bias overall, due to small numbers, inconsistency in the reporting and lack of information on blinding. Meta-analysis was not possible. Transcervical amnioinfusion was with room temperature saline at 10 mL per minute for 60 minutes, then 3 mL per minute until delivery versus no amnioinfusion. All women received intrauterine pressure catheter, acetaminophen and antibiotics (ampicillin or, if receiving Group B beta streptococcal prophylaxis, penicillin and gentamycin). We did not identify any trials that used transabdominal amnioinfusion.Compared to no amnioinfusion, transcervical amnioinfusion had no clear effect on the incidence of postpartum endometritis (risk ratio (RR) 1.50, 95% confidence interval (CI) 0.29 to 7.87; absolute risk 176/1000 (95% CI 34 to 96) versus 118/1000;low-quality evidence). Nor was there a clear effect in the incidence of neonatal infection (RR 3.00, 95% CI 0.13 to 68.84; absolute risk 0/1000 (95% CI 0 to 0) versus 0/1000; low-quality evidence). The outcome of perinatal death or severe morbidity (such as neonatal encephalopathy, intraventricular haemorrhage, admission to intensive/high care) was not reported in the included trial.In terms of this review's secondary outcomes, the rate of caesarean section was the same in both groups (RR 1.00, 95% CI 0.35 to 2.83; absolute risk 294/1000 (95% CI 103 to 832) versus 294/1000; low-quality evidence). There was no clear difference in the duration of maternal antibiotic treatment between the amnioinfusion and no amnioinfusion control group (mean difference (MD) 16 hours, 95% CI -1.75 to 33.75); nor in the duration of hospitalisation (MD 3.00 hours, 95% CI -15.49 to 21.49). The study did not report any information about how many babies had a low Apgar score at five minutes after birth.Women in the amnioinfusion group had a lower temperature at delivery compared to women in the control group (MD -0.38°C, 95% CI -0.74 to -0.02) but this outcome was not pre-specified in the protocol for this review.The majority of this review's secondary outcomes were not reported in the included study.
AUTHORS' CONCLUSIONS
There is insufficient evidence to fully evaluate the effectiveness of using transcervical amnioinfusion for chorioamnionitis and to assess the safety of this intervention or women's satisfaction. We did not identify any trials that used transabdominal amnioinfusion. The evidence in this review can neither support nor refute the use of transcervical amnioinfusion outside of clinical trials. We included one small study that reported on a limited number of outcomes of interest in this review. The numbers included in this review are too small for meaningful assessment of substantive outcomes, where reported. For those outcomes we assessed using GRADE (postpartum endometritis, neonatal infection, and caesarean section), we downgraded the quality of the evidence to low - with downgrading decisions based on small numbers and a lack of information on blinding. The included study did not report on this review's other primary outcome (perinatal death or severe morbidity).The reduction in pyrexia, though not a pre-specified outcome of this review, may be of relevance in terms of benefits to the fetus of reduced exposure to heat. We postulate that the temperature reduction found may be a direct cooling effect of amnioinfusion with room temperature fluid, rather than reduction of infection. Larger trials are needed to confirm and extend the findings of the trial reviewed here. These should be randomised controlled trials; participants, women with chorioamnionitis; interventions, amnioinfusion; comparisons, no amnioinfusion; outcomes, maternal and perinatal outcomes including neurodevelopmental measures.Further research is justified to determine possible benefits or risks of amnioinfusion for chorioamnionitis, and to investigate possible benefits of reducing temperature in fetuses considered at risk of neurological damage. Research should include randomised trials to examine transcervical or transabdominal amnioinfusion compared with no infusion for chorioamnionitis and examine outcomes listed in the methods of this review.
Topics: Amniotic Fluid; Anti-Bacterial Agents; Cervix Uteri; Cesarean Section; Chorioamnionitis; Endometritis; Female; Humans; Infant, Newborn; Infections; Length of Stay; Perinatal Death; Pregnancy
PubMed: 27556818
DOI: 10.1002/14651858.CD011622.pub2 -
BMC Pregnancy and Childbirth Nov 2022Intrauterine adhesions (IUAs) are one of the main reproductive system diseases in women worldwide. Fusion between the injured opposing walls leads to partial-to-complete...
BACKGROUND
Intrauterine adhesions (IUAs) are one of the main reproductive system diseases in women worldwide. Fusion between the injured opposing walls leads to partial-to-complete obliteration of the cavity and/or cervical canal. The main clinical manifestations in case of IUAs are menstrual disturbances, cyclic pain and reproductive disorders. The reproductive outcomes of women with IUAs remain limited and inefficient compared to women without IUAs, even after adhesiolysis. An exact understanding of the underlying mechanisms and processes to explain the compromised reproductive performance and outcomes in case of IUAs are lacking.
METHODS
A systematic literature review of MEDLINE-PubMed (1966 to January 2022) and EMBASE (1974 to January 2022) was performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies were included if they reported underlying causes, related mechanisms and processes to explain the association between IUAs and impaired reproductive performance, pregnancy and obstetric complications.
RESULTS
After an extensive review of the literature, 58 articles were identified reporting underlying mechanisms to explain the association between IUAs and impaired fertility. Intrauterine scarring influences the process of fertilization, reproductive performance and ultimately reproductive outcome. IUAs can disturb the cervico-utero-tubal sperm transport and result in an avascular and unresponsive endometrium with decreased receptivity and thickness. Abnormal decidualization and abnormal trophoblastic infiltration leads to placental attachment disorders. Moreover, the risk for premature delivery, intrauterine fetal growth restriction and fetal anomalies is increased in case of IUAs.
CONCLUSION
The impact of IUAs on reproductive performance, even after adhesiolysis, is becoming more apparent. The postulated mechanisms to explain the association are related to sperm transport, embryo implantation and placentation. Prevention, by preserving the basal layer of the endometrium is essential. Effective and evidence-based strategies for the prevention of endometrial injury and formation of IUAs, are urgently needed.
Topics: Male; Female; Pregnancy; Humans; Hysteroscopy; Placenta; Semen; Uterine Diseases; Tissue Adhesions
PubMed: 36376829
DOI: 10.1186/s12884-022-05164-2 -
Ultrasound in Obstetrics & Gynecology :... Jun 2023It is debated whether fetal endoscopic tracheal occlusion (FETO) is beneficial to fetuses with congenital diaphragmatic hernia (CDH) and whether FETO has different... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
It is debated whether fetal endoscopic tracheal occlusion (FETO) is beneficial to fetuses with congenital diaphragmatic hernia (CDH) and whether FETO has different effects in moderate and severe CDH. We conducted a systematic review and meta-analysis including the latest evidence to assess the overall effects of FETO on clinical outcomes of CDH.
METHODS
We searched PubMed, EMBASE, The Cochrane Library, China National Knowledge Infrastructure, China Science and Technology Journal Database and Wanfang Database to retrieve eligible studies published before 8 September 2022. No language or study design restrictions were applied. Studies were included if CDH fetuses underwent FETO surgery and were compared with a cohort that underwent expectant management, with at least one outcome reported. The primary outcomes were mortality at 1, 6 and 12 months after birth, rates of pulmonary hypertension, use of extracorporeal membrane oxygenation (ECMO) and prematurity. Meta-analysis was conducted to obtain pooled odds ratios (ORs) and mean differences. The quality of included studies and pooled evidence was also assessed.
RESULTS
A total of 1187 CDH fetuses from 20 studies were included in the quantitative synthesis. FETO significantly reduced 1-month (OR, 0.56 (95% CI, 0.34-0.93); P = 0.02, number needed to treat (NNT) = 7.67) and 6-month (OR, 0.34 (95% CI, 0.18-0.65); P = 0.0009, NNT = 5.26) CDH mortality (moderate/low quality of evidence). Subgroup analysis suggested that the effects of FETO on the rates of pulmonary hypertension and ECMO usage were significant in severe CDH (low/moderate quality of evidence) but not in moderate CDH (low/very low quality of evidence). FETO was also associated with an increased risk of preterm prelabor rupture of membranes before 37 weeks' gestation (OR, 4.94 (95% CI, 2.25-10.88); P < 0.0001, number needed to harm (NNH) = 3.13) and preterm birth before 37 weeks (OR, 5.24 (95% CI, 3.33-8.23); P < 0.00001, NNH = 2.79) (high/moderate quality of evidence). However, FETO was not associated with severe complications, such as preterm birth before 32 weeks, placental abruption or chorioamnionitis (very low/low quality of evidence).
CONCLUSIONS
FETO is associated with a reduction in mortality, rate of pulmonary hypertension and ECMO usage in severe CDH, while it reduces only the risk of mortality in moderate CDH. Although FETO increases the risk of late prematurity, it does not result in extreme prematurity. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.
Topics: Infant, Newborn; Female; Humans; Pregnancy; Hernias, Diaphragmatic, Congenital; Fetoscopy; Hypertension, Pulmonary; Premature Birth; Placenta; Fetus; Trachea
PubMed: 36704940
DOI: 10.1002/uog.26164 -
Archivos Argentinos de Pediatria Oct 2023Mercury is a toxic metal which can cross the placenta and the blood-brain barrier and cause the disruption of various cellular processes. Studies have investigated...
Mercury is a toxic metal which can cross the placenta and the blood-brain barrier and cause the disruption of various cellular processes. Studies have investigated mercury exposure and neurodevelopmental disorders; therefore, a critical and rigorous analysis of this evidence is required. The objective of this review was to evaluate the available scientific evidence on the effects of mercury exposure during the prenatal and postnatal periods and its relationship with the development of neurobehavioral disorders. A systematic search of the MEDLINE and ScienceDirect databases was conducted; the results were presented in tables and narrative synthesis. Only 31 studies met the eligibility criteria. Overall, the evidence on the effects of mercury exposure and neurodevelopmental disorders in children is limited. Learning disabilities, autism, and attention deficit hyperactivity disorder were some of the reported potential effects.
Topics: Pregnancy; Female; Child; Humans; Mercury; Neurodevelopmental Disorders; Attention Deficit Disorder with Hyperactivity; Autistic Disorder
PubMed: 37145892
DOI: 10.5546/aap.2022-02838.eng -
Reproductive Biology and Endocrinology... Jun 2023This systematic review and meta-analysis aimed to explore the relationship of endometrial thickness (EMT) with obstetric and neonatal outcomes in assisted reproductive... (Meta-Analysis)
Meta-Analysis Review
PURPOSE
This systematic review and meta-analysis aimed to explore the relationship of endometrial thickness (EMT) with obstetric and neonatal outcomes in assisted reproductive cycles.
METHODS
PubMed, EMBASE, Cochrane Library and Web of Science were searched for eligible studies through April 2023. Obstetric outcomes include placenta previa, placental abruption, hypertensive disorders of pregnancy (HDP), gestational diabetes mellitus (GDM) and cesarean section (CS). Neonatal outcomes include birthweight, low birth weight (LBW), gestational age (GA), preterm birth (PTB), small for gestational age (SGA) and large for gestational age (LGA). The effect size was estimated as odds ratio (OR) or mean difference (MD) with 95% confidence interval (CI) using a random-effects model. Inter-study heterogeneity was assessed by the chi-square homogeneity test. One-study removal method was used to determine the sensitivity of the meta-analysis.
RESULTS
Nineteen studies involving 76,404 cycles were included. The pooled results revealed significant differences between the thin endometrium group and the normal group in placental abruption (OR = 2.45, 95% CI: 1.11-5.38, P = 0.03; I = 0%), HDP (OR = 1.72, 95% CI: 1.44-2.05, P < 0.0001; I = 0%), CS (OR = 1.33, 95% CI: 1.06-1.67, P = 0.01; I = 77%), GA (MD = -1.27 day, 95% CI: -2.41- -1.02, P = 0.03; I = 73%), PTB (OR = 1.56, 95% CI: 1.34-1.81, P < 0.0001; I = 33%), birthweight (MD = -78.88 g, 95% CI: -115.79- -41.98, P < 0.0001; I = 48%), LBW (OR = 1.84, 95% CI: 1.52-2.22, P < 0.00001; I = 3%) and SGA (OR = 1.41, 95% CI: 1.17-1.70, P = 0.0003; I = 15%). No statistical differences were found in placenta previa, GDM, and LGA.
CONCLUSION
Thin endometrium was associated with lower birthweight or GA and higher risks of placental abruption, HDP, CS, PTB, LBW and SGA. Therefore, these pregnancies need special attention and close follow-up by obstetricians. Due to the limited number of included studies, further studies are needed to confirm the results.
Topics: Infant, Newborn; Pregnancy; Female; Humans; Birth Weight; Abruptio Placentae; Cesarean Section; Placenta; Placenta Previa; Premature Birth; Diabetes, Gestational
PubMed: 37312205
DOI: 10.1186/s12958-023-01105-6 -
Placenta Sep 2021Impaired placentation is an important contributing factor to intra-uterine growth restriction and pre-eclampsia in fetuses with congenital heart defects (CHD). These...
Impaired placentation is an important contributing factor to intra-uterine growth restriction and pre-eclampsia in fetuses with congenital heart defects (CHD). These pregnancy complications occur more frequently in pregnancies with fetal CHD. One of the most important factors influencing the life of children with CHD is neurodevelopmental delay, which seems to start already in utero. Delayed neurodevelopment in utero may be correlated or even (partly) explained by impaired placentation in CHD cases. This systematic review provides an overview of published literature on placental development in pregnancies with fetal CHD. A systematic search was performed and the Newcastle-Ottawa scale was used to access data quality. Primary outcomes were placenta size and weight, vascular and villous architecture, immunohistochemistry, angiogenic biomarkers and/or placental gene expression. A total of 1161 articles were reviewed and 21 studies were included. Studies including CHD with a genetic disorder or syndrome and/or multiple pregnancies were excluded. Lower placental weight and elevated rates of abnormal umbilical cord insertions were found in CHD. Cases with CHD more frequently showed microscopic placental abnormalities (i.e. abnormal villous maturation and increased maternal vascular malperfusion lesions), reduced levels of angiogenic biomarkers and increased levels of anti-angiogenic biomarkers in maternal serum and umbilical cord blood. Altered gene expression involved in placental development and fetal growth were found in maternal serum and CHD placentas. In conclusion, abnormal placentation is found in CHD. More extensive studies are needed to elucidate the contribution of impaired placentation to delayed neurodevelopment in CHD cases.
Topics: Biomarkers; Female; Fetal Development; Heart Defects, Congenital; Humans; Placenta; Placentation; Pregnancy
PubMed: 34388551
DOI: 10.1016/j.placenta.2021.07.297 -
BMC Pregnancy and Childbirth Sep 2023Prelabour rupture of membranes at term affects approximately 10% of women during pregnancy, and it is often associated with a higher risk of infection than when the...
INTRODUCTION
Prelabour rupture of membranes at term affects approximately 10% of women during pregnancy, and it is often associated with a higher risk of infection than when the membranes are intact. In an attempt to control the risk of infection, two main approaches have been used most widely in clinical practice: induction of labour (IOL) soon after the rupture of membranes, also called active management (AM), and watchful waiting for the spontaneous onset of labour, also called expectant management (EM). In addition, previous studies have demonstrated that vaginal examinations increase the risk of chorioamnionitis. However, the effect of vaginal examinations in the context of prelabour rupture of membranes have not been researched to the same extent.
METHODS
This systematic review analyses and critiques the latest research on the management of term prelabour rupture of membranes, including the effect of vaginal examinations during labour, with a focus on the outcomes of both normal birth, and chorioamnionitis. Due to its complexity, three research questions were identified using the PICO diagram, and subsequently, the results from these searches were combined. The systematic review aimed to identify randomised controlled trials (RCTs) and observational studies that compared active vs expectant management, included number of vaginal examinations and had chorioamnionitis and/or normal birth as outcomes. The following databases were used: MEDLINE, EMBASE, Maternity and Infant care, LILACS, CINAHL and the Cochrane Central Register of Controlled trials. Quality was assessed using a tool developed especifically for this study that included questions from CASP and the Cochrane risk of bias tool. Due to the high degree of heterogeneity meta-analysis was not deemed appropriate. Therefore, simple narrative analysis was carried out.
RESULTS
Thirty-two studies met the inclusion criteria, of which 27 were RCTs and 5 observational studies. The overall quality of the studies wasn't high, 15 out of the 32 studies were deemed to be low quality and only 17 out of 32 studies were deemed to be of intermediate quality. The systematic review revealed that the management of term prelabour rupture of membranes continues to be controversial. Previous research has compared active management (Induction of labour shortly after the rupture of membrane) against expectant management (watchful waiting for the spontaneous onset of labour). Although previous studies have demonstrated that vaginal examinations increase the risk of chorioamnionitis, no prospective studies have included an intervention to reduce the number of vaginal examinations.
CONCLUSION
A RCT assessing the consequences of active management and expectant management as well as the effect of vaginal examinations during labour for term prelabour rupture of membranes is necessary.
Topics: Female; Pregnancy; Infant; Child; Humans; Chorioamnionitis; Delivery, Obstetric; Labor, Obstetric; Databases, Factual; Infant Care
PubMed: 37684576
DOI: 10.1186/s12884-023-05878-x -
BMC Pediatrics Nov 2023Congenital abnormalities, as one of the fetal complications of placenta previa, may cause health problems or disability of the child throughout life. This study aimed to... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Congenital abnormalities, as one of the fetal complications of placenta previa, may cause health problems or disability of the child throughout life. This study aimed to determine the relationship between placenta previa and congenital abnormalities.
METHODS
Potential articles were retrieved from three electronic databases (PubMed/Medline, Scopus, and Web of Sciences) up to 21 May 2023 without limit of time and language. A random effect model was applied for meta-analysis. The heterogeneity was calculated based on I statistic and Cochrane Q-test. All analyses were conducted at the significance level of 0.05 using STATA software, version 14. The quality assessment of the included studies was performed using the improved Newcastle-Ottawa Scale.
RESULTS
In the initial search, 829 articles were retrieved. Finally, according to the inclusion criteria, eight studies were analyzed in the meta-analysis. A significant association was reported between placenta previa and risk of congenital abnormalities based on crude form (OR = 1.81, 95% CI = 1.34 to 2.28) and adjusted studies (OR = 6.38, 95% CI = 1.47 to 11.30). The high heterogeneity was observed among the studies reported based on adjusted and crude form, respectively (I = 97.9%, P = 0.000) (I = 80.6%, P = 0.000). Therefore, publication bias was not observed among studies. Seven studies of the included studies were of high quality.
CONCLUSION
Our study provides evidence that there is a positive and significant association between placenta previa and congenital malformations, including all structural anomalies, chromosomal defects, and congenital hypothyroidisms. Therefore, monitoring congenital abnormalities in the fetus of a mother with placenta previa is necessary.
Topics: Pregnancy; Female; Child; Humans; Placenta Previa; Network Meta-Analysis; Mothers
PubMed: 38031046
DOI: 10.1186/s12887-023-04433-z -
Acta Obstetricia Et Gynecologica... Mar 2018Women with a history of placenta-related pregnancy complications, such as preeclampsia, intrauterine growth restriction or preterm delivery, have an increased risk for... (Review)
Review
INTRODUCTION
Women with a history of placenta-related pregnancy complications, such as preeclampsia, intrauterine growth restriction or preterm delivery, have an increased risk for recurrence of such complications. This recurrence is likely the result of underlying endothelial dysfunction that leads to abnormal placentation, especially in complications with an early onset. This study provides an overview of biomarkers of placental development and function in pregnancies from women with a history of placenta-related complications.
MATERIAL AND METHODS
A systematic literature search was conducted limited to human studies and including keywords related to a history of placenta-related complications and markers of placental development and function. Two independent reviewers assessed eligibility and quality of 1553 retrieved unique articles.
RESULTS
Five articles reporting on placental development and function in women with an obstetric history of preeclampsia (n = 3), intrauterine growth restriction (n = 1) and preterm delivery (n = 2) were eligible for quality assessment. We identified associations between a history of preeclampsia and abnormal placental histological findings at term in the current pregnancy, but found contradictory results regarding presence of uterine artery notching. In women with a history of very preterm delivery (<32 weeks), one study showed associations with abnormal placental histology.
CONCLUSION
Literature on the association between a history of placenta-related complications and placental development and function in subsequent pregnancies is scarce and studies are heterogeneous. However, literature shows that placenta-related pregnancy complications are associated with subsequent placental histology.
Topics: Biomarkers; Female; Fetal Growth Retardation; Humans; Placenta; Placenta Diseases; Pre-Eclampsia; Pregnancy; Premature Birth; Recurrence
PubMed: 29125627
DOI: 10.1111/aogs.13259 -
Systematic Reviews Dec 2017Abnormal placental cord insertion (PCI) includes marginal cord insertion (MCI) and velamentous cord insertion (VCI). VCI has been shown to be associated with adverse... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Abnormal placental cord insertion (PCI) includes marginal cord insertion (MCI) and velamentous cord insertion (VCI). VCI has been shown to be associated with adverse pregnancy outcomes. This systematic review and meta-analysis aims to determine the association of abnormal PCI and adverse pregnancy outcomes.
METHODS
Embase, Medline, CINAHL, Scopus, Web of Science, ClinicalTrials.gov, and Cochrane Databases were searched in December 2016 (from inception to December 2016). The reference lists of eligible studies were scrutinized to identify further studies. Potentially eligible studies were reviewed by two authors independently using the following inclusion criteria: singleton pregnancies, velamentous cord insertion, marginal cord insertion, and pregnancy outcomes. Case reports and series were excluded. The methodological quality of the included studies was assessed using the Newcastle-Ottawa Scale. Outcomes for meta-analysis were dichotomous and results are presented as summary risk ratios with 95% confidence intervals.
RESULTS
Seventeen studies were included in the systematic review, all of which were assessed as good quality. Normal PCI and MCI were grouped together as non-VCI and compared with VCI in seven studies. Four studies compared MCI, VCI, and normal PCI separately. Two other studies compared MCI with normal PCI, and VCI was excluded from their analysis. Studies in this systematic review reported an association between abnormal PCI, defined differently across studies, with preterm birth, small for gestational age (SGA), low birthweight (< 2500 g), emergency cesarean delivery, and intrauterine fetal death. Four cohort studies comparing MCI, VCI, and normal PCI separately were included in a meta-analysis resulting in a statistically significant increased risk of emergency cesarean delivery for VCI (pooled RR 2.86, 95% CI 1.56-5.22, P = 0.0006) and abnormal PCI (pooled RR 1.77, 95% CI 1.33-2.36, P < 0.0001) compared to normal PCI.
CONCLUSIONS
The available evidence suggests an association between abnormal PCI and emergency cesarean delivery. However, the number of studies with comparable definitions of abnormal PCI was small, limiting the analysis of other adverse pregnancy outcomes, and further research is required.
Topics: Cesarean Section; Female; Fetal Death; Humans; Infant, Newborn; Infant, Small for Gestational Age; Placenta; Placenta Diseases; Pregnancy; Pregnancy Complications; Pregnancy Outcome; Premature Birth; Umbilical Cord
PubMed: 29208042
DOI: 10.1186/s13643-017-0641-1