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Global incidence of intraventricular hemorrhage among extremely preterm infants: a systematic literature review

  • Csaba Siffel EMAIL logo , Kristin D. Kistler and Sujata P. Sarda
Published/Copyright: March 19, 2021
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Journal of Perinatal Medicine
From the journal Journal of Perinatal Medicine Volume 49 Issue 9

Abstract

Objectives

To conduct a systematic literature review to evaluate the global incidence of intraventricular hemorrhage grade 2–4 among extremely preterm infants.

Methods

We performed searches in MEDLINE and Embase for intraventricular hemorrhage and prematurity cited in English language observational studies published from May 2006 to October 2017. Included studies analyzed data from infants born at ≤28 weeks’ gestational age and reported on intraventricular hemorrhage epidemiology.

Results

Ninety-eight eligible studies encompassed 39 articles from Europe, 31 from North America, 25 from Asia, five from Oceania, and none from Africa or South America; both Europe and North America were included in two publications. The reported global incidence range of intraventricular hemorrhage grade 3–4 was 5–52% (Europe: 5–52%; North America: 8–22%; Asia: 5–36%; Oceania: 8–13%). When only population-based studies were included, the incidence range of intraventricular hemorrhage grade 3–4 was 6–22%. The incidence range of intraventricular hemorrhage grade 2 was infrequently documented and ranged from 5–19% (including population-based studies). The incidence of intraventricular hemorrhage was generally inversely related to gestational age.

Conclusions

Intraventricular hemorrhage is a frequent complication of extremely preterm birth. Intraventricular hemorrhage incidence range varies by region, and the global incidence of intraventricular hemorrhage grade 2 is not well documented.

Keywords: epidemiology; extremely premature infant; intraventricular hemorrhage; neonatal intracranial hemorrhage; systematic literature review

Introduction

Intraventricular hemorrhage (IVH) in preterm infants occurs when a germinal matrix hemorrhage ruptures through the ependyma into the lateral ventricle [1], [2]. One of the most commonly used classification systems divides the severity of the IVH clinical spectrum into four grades: IVH grades 1 and 2 involve mild bleeding that is often self-limiting, and IVH grades 3 and 4 involve moderate to severe bleeding [3].

Preterm infants with IVH grade 3–4 are at high risk of death or of developing progressive ventricular dilatation leading to posthemorrhagic hydrocephalus [4], [5], [6], which may require neurosurgical intervention, for example shunt surgery, a procedure that carries a risk of complications [6], [7], [8], [9]. IVH grades 3 and 4, with or without documented complications, place affected neonates at risk for long-term neurologic and neurodevelopmental disability, including seizures, cognitive and executive function impairment, and cerebral palsy [10], [11], [12]. Low-grade IVH in extremely preterm infants has also been associated with adverse neurodevelopmental outcomes [13].

The advances in neonatal intensive care that have improved the survival of extremely preterm infants have, by extension, led to a relative increase in the number of infants at high risk of developing IVH [10], [14], [15]. The reported incidence of IVH in preterm infants in North America declined during the 1980s [16], but more recent studies have reported a stable or increasing trend [17], [18], [19]. A greater understanding of the changing epidemiology of comorbidities among extremely preterm infants may enhance the measurement of disease burden, allocation of public health resources, and objectives of clinical research. Therefore, we undertook a systematic review of the published literature to report incidence estimates for IVH grade 2–4 in this vulnerable patient population.

Methods

Search strategy

The study was conducted according to Preferred Items for Systematic Review and Meta-Analyses (PRISMA) recommendations [20]. The IVH-related searches were nested within a larger systematic literature review that examined multiple neonatal comorbidities, and the study methods have been described previously [21]. In brief, we developed search terms based on medical subject headings, Emtree terms (Embase), and free-text words associated with prematurity and IVH (Supplementary Tables 1 and 2). The IVH complication “periventricular hemorrhagic infarction” was not included in the search terms. A specific IVH grade or severity was not included in the search terms.

Both peer-reviewed articles and conference abstracts were included in the review. As described previously [21], searches were initially conducted in MEDLINE and Embase for conference abstracts and articles published from May 2006 to May 2016. Subsequently, an updated search was conducted using an identical approach that captured abstracts and articles published from May 2016 to October 2017. Retrieved citations and abstracts were screened by K.K. and Evidera research staff. During the course of the project, grade 2 IVH became a severity level of particular interest and a supplemental, targeted, nonsystematic review was conducted in 2017 with the aim of identifying additional articles on IVH grade 2 not previously identified in the systematic literature review. IVH grade ≥2 is of interest because this population could be targeted for potential future treatment of IVH.

Study selection

The aim of the current review was to identify the global incidence of IVH among extremely preterm infants. The World Health Organization defines extreme prematurity as birth at <28 weeks’ gestational age (GA) [22]. We found that not all studies stratified IVH frequency according to this cutoff and we felt that excluding papers reporting IVH among infants born at 28 weeks’ GA would potentially exclude data that were relevant to providing a full picture of this morbidity. Therefore, studies that included information on infants born at ≤28 weeks’ GA were included in the current study.

IVH is graded most often according to Papile et al. criteria (grade 1: germinal matrix hemorrhage; grade 2: IVH without ventricular dilatation; grade 3: IVH with ventricular dilatation; and grade 4: IVH extending into adjacent brain parenchyma) [3]. IVH is also graded according to Volpe (grade 1: germinal matrix hemorrhage with no or minimal IVH; grade 2: IVH in 10–50% of ventricular area on parasagittal view; grade 3: IVH in >50% of ventricular area on parasagittal view, usually distends lateral ventricle; periventricular hemorrhagic infarction [often referred to as grade 4 IVH]) [23]. The definition of IVH was not included in the protocol for the current study. Where available, the definitions used in included studies are reported for context. No a priori case definition inclusion criteria were used to determine study eligibility.

Eligible publications were prospective and retrospective observational studies published in English. Articles reporting data from the same study population or data source were grouped to avoid duplicate counting. The incidence of IVH was reported as a range.

Data extraction

A standardized Microsoft Excel® form was utilized to extract relevant information from each eligible publication, which included incidence of IVH and definitions of IVH. Data on IVH severity and GA at birth were extracted where available. Note: only IVH grades 2, 3, 4, and overall grade are included in the current analysis; incidence of IVH grade 1 was extracted, but the data were not summarized and are not included in the current review. Grade 1 was outside the scope of the current study because it is more common than grades 2, 3 and 4 and because it is not generally considered to have a clinical impact on later neurodevelopmental outcomes; our focus was on the more severe grades of IVH.

Ethical approval

The conducted research is not related to either human or animal use.

Results

Literature search results

The parent MEDLINE and Embase searches on neonatal comorbidities identified 3,952 articles (Figure 1). A total of 2,198 articles were excluded according to study exclusion criteria. Of 1,754 articles retrieved and reviewed in full text, 1,660 were rejected for not meeting IVH-related study inclusion criteria. Thus, 94 articles met the study inclusion criteria and were included in the review. An additional four articles were identified from the grade 2 targeted literature review [5], [24], [25], [26], bringing the total number of included articles to 98.

Figure 1: PRISMA flowchart showing the study selection process for publications reporting the incidence of intraventricular hemorrhage. aTwo articles reported both on Europe and North America [27], [28]. bAll Australian sources.
Figure 1:

PRISMA flowchart showing the study selection process for publications reporting the incidence of intraventricular hemorrhage.

aTwo articles reported both on Europe and North America [27], [28]. bAll Australian sources.

In the systematic literature review, 38 articles (28 distinct data sources) reported data from Europe [27], [28], [29], [30], [31], [32], [33], [34], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50], [51], [52], [53], [54], [55], [56], [57], [58], [59], [60], [61], [62], [63], [64], 29 articles (15 data sources) from North America [15], [27], [28], [65], [66], [67], [68], [69], [70], [71], [72], [73], [74], [75], [76], [77], [78], [79], [80], [81], [82], [83], [84], [85], [86], [87], [88], [89], [90], 24 articles (19 data sources) from Asia [91], [92], [93], [94], [95], [96], [97], [98], [99], [100], [101], [102], [103], [104], [105], [106], [107], [108], [109], [110], [111], [112], [113], [114], and five articles (four data sources) from Oceania (Australia only) [115], [116], [117], [118], [119]. Two articles reported data from both Europe and North America [27], [28]. No published data from Africa or South America reporting the incidence/prevalence of IVH were found. The additional targeted search yielded one additional article reporting data from Europe [24], two articles reporting data from North America (two data sources) [25], [26], and one article from Asia [5].

Heterogeneity was detected across studies with respect to study setting, IVH and preterm definitions, and sample size (Supplementary Tables 3–5). The majority of studies (57.4% [54/94]) reporting IVH incidence data defined IVH according to Papile et al. criteria [3]. However, a significant minority either did not report the IVH definition used or used different criteria. Some studies imposed specific criteria when calculating IVH incidence, such as only considering infants who had survived to a specific point in time (e.g., to discharge).

Global incidence of IVH by severity; grade 3–4, grade 2 and overall

The overall reported incidence range of IVH grade 3–4 reported in the 98 identified articles was 5–52% (Table 1). The majority of studies in Europe, North America, Asia, and Oceania reported an IVH grade 3–4 incidence of <20% (Supplementary Tables 3–5). The reported incidence range of IVH grade 3–4 was 6–22% when only the 18 population-based sources (from studies that reported incidence of IVH grade 3–4) were included.

Table 1:

Reported incidence of intraventricular hemorrhage grade 3–4 among infants born at ≤28 weeks’ gestational age, by region.

Region Incidence range (no. of distinct data sources)
All sources Population-based studies
Europe 5–52% (28) 6–17% (8)
North America 8–22% (14) 11–22% (5)
Asia 5–36% (19) 10–14% (3)
Oceania 8–13% (4)a 12–13% (2)a
Africa No publications identified No publications identified
South America No publications identified No publications identified

  1. aAll Australian sources.

As shown in Table 2, the incidence of IVH grade 2 ranged from 5 to 19% among the 10 data sources (11 articles) identified by the searches [5], [15], [24], [25], [26], [59], [61], [73], [101], [104], [109]. When only population-based studies were included (conducted in North America and Asia), the reported incidence range of IVH grade 2 was 5–11%.

Table 2:

Reported incidence of intraventricular hemorrhage grade 2 among infants born at ≤28 weeks’ gestational age, by region.

Region Incidence range (no. of distinct data sources)
All sources Population-based studies
Europe 8–14% (3) No publications found
North America 5–14% (3)a 5–6% (1)
Asia 6–19% (4) 11% (1)b
Oceania No publications identified No publications identified
Africa No publications identified No publications identified
South America No publications identified No publications identified

  1. aAll US sources. bKorean source.

The overall global reported incidence of IVH (all grades) ranged from 7 to 72% (Supplementary Tables 3–5). When only population studies were included, the incidence was 7–49% (among infants with spontaneous intestinal perforation).

Europe

The 29 distinct European data sources included 18 single-institution, three multi-institution, and eight population-based studies. Sample sizes ranged from 27 to 1,498 infants (Supplementary Table 3). The proportion of extremely preterm infants in Europe who developed IVH grade 3–4 ranged from 5% of 99 infants born at <28 weeks’ GA from the University Hospital of Antwerp, Belgium [29] to 52% of 247 infants born at 25–28 weeks’ GA during 2007–2010 in three Romanian hospitals [52], [53]. However, a later analysis revealed that the incidence of IVH grade 3–4 in the three Romanian hospitals was much lower (12%) among infants who were born during 2011–2014 [53]. The proportion of extremely premature infants who developed IVH grade 3–4 in population-based studies ranged from 6 to 8% of infants born at 24–27 weeks’ GA from the Swiss Neonatal Network [30], [31], to 17% of infants with a birth weight of <1,000 g (58% born at 22–26 weeks’ GA) in Finland [57]. In the largest population-based study, the incidence of IVH grade 3–4 was 11–17% among 599–1,498 infants born at 23–28 weeks’ GA in all maternity units in France (EPIPAGE-2) [49], [50], [51].

In three data sources, IVH grade 2 incidence was 8% of 132 infants born at 23–27 weeks’ GA from a single institution in Switzerland [61], 8% of 84 infants born at ≤28 weeks’ GA from a single institution in Italy [24], and 14% of 279 infants born at ≤28 weeks’ GA from a single institution in Germany [59].

For the two European sources reporting IVH incidence with respect to GA at birth (one multi-institution and one population-based), infants born at the younger end of the range of extreme prematurity tended to have a higher incidence of IVH grade 3–4, although findings from the later Romanian study were more variable (Figure 2) [32], [52], [53]. In the population-based study, 36% of infants born at 23 weeks’ GA had IVH grade 3–4 compared with an incidence of 10% for infants born at 27 weeks’ GA [32].

Figure 2: Incidence of IVH grade 3–4 and IVH grade 2, stratified by GA at birth. aData collected at three institutions. bDenominator for incidence included only infants surviving to at least 18–24 months’ corrected age. cFrom the sonogram with the most severe findings. Proportions were determined among those who had sonograms performed within 28 days after birth. dAmong infants who had cranial sonography within 28 days. eDefinition of IVH not reported. IVH, intraventricular hemorrhage; NR, not reported; wGA, weeks’ gestational age.
Figure 2:

Incidence of IVH grade 3–4 and IVH grade 2, stratified by GA at birth.

aData collected at three institutions. bDenominator for incidence included only infants surviving to at least 18–24 months’ corrected age. cFrom the sonogram with the most severe findings. Proportions were determined among those who had sonograms performed within 28 days after birth. dAmong infants who had cranial sonography within 28 days. eDefinition of IVH not reported. IVH, intraventricular hemorrhage; NR, not reported; wGA, weeks’ gestational age.

North America

The 17 North American data sources included eight single-institution, two multi-institution, and seven population-based studies (Supplementary Table 4). The range of sample sizes was 40–12,705 infants. Across North American studies, the incidence of IVH was 8% among infants born at 24–28 weeks’ GA at Rainbow Babies & Children’s Hospital in the United States [65] to 22% (IVH or periventricular leukomalacia) among infants born at <29 weeks’ GA in the Canadian Neonatal Network [79]. An IVH incidence of 12% was observed in the largest population-based study (Pediatrix; n=12,705) [86]. In addition, analysis of the National Institute of Child Health and Human Development (NICHD) Neonatal Research Network revealed that 25% of infants born with an extremely low birth weight at 23–28 weeks’ GA had intracranial hemorrhage [85].

All three North American data sources reporting IVH grade 2 incidence were from the United States: 5% of infants born at ≤27 weeks’ GA in an Oklahoma institution [26], 5–6% of infants born at 22–28 weeks’ GA with a birth weight of 401–1,500 g from the Neonatal Research Network [15], [73], and 14% of infants with a birth weight <1,000 g (mean GA: 25.6 weeks) at an institution in Virginia [25]. The incidence of IVH grade 2 ranged from 2 to 12% across the individual Neonatal Research Network centers between 2003 and 2007 among infants born at 22–28 weeks’ GA who had survived for >12 h [15].

As in Europe, IVH grade 3–4 incidence was highest among low-GA infants (Figure 2) [15], [86]. In the two population-based studies reporting such data, IVH incidences were 36 and 27% among infants born at 23 weeks’ GA, falling to 11 and 5%, respectively, among infants born at 27 weeks’ GA [15], [86]. IVH incidences among infants born at 28 weeks’ GA were 7 and 3% [15], [86]. Data from the Neonatal Research Network also showed lower IVH grade 2 incidence as GA at birth increased (9% at 23 weeks’ GA and 4% at 28 weeks’ GA) [15].

Asia and Oceania

The 20 Asian data sources (14 single-institution; three multi-institution; three population-based) and the four from Oceania (two single-institution; two population-based; all Australian sources) reported sample sizes from 41 to 9,149 infants (Supplementary Table 5). The reported incidence of severe IVH was 5–36% in Asia, and 8–13% in Australia (Table 1). Two of the four Australian sources included infants born at ≤29 weeks’ GA [116], [117], [119]. In the four population-based studies, the incidence of IVH grade 3–4 among infants born at ≤28 weeks’ GA was 10–12% in Japan [98], [99], 14% in Taiwan [103], and 12–13% in Australia [115], [117], [119]. Our separate targeted search identified population-based data from 55 Korean Neonatal Network centers (2013–2014) showing an IVH grade 3–4 incidence of 10% among 2,323 infants born at ≤28 weeks’ GA [5].

In the three single-institution studies conducted in Asia, IVH grade 2 incidence was 6% among infants born at 23–26 weeks’ GA at a hospital in Oman [104], 10% among infants born at 23–28 weeks’ GA at a single institution in Singapore [101], and 19% among infants born at <25 weeks’ GA at a medical center in Korea [109]. The Korean Neonatal Network study reported an IVH grade 2 incidence of 11% [5].

Asian studies showed an inverse relationship between IVH incidence and GA at birth [5], [94]. Figure 2 shows a substantial reduction in IVH grade 3–4 incidence as GA increased among 322 infants admitted to a neonatal intensive care unit (ICU) in Hong Kong, China [94]. IVH incidence in that study was 27% for infants born at 23 weeks’ GA and 4% for infants born at 28 weeks’ GA. In the Korean Neonatal Network study [5], IVH grade 3–4 incidence was 37, 20, and 9% among infants born at 23–24, 25–26, and 27–28 weeks’ GA, respectively. Corresponding incidences of IVH grade ≥2 in these GA cohorts were 51, 32, and 17% [5].

Discussion

Data from studies conducted in Europe, North America, Asia, and Oceania show that IVH grade 3–4 is a frequent complication following extremely preterm birth. The broad incidence range for IVH grade 3–4 (5–52%) is indicative of differing birth weights and GAs of neonates among study populations, and variable ICU practices and diagnostic criteria across study institutions. For instance, the five-fold higher risk of IVH grade 3–4 in Romanian ICUs between 2007 and 2010 than in centers of excellence worldwide has been attributed to the restrained application of active perinatal management [52]. Subsequent adoption of perinatal and neonatal interventions such as surfactant therapy and cesarean delivery in Romanian ICUs between 2011 and 2014 resulted in a reduced incidence of IVH grade 3–4 that approximated population-based data from centers of excellence (12 vs. 6–22%) [53].

Low-grade IVH is not generally considered to be of clinical significance, which could explain the low number of articles (n=11) we identified that reported the incidence of grade 2 IVH. However, there is evidence that low-grade hemorrhages increase the risk for neurodevelopmental impairment in preterm infants [13]. Observations that the incidence of IVH is inversely related to weeks’ GA at birth were confirmed by several studies for both IVH grade 3–4 and IVH grade 2. The trends appeared linear and were most obvious when assessing data from the large population-based studies.

These findings suggest that a more uniform diagnosis of IVH is necessary when reporting observational data, which requires stratification by GA and birth weight. Case definitions of IVH were not consistent among included studies. Although IVH was frequently defined according to Papile et al. criteria [3], other definitions (e.g., Volpe) were also utilized. Neonatal survival rates also affected the reported incidence of IVH; many infants who died before a study-specific time point or who had congenital anomalies were excluded from incidence calculations.

Our analysis has some limitations, some of which relate to the wider study and have been discussed previously [21]. These include differences in the study definitions relating to IVH and extremely preterm birth. Specific criteria for calculating IVH incidence were not stipulated or stated explicitly in some studies. It could not be determined routinely whether or not IVH incidence included all live-born neonates. Hence, IVH incidence could have been underestimated. Data collection methods and analysis in included studies varied between institutions. Further, information on the timing of the assessments used to diagnose IVH and the rigor of the readings were not widely reported in included studies. Cranial ultrasound (CUS) is the most common method used to diagnose neonatal brain injuries and has the advantage of being readily available and non-invasive. However, grade 1 and 2 lesions can be difficult to diagnose with CUS, and subtle white matter injury may not be recognized [120], [121]. Magnetic resonance imaging has been shown to better detect subtle white matter lesions than CUS [122]. The current study focused on IVH; however, white matter injury (e.g., periventricular leukomalacia) is a major determinant of neurodevelopmental outcome and can accompany severe IVH. Nonetheless, our extensive systematic literature review identified a number of studies that enrolled a high number of infants, and which reported consistent findings for IVH incidence by GA. This observation supports the method by which we stratified our search results by study design and emphasized data from population-based studies, as they are more generalizable than single-site studies.

Conclusions

In conclusion, IVH incidence data indicate that the likelihood of an extremely preterm infant having IVH grade 3–4 is high, particularly among infants with the lowest GAs. More data on the incidence of IVH grade 2 are required to quantify disease burden. The development of novel therapies is essential to help reduce or prevent IVH occurrence.

Corresponding author: Csaba Siffel, MD, PhD, Global Evidence and Outcomes, Takeda, Lexington, MA, USA; and College of Allied Health Sciences, Augusta University, Augusta, GA, USA, E-mail:

Funding source: Takeda Pharmaceutical Company

Acknowledgments

John Germak, MD, of Takeda, reviewed the draft for medical accuracy. Juliana F. M. Lewis, MPH, formerly of Evidera, participated in the systematic literature search and analysis of results. Under direction of the authors and in accordance with GPP3 guidelines, Malcolm Darkes, PhD, MPS, and Rosalind Bonomally, MSc, of Excel Medical Affairs, provided writing assistance for this publication. Shire, a Takeda company, provided funding to Excel Medical Affairs for medical writing support.

  1. Research funding: This study was funded by Shire, a Takeda company.

  2. Author contributions: All authors have accepted responsibility for the entire content of this manuscript and approved its submission.

  3. Competing interests: C.S. is an employee of and holds stock/stock options in Takeda. K.D.K is an employee of Evidera and was a paid consultant to Shire, a Takeda company, in relation to this study. S.P.S was an employee of Takeda at the time of the study.

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Supplementary Material

The online version of this article offers supplementary material (https://doi.org/10.1515/jpm-2020-0331).

Received: 2020-07-14
Accepted: 2021-02-16
Published Online: 2021-03-19
Published in Print: 2021-11-25

© 2021 Csaba Siffel et al., published by De Gruyter, Berlin/Boston

This work is licensed under the Creative Commons Attribution 4.0 International License.

Articles in the same Issue

  1. Frontmatter
  2. Review
  3. Global incidence of intraventricular hemorrhage among extremely preterm infants: a systematic literature review
  4. Commentary
  5. Professional integrity in maternal – fetal innovation and research: an essential component of perinatal medicine
  6. WAPM Recommendations
  7. WAPM-World Association of Perinatal Medicine Practice Guidelines: Fetal central nervous system examination
  8. Corner of Academy
  9. Education in developing countries and reducing maternal mortality: a forgotten piece of the puzzle?
  10. Original Articles – Obstetrics
  11. The contemporary value of dedicated preterm birth clinics for high-risk singleton pregnancies: 15-year outcomes from a leading maternal centre
  12. Chorioamnionitis after premature rupture of membranes in nulliparas undergoing labor induction: prostaglandin E2 vs. oxytocin
  13. Maternal and fetal outcomes in pregnancies with obstructive sleep apnea
  14. Assessing the involvement of the placental microbiome and virome in preeclampsia using non coding RNA sequencing
  15. Risk of metformin failure in the treatment of women with gestational diabetes
  16. Can we improve our ability to interpret category II fetal heart rate tracings using additional clinical parameters?
  17. New obstetric systemic inflammatory response syndrome criteria for early identification of high-risk of sepsis in obstetric patients
  18. Bacteria in the amniotic fluid without inflammation: early colonization vs. contamination
  19. Intertwin differences in umbilical artery pulsatility index are associated with infant survival in twin-to-twin transfusion syndrome
  20. Maternal and neonatal outcomes in women with disorders of lipid metabolism
  21. The use of PAMG-1 testing in patients with preterm labor, intact membranes and a short sonographic cervix reduces the rate of unnecessary antenatal glucocorticoid administration
  22. Original Articles – Neonates
  23. The effect of postnatal corticosteroids on growth parameters in infants with bronchopulmonary dysplasia
  24. Are neonatal outcomes of triplet pregnancies different from those of singletons according to gestational age?
  25. Impact of paternal presence and parental social-demographic characteristics on birth outcomes
  26. Letter to the Editor
  27. Comment on: “amniotic fluid embolism – implementation of international diagnosis criteria and subsequent pregnancy recurrence risk”
https://doi.org/10.1515/jpm-2020-0331
Keywords for this article
epidemiology; extremely premature infant; intraventricular hemorrhage; neonatal intracranial hemorrhage; systematic literature review
Creative Commons
BY 4.0

Articles in the same Issue

  1. Frontmatter
  2. Review
  3. Global incidence of intraventricular hemorrhage among extremely preterm infants: a systematic literature review
  4. Commentary
  5. Professional integrity in maternal – fetal innovation and research: an essential component of perinatal medicine
  6. WAPM Recommendations
  7. WAPM-World Association of Perinatal Medicine Practice Guidelines: Fetal central nervous system examination
  8. Corner of Academy
  9. Education in developing countries and reducing maternal mortality: a forgotten piece of the puzzle?
  10. Original Articles – Obstetrics
  11. The contemporary value of dedicated preterm birth clinics for high-risk singleton pregnancies: 15-year outcomes from a leading maternal centre
  12. Chorioamnionitis after premature rupture of membranes in nulliparas undergoing labor induction: prostaglandin E2 vs. oxytocin
  13. Maternal and fetal outcomes in pregnancies with obstructive sleep apnea
  14. Assessing the involvement of the placental microbiome and virome in preeclampsia using non coding RNA sequencing
  15. Risk of metformin failure in the treatment of women with gestational diabetes
  16. Can we improve our ability to interpret category II fetal heart rate tracings using additional clinical parameters?
  17. New obstetric systemic inflammatory response syndrome criteria for early identification of high-risk of sepsis in obstetric patients
  18. Bacteria in the amniotic fluid without inflammation: early colonization vs. contamination
  19. Intertwin differences in umbilical artery pulsatility index are associated with infant survival in twin-to-twin transfusion syndrome
  20. Maternal and neonatal outcomes in women with disorders of lipid metabolism
  21. The use of PAMG-1 testing in patients with preterm labor, intact membranes and a short sonographic cervix reduces the rate of unnecessary antenatal glucocorticoid administration
  22. Original Articles – Neonates
  23. The effect of postnatal corticosteroids on growth parameters in infants with bronchopulmonary dysplasia
  24. Are neonatal outcomes of triplet pregnancies different from those of singletons according to gestational age?
  25. Impact of paternal presence and parental social-demographic characteristics on birth outcomes
  26. Letter to the Editor
  27. Comment on: “amniotic fluid embolism – implementation of international diagnosis criteria and subsequent pregnancy recurrence risk”
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