Preeclampsia and Retinopathy of Prematurity in Very-Low-Birth-Weight Infants: A Population-Based Study

Retinopathy of prematurity protection conferred by uteroplacental insufficiency through erythropoietin signaling in an experimental Murine Model

BACKGROUND

Recent clinical studies suggest that preeclampsia, characterized by uteroplacental insufficiency (UPI) and infant intrauterine growth restriction (IUGR), may be protective against retinopathy of prematurity (ROP) in preterm infants. Experimental models of UPI/IUGR have found an association of erythropoietin (EPO) with less severe oxygen-induced retinopathy (OIR); however, it is unclear if EPO/EPO receptor (EPOR) signaling was involved. We hypothesized that maternal UPI and resultant infant IUGR would protect against features of ROP through EPO/EPOR signaling.

METHODS

We compared transgenic mice with hypoactive EPOR signaling (hWtEPOR) to littermate wild-type mice (mWtEpoR) in a novel combined model of IUGR and ROP. Thromboxane A2 (TXA2) was infused into pregnant C57Bl/6J dams to produce UPI/IUGR; postnatal pups and their foster dams were subjected to a murine OIR model.

RESULTS

Following hyperoxia, hematocrits were similar between littermate wild-type (mWtEpoR) TXA2/OIR and vehicle/OIR pups. mWtEpoR TXA2/OIR had increased serum EPO, retinal EPO and VEGF, and decreased avascular retinal area (AVA) compared to vehicle/OIR pups. In comparison to the mWtEpoR TXA2/OIR pups, AVA was not reduced in hWtEPOR TXA2/OIR pups.

CONCLUSION

Our findings provide biologic evidence that UPI/OIR-induced endogenous EPOR signaling confers protection against hyperoxia-induced vascular damage that may be related to pathophysiology in ROP.

IMPACT

Maternal preeclampsia and infant growth restriction confer retinovascular protection against high oxygen-induced damage through endogenous erythropoietin signaling.

Downregulation of TCL6 protected human trophoblast cells from LPS-induced inflammation and ferroptosis

Dysregulation of noncoding RNAs has been reported to have a close correlation with preeclampsia(PE)development. TCL6 was upregulated in patients with PE. In this study, we examined the impacts of TCL6 on modulating HTR-8/SVneo cells induced by LPS. LPS (100 and 200 ng/ml) was applied to induce inflammation in trophoblast cells HTR-8/SVneo. Cell viability, apoptosis, and transwell experiments were conducted. The ELISA methods were used for pro-inflammatory cytokines IL-1β, IL-6, and TNF-α. MDA, GSH, and GPX kits were employed. Transfection was performed for expression regulation of TCL6, miR-485-5p, and TFRC in cells. Bioinformatic online tools were used to predict the targeting sites. Luciferase and RNA immunoprecipitation-qPCR were done to verify the interactions of TCL6, miR-485-5p, and TFRC. RNA expression levels were measured using RT-qPCR, and protein expression of TFRC and GPX4 was detected using a western blot. The free Fe (II) contents were measured. LPS decreased viability, invasion, and migration but enhanced apoptosis, ferroptosis, and inflammation. TCL6 expression was enhanced by LPS induction. The knockdown of TCL6 increased HTR-8/SVneo cell viability and invasion but inhibited cell apoptosis, inflammation, and ferroptosis while inhibition of miR-485-5p could reverse this through TFRC regulation. Moreover, miR-485-5p was sponged by TCL6 and bound to TFRC. TCL6 protected trophoblast cells from LPS-induced injury through the TFRC pathway.

Association between endotypes of prematurity and pharmacological closure of patent ductus arteriosus: A systematic review and meta-analysis

Introduction

Endotypes leading to very and extremely preterm birth are clustered into two groups: infection/inflammation and dysfunctional placentation. We conducted a systematic review of observational studies exploring the association between these two endotypes and the pharmacological closure of patent ductus arteriosus (PDA) induced by cyclooxygenase (COX) inhibitors. Chorioamnionitis represented the infectious-inflammatory endotype, while dysfunctional placentation proxies were hypertensive disorders of pregnancy (HDP) and small for gestational age (SGA) or intrauterine growth restriction.

Methods

PubMed/Medline and Embase databases were searched. The random-effects odds ratio (OR) and 95% confidence interval (CI) were calculated for each association. We included 30 studies (12,639 infants).

Results

Meta-analysis showed a significant association between exposure to HDP and increased rate of pharmacological closure of PDA (17 studies, OR 1.41, 95% CI 1.10-1.81, p = 0.006). In contrast, neither chorioamnionitis (13 studies, OR 0.75, 95% CI 0.47-1.18, p = 0.211) nor SGA (17 studies, OR 1.20, 95% CI 0.96-1.50, p = 0.115) were significantly associated with the response to therapy. Subgroup analyses showed that the higher response to COX inhibitors in the HDP group was significant for indomethacin (OR 1.568, 95% CI 1.147-2.141, p = 0.005) but not for ibuprofen (OR 1.107, 95% CI 0.248-4.392, p = 0.894) or for the studies using both drugs (OR 1.280, 95% CI 0.935-1.751, p = 0.124). However, meta-regression showed that this difference between the drugs was not statistically significant (p = 0.404).

Discussion/Conclusion

Our data suggest that the pathologic condition that triggers prematurity may alter the response to pharmacological treatment of PDA. The DA of infants exposed to HDP appears to be more responsive to COX inhibitors.

Association of patent ductus arteriosus with fetal factors and endotypes of prematurity

During fetal life, the ductus arteriosus (DA) acquires the mechanisms for its postnatal closure following a thorough developmental program. This program can be interrupted by preterm birth and is also susceptible to alteration during fetal life by numerous physiological and pathological stimuli. In this review, we aim to summarize the evidence on how physiological and pathological factors affect DA development, eventually leading to patent DA (PDA). Specifically, we reviewed the associations of sex, race, and pathophysiological pathways leading to very preterm birth (endotypes) with PDA incidence and pharmacological closure. Summary of evidence suggests that there are no male-female differences in the incidence of PDA among very preterm infants. In contrast, risk of developing PDA appears to be higher in infants exposed to chorioamnionitis or who are small for gestational age. Finally, hypertensive disorders of pregnancy may be associated with a better response to pharmacological treatment of PDA. All of this evidence comes from observational studies and therefore associations do not imply causation. The current trend for many neonatologists is to wait for the natural evolution of preterm PDA. Continued research is needed to identify which fetal and perinatal factors modulate the eventual late closure of PDA in very and extremely preterm infants.

Consequences of early-onset preeclampsia on neonatal morbidity and mortality

Preterm birth is the leading cause of perinatal morbidity and mortality in developed countries. Common reasons for indicated preterm births include pre-eclampsia. The increase in incidences of morbidity and mortality observed in neonates resulting from pregnancies complicated by preeclampsia is also due to alterations in angiogenic and pro-inflammatory factors that directly affect the neonatal health. This review was prepared with the aim of gathering the information available at PubMed/MEDLINE, in the years from 2011 to 2021, on the consequences of neonatal morbidity and mortality of early-onset preeclampsia. There is great controversy in the literature and paucity of studies. Early onset pre-eclampsia has been linked to fetal growth restriction (FGR). Most studies support its association with respiratory distress syndrome (RDS). Most studies point to an association between preeclampsia and bronchopulmonary dysplasia (BPD), with the highest risk in FGR. The association between preeclampsia, patent ductus arteriosus (PDA) and sepsis is not supported by the literature. The association to necrotizing enterocolitis (NEC) is controversial. The risk of spontaneous intestinal perforation (SIP) seems to be increased with preeclampsia. The association between intraventricular hemorrhage (IVH) and preeclampsia is controversial, however, preeclampsia seems to have a protective effect on periventricular leukomalacia (PVL). Most of the evidence points to the non-association between preeclampsia and retinopathy of prematurity (ROP). Hematological changes such as neutropenia, thrombocytopenia and increased nucleated red blood cell counts have been shown to be associated with preeclampsia. The evidence is still quite controversial regarding mortality. The early installation of preeclampsia will have direct consequences on neonatal morbidity. Gestational age at preterm birth is the main risk factor on neonatal morbidity. Obstetricians should aim to prolong the pregnancies complicated by early-onset severe preeclampsia as far as maternal conditions allow. This policy may contribute to improve the neonatal outcomes.

Neonatal outcomes of twins <29 weeks gestation of mothers with hypertensive disorders of pregnancy

BACKGROUND

Hypertensive disorders of pregnancy (HDP) are associated with dysfunctional placentation and are a major cause of maternal and neonatal morbidity and mortality. Twin pregnancies have a larger placental mass and are a risk factor for HDP. The effect of HDP on neonatal outcomes in twin pregnancies is unknown.

METHODS

Retrospective cohort study using the Canadian Neonatal Network database from 2010-2018 of twin infants <29 weeks gestation born to mothers with HDP and normotensive pregnancies. Using multivariable models, we determined adjusted odds ratios (AORs) and 95% confidence intervals (CI) for mortality, bronchopulmonary dysplasia, severe neurologic injury, severe retinopathy of prematurity (ROP), necrotizing enterocolitis, and nosocomial infection in twin infants of mothers with HDP compared to twin infants of normotensive mothers.

RESULTS

Of the 2414 eligible twin infants <29 weeks gestational age, 164 (6.8%) were born to mothers with HDP and had higher odds of severe ROP (AOR 2.48, 95% CI 1.34-4.59). Preterm twin infants born to mothers with HDP also had higher odds of mortality (AOR 2.02, 95% CI 1.23-3.32). There was no difference in other outcomes.

CONCLUSION

Preterm twin infants <29 weeks gestation of HDP mothers have higher odds of severe ROP and mortality.

IMPACT

Hypertensive disorders of pregnancy, associated with placental dysfunction, are a major cause of maternal and neonatal morbidity and mortality. Twin pregnancy, associated with a larger placental mass, is a risk factor for hypertensive disorders of pregnancy. The effect of hypertensive disorders of pregnancy on outcomes of preterm twins is unknown. Preterm twins of mothers with hypertensive disorders of pregnancy are at higher risk of severe retinopathy of prematurity and mortality. Our data can be used to counsel parents and identify infants at higher risk of severe retinopathy of prematurity and mortality.

Incidence and Characteristics of Retinopathy of Prematurity Patients With Late Gestational Age and Large Birth Weight in South China

Purpose

To investigate the incidence and characteristics of retinopathy of prematurity (ROP) premature infants with late gestational age (GA) and large birth weight (BW) and show a 7-year trend of ROP incidence in South China.

Methods

This retrospective, cross-sectional study included premature infants who received ROP screening in a 7-year period (from 2010 to 2016) at the Sun Yat-sen Memorial Hospital (SYSMH), Guangzhou, South China. Infants were screened if they had GA <37 weeks or BW <2,500 g. All screened infants were divided into two groups: Group 1 (with both GA ≥ 35 weeks and BW ≥ 1,750 g) and Group 2 (others). The characteristics of ROP infants in Group 1 were analyzed and compared with those in Group 2.

Results

A total of 911 premature infants were screened, with 282 infants in Group 1 and 629 in Group 2. Both the incidences of any ROP (6.7 vs. 8.3%, p = 0.50) and Type 1 ROP (1.4 vs. 1.7%, p = 0.72) in Group 1 were comparable with those in Group 2. Lower proportions of respiratory distress (15.8 vs. 71.2%, p < 0.001), blood transfusion (5.3 vs. 32.7%, p = 0.028), and oxygen administration (31.6 vs. 86.5%, p < 0.001) among ROP patients in Group 1 than those in Group 2 were revealed. Vaginal delivery [OR: 4.73 (1.83–12.26)] was identified as a factor associated with ROP among the infants in Group 1. Forty percent (6/15) of Type 1 ROP in this study would have been missed under the current screening criteria in China (GA ≤ 34 weeks and/or BW ≤ 2,000 g). Trends of increased incidence of Type 1 ROP and decreased BW were exhibited in the 7-year study period.

Conclusions

These findings indicate that even the premature infants with late GA and large BW also have a high risk of developing ROP, especially for those delivered by vagina. The findings may provide a significant reference for ROP screening and neonatal care in South China and other regions with similar conditions.

Pregnancy-induced hypertension and retinopathy of prematurity: a meta-analysis

PURPOSE

Retinopathy of prematurity (ROP), one of the leading causes of childhood blindness, is a complex condition in which various antenatal and neonatal factors participate at different stages of the disease. This meta-analysis was conducted to investigate whether pregnancy-induced hypertension (PIH) was associated with ROP by summarizing all available evidence.

METHODS

PubMed, EMBASE, Web of Science, EBSCO and SCOPUS databases were searched for all relevant studies published from inception to April 2020. Studies investigating the association between PIH and ROP were included.

RESULTS

A total of 29 studies were finally included for the meta-analysis after study selection. The results showed there are both no significant association between PIH and the occurrence of ROP in case-control studies (OR 0.91, 95%CI 0.59 to 1.40, I²  = 81%, p = 0.67) and cohort studies (OR 1.32, 95%CI 0.89 to 1.98, I²  = 93%, p = 0.17). The conclusion was same between pre-eclampsia and ROP (OR 0.82, 95%CI: 0.50 to 1.35, I²  = 83%, p = 0.43 in case-control studies and OR 1.70, 95%CI: 0.82 to 3.50, I²  = 95%, p = 0.15 in cohort studies).

CONCLUSION

In summary, this meta-analysis did not reveal a consistent result, the conclusion remains inconclusive, and further studies will be needed to come to a conclusion for the effect of maternal PIH on ROP and foster a better understanding of the prevention of ROP.

Retinopathy prematurity: a systematic review and meta-analysis study based on neonatal and maternal risk factors

BACKGROUND

Retinopathy of prematurity is the abnormal development of retinal arteries in preterm neonates less than 32 weeks and weighing 1500 g, and less, which can lead to visual impairment during life and blindness. This study aims to investigate the relationship between some clinical characteristics of neonates and mothers with Retinopathy of prematurity in the world via a systematic review and meta-analysis.

MATERIALS AND METHODS

The present study is a systematic review and meta-analysis on the relationship between maternal and neonatal clinical variables with Retinopathy of prematurity in the world from the beginning of 2000 to the end of 2020. Accordingly, all English articles published on the topic were searched in scientific databases of Web of Science, PubMed, Google Scholar, Science Direct, and Scopus. The articles were searched independently by two researchers. Statistical analysis of data was performed using fixed and random effects model statistical tests in the meta-analysis, Cochran, meta-regression, I² index, Funnel plot, and Begg's by STATA software program, version 14.

RESULT

A total of 191 studies with a sample size of 140,921 persons were including in the meta-analysis. Accordingly, Preterm delivery ≤28 weeks (OR:6.3, 95% CI:4.9-8.1), Birth Weight ≤1000 g (OR:5.8, 95% CI:4.8-6.8), Birth Weight ≤1500 g (OR:4.8, 95% CI:3.8-6.1), PROM (OR:1.2, 95% CI:1.0-1.4), induced fertility (OR:1.9, 95% CI:1.1-3.0) and Chorioamnionitis (OR:1.5, 95% CI:1.0-2.2) There was a statistically significant association with retinopathy.

CONCLUSION

Based on the results of the present meta-analysis, the risk of retinopathy of prematurity in neonates born at 28 weeks and less, LBW (weight 1500 g and less), neonatal hypotension, chorioamnionitis, and induced fertility increases.

Ocular findings and growth in 5-year-old preterm children born to mothers with preeclampsia

PURPOSE

To evaluate growth, blood pressure and ophthalmological status in preschool children born preterm to mothers with preeclampsia.

METHODS

In a prospective cohort study, 78 children (34 girls) born preterm without retinopathy of prematurity were examined regarding length/height, weight, head circumference and insulin-like growth factor I (IGF-I) at birth and at 5 years of age. At 5 years, IGF-binding protein 3 and blood pressure were also measured. A detailed ophthalmological examination including ocular dimensions, fundus morphology, visual fields, visual evoked potentials and perceptual visual dysfunction was performed. Children born to preeclamptic mothers (n = 24) were compared to children with non-preeclamptic mothers (n = 54).

RESULTS

Children exposed to preeclampsia had lower weight (p = 0.0002, mean difference -1.46, 95% CI -2.09; -0.83), length (p = 0.013, -1.10, 95% CI -1.92; -0.23) and IGF-I levels (p = 0.0002, -26.0, 95% CI -36.0; -16.1) at birth compared to non-exposed children. At 5 years of age, the preeclamptic group had larger optic cup areas (p = 0.0006, 0.32, 95% CI 0.15; 0.46, in right eye, p = 0.049, 0.18, 95% CI 0.001; 0.35, in left eye). There was no significant difference between the groups regarding other ophthalmological findings or blood pressure. Children with reduced eye motility had lower neonatal IGF-I levels (p = 0.033, 15.5, 95% CI 1.1; 30.3).

CONCLUSION

Preeclampsia was shown to affect growth and IGF-I levels, confirming previous studies. Children exposed to preeclampsia were shown to have larger optic cup areas. Furthermore, lower neonatal IGF-I levels were seen in preterm children with reduced eye motility at 5 years of age.

Effect of red blood cell transfusion on the development of retinopathy of prematurity: A systematic review and meta-analysis

BACKGROUND

The effect of red blood cell (RBC) transfusion on retinopathy of prematurity (ROP) is difficult to establish, because ROP may also be influenced by other factors. Therefore, we carried out a systematic review and meta-analysis to explore the relationship between RBC transfusion and the development of ROP.

METHODS

The PubMed, Embase, Cochrane Library and Web of Science databases were searched from their inception to September 1, 2019. Observational studies that reported the relationship between RBC transfusion and ROP after adjusting for other potential risk factors were included. The combined result was analyzed by a random effect model. Heterogeneity and publication bias were tested, and sensitivity analysis was performed.

RESULTS

Of the 2628 identified records, 18 studies including 15072 preterm infants and 5620 cases of ROP were included. A random effect model was used and revealed that RBC transfusion was significantly associated with ROP (pooled OR = 1.50, 95% CI: 1.27-1.76), with moderate heterogeneity among the included studies (I2 = 44.2%). Subgroup analysis indicated that RBC transfusion was more closely related to ROP in the group with a gestational age (GA) ≤32 weeks (OR = 1.77, 95% CI: 1.29-2.43) but not in the groups with a GA ≤34 weeks (OR = 1.36, 95% CI: 0.85-2.18) or a GA <37 weeks (OR = 1.25, 95% CI: 0.86-1.82). No obvious publication bias was found based on the funnel plot and Egger's test. Removing any single study did not significantly alter the combined result in the sensitivity analysis.

CONCLUSIONS

Our study revealed that RBC transfusion is an independent risk factor for the development of ROP, especially in younger preterm infants. However, there seemed to be no evidence to support an effect of RBC transfusion on ROP in older groups. Further studies addressing this issue in older preterm neonates are warranted.

Current evidence and outcomes for retinopathy of prematurity prevention: insight into novel maternal and placental contributions

Retinopathy of prematurity (ROP) is a blinding morbidity of preterm infants, which represents a significant clinical problem, accounting for up to 40% of all childhood blindness. ROP displays a range of severity, though even mild disease may result in life-long visual impairment. This is complicated by the fact that our current treatments have significant ocular and potentially systemic effects. Therefore, disease prevention is desperately needed to mitigate the life-long deleterious effects of ROP for preterm infants. Although ROP demonstrates a delayed onset of retinal disease following preterm birth, representing a potential window for prevention, we have been unable to sufficiently alter the natural disease course and meaningfully prevent ROP. Prevention therapeutics requires knowledge of early ROP molecular changes and risk, occurring prior to clinical retinal disease. While we still have an incomplete understanding of these disease mechanisms, emerging data integrating contributions of maternal/placental pathobiology with ROP are poised to inform novel approaches to prevention. Herein, we review the molecular basis for current prevention strategies and the clinical outcomes of these interventions. We also discuss how insights into early ROP pathophysiology may be gained by a better understanding of maternal and placental factors playing a role in preterm birth.

Cumulative evidence for association of sepsis and retinopathy of prematurity

BACKGROUND

Retinopathy of prematurity (ROP) is a retinal vasoproliferative disease affected by multiple factors such as infection and preterm birth. The role of sepsis in the development of ROP remains controversial. This systematic review and meta-analysis aimed to identify the impact of sepsis on ROP.

METHODS

The PubMed, Embase, and Cochrane Library databases were searched using terms related to sepsis and ROP. Cohort or case-control studies that reported the association of sepsis and ROP were eligible. The odds ratios (ORs) together with the 95% confidence interval (CI) were extracted from the studies or computed by authors if not provided.

RESULTS

Thirty-four studies were ultimately included in this meta-analysis. The pooled results showed that sepsis increased the risk for the development of any stage ROP (OR = 2.16; 95% CI: 1.65-2.82). Both early onset (OR = 2.50; 95% CI: 1.97-3.18) and late-onset (OR = 1.37; 95% CI: 1.22-1.55) sepsis were associated with severe ROP. Furthermore, both bacterial sepsis (OR = 1.74; 95% CI: 1.21-2.50) and fungal sepsis (OR = 2.96; 95% CI: 2.05-4.28) were also found to be associated with severe ROP.

CONCLUSION

Sepsis increased the risk of any stage ROP, especially for the severe ROP. Further high-quality clinical studies are needed to eliminate heterogeneity and publication bias to validate these findings.

Outcomes of singleton small for gestational age preterm infants exposed to maternal hypertension: a retrospective cohort study

BACKGROUND

Hypertensive disorders of pregnancy (HDP) are a major cause of small for gestational age (SGA). Preterm SGA infants have higher rates of adverse outcomes than appropriate for gestational age infants. However, the outcomes are not well established in the setting of HDP.

METHODS

Retrospective population-based study using the Canadian Neonatal Network database from January 1, 2010 to December 31, 2016 of SGA infants <33 weeks gestation. Using multivariable models, we determined the adjusted odds ratios (AORs) with 95% confidence intervals (CI) for mortality, bronchopulmonary dysplasia (BPD), severe intraventricular hemorrhage (IVH), severe retinopathy of prematurity, necrotizing enterocolitis, late-onset sepsis, and patent ductus arteriosus (PDA) in infants of HDP mothers and compared them to infants of non-HDP mothers.

RESULTS

Of the 2081 eligible SGA infants, 1317 (63%) were born to HDP mothers and had lower odds of mortality (AOR 0.57, 95% CI 0.39-0.83) and BPD (AOR 0.69, 95% CI 0.53-0.90). Sub-group analysis demonstrated decreased mortality in 26-28 and 29-32 weeks gestation groups, decreased BPD in 29-32 weeks gestation group, and decreased PDA in <26 weeks gestation group.

CONCLUSION

Preterm SGA infants of HDP mothers have lower odds of mortality and BPD compared to infants of non-HDP mothers.

Association between sepsis and retinopathy of prematurity: a systematic review and meta-analysis

OBJECTIVE

To explore the association between sepsis and retinopathy of prematurity (ROP) in premature infants.

DESIGN

A systematic review and meta-analysis.

DATA SOURCES

We performed a systematic search of PubMed, the Cochrane Library and Embase from 1 January, 2000, to 1 January, 2018, with no language restrictions and reported the relationship between sepsis and ROP.

ELIGIBILITY CRITERIA

Original observational studies, including cohort studies and case-control studies.

DATA EXTRACTION AND SYNTHESIS

Two reviewers independently completed the study selection and data extraction. The OR and corresponding 95% CI were used to measure the risk of sepsis in patients with ROP. The heterogeneity between studies was evaluated using Cochran's Q test and the I2 statistic. The Newcastle-Ottawa Scale was adopted to evaluate the quality of each of the included studies, and the Grading of Recommendations Assessment, Development and Evaluation approach was used to assess the quality of the evidence.

RESULTS

Sixteen studies with a total sample size of 12 466 premature infants and 2494 cases of ROP were included in this meta-analysis. Adjusted analysis showed that sepsis was closely related to any stage of ROP (OR = 1.57, 95% CI 1.31 to 1.89) and severe stage of ROP (OR = 2.33, 95% CI 1.21 to 4.51) in premature infants, with 56.3% and 81.8% heterogeneity, respectively. Subgroup analyses showed that heterogeneity was obvious in prospective cohort studies (I2 = 62.1%, p<0.001). In a sensitivity analysis, we found that removing any single study did not significantly change the overall effect value. The quality of the evidence was rated as low for both any stage of ROP and severe stage of ROP.

CONCLUSIONS

Sepsis increases the risk of ROP in preterm infants. However, considering that all included studies are observational and causality can rarely be established, additional evidence is needed to substantiate this finding and provide advice for practice.

Extreme prematurity, treated retinopathy, bronchopulmonary dysplasia and cerebral palsy are significant risk factors for ophthalmological abnormalities at 6.5 years of age

AIM

This study evaluated the contributions of various prenatal and postnatal predictive factors to a documented high prevalence of ophthalmological abnormalities in children aged 6.5 years who were born extremely preterm.

METHODS

We carried out a prospective population-based study of all children born in Sweden at a gestational age of 22 + 0 to 26 + 6 weeks based on the Extremely Preterm Infants in Sweden Study. The main outcome measures were a combined score of visual impairment, refractive errors and strabismus at 6.5 years of age. Models of univariate and multivariable regression were used to analyse potential prenatal and postnatal predictive factors at different clinically relevant time-points from one minute after birth to 30 months.

RESULTS

We focused on 399 known extremely preterm survivors and compared them to 300 full-term controls. Significant antecedents for ophthalmological abnormalities included prematurity per se, retinopathy of prematurity that required treatment, severe bronchopulmonary dysplasia and cerebral palsy. Severe intraventricular haemorrhage was no longer a significant risk factor when we adjusted it for the 30-month cognitive and neuromotor development outcomes.

CONCLUSION

This time-course risk analysis model showed a changing panorama of significant risk factors for ophthalmological abnormalities in children aged 6.5 years who were born extremely preterm.

Retinopathy of prematurity: a review of risk factors and their clinical significance

Retinopathy of prematurity (ROP) is a retinal vasoproliferative disease that affects premature infants. Despite improvements in neonatal care and management guidelines, ROP remains a leading cause of childhood blindness worldwide. Current screening guidelines are primarily based on two risk factors: birth weight and gestational age; however, many investigators have suggested other risk factors, including maternal factors, prenatal and perinatal factors, demographics, medical interventions, comorbidities of prematurity, nutrition, and genetic factors. We review the existing literature addressing various possible ROP risk factors. Although there have been contradictory reports, and the risk may vary between different populations, understanding ROP risk factors is essential to develop predictive models, to gain insights into pathophysiology of retinal vascular diseases and diseases of prematurity, and to determine future directions in management of and research in ROP.

Maternal pre-eclampsia and long-term offspring health: Is there a shadow cast?

Pre-eclampsia is a common pregnancy disorder with important short-term complications for mother and baby. Evidence suggests pre-eclampsia also has implications for the mother beyond pregnancy, as well as long-term effects on offspring health. Limited research has linked pre-eclampsia with changes in offspring blood pressure, BMI, and stroke risk. Underpinning mechanisms are poorly understood, but developmental programming may be involved. Research in this area has been hindered by difficulties in defining pre-eclampsia and problems with study design. Further targeted evaluation through to adulthood is required to determine the long-term impact of pre-eclampsia on offspring disease risk and how this develops.

Pregnancy-induced hypertension and neonatal outcomes: a systematic review and meta-analysis

OBJECTIVE

Pregnancy-induced hypertension (PIH) is associated with preterm delivery but its independent impact on neonatal outcomes remains unclear. We sought to systematically review and meta-analyze clinical outcomes of preterm infants <37 weeks' gestation born to mothers with and without PIH.

STUDY DESIGN

Medline, Embase, PsychINFO and CINAHL were searched from January 2000 to October 2016. Studies with low-moderate risk of bias reporting neonatal outcomes based on PIH as primary exposure variable were included. Data were extracted independently by two co-authors.

RESULTS

PIH was associated with lower mortality (3 studies; adjusted odds ratio (aOR) 0.65; 95% confidence interval (CI) 0.54 to 0.79), lower severe retinopathy of prematurity (ROP) (2 studies; aOR 0.83; 0.72 to 0.96) and lower severe brain injury (2 studies; unadjusted OR (uOR) 0.57; 0.49 to 0.66). No association between PIH and short-term respiratory outcomes, bronchopulmonary dysplasia (BPD) or necrotizing enterocolitis (NEC) was identified. In subgroup analysis among infants <29 weeks' gestation, BPD odds were higher (3 studies; aOR 1.15; 1.06 to 1.26), whereas mortality lower (2 studies; aOR 0.73; 0.69 to 0.77). In subgroup analysis limited to severe PIH, odds of mortality (3 studies; uOR 2.36; 1.07 to 5.22) and invasive ventilation (3 studies; uOR 3.26; 1.11 to 9.61) were higher. In subgroup analysis limited to preeclampsia, odds of BPD (3 studies; uOR 1.21; 95% CI:1.03 to 1.43) and NEC were higher (3 studies; uOR 2.79; 95% CI:1.57 to 4.96).

CONCLUSION

PIH was associated with reduced odds of mortality and ROP (all infants), but higher odds for BPD (<29 weeks' gestation). The paradoxical reduction in mortality may be due to survival bias and deserves further exploration in future studies.

Pre-eclampsia and the risk of retinopathy of prematurity in preterm infants with birth weight <1500 g and/or <31 weeks' gestation

Objective

To evaluate the relationship between pre-eclampsia and development of retinopathy of prematurity (ROP) in infants with birth weight of <1500 g and/or gestation <31 weeks.

Methods

A retrospective cohort study comprising infants born to mothers with pre-eclampsia between January 2007 and June 2010 at a single tertiary care centre. Their ROP outcome was compared with infants born to the next two normotensive mothers with a ±1 week gestational age difference. Pearson χ² test was used for categorical variables and Mann-Whitney U test was used for continuous variables. Multivariable regression was used to estimate the OR of ROP with prenatal pre-eclampsia exposure and adjust for confounders.

Results

Of the 97 infants in the pre-eclampsia group, 27 (27%) developed ROP and of the 185 infants in the normotensive group, 50 (27%) developed ROP. On multivariable regression modelling, pre-eclampsia was not a risk factor for the development of ROP (OR 1.4, 95% CI 0.46 to 4.1). Gestational age, intrauterine growth restriction and blood transfusion were significant risk factors for the development of ROP.

Conclusions

In our cohort, pre-eclampsia was not a significant risk factor for the development of ROP. Intrauterine growth restricted infants of pre-eclamptic and normotensive mothers were at higher risk of ROP.

Role of cytokines and treatment algorithms in retinopathy of prematurity

PURPOSE OF REVIEW

Currently, severe retinopathy of prematurity (ROP) is diagnosed by clinical evaluation and not a laboratory test. Laser is still considered standard care. However, anti-vascular endothelial growth factor (VEGF) agents are being used and there are questions whether and/or if to use them, what dose or type of agent should be considered and what agent may be most beneficial in specific cases. Also unclear are the effects of laser or anti-VEGF on severe ROP, refractive outcomes or infant development. This article reviews recent studies related to these questions and other trials for severe ROP.

RECENT FINDINGS

Imaging studies identify biomarkers of risk (plus disease, stage 3 ROP, and ROP in zone I). Intravitreal bevacizumab or ranibizumab are reported effective in treating aggressive posterior ROP in small series. Recurrences and effects on myopia vary among studies. Use of anti-VEGF agents affects cytokines in the infant blood and reduces systemic VEGF for up to 2 months, raising potential safety concerns. The effects of treatment vary based on infant size and are not comparable. Evidence for most studies is not high.

SUMMARY

Studies support experimental evidence that inhibiting VEGF reduces stage 3 ROP and peripheral avascular retina. Ongoing large-scale clinical trials may provide clarity for best treatments of severe ROP. Current guidelines hold for screening and treatment for type 1 ROP.

Association of maternal hypertensive disorders with retinopathy of prematurity: A systematic review and meta-analysis

BACKGROUD

The role of maternal hypertensive disorders in pregnancy (HDP) in the development of retinopathy of prematurity (ROP) is unclear.

METHODS

Studies were retrieved through literature searches in PubMed, EMBASE, Web of Science and the Cochrane Library up to May 5, 2016 without language restrictions. Cohort or case-control studies that reported the association of maternal hypertensive disorders and retinopathy of prematurity were eligible. Either a fixed- or a random-effects model was used to calculate the overall combined risk estimates.

RESULTS

Thirteen cohort studies involving a total of 45082 individuals were included in the review. The pooled odds ratios of maternal hypertensive disorders in pregnancy for any stage and severe stages of ROP was 1.12 (95%CI: 0.90-1.40) and 0.80 (95%CI: 0.47-1.35), respectively. Sensitivity analyses confirmed that no single study qualitatively influenced the pooled OR. However, substantial heterogeneity and publication bias were observed in the meta-analysis.

CONCLUSIONS

Additional larger, prospective and well-adjusted studies are needed to determine the association between HDP and ROP, especially regarding the effects of different types of maternal hypertensive disorders in pregnancy on retinopathy of prematurity.

Association of Gestational Hypertensive Disorders with Retinopathy of prematurity: A Systematic Review and Meta-analysis

The role of gestational hypertensive disorders, which includes both pre-eclampsia and gestational hypertension, in the development of retinopathy of prematurity (ROP) has been controversial. Therefore, this systematic review and meta-analysis is to evaluate the association between gestational hypertensive disoders and ROP. Eligible studies published up to June 5, 2016 were identified from MEDLINE and EMBASE that evaluated the association between the two conditions. Totally 1142 published records were retrieved for screening, 925 of them eligible for detailed evaluation. Finally 19 studies involving 45281 infants with 5388 cases of ROP met our criteria for meta-analysis. Gestational hypertensive disorders were not associated with ROP (unadjusted OR: 0.89; P = 0.38; adjusted OR: 1.35; P = 0.18). Subgroup analyses also revealed no significant association between ROP with pre-eclampsia (unadjusted OR: 0.85; P = 0.29; adjusted OR:1.29; P = 0.28) or with gestational hypertension (unadjusted OR: 1.10; P = 0.39; adjusted OR: 1.25; P = 0.60) separately. Sensitivity analysis indicated our results were robust. We concluded no significant association between gestational hypertensive disorders and ROP. More large scale well-conducted prospective cohorts on the topic are needed.