Retinopathy of prematurity in small-for-gestational age infants compared with those of appropriate size for gestational age

Retinopathy of Prematurity-Targeting Hypoxic and Redox Signaling Pathways

Retinopathy of prematurity (ROP) is a proliferative vascular ailment affecting the retina. It is the main risk factor for visual impairment and blindness in infants and young children worldwide. If left undiagnosed and untreated, it can progress to retinal detachment and severe visual impairment. Geographical variations in ROP epidemiology have emerged over recent decades, attributable to differing levels of care provided to preterm infants across countries and regions. Our understanding of the causes of ROP, screening, diagnosis, treatment, and associated risk factors continues to advance. This review article aims to present the pathophysiological mechanisms of ROP, including its treatment. Specifically, it delves into the latest cutting-edge treatment approaches targeting hypoxia and redox signaling pathways for this condition.

Association between fetal growth-restriction and retinopathy of prematurity using a unique identical twin model

BACKGROUND

Research in singletons identified fetal growth restriction (FGR) as a risk factor for retinopathy of prematurity (ROP), but is generally subject to confounding by genetic, obstetric, and maternal factors. We investigated the effect of FGR on ROP in growth-discordant identical twins, thereby controlling for confounding factors.

METHODS

All data of monochorionic (MC) twin pairs with a birth weight discordance ≥20% born in our center between 2010 and 2021 were retrospectively reviewed for the presence of ROP. Potential risk factors for ROP were analyzed. Outcomes were compared between the smaller and larger twin.

RESULTS

We included 88 MC twin pairs with growth discordance. In 34% (30/88), both neonates were at risk of ROP. Prevalence of ROP was higher among the smaller twin compared to the larger twin, 30% (9/30) versus 13% (4/30), respectively (OR 2.8, 95% CI: 1.2-6.6). The smaller twin had a longer duration of mechanical ventilation (8 (1-20) versus 2 (1-4) days) and received their first red blood cell transfusion at an earlier postmenstrual age (29.6 (28.1-31.6) versus 30.4 (29.7-32.6) weeks).

CONCLUSIONS

In this identical twin model, FGR is associated with almost tripled odds of ROP development, suggesting that both unfavorable antenatal growth conditions and adverse neonatal outcomes affect postnatal retinal vascular proliferation.

IMPACT

Fetal growth restriction in growth-discordant identical twins is associated with almost tripled odds of developing retinopathy of prematurity in the smaller twin. Since these twins do not only differ in birth weight but also duration of mechanical ventilation and timing of the first red blood cell transfusion, both unfavorable antenatal growth conditions and adverse neonatal outcomes can affect postnatal retinal vascular proliferation. More attention for preventing retinopathy of prematurity is needed in those with fetal growth restriction who received prolonged duration of mechanical ventilation, oxygen supplementation, or a first red blood cell transfusion <32 weeks postmenstrual age.

Development and Validation of a Deep Learning Model to Predict the Occurrence and Severity of Retinopathy of Prematurity

Importance

Retinopathy of prematurity (ROP) is the leading cause of childhood blindness worldwide. Prediction of ROP before onset holds great promise for reducing the risk of blindness.

Objective

To develop and validate a deep learning (DL) system to predict the occurrence and severity of ROP before 45 weeks' postmenstrual age.

Design, Setting, and Participants

This retrospective prognostic study included 7033 retinal photographs of 725 infants in the training set and 763 retinal photographs of 90 infants in the external validation set, along with 46 characteristics for each infant. All images of both eyes from the same infant taken at the first screening were labeled according to the final diagnosis made between the first screening and 45 weeks' postmenstrual age. The DL system was developed using retinal photographs from the first ROP screening and clinical characteristics before or at the first screening in infants born between June 3, 2017, and August 28, 2019.

Exposures

Two models were specifically designed for predictions of the occurrence (occurrence network [OC-Net]) and severity (severity network [SE-Net]) of ROP. Five-fold cross-validation was applied for internal validation.

Main Outcomes and Measures

Area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, and specificity to evaluate the performance in ROP prediction.

Results

This study included 815 infants (450 [55.2%] boys) with mean birth weight of 1.91 kg (95% CI, 1.87-1.95 kg) and mean gestational age of 33.1 weeks (95% CI, 32.9-33.3 weeks). In internal validation, mean AUC, accuracy, sensitivity, and specificity were 0.90 (95% CI, 0.88-0.92), 52.8% (95% CI, 49.2%-56.4%), 100% (95% CI, 97.4%-100%), and 37.8% (95% CI, 33.7%-42.1%), respectively, for OC-Net to predict ROP occurrence and 0.87 (95% CI, 0.82-0.91), 68.0% (95% CI, 61.2%-74.8%), 100% (95% CI, 93.2%-100%), and 46.6% (95% CI, 37.3%-56.0%), respectively, for SE-Net to predict severe ROP. In external validation, the AUC, accuracy, sensitivity, and specificity were 0.94, 33.3%, 100%, and 7.5%, respectively, for OC-Net, and 0.88, 56.0%, 100%, and 35.3%, respectively, for SE-Net.

Conclusions and Relevance

In this study, the DL system achieved promising accuracy in ROP prediction. This DL system is potentially useful in identifying infants with high risk of developing ROP.

Incidence of retinopathy of prematurity treatment in extremely preterm infants in China

BACKGROUND

Retinopathy of prematurity (ROP) continues to be a major cause of visual impairment and blindness in premature infants and children.

OBJECTIVES

To investigate the incidence of severe ROP receiving treatment in extremely preterm (EP) infants in China over time. The risk factors for ROP treatment were also assessed.

METHODS

This was a multicentre retrospective study and a subanalysis of baseline data from the "Outcomes of EP infants in China 2010-2019" study. This study was conducted in 68 tertiary neonatal care centres from 31 provinces of China. Infants with a gestational age of 23⁰ -27⁶  weeks and admitted to a neonatal unit within the first 72 h of life between 2010 and 2019 were enrolled. Incidence of ROP was analysed in infants who survived to 32 weeks postmenstrual age and screened for ROP. Multivariable modified Poisson regression models were used to identify risk factors for ROP treatment.

RESULTS

Among 7295 eligible infants, 4701 (64.5%) survived to 32 weeks postmenstrual age and met ROP screening criteria. Of the 3756 infants who screened and with ROP data, 2320 (61.8%) developed ROP of any stage. The overall incidence of ROP treatment was 12.6%, decreasing from 45.5% at 23 weeks to 8.3% at 27 weeks. During the 10-year period, the incidence of ROP treatment did not change, although the incidence of any ROP increased over time. Independent risk factors associated with ROP treatment included lower gestational age, small for gestational age, multiple birth, severe intraventricular haemorrhage, patent ductus arteriosus and supplemental oxygen duration.

CONCLUSIONS

The incidence of EP infants receiving ROP treatment showed no change during this 10-year period in China. Prevention of prematurity and foetal growth restriction, judicious use of oxygen and reducing comorbidities are promising factors that may reduce the incidence of ROP needing treatment in these high-risk infants.

Delayed cord clamping in small for gestational age preterm infants

BACKGROUND

Infants with restricted growth for age are frequently exposed to insufficient placental circulation and are more likely to develop postnatal complications. Delayed cord clamping at birth for these infants requires further exploration.

OBJECTIVE

This study aimed to compare the short-term neonatal outcomes of delayed cord clamping with that of early cord clamping in small for gestational age preterm infants and to explore whether the effects of delayed cord clamping in small for gestational age preterm infants are different from that in non-small for gestational age preterm infants.

STUDY DESIGN

We conducted a national retrospective cohort study, including infants born at <33 weeks' gestation and admitted to the Canadian Neonatal Network units between January 2015 and December 2017. Small for gestational age infants (birthweight of <10th percentile for gestational age and sex) who received delayed cord clamping ≥30 seconds were compared with those who received early cord clamping. In addition, non-small for gestational age infants who received delayed cord clamping were compared with those who received early cord clamping. The main study outcomes included composite outcome of mortality or major morbidity, neonatal morbidity rate, mortality rate, peak serum bilirubin, and number of blood transfusions. Multivariable logistic and linear regression models with a generalized estimation equation approach were used to account for the clustering of infants within centers.

RESULTS

Overall, 9722 infants met the inclusion criteria. Of those infants, 1027 (10.6%) were small for gestational age. The median (interquartile range) gestational age was 31 weeks (range, 28-32 weeks). After adjusting for potential confounders, delayed cord clamping in small for gestational age infants was associated with a reduction in the composite outcome of mortality or major morbidity (adjusted odds ratio, 0.60; 95% confidence interval, 0.42-0.86) compared with early cord clamping. There was no difference between the 2 groups in peak serum bilirubin. Many associated benefits of delayed cord clamping in small for gestational age infants were similar to those in non-small for gestational age infants.

CONCLUSION

Delayed cord clamping in small for gestational age preterm infants was associated with decreased odds of mortality or major morbidity. Many of the benefits of delayed cord clamping in the small for gestational age preterm infants were similar to those identified in the non-small for gestational age preterm infants.

Incidence and Risk Factors for Retinopathy of Prematurity (ROP) in Biggest Neonatal Intensive Care Unit in Itay Elbaroud City, Behera Province, Egypt

Aim of the Work

To evaluate the incidence and risk factors for development of retinopathy of prematurity (ROP) in the biggest neonatal intensive care unit (NICU) in Itay Elbaroud City, Behera province, Egypt.

Methods

We studied data of 240 newly born infants with gestational age (GA) ≤34 weeks or birth weight (BW) ≤2000 g or infants with unstable course who were admitted to the biggest NICU in Itay Elbaroud City, Behera province, Egypt, 
between October 1, 2018 and October 31, 2020. There is no standard screening system in Egypt. Furthermore, we had screened babies more than 1500 g, more than 32 weeks and found signs of ROP, so we decided to expand our inclusion criteria to include babies up to 2000 g of birth weight and up to 34 weeks gestational age in addition to older and heavier babies with unstable course in NICUs. Clinical information about perinatal neonates was collected by reviewing medical charts. The main outcomes are the incidence and severity of ROP. The relationship of clinical risk factors and the development of ROP were analyzed.

Results

The overall incidence of ROP was 34.1%, and the overall incidence of type 1 ROP was 26.3% of infants. ROP was significantly associated with GA (odds ratio; OR: 6.8; (3.7–12.3), BW (OR: 4.1; 2.3–7.3), apnea, supplementary oxygen administration, and thrombocytopenia.

Conclusion

The incidence of ROP is high in Itay Elbaroud city, Behera Province, Egypt. Immaturity, low birth weight, low gestational age, oxygen administration, apnea, thrombocytopenia, and jaundice are important risk factors for development of ROP.

Short-term outcomes of Jewish and Arab preterms: a population-based comparison

OBJECTIVE

To compare short-term outcomes of Arabs versus Jewish infants in Israel.

METHODS

We used the Israel national VLBW infant database to compare adjusted mortality and major morbidities rates of Arabs versus Jewish infants delivered between January 1995 and December 2016. Multivariable logistic regression analyses were performed to study the association of ethnicity with the odds for mortality and neonatal morbidities.

RESULTS

The study population comprised 22431 VLBW, very preterm (<32 weeks gestation) infants (27.7% Arabs and 72.3% Jewish) without congenital malformations. The Arab infants had significantly higher odds ratios for mortality, and most neonatal morbidities. Despite the significant decline in mortality over time in both ethnic groups, the difference in mortality rates remained unchanged over time.

CONCLUSIONS

We found significant ethic disparity that remained unchanged over time. Some of the disparities identified in this study may be amenable to improvement through proper policies and education.

Prenatal intrauterine growth restriction and risk of retinopathy of prematurity

Low birthweight and decreased postnatal weight gain are known predictors of worse retinopathy of prematurity (ROP) but the role of prenatal growth patterns in ROP remains inconclusive. To distinguish small for gestational age (SGA) from intrauterine growth restriction (IUGR) as independent predictors of ROP, we performed a retrospective cohort study of patients who received ROP screening examinations at a level IV neonatal intensive care unit over a 7-year period. Data on IUGR and SGA status, worst stage of and need for treatment for ROP, and postnatal growth was obtained. 343 infants were included for analysis (mean gestational age = 28.6 weeks and birth weight = 1138.2 g). IUGR infants were more likely to have a worse stage of ROP and treatment-requiring ROP (both p < 0.0001) compared to non-IUGR infants. IUGR infants were more likely to be older at worst stage of ROP (p < 0.0001) and to develop postnatal growth failure (p = 0.01) than non-IUGR infants. Independent of postnatal growth failure status, IUGR infants had a 4-5 × increased risk of needing ROP treatment (p < 0.001) compared to non-IUGR infants. SGA versus appropriate for gestational age infants did not demonstrate differences in retinopathy outcomes, age at worst ROP stage, or postnatal growth failure. These findings emphasize the importance of prenatal growth on ROP development.

Association of small for gestational age with retinopathy of prematurity: a systematic review and meta-analysis

CONTEXT

The association between small for gestational age (SGA) and retinopathy of prematurity (ROP) is unclear.

OBJECTIVE

A systematic review and meta-analysis was conducted to evaluate the association between ROP and SGA in preterm infants <37 weeks' gestational age (GA) admitted to neonatal intensive care unit.

METHODS

Medline, PubMed, Web of Science and Cochrane Central databases were searched from inception through 15 January 2019. Studies reporting outcomes based on SGA as the primary exposure variable were included. Data were extracted independently by two coauthors. Modified Newcastle-Ottawa scale was used for risk of bias assessment.

RESULTS

Database search yielded 536 records (Medline=152, PubMed=171, Web of Science=144 and Cochrane Central=69). Twenty-one studies evaluating 190 946 infants were included. SGA was associated with significantly higher odds of any stage of ROP on unadjusted analysis (unadjusted OR (uOR) 1.55; 95% CI 1.22 to 1.98; 10 studies) but not on adjusted analysis (adjusted OR (aOR) 2.16; 95% CI 0.66 to 7.11; 3 studies). SGA was associated with significantly higher odds of severe ROP (aOR 1.92; 95% CI 1.57 to 2.34; nine studies). SGA was also significantly associated with higher odds of treated ROP (aOR 1.39; 95% CI 1.18 to 1.65; three studies). In subgroup analysis of infants <29 weeks' GA, SGA was significantly associated with increased odds of ROP (uOR 1.64; 95% CI 1.19 to 2.26; two studies), severe ROP (aOR 1.61; 95% CI 1.23 to 2.10; four studies) and treated ROP (aOR 1.37; 95% CI 1.16 to 1.62; two studies).

CONCLUSION

SGA was associated with increased odds of any stage of ROP, severe ROP and treated ROP in preterm infants. Neonatologists should incorporate SGA into the risk assessment during ROP evaluation and while providing counselling to the families of preterm SGA infants. ROP screening guidelines should look into the frequency of follow-up examination in SGA infants in aim to offer early detection and treatment.

Refining evidence-based retinopathy of prematurity screening guidelines: The SCREENROP study

Purpose

Retinopathy of prematurity (ROP) is a potentially blinding condition affecting premature infants for which less than 10% of babies undergoing screening require treatment. This study assessed and validated predictors of developing clinically significant ROP (type 2 or worse) and ROP requiring treatment.

Design

Nationwide retrospective cohort study.

Methods

This study included infants born between January 2014 and June 2016, admitted to level 3 neonatal intensive care units across Canada who underwent ROP screening. Data were derived from the Canadian Neonatal Network database. Predefined ≥ 1% risk for clinically significant retinopathy or prematurity and ROP requiring treatment was set as threshold for screening. Thirty-two potential predictors were analyzed, to identify and validate the most important ones for predicting clinically significant ROP. The predictors were determined on a derivation cohort and tested on a validation cohort. Multivariable logistic regression modeling was used for analysis.

Results

Using a sample of 4,888 babies and analyzing 32 potential predictors, capturing babies with ≥1% risk of developing clinically significant ROP equated to screening babies with birth weight (BW) <1,300 g or gestational age (GA) <30 weeks while capturing babies with ≥1% risk of requiring ROP treatment equated to screening babies with BW <1,200 g or GA <29 weeks.

Conclusions

The Canadian ROP screening criteria can be modified to screen babies with BW <1,200 g or GA <30 weeks. Using these criteria, babies requiring treatment would be identified while reducing the number of babies screened unnecessarily.

Algorithm for predicting threshold retinopathy of prematurity is insufficient and fundus examinations are still needed before 31 weeks

AIM

We evaluated the weight, insulin-like growth factor-1, neonatal, retinopathy of prematurity (WINROP) algorithm for very premature infants.

METHOD

Infants born before 32 weeks who had undergone fundus examinations in the neonatal intensive care unit at the University Hospital of Nancy were included in this French retrospective cohort study from July 2012 to July 2016. We evaluated how well the WINROP software predicted threshold retinopathy of prematurity (ROP).

RESULTS

We studied 570 infants with a mean gestational age of 28.7 ± 1.8 weeks and a mean birth weight of 1110 ± 297 g: 28.1% had ROP and 1.2% had threshold ROP. The overall WINROP sensitivity was 57.1%, specificity was 46.0%, predictive positive value was 1.3% and predictive negative value was 98.9%. At more than 30 weeks of gestation or 1250 g, these figures rose to a respective specificity of 100% and 95.7% and respective predictive negative value of 100% and 100%. There were independent associations between the severity of ROP and the Apgar score at five minutes, the duration of oxygen therapy and non-invasive ventilation.

CONCLUSION

WINROP worked better on preterm infants born from 31 weeks onwards or weighing over 1250 g. Fundus examinations remain necessary for infants born earlier or lighter.

Effect of birth weight on retinopathy of prematurity in discordant twin pairs

Purpose:

Since twin pairs with discordance have equal gestational age (GA), discordant twins may constitute an appropriate group to investigate the specific effect that birth weight (BW) has on the development of retinopathy of prematurity (ROP). The present study aims to investigate the effect of BW on any and severe stages of ROP development in twin pairs.

Methods:

Fifty-two discordant twin pairs (104 preterms) born ≤32 gestational weeks, who were diagnosed with a minimum of 18% discordance between their BWs, were retrospectively analyzed. Twin pairs were separated into two groups based on the BW of each pair. The rate of any stage of ROP, Type 1 ROP, and perinatal risk factors were compared statistically among twin pairs.

Results:

The rate of any stage of ROP and Type 1 ROP was 24.0% and 4.8% in the whole group, respectively. A statistically significant difference was shown between lower and higher BW groups at any stage of ROP development (34.6% vs. 13.4%, P = 0.02). However, no difference was observed in Type 1 ROP development (7.7% vs. 1.9%, P = 0.17). No significant differences were found between twin pairs regarding neonatal morbidities. The number of small GA (SGA) infants in the smaller twin group was statistically higher than larger group and regression analysis showed that being SGA had significant correlation with any stage of ROP (odds ratio: 4.98, P = 0.02).

Conclusion:

This study showed that BW serves an effective role at any stage of ROP development in discordant twin pairs; however, no significant difference in terms of Type 1 ROP.

Characteristic clinical features associated with aggressive posterior retinopathy of prematurity

PurposeTo identify the risk factors for, and clinical features and treatment outcomes of aggressive posterior retinopathy of prematurity (APROP) in Korean infants.MethodsAmong 770 premature infants who underwent screening, 105 infants (198 eyes, 13.63%) received treatment for ROP. A total of 24 infants (48 eyes, 3.12%) developed APROP while 81 infants (150 eyes, 10.52%) developed non-APROP treatment-requiring type. The medical records of ROP-treated infants were reviewed retrospectively. The associated systemic and maternal risk factors were analyzed and anatomical outcomes were compared according to the severity of ROP and treatment modalities.ResultsThe mean gestational age and birth weight at birth in the APROP group were significantly lower than those in the non-APROP group (P=0.019, P<0.001, respectively). Infants who were born small for their GA developed APROP more frequently than non-APROP patients (P<0.001). Chorioamnionitis-positive infants also showed higher incidence rate of APROP (APROP vs non-APROP; P<0.001 and zone I APROP vs posterior zone II APROP; P=0.036, respectively). Infants with APROP required heavier laser treatment with a higher retreatment rate compared to infants with non-APROP. Favorable anatomical outcomes were achieved in 95.3% from treatment-requiring non-APROP group, 85.7% from zone I APROP and 84.6% from posterior zone II APROP group.ConclusionIntrauterine growth restriction and chorioamnionitis were associated with development of APROP. These findings suggest that perinatal maternal environment inhibiting normal retinal vascular growth in utero may contribute to increasing the risk of APROP in premature infants.

Retinopathy of prematurity like retinopathy in full-term infants

PURPOSE

The purpose of this study is to assess clinical characteristics, risk factors, and management outcomes of retinal changes similar to retinopathy of prematurity (ROP), seen in full-term infants.

PATIENTS AND METHODS

This is a retrospective review of 46 eyes of 23 patients, born at full term or near full term and diagnosed to have active ROP-like retinopathy or sequelae of ROP-like retinopathy.

RESULTS

Mean birth weight (BW) and gestational age (GA) were 2342 ± 923 g (range, 1200-4160 g) and 38.5 ± 1.85 weeks (range, 37-40 weeks). Mean age at the time of diagnosis was 3.5 ± 8.75 years (range, 1 month-16 years). Stage 1 and 2 of retinopathy was seen in 10 eyes (21.7%), threshold disease with plus disease in 12 eyes (26%) and Stage 4 or 5 in 14 eyes (30.4%). Involutional sequelae were noted in 10 eyes (21.7%). Twenty-one eyes (45.6%) underwent appropriate treatment in the form of laser, cryotherapy, or retinal detachment surgery. Eight eyes (17.4%) with advanced sequelae such as total closed funnel retinal detachment and macular fold were not treated. Mean follow-up was 3 years (range, 1 month to 12 years). At the last follow-up, 29 eyes (63%) had a favorable structural outcome (P < 0.001). Among the patients in whom visual acuity could be assessed (16 eyes), favorable visual outcome was noted in 9 eyes (56.2%). Low BW (P = 0.038), multiple births (P = 0.013), respiratory distress syndrome (RDS) (P = 0.001), phototherapy (P = 0.001), and oxygen administration (P < 0.001) were significantly associated with the development of ROP-like retinopathy in these full-term infants.

CONCLUSIONS

ROP-like retinopathy can occur in full-term and near full-term infants and can potentially lead to permanent visual impairment. Screening of infants with risk factors such as oxygen administration, RDS, multiple births, and low BW, regardless of GA, may reduce visual impairment.

Screening and Treatment in Retinopathy of Prematurity

BACKGROUND

More than 11 000 children are examined for possible retinopathy of prematurity in Germany each year, and 2-5% of them are treated for it. Even though screening and treatment programs are in place, the affected children can still suffer visual impairment.

METHODS

In this article, we summarize the pathogenesis, screening, and treatment of retinopathy of prematurity on the basis of a selective review of pertinent literature, retrieved by a PubMed search. The article centers on publications from 2011 to 2015 on the new option of treatment with VEGF inhibitors and discusses it in comparison to laser therapy.

RESULTS

All premature neonates with a low gestational age at birth, low birth weight, or prolonged exposure to supplemental oxygen must undergo screening by an ophthalmologist. Laser therapy is effective for stages 1-3 and for aggressive posterior retinopathy of prematurity. Its disadvantages are the induction of scarring and the development of severe myopia in 17-40% of the children so treated. Anti-VEGF treatment (VEGF = vascular endothelial growth factor) does not induce any visible scarring and seems to cause less myopia, but long-term data on safety, dosing, and the choice of anti-VEGF drug are still lacking.

CONCLUSION

The available evidence for anti-VEGF treatment is on a much lower level than the evidence for laser therapy. Anti-VEGF may be a way to avoid the disadvantages of laser therapy (scarring and severe myopia). Unlike laser therapy, however, the intravitreal injection of VEGF inhibitors may suppress systemic VEGF levels and potentially harm the developing brain, lungs, or other organs. The currently open questions about anti-VEGF treatment concern its dosing, choice of drug, and long-term safety.

Retinal Oximetry with Scanning Laser Ophthalmoscope in Infants

Purpose

Dual wavelength retinal oximetry has been developed for adults, but is not available for infants. Retinal oximetry may provide insight into the pathophysiology of oxygen-mediated diseases like retinopathy of prematurity. More insight in the oxygen metabolism of the retina in infants may provide valuable clues for better understanding and subsequent prevention or treatment of the disease. The measurements of oxygen saturation are obtained with two fundus images simultaneously captured in two different wavelengths of light. The comparison in light absorption of oxygenated and deoxygenated hemoglobin can be used to estimate the oxygen saturation within the retinal vessels by means of a software algorithm. This study aims to make retinal oximetry available for neonates. The first step towards estimating retinal oxygen saturation is determining the optical density ratio. Therefore, the purpose of this study is to image healthy newborn infants with a scanning laser ophthalmoscope and determine the optical density ratio for retinal oximetry analysis.

Methods

Images of the retina of full-term healthy infants were obtained with an SLO, Optomap 200Tx (Optos), with two laser wavelengths (532nm and 633nm). The infant lay face down on the lower arm of the parent, while the parent supported the chest and chin with one hand, and stabilized the back with the other hand. No mydriatics or eyelid specula were used during this study. The images were analyzed with modified Oxymap Analyzer software for calculation of the Optical Density Ratio (ODR) and vessel width. The ODR is inversely and approximately linearly related to the oxygen saturation. Measurements were included from the superotemporal vessel pair. A paired t-test was used for statistical analysis.

Results

Fifty-nine infants, (58% female), were included with mean gestational age of 40 ± 1.3 weeks (mean ± SD) and mean post-natal age of 16 ± 4.8 days. A total of 28 images were selected for retinal oximetry analysis. The ODR was 0.256 ± 0.041 for the arterioles and 0.421 ± 0.089 for the venules (n = 28, p < 0.001). The measured vessel-width for the arterioles was 14.1 ± 2.7 pixels and for the venules 19.7 ± 3.7 pixels (n = 28, p < 0.001).

Conclusions

Retinal oximetry can be performed in newborn infants by combining an SLO and a dual-wavelength algorithm software. Sensitivity of the approach is indicated by the fact that the ODR measurements are significantly different between the arterioles and the venules. However, more variability in ODR is seen with the SLO approach in babies than is seen with conventional oximetry in adults. This approach is completely non-invasive, non-contact and even avoids the use of mydriatics or eyelid specula.

The effect of oxygen saturation targeting on retinal blood vessel growth using retinal image data from the BOOST-II UK Trial

PURPOSE

Retinopathy of prematurity (ROP) is a disorder of developing retinal blood vessels in preterm infants. The purpose of this nested study was to investigate the effects of higher (91-95%) and lower (85-89%) oxygen saturation (SpO2) targeting on retinal blood vessel growth in preterm infants.

METHODS

Retinal blood vessel growth in the higher (91-95%) and lower (85-89%) oxygen saturation (SpO2) targeting groups was compared. Suitable RetCam (Clarity, Pleasanton, CA, USA) images collected in the BOOST-II UK trial were used. The distances between the centre of the optic disc and the ROP ridge in the temporal and nasal retina were measured in pixel units.

RESULTS

Images from 38 infants were studied, 20 from the higher SpO2 target group and 18 from the lower SpO2 target group. On average, temporal blood vessels extended further from the optic disc than nasal blood vessels, mean (standard deviation (SD)) 463.39 (55.05) pixels compared with 360.13 (44.47) pixels, respectively, P<0.0001. Temporal blood vessels extended less far from the optic disc in the higher SpO2 target group than in the lower SpO2 target group: mean (SD) 449.83 (56.16) pixels compared with 480.02 (49.94), respectively, P=0.055. Nasal retinal blood vessel measurements were broadly similar in the higher and lower SpO2 target groups; mean (SD) 353.96 (41.95) compared with 370.00 (48.82) pixels, respectively, P=0.38.

CONCLUSIONS

Relatively high oxygen saturation targeting (91-95%) was associated with a trend (P=0.055) towards reduced retinal blood vessel growth in this study of preterm infants.

Mortality and morbidity risks vary with birth weight standard deviation score in growth restricted extremely preterm infants

OBJECTIVE

To assess whether the mortality and morbidity risks vary with birth weight standard deviation score (BWSDS) in growth restricted extremely preterm infants.

STUDY DESIGN

This was a multicenter retrospective cohort study using the database of the Neonatal Research Network of Japan and including 9149 infants born between 2003 and 2010 at <28 weeks gestation. According to the BWSDSs, the infants were classified as: <-2.0, -2.0 to -1.5, -1.5 to -1.0, -1.0 to -0.5, and ≥-0.5. Infants with BWSDS≥-0.5 were defined as non-growth restricted group.

RESULTS

After adjusting for covariates, the risks of mortality and some morbidities were different among the BWSDS groups. Compared with non-growth restricted group, the adjusted odds ratio (aOR) for mortality [aOR, 1.69; 95% confidence interval (CI), 1.35-2.12] and chronic lung disease (CLD) (aOR, 1.28; 95% CI, 1.07-1.54) were higher among the infants with BWSDS -1.5 to <-1.0. The aOR for severe retinopathy of prematurity (ROP) (aOR, 1.36; 95% CI, 1.09-1.71) and sepsis (aOR, 1.72; 95% CI, 1.32-2.24) were higher among the infants with BWSDS -2.0 to <-1.5. The aOR for necrotizing enterocolitis (NEC) (aOR, 2.41; 95% CI, 1.64-3.55) was increased at a BWSDS<-2.0.

CONCLUSION

Being growth restricted extremely preterm infants confer additional risks for mortality and morbidities such as CLD, ROP, sepsis and NEC, and these risks may vary with BWSDS.

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

Preeclampsia and retinopathy of prematurity (ROP) are associated with impaired angiogenesis. Previous studies on the relationship between preeclampsia and ROP have produced conflicting results. The goal of this study was to evaluate the association between maternal preeclampsia and ROP using a large population-based cohort of very-low-birth-weight (VLBW) infants from 21 neonatal departments registered in the database of the Premature Baby Foundation of Taiwan. Multivariable logistic regression analysis was used to estimate the adjusted odds ratios (OR) and 95% confidence intervals (CI) for preeclampsia with reference to ROP and severe ROP. A total of 5,718 VLBW infants (844 cases with maternal preeclampsia) were included for analysis. The overall incidences of mild and severe ROP were 36.0% and 12.2%, respectively. Univariable analysis showed lower GA and lower birth weight, vaginal delivery, non-SGA, RDS, PDA, sepsis, transfusion, and absence of maternal preeclampsia to be associated with mild and severe ROP development. However, OR (95% CI) adjusted for the variables that were significant according to univariable analysis showed the risks of developing any-stage ROP and severe ROP for maternal preeclampsia to be 1.00 (0.84–1.20) and 0.89 (0.63–1.25), respectively. The results remained unchanged in stratified analyses according to SGA status. Our data showed that maternal preeclampsia was not associated with the subsequent development of any stage or severe ROP in VLBW infants.

Treatment of retinopathy of prematurity in Northern Ireland, 2000-2011: a population-based study

PURPOSE

To evaluate the incidence of treatment-requiring retinopathy of prematurity (ROP) over a 12-year-period in Northern Ireland.

METHODS

The medical records of all infants treated for ROP from January 2000 to December 2011 were retrospectively reviewed and cross-referenced with the Neonatal Intensive Care Outcomes Research and Evaluation (NICORE) database.

RESULTS

The Northern Ireland population data showed an increase in the number of live births from 2000 to 2011. The proportion of babies born with a birth weight <1501 g and/or <32 weeks' gestational age remained constant (χ(2) trend = 3.220, P = 0.0727), although the proportion of these babies who died prior to 42 weeks' gestation decreased from 2000 to 2011 (P = 0.0196 using χ(2) for trend = 5.445; P = 0.0354 using χ(2) = 20.809). The prevalence of treatment-requiring ROP in these infants increased from 1.05% in 2000 to 5.78% in 2011 (P < 0.001 using χ(2) trend = 16.309; P < 0.001 using χ(2) = 31.378).

CONCLUSIONS

The present population-based study highlights that the incidence of treatment- requiring ROP is increasing in Northern Ireland. The increasing number of infants requiring treatment will need to be taken into consideration in the commissioning process for ROP services in Northern Ireland.

Incidence and risk factors of retinopathy of prematurity in two neonatal intensive care units in North and South China

BACKGROUND

To investigate the incidence and risk factors of retinopathy of prematurity (ROP) in two Neonatal Intensive Care Units in North and South of China, respectively.

METHODS

We studied data concerning 472 infants with gestational age (GA) ≤ 34 weeks or birth weight (BW) ≤ 2000 g who were admitted to the Zhujiang Hospital of Southern Medical University and the Fourth Hospital of Shijiazhuang between January 1, 2011 and December 31, 2011. Clinical information about perinatal neonates was collected and was confirmed by reviewing medical charts. The incidence and severity of ROP were assessed in the screened population. Main outcome measures are the incidence and severity of ROP. The relationship of clinical risk factors and the development of ROP were analyzed.

RESULTS

The overall incidence of ROP was 12.7%, and the overall incidence of type 1 ROP was 2.3%; 9.4% of infants in Zhujiang Hospital had ROP compared to 15.0% infants in the Fourth Hospital of Shijiazhuang developed ROP, and the difference is statistically significant. ROP was significantly associated with GA (odds ratio [OR]: 0.77 [0.62-0.95], P = 0.015), BW (OR: 0.998 [0.996-0.999], P = 0.008), maternal supplemental oxygen administration before and during delivery (OR: 4.27 [1.21-15.10], P = 0.024) and preeclampsia (OR: 6.07 [1.73-21.36] P = 0.005). The risk factors for ROP are different in two hospitals. In Zhujiang Hospital, BW is the independent risk factors for ROP while GA, BW and preeclampsia in the Fourth Hospital in Shijiazhuang Conclusions: Retinopathy of prematurity incidence is different based on area. Incidence of ROP is still high in China. More efforts need to prevent ROP.

Association of maternal hypertension and chorioamnionitis with preterm outcomes

OBJECTIVES

We compared the relative effect of hypertensive disorders of pregnancy and chorioamnionitis on adverse neonatal outcomes in very preterm neonates, and studied whether gestational age (GA) modulates these effects.

METHODS

A cohort of neonates 23 to 30 weeks' GA, born in 2008 to 2011 in 82 hospitals adhering to the Italian Neonatal Network, was analyzed. Infants born from mothers who had hypertensive disorders (N = 2096) were compared with those born after chorioamnionitis (N = 1510). Statistical analysis employed logistic models, adjusting for GA, hospital, and potential confounders.

RESULTS

Overall mortality was higher after hypertension than after chorioamnionitis (odds ratio [OR], 1.39; 95% confidence interval [CI], 1.08-1.80), but this relationship changed across GA weeks; the OR for hypertension was highest at low GA, whereas from 28 weeks' GA onward, mortality was higher for chorioamnionitis. For other outcomes, the relative risks were constant across GA; infants born after hypertension had an increased risk for bronchopulmonary dysplasia (OR, 2.20; 95% CI, 1.68-2.88) and severe retinopathy of prematurity (OR, 1.48; 95% CI, 1.02-2.15), whereas there was a lower risk for early-onset sepsis (OR, 0.25; 95% CI, 0.19-0.34), severe intraventricular hemorrhage (OR, 0.65; 95% CI, 0.48-0.88), periventricular leukomalacia (OR, 0.70; 95% CI, 0.48-1.01), and surgical necrotizing enterocolitis or gastrointestinal perforation (OR, 0.47; 95% CI, 0.31-0.72).

CONCLUSIONS

Mortality and other adverse outcomes in very preterm infants depend on antecedents of preterm birth. Hypertension and chorioamnionitis are associated with different patterns of outcomes; for mortality, the effect changes across GA weeks.

Association of Maternal Age to Development and Progression of Retinopathy of Prematurity in Infants of Gestational Age under 33 Weeks

Aim. To find predictive and indicative markers of risk for development of retinopathy of prematurity (ROP) and its progression to the stage requiring laser treatment, in premature infants whose gestational age (GA) was under 33 weeks. Methods. We retrospectively reviewed medical records of 197 premature infants born in 2005-2010 whose GA < 33 weeks and underwent eye screening at Keio University Hospital. The association between candidate risk factors and development or progression of ROP was assessed. Results. Among the 182 eligible infants (median GA, 29.1 weeks; median birth weight (BW), 1028 g), 84 (46%) developed any stage of ROP, of which 45 (25%) required laser treatment. Multivariate analysis using a stepwise method showed that GA (P = 0.002; 95% confidence interval (CI), 0.508-0.858), BW (P < 0.001; 95% CI, 0.994-0.998), and lower maternal age (P = 0.032; 95% CI, 0.819-0.991) were the risk factors for ROP development and GA (P < 0.001; 95% CI, 0.387-0.609) and lower maternal age (P = 0.012; 95% CI, 0.795-0.973) were for laser treatment. The odds ratio of requiring laser treatment was 3.3 when the maternal age was <33 years. Conclusion. ROP was more likely to be developed and progressed in infants born from younger mother and low GA.

Nationwide inventory of risk factors for retinopathy of prematurity in the Netherlands

OBJECTIVES

To study the incidence and risk factors for retinopathy of prematurity (ROP) in the Netherlands.

STUDY DESIGN

Prospective, approximating population-based study that included infants with gestational age (GA) <32 weeks and/or birth weight (BW) <1500 g born in 2009. Pediatricians and ophthalmologists of all hospitals involved in care for premature infants reported data that were matched with the national perinatal database for risk factor analysis.

RESULTS

Of 1380 infants, median GA 29.8 weeks (IQR 28.1-31.1) and median BW 1260 g (IQR 1020-1500), ROP developed in 21.9%. Logistic regression identified GA and BW as risk factors for ROP (P < .001). After adjustment for GA and BW, additional risk factors were inhaled nitric oxide (iNO; OR 2.6, 95% CI 1.1-6.2, P = .03), stay at a neonatal intensive care unit >28 days (OR 1.6, 95% CI 1.1-2.6, P = .03), and artificial ventilation >7 days (OR 1.6, 95% CI 1.1-2.5, P = .02). Prenatal glucocorticoids (OR 0.6, 95% CI 0.4-0.8, P < .001) and female sex (OR 0.7, 95% CI 0.5-0.99, P = .04) showed a lesser incidence of ROP. iNO remained significant after correction for all significant factors (OR 2.6, 95% CI 1.1-6.2, P = .03).

CONCLUSION

In addition to established risk factors (GA, BW, stay at a neonatal intensive care unit >28 days, and artificial ventilation >7 days), treatment with iNO as risk factor for ROP is a novel finding.

Prediction of severe retinopathy of prematurity using the WINROP algorithm in a birth cohort in South East Scotland

PURPOSE

We tested the ability of the 'Weight, IGF-1, Neonatal Retinopathy of Prematurity (WINROP)' clinical algorithm to detect preterm infants at risk of severe Retinopathy of Prematurity (ROP) in a birth cohort in the South East of Scotland. In particular, we asked the question: 'are weekly weight measurements essential when using the WINROP algorithm?'

STUDY DESIGN

This was a retrospective cohort study. Anonymised clinical data were uploaded to the online WINROP site, and infants at risk of developing severe ROP were identified. The results using WINROP were compared with the actual ROP screening outcomes. Infants with incomplete weight data were included in the whole group, but were excluded from a subgroup analysis of infants with complete weight data. In addition, data were manipulated to test whether missing weight data points in the early neonatal period would lead to loss of sensitivity of the algorithm.

RESULTS

The WINROP algorithm had 73% sensitivity for detecting infants at risk of severe ROP when all infants were included and 87% when the complete weight data subgroup was analysed. Manipulation of data from the complete weight data subgroup demonstrated that one or two missing weight data points in the early postnatal period lead to loss of sensitivity performance by WINROP.

IMPLICATIONS

The WINROP program offers a non-invasive method of identifying infants at high risk of severe ROP and also identifying those not at risk. However, for WINROP to function optimally, it has to be used as recommended and designed, namely weekly body weight measurements are required.

Retinopathy of prematurity

The immature retinas of preterm neonates are susceptible to insults that disrupt neurovascular growth, leading to retinopathy of prematurity. Suppression of growth factors due to hyperoxia and loss of the maternal-fetal interaction result in an arrest of retinal vascularisation (phase 1). Subsequently, the increasingly metabolically active, yet poorly vascularised, retina becomes hypoxic, stimulating growth factor-induced vasoproliferation (phase 2), which can cause retinal detachment. In very premature infants, controlled oxygen administration reduces but does not eliminate retinopathy of prematurity. Identification and control of factors that contribute to development of retinopathy of prematurity is essential to prevent progression to severe sight-threatening disease and to limit comorbidities with which the disease shares modifiable risk factors. Strategies to prevent retinopathy of prematurity will depend on optimisation of oxygen saturation, nutrition, and normalisation of concentrations of essential factors such as insulin-like growth factor 1 and ω-3 polyunsaturated fatty acids, as well as curbing of the effects of infection and inflammation to promote normal growth and limit suppression of neurovascular development.

Pregnancy disorders leading to very preterm birth influence neonatal outcomes: results of the population-based ACTION cohort study

BACKGROUND

We examined the relationships between -pregnancy disorders leading to very preterm birth -(spontaneous preterm labor, prelabor premature rupture of -membranes (PPROM), hypertension/preeclampsia, -intrauterine growth restriction (IUGR), antenatal hemorrhage, and maternal -infection), both in isolation and grouped together as -"disorders of placentation" (hypertensive disorders and IUGR) vs. -"presumed infection/inflammation" (all the others), and several unfavorable neonatal outcomes.

METHODS

We examined a population-based prospective cohort of 2,085 singleton infants of 23-31 wk gestational age (GA) born in six Italian regions (the Accesso alle Cure e Terapie Intensive Ostetriche e Neonatali (ACTION) study).

RESULTS

Neonates born following disorders of placentation had a higher GA and better overall outcomes than those born following infection/inflammation. After adjustment for GA, however, they showed higher risk of mortality (odds ratio, OR: 1.4; 95% confidence interval, CI: 1.0-2.0), bronchopulmonary dysplasia (BPD) (OR: 2.5; CI: 1.8-3.6), and retinopathy of prematurity (ROP) (OR: 2.0; CI: 1.1-3.5), especially in growth-restricted infants, and a lower risk of intraventricular hemorrhage (IVH) (OR: 0.5; CI: 0.3-0.8) and periventricular leukomalacia (PVL) (OR: 0.6; CI: 0.4-1.1) as compared with infants born following -infection/inflammation disorders.

CONCLUSION

Our data confirm the hypothesis that, in very preterm infants, adverse outcomes are both a function of immaturity (low GA) and of complications leading to preterm birth. The profile of risk is different in different pregnancy disorders.

Increased morbidity and mortality in very preterm/VLBW infants with congenital heart disease

PURPOSE

To study the association between congenital heart diseases (CHD) and in-hospital mortality and morbidity of very preterm/very low birth weight (VLBW) infants.

METHODS

The area-based prospective cohort study ACTION included all infants with gestational age (GA) 22-31 weeks or birth weight <1,500 g admitted to neonatal care between July 2003 and June 2005 in six Italian regions (n = 3,684). CHD were coded according to ICD9-CM. Cluster multivariable logistic regression analyses were used to assess the relationship between CHD and mortality and selected morbidities [neonatal infection, ultrasound brain abnormalities, retinopathy of prematurity (ROP), and bronchopulmonary dysplasia (BPD)] adjusting for potential confounders.

RESULTS

Seventy-one patients had CHD [19.3 ‰, 95 % confidence interval (CI) 15.1-24.2 ‰]. The most common lesions were isolated atrial and ventricular septal defects (31.1 and 26.8 %, respectively), pulmonary valvar stenosis (12.7 %), and tetralogy of Fallot (5.6 %). Compared with other infants, CHD patients showed significantly higher GA and frequency of small for gestational age (SGA, i.e., birth weight ≤3rd centile). After adjustment for GA, sex, SGA, presence of extracardiac malformations or chromosomal anomalies, and region of birth, CHD patients had a significantly higher likelihood of infection, BPD, ROP, and, after 27 weeks gestation only, hospital mortality. The increased risk of ROP appeared to be partly due to infection.

CONCLUSIONS

In very preterm/VLBW infants CHD are more prevalent than in the general liveborn population, and confer an increased risk of death and serious morbidities independently of other risk factors. These results may be useful to better tailor prognostic assessment and diagnostic and therapeutic interventions for these children.

Preeclampsia and retinopathy of prematurity in preterm births

OBJECTIVE

The relationship between gestational hypertension, preeclampsia, and the risk of retinopathy of prematurity (ROP) remains unclear. Thus, we used a large cohort database to study the influence of maternal gestational hypertension and preeclampsia on the occurrence of ROP in preterm infants.

METHODS

We used data from a previous retrospective cohort study that includes 25,473 eligible preterm neonates. We examined the association between gestational hypertension, preeclampsia, and ROP while controlling for potential confounders by multiple logistic regression analysis.

RESULTS

Of the 8758 early preterm infants (gestational age <34 weeks), 1024 (11.69%) had ROP, while of the 16,715 late preterm infants, only 29 (0.17%) had ROP. After adjusting for confounders, preeclampsia was associated with a significantly reduced risk of ROP (adjusted odds ratio [aOR], 0.65; 95% confidence interval [CI], 0.49-0.86 for early preterm birth; aOR, 0.10; 95% CI, 0.01-0.93 for late preterm birth; aOR, 0.66; 95% CI, 0.50-0.87 for all preterm births). Gestational hypertension was not significantly associated with ROP at early or late preterm births.

CONCLUSIONS

Preeclampsia, but not gestational hypertension, was associated with a reduced risk of ROP in preterm births.

Mortality and morbidity in preterm small-for-gestational-age infants: a population-based study

OBJECTIVE

We sought to evaluate the impact of severity of growth restriction on mortality and major neonatal morbidity among very-low-birthweight small-for-gestational-age infants.

STUDY DESIGN

This was a population-based observational study using data collected by the Israel National Very-Low-Birth-Weight Infant Database 1995 through 2007 including infants 24-31 weeks' gestation, with birthweight (BW) ≤ 50th percentile without major malformations. Four BW percentile groups were considered: < 3rd, 3rd-< 10th, 10th-< 25th, and a reference group 25th-50th percentile. Univariate and multivariable logistic regression analyses were performed.

RESULTS

Infants of BW 3rd-< 10th percentile were at increased risk for grades 3-4 retinopathy of prematurity (odds ratio [OR], 2.07; 95% confidence interval [CI], 1.54-2.78), bronchopulmonary dysplasia (OR, 2.52; 95% CI, 2.03-3.12), necrotizing enterocolitis (OR, 1.32; 95% CI, 1.04-1.68), and mortality (OR, 2.37; 95% CI, 1.94-2.90). The risk was further increased among infants of BW < 3rd percentile.

CONCLUSION

Growth restriction severity may serve as a clinical marker of degree of risk for neonatal mortality and various morbidities.

Analysis of incidence and risk factors of retinopathy of prematurity among very-low-birth-weight infants in North Taiwan

BACKGROUND

Although significant advances have been made in perinatal care, retinopathy of prematurity (ROP) remains a serious complication in prematurely born individuals. There have been limited studies on ROP in Taiwan, and most of those existing reports are outdated.

METHODS

This retrospective study included 252 very-low-birth-weight (VLBW) infants admitted to the neonatal intensive care unit of Chang Gung Children's Hospital over a 2-year period between July 2005 and June 2007. All infants were examined for ROP according to the guidelines published by the American Academy of Pediatrics. The relationship between clinical risk factors and the development of ROP was analyzed.

RESULTS

Of the 252 VLBW infants, 216 met the screening criteria. Of the 216, 99 (45.8%) had ROP. Compared with neonates born at 29 weeks of gestational age (GA) or later, those very premature infants of ≤25 weeks' and 26-28 weeks' GA had increased odds ratios (OR) of 8.49 and 3.19, respectively, for the development of severe ROP. No ROP was detected in infants of greater than 33 weeks' GA. The simultaneous presence of a low GA, low birth weight (LBW), lower Apgar scores, hypotension, patent ductus arteriosus, septicemia, intraventricular hemorrhage, ventilator dependence, and use of postnatal steroids was associated with severe ROP. Using multiple logistic regression analyses for ROP, only maternal preeclampsia [OR, 2.52; confidence interval (CI), 1.32-4.7]; duration of mechanical ventilation (OR, 1.06; CI, 1.04-1.08); and LBW (OR, 2.62; CI, 1.370-3.375) predicted the development of threshold ROP.

CONCLUSION

The incidence of ROP among VLBW infants was 45.8%; 19.0% had severe ROP. Infants of lower GAs and/or with LBW, whose mother had preeclampsia or who had a long duration of mechanical ventilation are at risk for the development of threshold ROP.

The role of hemoglobin variant replacement in retinopathy of prematurity

OBJECTIVE

To conduct tests of relationships between different factors that could influence the course of retinopathy of prematurity (ROP) and ROP, particularly the role of hemoglobin variant replacement in adult blood transfusions.

METHODS

A retrospective, observational study of 83 infants born between 23 and 34 wks gestation was conducted.

RESULTS

The infants without ROP, with 1 and 2 stage of ROP and with ≥ 3 stage of ROP received Q 28 (12-134); 51 (14-149); 156 (38-244) ml/kg of transfused blood, respectively, and the factor Qt was 1,545 (560-10,045); 3,093 (614-13,419); 11,907 (1,288-20,638) (ml/kg)·day, respectively. For the same groups MCV(35) (mean cell volume at the arbitrary time of the 35(th) wk post-conception) was 92.3 (82.9-110.5); 91.0 (79.3-101.4); 87.1 (80.2-94.8) fl, respectively, and factor P(MCV)/t was 99.5 (89.2-108.8); 96.3 (84.6-106.3); 90.7 (85.3-96.5) fl, respectively. There is high influence on the stage of ROP of the amount of transfused blood and MCV, both with or without the time factor. The statistical differences between P(MCV)/t were more significant than the differences between MCV(35), for different stages of ROP.

CONCLUSIONS

The influence of the time factor on the statistical differences of MCV but not on the amount of transfused adult blood suggests that HbF - HbA replacement may play a role in ROP development.

Low gestational age and chronic lung disease are synergistic risk factors for retinopathy of prematurity

AIMS

This retrospective, population based study was designed to investigate risk factors for development of retinopathy of prematurity (ROP) and their possible interrelationships, in neonates of gestational age (GA) <32 weeks born in a well-defined geographical region. STUDY DESIGN-SUBJECTS: The study population included all preterm infants born alive with GA 24-32 weeks in Northwestern Greece during a 9-year period and hospitalised in the regional neonatal intensive care unit (NICU).

OUTCOME MEASUREMENTS

The association was assessed of the presence of ROP with maternal factors: age, pathology of pregnancy, in-vitro fertilisation, multiple gestation, mode of delivery, perinatal factors: gender, antenatal steroids, transportation, resuscitation, GA, birth weight (BW), small for GA status and postnatal morbidity: chronic lung disease (CLD), intraventricular haemorrhage (IVH), necrotizing enterocolitis (NEC), respiratory distress syndrome (RDS), maximum O(2) needs, hypoxic/hyperoxic episodes, patent ductus arteriosus (PDA), sepsis, using multiple logistic regression analysis.

RESULTS

Of 189 infants without congenital anomalies born at GA 24-32 weeks ROP was diagnosed in 24 (12.7%) (>grade 2: 6). Logistic regression analysis showed ROP to be strongly associated with GA, odds ratio (OR) 2.1, confidence interval (CI) 1.3-3.3, p<0.01 and CLD, OR 10.2, CI 2.3-44, p<0.01, respectively, independent of confounding factors. By estimating interaction on an additive scale it was shown that the combined risk effect of GA and CLD was larger than the sum of the individual risk effects, implying synergistic effect.

CONCLUSIONS

ROP was closely and independently related to both low GA and the diagnosis of CLD, which were interrelated in the development of ROP.

A co-twin study of the relative effect of birth weight and gestational age on retinopathy of prematurity

PURPOSE

To determine the relative effect of birth weight and gestational age on retinopathy of prematurity (ROP) using preterm twin pairs discordant for birth weight.

METHODS

This study was a retrospective cohort study including 55 consecutive twin pairs of 110 preterm infants (gestational age ≤33 weeks). The outcomes of ROP including occurrence (any stage), severe ROP (stage 3 or more), and clinically significant ROP requiring laser treatment were compared between twins with the lower birth weight from each pair and their co-twins with the higher birth weight. Using twin pairs having different birth weight and identical gestational age, the independent effects of prematurity and intrauterine growth on ROP could be evaluated. Other perinatal morbidities related to prematurity were also compared between twin pairs.

RESULTS

No significant differences in ROP between larger and smaller infants were observed in the twin-paired analysis while analysis on individual infants showed strong association between small birth weight and ROP outcomes. However, in both the larger and smaller infant groups, gestational age of <28 weeks was significantly associated with ROP outcomes. No differences were found between twin pairs regarding other perinatal morbidities including bronchopulmonary dysplasia, respiratory distress syndrome, patent ductus arteriosus, intraventricular hemorrhage, and periventricular leukomalacia.

CONCLUSIONS

Birth weight is not associated with ROP, while gestational age is in the twin-paired study, suggesting that gestational age is a better predictor of ROP than birth weight. This indicates that maturity is more important in the pathogenesis of ROP than intrauterine growth.

Adjusted poor weight gain for birth weight and gestational age as a predictor of severe ROP in VLBW infants

AIM

To analyze relative weight gain by 2-week intervals up to 6 weeks after birth in order to predict the development of retinopathy of prematurity (ROP) requiring treatment among very low birth weight (BW) infants.

METHODS

A prospective study including infants with BW ≤1500 g born in a single tertiary intensive care unit over 1-year period was conducted. Body weight measurements were recorded weekly and relative weight gains (g/kg/day) were calculated. The main outcome was development of ROP requiring treatment.

RESULTS

Mean BW and gestational age (GA) of the whole cohort were 1165±223 g and 29.3±2.3 weeks, respectively. Relative weight gain at 2 weeks and 4 weeks postnatal age were significantly lower in infants with severe ROP (P=0.041 and P=0.017, respectively). Relative weight gain at 6 weeks was not different between groups. Infants with severe ROP gained 6.7±4 g/kg/day in the first 4 weeks of life, compared with 9.3±4.5 g/kg/day for those with mild or no ROP. After adjusted for BW and GA in logistic regression poor relative weight gain in the first 4 weeks was found to be related to severe ROP (P=0.015). When all the other risk factors significant for severe ROP were included in the logistic regression poor weight gain did not arise as an independent risk factor.

CONCLUSION

Poor postnatal weight gain in the first 4 weeks of life is the end result of several comorbidities rather than being an independent risk factor. Poor weight gain can be an additional predictor of severe ROP in very low BW infants.

Maternal preeclampsia protects preterm infants against severe retinopathy of prematurity

OBJECTIVE

To study the influence of maternal preeclampsia on the occurrence of retinopathy of prematurity.

STUDY DESIGN

A prospective cohort study of 324 preterm neonates with birth weight ≤ 1500 g and gestational age ≤ 32 weeks. Multiple maternal and perinatal factors were analyzed for association and confounding by multiple logistic regression analysis.

RESULTS

Mean birth weight was 1128 ± 240 g, and mean gestational age 29.7 ± 1.9 weeks. Twenty-four newborns (7.4%) had severe retinopathy of prematurity; 97 had any stage of retinopathy, and 227 had no retinopathy of prematurity. Preeclampsia and complete antenatal steroid treatment course reduced the risk for any stage of retinopathy of prematurity by 60% and 54%, respectively. Preeclampsia reduced the risk for severe retinopathy of prematurity by 80%.

CONCLUSIONS

Preeclampsia lowered the risk for occurrence of any stage and severe retinopathy of prematurity in very low birth weight infants.