This is a retrospective single-center cohort study. The comparison in short- and long-term outcomes will be made between those with and without primary microcephaly in infants weighing ≤ 500 g.
This is a retrospective single-center cohort study. The study setting is a level IV neonatal intensive care unit (NICU) at Nagano Children's Hospital in Nagano, Japan. We will retrospectively collect the data of those who were admitted to Nagano Children's Hospital NICU between January 1, 2015, and December 31, 2019. Eligible infants will be identified using our neonatal database and clinical records. The extracted data includes maternal background information and clinical course, infant's status at birth, the clinical course in NICU, and the follow-up data at 6 and 18 months of corrected age. Among the eligible infants, those with a z score of birth head circumference \< -2 will be classified into the Microcephaly group and others into the Control group. The z score is calculated using the Japanese growth standard.
Study Type
OBSERVATIONAL
Enrollment
22
Those with a z score of birth head circumference \< -2 (primary microcephaly) are classified into the Microcephaly group.
Nagano Children's Hospital
Azumino, Nagano, Japan
Rate of neurodevelopmental impairment
Having at least one of the following conditions: cognitive impairment, cerebral palsy, visual impairment, or hearing impairment. Cognitive impairment was defined as a modified DQ score of ≤ 70 using the Kyoto Scale of Psychological Development. CP was defined as (1) a non-progressive disorder of the central nervous system appearing in the early years of life and clinically characterized by a persistent but not unchanging impairment of movement and posture and/or (2) the Gross Motor Function Classification System level ≥ II. Visual impairment was defined as unilateral or bilateral blindness, or any other condition requiring corrective lenses, which were diagnosed or determined by ophthalmologists. Hearing impairment was defined as unilateral or bilateral hearing loss that requires a hearing aid. The diagnosis of hearing loss was made by otolaryngologists using auditory steady-state response.
Time frame: 3 years of age
Survival rate
Survival rate is the proportion of those have survived.
Time frame: At discharge from neonatal intensive care unit, an average at 40 weeks' postmenstrual age.
Rate of severe bronchopulmonary dysplasia
The definition of bronchopulmonary dysplasia proposed by the National Institute of Child Health and Human Development is used to classify the severity of bronchopulmonary dysplasia. Those who need ≥ 30% of oxygen or any mechanical respiratory support at 36 weeks of gestation are classified as having severe bronchopulmonary dysplasia.
Time frame: At 36 weeks' postmenstrual age
Rate of need for surgery for patent ductus arteriosus
Patent ductus arteriosus is diagnosed by neonatologists using echocardiography and clinical signs.
Time frame: In neonatal intensive care unit, an average of up to 4 weeks of life
Rate of severe intraventricular hemorrhage
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Intraventricular hemorrhage is diagnosed by neonatologists using head ultrasound. Severe IVH was defined as grade III or IV by the classification of Papile.
Time frame: In neonatal intensive care unit, an average of up to 2 weeks of life
Rate of periventricular leukomalacia
Periventricular leukomalacia is diagnosed using head ultrasound or magnetic resonance imaging, typically cysts formation in the periventricular white matter.
Time frame: In neonatal intensive care unit, an average of up to 40 weeks' postmenstrual age
Rate of necrotizing enterocolitis
The diagnosis with necrotizing enterocolitis.
Time frame: In neonatal intensive care unit, an average of up to 2 weeks of life
Rate of sepsis
Sepsis is defined as septicemia or bacteremia with a positive culture result of the blood and/or cerebrospinal fluid.
Time frame: In neonatal intensive care unit, an average of up to 4 weeks of life
Rate of need for treatment for retinopathy of prematurity
The diagnosis of retinopathy of prematurity and the decision on the need for treatment were made by ophthalmologic examination.
Time frame: In neonatal intensive care unit, an average of up to 40 weeks' postmenstrual age
Weight
Physical measurement.
Time frame: At 40 weeks' postmenstrual age or at discharge (approximately 40 weeks' postmenstrual age)
Length
Physical measurement.
Time frame: At 40 weeks' postmenstrual age or at discharge (approximately 40 weeks' postmenstrual age)
Head circumference
Physical measurement.
Time frame: At 40 weeks' postmenstrual age or at discharge (approximately 40 weeks' postmenstrual age)
Postmenstrual age
Postmenstrual age is calculated based on their gestational age and date at birth.
Time frame: At discharge, an average at 40 weeks' postmenstrual age
Need for home oxygen therapy
Need for home oxygen therapy.
Time frame: At discharge, an average at 40 weeks' postmenstrual age
Tracheostomy
Need for tracheostomy.
Time frame: In neonatal intensive care unit, an average at 40 weeks' postmenstrual age
Length of hospital stay
The initial hospitalization.
Time frame: In neonatal intensive care unit, an average at 40 weeks' postmenstrual age
Survival rate
Survival rate is the proportion of those have survived.
Time frame: At 3 years of age
Modified developmental quotient
Modified developmental quotient is calculated by dividing developmental age (measured by the Kyoto Scale of Psychological Development) by the corrected age.
Time frame: At 3 years of age
Rate of cerebral palsy
Cerebral palsy is defined as (1) a non-progressive disorder of the central nervous system appearing in early years of life and clinically characterized by a persistent but not unchanging impairment of movement and posture and/or (2) the Gross Motor Function Classification System level ≥ II.
Time frame: At 3 years of age
Rate of visual impairment
Visual impairment is defined as unilateral or bilateral blindness, or any other condition requiring corrective lenses, which were diagnosed or determined by ophthalmologists.
Time frame: At 3 years of age
Rate of hearing impairment
Hearing impairment is defined as unilateral or bilateral hearing loss that requires a hearing aid. The diagnosis of hearing loss was made by otolaryngologists using auditory steady-state response.
Time frame: At 3 years of age
Rate of those who need home oxygen therapy
Need for home oxygen therapy.
Time frame: At 3 years of age
Rate of those who need tracheostomy
Need for tracheostomy.
Time frame: At 3 years of age
Rate of those who need tube feeding or gastrostomy
Need for tube feeding or gastrostomy.
Time frame: At 3 years of age
Rate of those who need rehospitalization
Need for rehospitalization.
Time frame: After 18 months of corrected age unit until 3 years of age
Weight
Physical measurement.
Time frame: At 3 years of age
Height
Physical measurement.
Time frame: At 3 years of age
Head circumference
Physical measurement.
Time frame: At 3 years of age