A Research Study in Chinese Children With a Low Level of Hormone to Grow. Treatment is Somapacitan Once a Week Compared to Norditropin® Once a Day.

Inclusion Criteria: * Informed consent of parent or legally acceptable representative of participant and child assent, as age-appropriate must be obtained before any trial related activities * The parent or legally acceptable representative of the child must sign and date the Informed consent form (according to local requirements) * The child must sign and date child assent form or provide oral assent (if required according to local requirements) * Prepubertal children: a) Boys: Age more than or equal to 2 years and 26 weeks and less than or equal to 11.0 years at the time of signing informed consent. * Testis volume less than 4 ml. b) Girls: Age more than or equal to 2 years and 26 weeks and less than or equal to 10.0 years at the time of signing informed consent. Tanner stage 1 for breast development (no palpable glandular breast tissue) * Confirmed diagnosis of growth hormone deficiency determined by two different growth hormone stimulation tests performed within 12 months prior to randomisation, defined as a peak growth hormone level of less than or equal to 10.0 ng/ml using the WHO International Somatropin 98/574 standard * If only one growth hormone stimulation test is available before screening, then confirmation of growth hormone deficiency by second and different growth hormone stimulation test must be done * For children with at least 2 additional pituitary hormone deficiencies (other than growth hormone deficiency) only one growth hormone stimulation test is needed * Impaired height defined as at least 2.0 standard deviations below the mean height for chronological age and gender according to Chinese general population standards at screening * Impaired height velocity defined as annualised height velocity at screening less than 7cm/year for subjects between 2.5 and 3 years old and less than 5 cm/year for subjects from 3 years and above calculated over a time span of minimum 3 months and maximum 18 months prior to screening according to Chinese guideline and expert consensus on children with short stature and GH therapy * No prior exposure to growth hormone therapy or IGF-I treatment * Bone age less than chronological age at screening * Body Mass Index more than 5th and less than 95th percentile, Body Mass Index-for-age growth charts according to Chinese general population standards. * IGF-I \< -1.0 SDS at screening, compared to age and gender normalized range measured at central laboratory * No intracranial tumour confirmed by magnetic resonance imaging or computer tomography scan. An image or scan taken within 9 months prior to screening can be used as screening data if the medical evaluation and conclusion is available Exclusion Criteria: * Known or suspected hypersensitivity to trial product(s) or related products. * Previous participation in this trial. Participation is defined as randomisation. * Receipt of any investigational medicinal product within 3 months before screening or participation in another clinical trial before randomisation * Any known or suspected clinically significant abnormality likely to affect growth or the ability to evaluate growth with standing height measurements: * Turner Syndrome (including mosaicisms) * Chromosomal aneuploidy and significant gene mutations causing medical "syndromes" with short stature, including but not limited to Laron syndrome, Noonan syndrome, Prader-Willi Syndrome, abnormal SHOX-1 gene analysis or absence of GH receptors * Significant spinal abnormalities including but not limited to scoliosis, kyphosis and spina bifida variants * Congenital abnormalities (causing skeletal abnormalities), including but not limited to Russell-Silver Syndrome or skeletal dysplasias * Family history of skeletal dysplasia * Children born small for gestational age (birth weight 10th percentile of the recommended gender-specific birth weight for gestational age according to national standards in China5 * Children diagnosed with diabetes mellitus or screening values from central laboratory of 1. fasting plasma glucose more than or equal to 126 mg/dl (7.0 mmol/L) or 2. HbA1c more than or equal to 6.5 % * Current inflammatory diseases requiring systemic corticosteroid treatment for longer than 2 consecutive weeks within the last 3 months prior to screening * Children requiring inhaled glucocorticoid therapy at a dose greater than 400 µg/day of inhaled budesonide or equivalents for longer than 4 consecutive weeks within the last 12 months prior to screening * Concomitant administration of other treatments that may have an effect on growth, e.g. but not limited to methylphenidate for treatment of attention deficit hyperactivity disorder (ADHD) * Diagnosis of attention deficit hyperactivity disorder * Prior history or presence of malignancy including intracranial tumours * Prior history or known presence of active Hepatitis B or Hepatitis C (exceptions to this exclusion criterion is the presence of antibodies due to vaccination against Hepatitis B) * Any clinically significant abnormal laboratory screening tests, as judged by the study doctor * Any disorder which, in the opinion of the study doctor, might jeopardise Participant's safety or compliance with the protocol * The participant or the parent/legally acceptable representative is likely to be non-compliant in respect to trial conduct, as judged by the study doctor * Children with hypothyroidism and/or adrenal insufficiency not on adequate and stable replacement therapy for at least 90 days prior to randomisation.