Clinical Study of Pegylated Somatropin (PEG Somatropin) to Treat SGA Children With Short Stature

Inclusion Criteria: * The patients are diagnosed as being clinically full term small for gestational age infant. * Girl are 3-6 years old, boys are 3-7 years old. * Be in preadolescence (Tanner stage 1). * The child did not achieve catch-up growth when he/she entered the group (the definition of catch-up growth is that the height is higher the third percentile with the same age and gender) (Appendix 2 and 3). * The height of child is shorter than -2SDS of the median of normal children with the same age and gender when he/she entered the group (the mean height and height standard deviation of normal children with the same age and gender of normal children regard the height data in the physical development investigation data of children aged 0-18 in 9 cities of China (2005) as standard \[13\], Appendix 4 and 5). * Within a year before entering the group, after any growth hormone stimulation test, the peak concentration of growth hormone in serum\>10 µg/L. * Bone age≤ the actual age+1. * The function of glucose regulation is normal: fasting blood glucose \< 5.6mmol/L. * Birth gestational age ≥ 37 weeks. * The subjects and their guardians sign the informed consent (if the subjects is lack of ability for signing the informed consent, his legal guardian can write the subjects name instead). * All experimental drug groups completed the main phase (52 weeks) of Phase II clinical trials, and the participants with complete follow-up records can enter the extension phase, provided that…