Although babies develop at different rates, most follow a basic time track. However, babies born prematurely may be a few weeks or months slower. If your baby doesn’t seem to be reaching certain developmental milestones after a few weeks of usual age, be sure to take him to the doctor. There may not actually be anything wrong, but if your baby is really developmentally delayed, you definitely still want to catch it early so that your doctor can diagnose your baby and start treatment sooner. Generally speaking, you need to trust your instincts. If there is something about the way your baby moves that seems strange or wrong to you, make sure you consult your doctor. After all, you know your baby best. Here are some signs that your baby may have a developmental problem, and you may want to print it out as a checklist to assess your baby’s development. There are several factors that cause growth retardation: 1. Genetic factors: It can manifest as familial short stature. 2, maternal factors: nutritional deficiencies, emotional abnormalities, use of drugs, exposure to radiation and the environment can have a great impact on the growth and development of the fetus. 3.Nutrition and distribution: Adequate nutrition and balanced nutrient supply for children play an important role in growth and development. 4, chronic diseases: such as chronic infections, chronic liver disease, malnutrition, congenital heart disease, congenital renal tubular disease, etc. can lead to growth retardation in children. If your baby has the following conditions, it is recommended that you take him to the doctor: i. Newborn ~ 2 months old After 2 months old: When you pick up your lying baby, he cannot lift his head. After 2 months old: Still feels particularly stiff or limp. After 2 months old: When you hold him in your arms, he will struggle his back and neck outward as if he wants to push you away. 2. 3-6 months old At 4 months old: He can’t grasp or reach for toys, has difficulty lifting his head, doesn’t put things in his mouth, and his legs don’t know how to push down when his feet are on the hard ground. After 4 months of age: the newborn baby’s startle reflex is still present (falls backwards or stretches out his arms and legs when startled, stretches his neck, then quickly retracts his arms and starts to cry). At 6 months of age: there is support and will not sit. After 6 months of age: There is also an asymmetrical neck tension reflex (when his head is turned to one side, the arm on that side will straighten while the arm on the other side will bend as if he is holding a sword). 3. 7 to 9 months old At 7 months old, the baby cannot lift his head after being pulled up into a sitting position, cannot put things in his mouth, cannot reach for things, and cannot support a certain amount of weight with his legs. At 8 months of age: Cannot sit independently. 4. 9-12 months old After 10 months old: When crawling, the body tilts to one side and uses the arms and legs of one side to push, while the other side drags. At 12 months old: Can’t crawl or stand with support yet. V. 13～24 months old At 18 months old: Can’t walk A few months after learning to walk, they are still not confident in walking or keep walking on their tiptoes.