Neurodevelopmental problems have been linked to lack of maternal thyroid hormones, at a time when their own thyroid is unable to meet postnatal needs. Cardiovascular complications may arise from the failure of the ductus arteriosus to close after birth: patent ductus arteriosus (PDA). Respiratory problems are common, specifically the respiratory distress syndrome (RDS or IRDS) (previously called hyaline membrane disease). Another problem can be chronic lung disease (previously called bronchopulmonary dysplasia or BPD). Gastrointestinal and metabolic issues can arise from neonatal hypoglycemia, feeding difficulties, rickets of prematurity, hypocalcemia, inguinal hernia, and necrotizing enterocolitis (NEC). Hematologic complications include anemia of prematurity, thrombocytopenia, and hyperbilirubinemia (jaundice) that can lead to kernicterus. Infection, including sepsis, pneumonia, and urinary tract infection [1]

Survival
The chance of survival at 22 weeks is about 6%, while at 23 weeks it is 26%, 24 weeks 55% and 25 weeks about 72% as of 2016. With extensive treatment up to 30% of those who survive birth at 22 weeks survive longer term as of 2019. The chances of survival without long-term difficulties is less. Of those who survive following birth at 22 weeks 33% have severe disabilities. In the developed world overall survival is about 90% while in low-income countries survival rates are about 10%.Some children will adjust well during childhood and adolescence, although disability is more likely nearer the limits of viability. A large study followed children born between 22 and 25 weeks until the age of 6 years old.
The clinical decision to discard the gastric residuals (versus re-feeding) is often individualized based on the quantity and quality of the residual. Some experts also suggest replacing the fresh milk or curded milk and bile-stained aspirates, but not replacing haemorrhagic residual. Evidence to support or refute the practice of re-feeding preterm infants with gastric residuals is lacking. Hearing assessment
The Joint Committee on Infant Hearing (JCIH) state that for preterm infants who are in the neonatal intensive care unit (NICU) for a prolonged time should have a diagnostic audiologic evaluation before they are discharged from the hospital. Well babies follow a 1-2-3-month benchmark timeline where they are screened, diagnosed, and receiving intervention for a hearing loss. However, very premature babies it might not be possible to complete a hearing screen at one month of age due to several factors. Once the baby is stable an audiologic evaluation should be performed. For premature babies in the NICU, auditory brainstem response (ABR) testing is recommended. If the infant doesnt pass the screen, they should be referred for an audiologic evaluation by an audiologist. If the infant is on aminoglycosides such as gentamicin for less than five days they should be monitored and have a follow up 6–7 months of being discharged from the hospital to ensure there is no late onset hearing loss due to the medication. Outcomes and prognosis
Preterm births can result in a range of problems including mortality and physical and mental delays.