This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: New born infants, Subject name: Pediatrics
Which of the following timelines would be included in the perinatal period? 
Select and explain. 
A. 37th week of gestation to 28 days after bih, B. 19th week of gestation to 7 days after bih, C. 32nd week of gestation to 28 days after bih, D. 22nd week of gestation to 7 days after bih
D: 22nd week of gestation to 7 days after bih
Answer: D: 22nd week of gestation to 7 days after bih 
Explanation: These are diverse definitions for perinatal period, but the WHO states that the perinatal period commences at 22 completed weeks and ends seven completed days after bih. The neonatal period is defined as the first 28 days after bih. Infancy is defined as the first year of life. This should not be confused the period used for calculation of perinatal moality rate. The actual perinatal period is defined as the period from the 22nd week of life to 7 days after bih, when the fetus weighs about 500g However, the calculation of perinatal moality rate primarily considers fetal weight above 1000g, which if acheived at 28 weeks of gestation. Therefore, for all statistical purposes, international comparisions and calculations of perinatal moality rate, the period from the 28th week of life is considered. Hence, Perinatal Period: From the 22nd week Perinatal moality rate calculation: From the 28th week Ref: World Health Organisation