<prompt> Perinatal period corresponds to28 weeks of gestation to 7 days after bihPeriod of labour to newborn periodThird trimester of pregnancy to newborn period36 weeks of gestation to 3 days after bih  <response>: Peaining to the period immediately before and after bih. The perinatal period is defined in diverse ways. Depending on the definition, it stas at the 20th to 28th week of gestation and ends 1 to 4 weeks after bih. Ref : Nelson paediatrics chapter : Growth and develop 