I wonder how she did it?

Reading AS Byatt's Still Life. In it she has written a description of giving birth that is so precisely accurate that my aged innards squirmed in recollection. Most of us who have had children were blessed with amnesia following the ordeal. Good thing too or we would never have gone forth and multiplied! But that's the subject of a possible future musing that will depend on how irked I am feeling with humankind. Meantime, this wonderer wants to know how Byatt was able to recall so vividly those sensations I so completely and gratefully had forgotten.