Highly individualized egg retrieval (HIER)

HIER is a protocol where follicles are triggered at earlier times to improve embryology outcomes in older women. For example, many centers will trigger follicles when they reach 18-22 mm regardless of age, while a HIER protocol may trigger women <40 at this range or at 12-14 mm for women aged 45 or older. The immature eggs retrieved can be cultured to M2 by rescue IVM. The HIER protocol is a way to optimize an egg retrieval for older women, although studies are limited.