Immature ovum

When meiosis I is completed, one secondary oocyte and one polar body is created.

This is the stage where immature ova spend most of their lifetime, more specifically in diplotene of prophase I of meiosis.

Thus, an immature ovum can spend up to ~55 years as a primary oocyte (the last ovulation before menopause).

Secondary oocytes are the immature ovum shortly after ovulation, to fertilization, where it turns into an ootid.

However, it fills the purpose as the female counterpart of the male spermatid in spermatogenesis.