While oocytes are ovulated, CD9-deficient oocytes do not properly fuse with sperm upon fertilization. A few follicle cells are stimulated to grow but only one oocyte is ovulated. Pseudo-pregnancy frequently occurs in canids that have ovulated but failed to conceive. The risk of ovarian cancer increases in women who have ovulated more over their lifetime. Newly ovulated eggs and early-stage embryos are enclosed in a thin, ellipsoid, golden-brown capsule. Like some iguanids, only recently ovulated females are receptive to mating. He noticed that female Xenopus frogs ovulated within hours of being injected with the extract. Ovulated eggs become arrested in metaphase II until fertilization triggers the second meiotic division. Ovulated eggs are fertilized externally and take approximately 24 hours to develop into planula.