The luteal phase is the latter phase of the estrous cycle in animals. It begins with the formation of the corpus luteum and ends in either pregnancy or luteolysis. The main hormone controlling this stage is progesterone. Bagnell, C. 2005. "Animal Reproduction". Rutgers University Department of Animal Sciences.

Luteal phase defect

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Luteal phase defect (LPD) is believed to interfere with the implantation of embryos Diaz, S. et. al. Relative contributions of anovulation and luteal phase defect to the reduced pregnancy rate of breastfeeding women. Fertility and Sterility. 1992 Sep;58(3):498-503. PMID 1521642.. The Lactational Amenorrhea Method of birth control works primarily by preventing ovulation, but is also known to cause LPD.

References

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Reproductive system