Changes

== Pregnancy and Parturition ==

== Pregnancy and Parturition ==

In most domestic species, pregnancy is maintained by hormonal feedback from the corpus luteum and, in many species, the placenta. The corpus luteum is maintained in early pregnancy and progesterone levels remain elevated as a result. This maintains negative feedback to the hypothalamus and anterior pituitary gland which inhibits further follicular development and ovulation. In polyoestrous species, it prevents the return to oestrus. In many species the [[Endocrine System_-_Placenta_-_Anatomy_%26_Physiology|placenta]] will take over or supplement the corpus luteum as the source of progesterone during pregnancy; the placenta is a source of many of the hormones that  regulate changes during preganancy, stimulating mammary growth, the growth of the myometrium, preparation for parturition, and secreting chorionic gonadotrophin in species where this is required for the [[Gestation -Maternal Recognition of Pregnancy - Anatomy & Physiology|maternal recognition of pregnancy]]. [[Gestation -Litter Sizes - Anatomy & Physiology|Litter sizes]] vary between species, and the method of [[Gestation -Diagnosis of Pregnancy - Anatomy & Physiology|diagnosing pregnancy]] varies between species also.  

In most domestic species, pregnancy is maintained by hormonal feedback from the corpus luteum and, in many species, the placenta. The corpus luteum is maintained in early pregnancy and progesterone levels remain elevated as a result. This maintains negative feedback to the hypothalamus and anterior pituitary gland which inhibits further follicular development and ovulation. In polyoestrous species, it prevents the return to oestrus. In many species the [[Endocrine System_-_Placenta_-_Anatomy_%26_Physiology|placenta]] will take over or supplement the corpus luteum as the source of progesterone during pregnancy; the placenta is a source of many of the hormones that  regulate changes during preganancy, stimulating mammary growth, the growth of the myometrium, preparation for parturition, and secreting chorionic gonadotrophin in species where this is required for the [[Gestation -Maternal Recognition of Pregnancy - Anatomy & Physiology|maternal recognition of pregnancy]]. [[Gestation -Litter Sizes - Anatomy & Physiology|Litter sizes]] vary between species, and methods of [[Gestation -Diagnosis of Pregnancy - Anatomy & Physiology|diagnosing pregnancy]] also vary between species.