<P> During human pregnancy , progesterone is produced in increasingly high amounts by the ovaries and placenta . At first , the source is the corpus luteum that has been `` rescued '' by the presence of human chorionic gonadotropin ( hCG ) from the conceptus . However , after the 8th week , production of progesterone shifts to the placenta . The placenta utilizes maternal cholesterol as the initial substrate , and most of the produced progesterone enters the maternal circulation , but some is picked up by the fetal circulation and used as substrate for fetal corticosteroids . At term the placenta produces about 250 mg progesterone per day . </P>
<P> During human pregnancy , progesterone is produced in increasingly high amounts by the ovaries and placenta . At first , the source is the corpus luteum that has been `` rescued '' by the presence of human chorionic gonadotropin ( hCG ) from the conceptus . However , after the 8th week , production of progesterone shifts to the placenta . The placenta utilizes maternal cholesterol as the initial substrate , and most of the produced progesterone enters the maternal circulation , but some is picked up by the fetal circulation and used as substrate for fetal corticosteroids . At term the placenta produces about 250 mg progesterone per day . </P>
where does the progesterone that helps maintain the pregnancy come from
where does the progesterone that helps maintain the pregnancy come from
the ovaries placenta
the ovaries placenta