Insufficient progesterone during this phase results in estrogen dominance, leading to a shortening of the luteal phase, (called luteal phase defect). A shortened luteal phase with too much estrogen and not enough progesterone can cause heavy periods, scanty periods, too frequent periods or no periods at all.
Prolactin, another pituitary hormone, may also be elevate during this time, causing breast tenderness and pain, classic symptoms of PMS. Vitex is not a phytoestrogen, rather it works through the hypothalamus-pituitary axis, (an important chemical pathway) to balance female hormones. Vitex extract has been extensively studied in Europe, particularly Germany, where it has been used since the 1950's. Clinical studies show that vitex extract reduces headaches, breast tenderness, bloating, fatigue, cravings for sweets, feeling of anxiety and irritability, depression and mood swings, often after only one month. Vitex is also recommended for teenage acne.