Lack of progesterone causes what?

Negative Effects. Progesterone can help prevent estrogen from becoming harmful to our health among other protective factors. As a natural balancer, Progesterone helps reduce irritability, weight gain, anxiety, hair loss, low libido, fibrocystic breasts, endometriosis, and uterine fibroids, to name a few. If you think you have hormonal imbalance, be sure to check with your doctor to come up with the best treatment.
Progesterone. In a reproductive age woman low luteal Progesterone usually means she did not ovulate. In ovulatory cycles if Progesterone is low, it is usually called a luteal-phase defect, although experts disagree about how important it is. Purely theoretically, no Progesterone at all would mean death because your body couldn't make cortisol.