A healthy reproductive system is a well-tuned machine in which multiple organs and processes work together to create ideal environments for conception and pregnancy. When any part of this system fails or doesn't live up to its ideal role, infertility can occur. The progesterone hormone is one of many reproductive "workers" in the body that can prevent fertility if it's not up for the job.
For example, progesterone is supposed to prepare the endometrium – the inner lining of the uterus -- for receiving a fertilized egg. If it doesn't, the egg will not implant, and the endometrium will continue toward the process of menstruation.
The progesterone hormone also counteracts the negative consequences of unchecked estrogen [source: Project Aware]. So some of the effects of low progesterone in the body are similar to those of high estrogen levels:
- anxiety and mood swings
- tender breasts
- uterine fibroids
- irregular or heavy periods
Of course, low progesterone isn't the only imbalance that can cause problems in a woman's body. High progesterone can also lead to fertility and health issues. We'll discuss that next.