Let’s start by looking at the menstrual cycle and talking about what each hormone does. Progesterone levels are relatively low during the first half of the cycle. First, FSH stimulates an ovarian follicle to develop, which causes an egg to mature and increases estrogen production. Then, as estrogen levels rise, FSH production declines and LH production increases. A rise in LH levels indicates that ovulation, or an egg being released from the ovary, is about to occur. After ovulation comes the luteal phase, where progesterone is produced by the corpus luteum, which is the empty follicle from which the egg was released. Therefore, the presence of progesterone indicates that ovulation has, in fact, occurred.
But what does progesterone really do? Each month, estrogen is released before ovulation and stimulates the uterine lining to build up. After ovulation, progesterone acts to stabilize the uterine lining. Basically, progesterone’s role is to prepare the uterine lining for a pregnancy, allowing it to become receptive to the fertilized egg so that it can attach, implant, and thrive for the duration of the pregnancy.
Ideally, after ovulation, progesterone levels stay high. Since progesterone is involved in stabilizing the uterine lining, high levels of progesterone are needed for the embryo to attach in the womb and to maintain the pregnancy. Up to about the 8th week of pregnancy, the corpus luteum produces progesterone to support the pregnancy. After the 8th week of pregnancy, progesterone production is taken over by the placenta and continues to nourish the embryo for the duration of the pregnancy.
The many ways that progesterone affects ovulation and conception also highlights the importance of the luteal phase. The post-ovulation luteal phase is when progesterone levels rise to prepare the uterus for pregnancy. If the luteal phase doesn’t last long enough or progesterone levels are not high enough, the uterine lining is not stable and the fertilized egg can’t attach and thrive.
By charting or testing hormone levels, you can not only measure how long your luteal phase is, but you can also predict ovulation by measuring LH levels with ovulation tests and confirm ovulation and sufficient progesterone levels by using Proov tests.
All of these tools together help paint the bigger picture of how hormones can affect fertility, conception, and pregnancy. So, do you have progesterone? Find out in 5 minutes, at home with Proov.