Estrogen and progesterone work in tandem. During the menstrual cycle, estrogen helps release mature egg from the ovaries in the follicular phase, while progesterone takes over after ovulation and helps thicken uterus lining. During pregnancy, increased progesterone keeps estrogen (responsible for labor contractions) in check, preventing premature birth and miscarriage.
Estrogen And Progesterone – The Power Hormone Duo
What if there are only two hormones that are involved in all things fertility, pregnancy and everything related to female reproductive and general health. Would you take them lightly? Seriously speaking, no one should.
I know most of you are probably very well aware of the significance and role of these hormones, but I really wanted to present here a summary of the most interesting facts about them. For the most part, estrogen and progesterone are responsible for opposing actions in the female body, each one balancing out the other’s effects.
You may think that having one thing canceling out the effects of another is counter-intuitive, but in fact, feedback loops are a very sophisticated way to keep complicated systems in balance and this is how it is achieved in nature.
The levels of each hormone are further controlled by another hormone duo, named FSH (Follicle Stimulation Hormone) and LH (Luteinizing Hormone), which are produced in the pituitary gland of the brain.
The characteristic features for each of these hormones are:
Estrogen = dynamic growth, active change, expulsion
Progesterone = relaxation, maintenance, gradual growth
Hormonal Fluctuations During Menstrual Cycle
During the menstrual cycle, the two hormones are produced at different phases of the cycle and serve different purposes. Our precious egg will not be released, unless a sudden surge of estrogen from the ovaries happens during the follicular phase of the ovarian cycle.
But then, as soon as ovulation happens, estrogen falls and progesterone levels rise significantly, promoting the thickening of the uterus lining.
This is the luteal phase and as you can guess, the dominant player here is progesterone. If for any reason there is not enough progesterone produced after ovulation or the duration of the luteal phase is too short, implantation of the fertilized egg may be sabotaged from the very beginning. If conception and, therefore, implantation don’t happen, then a sudden drop in both estrogen and progesterone trigger the period, which is essentially the shedding of all the uterine tissues created during the luteal phase. As soon as estrogen levels start to build up, the cycle is repeated.
If conception and, therefore, implantation don’t happen, then a sudden drop in both estrogen and progesterone trigger the period, which is essentially the shedding of all the uterine tissues created during the luteal phase. As soon as estrogen levels start to build up, the cycle is repeated.
The following graphic summarizes pretty well the above process during the menstrual cycle.
Role Of Hormones During Pregnancy
But, it is during pregnancy that you can really see the antagonistic roles of estrogen and progesterone and how sufficient progesterone is your ticket to a successful full term pregnancy.
In a nutshell, estrogen can cause contractions and is a major player during birth or a miscarriage, which is why it needs to be kept under control by sufficient progesterone, which relaxes the uterus and prevents contractions. For a pregnancy to move forward, there must be sufficient progesterone. Too much estrogen can definitely be abortive, but not all estrogen is bad.
Some of it are necessary because it stimulates growth and cell multiplication, which are critical for the baby’s development and, of course, the growth of the placenta and all the maternal organs that support the pregnancy. The following infographic is a good summary of the most important effects and characteristics of the two hormones.
So, in pregnancy, it is more like a carefully orchestrated balance between estrogen and progesterone that must be maintained, rather than the domination of one or the other.