5 Reasons why Progesterone is critical to Conception and Pregnancy

As the name suggests, progest-erone – as in “pro-gestation” – is critical to conception and pregnancy. But we don’t hear much about this super hormone that not only indicates ovulation is occurring properly, but also prepares the uterus to receive a fertilized embryo for implantation. So why is progesterone so important when trying to conceive? Let’s find out.

Progesterone confirms ovulation.  At the beginning of each menstrual cycle, progesterone levels are relatively low. First, Follicle Stimulating Hormone, or 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 Luteinizing Hormone, or LH, production increases. A spike in LH levels indicates that ovulation, or an egg being released from the ovary, is about to occur. Many ovulation predictor kits measure LH, as the presence of this hormone is “predictive” of ovulation. After ovulation comes the luteal phase, where the corpus luteum produces progesterone.  The corpus luteum is the empty follicle from which the egg was released. The presence of progesterone indicates that ovulation has, in fact, occurred, because if no egg is released, there is no empty follicle, or corpus luteum, to produce it!

Progesterone stabilizes the uterine lining. Each month, estrogen is released before ovulation and stimulates the uterine lining to build up. After ovulation, progesterone acts to stabilize the uterine lining so it is at the optimal thickness to support implantation. 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.

Progesterone enables a fertilized embryo to implant. Since progesterone is involved in stabilizing the uterine lining, high levels of progesterone are needed for the embryo to attach in the womb. Implantation typically occurs 7-10 days after ovulation. Up until about the 8th week of pregnancy, the corpus luteum produces progesterone to support the pregnancy. After about the 8th week of pregnancy, progesterone production is taken over by the placenta and continues to nourish the fetus for the duration of the pregnancy.

Progesterone is needed to maintain pregnancy. Whether generated from the corpus luteum or the placenta, progesterone levels remain elevated during pregnancy to support a healthy uterine environment for the growing fetus. It has some side benefits too. That “pregnancy glow”? That’s mighty progesterone at work making the skin appear firmer and brighter! 

Tracking progesterone shows the full picture. While traditional ovulation predictor kits are great for determining the best time for intercourse when trying to conceive, they fail to show the full picture. The menstrual cycle has 2 distinct phases. The first is the follicular phase, which is comprised of menstruation and the fertile window. This is the time leading up to ovulation. The second is the luteal phase, which is the time after ovulation and is critical for enabling conception and implantation.  Progesterone is the dominant hormone present during the luteal phase. By using ovulation predictor kits to track hormones during the follicular phase and tracking progesterone during the luteal phase, women can understand both halves of their cycle and therefore, the full menstrual picture!

Up until now, progesterone testing required a blood sample, either at the doctor’s office or via mail-in kit. Proov rapid response progesterone test strips enable women to track progesterone at home, in 5 minutes, using urine instead of blood. Just collect a first morning urine sample, dip the strip, wait 5 minutes and read results!  One line is positive, and two lines are negative. Proov test strips empower women to know more about their bodies and understand if their hormone levels are adequate to enable proper ovulation and conception by tracking levels of the critical female hormone: progesterone.

Reference:  Tolga B Mesen, MD and Steven L. Young, MD, PhD “Progesterone and the Luteal Phase: A Requisite to Reproduction” Published online January 2015 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4436586/