Once you got your Pearl kit you will find that there are two to three different types of hormonal testing strips coming with it – colored either blue for FSH, pink for LH or purple for PdG (if you have a kit with additional Proov tests).
You can find further information on how to measure here.
FSH stands for follicle stimulating hormone and is one of the most important hormones in the female reproductive system. Its main functions are to control both- your menstrual cycle and the release of eggs from your ovaries (ovulation): At the beginning of each cycle, FSH signals the ovaries to start follicle growth- with each follicle containing an egg. The growing follicle then produces estrogen to prepare the uterus for pregnancy. Increased estrogen on the other hand, leads to a sudden rise in LH- levels. Before the Fertile Window opens, FSH decreases.
LH stands for luteinizing hormone and plays a vital role in controlling the reproductive system since it is regulating the function of the ovaries. For the first two weeks of your menstrual cycle, LH is necessary for stimulation of the ovarian follicles (which have grown due to rising FSH levels). These ovarian follicles are responsible for the production of estrogen. Around day 14 of your cycle, LH levels rise- this then leads the ovarian follicle to tear and by that to release a mature egg from the ovary. You know this process as ovulation- it’s the process where the egg travels down the oviduct where it then can convene with sperm and be fertilized. If a successful fertilization has taken place, LH causes the manufacturing of progesterone, which is a hormone that prepares your uterus for pregnancy.
A balanced level of luteinizing hormone is key to causing and maintaining fertility and by measuring the levels of LH in urine, you can predict the timing of its surge and by that the time of your ovulation. For instance, if your LH-levels are low ovulation does not occur.
The purple strip is responsible for measuring your PdG- levels. PdG is short for Pregnanediol Glucuronide and is a urine metabolite of the progesterone hormone. Progesterone builds the uterine wall, so it may house and protect the growing fetus. PdG has been shown to directly correlate with the presence of progesterone in blood. By measuring PdG, the purple strips help you to confirm whether ovulation has occurred. Studies have shown, that PdG levels in urine typically rise 24-36 hours after a successful ovulation (e.g. above noted graph). With a fertilized egg, progesterone and estrogen levels remain high in order to support the growing fetus. If no conception has taken place, progesterone and estrogen levels decrease, the uterine wall breaks down, menstruation bleeding begins, and the cycle starts all over. Adequate progesterone levels are essential for both, getting pregnant and supporting a healthy pregnancy.