The impact of hormone changes on the symptoms of premenstrual syndrome (PMS)

Hormonal Changes are one of the most widely studied causes of pre menstrual syndrome (PMS).

PMS occurs near the end of your menstrual cycle, within seven to 14 days before menstruation. During your cycle, an egg matures and is released from the ovaries for possible fertilization. The hormones oestrogen (sometimes spelt estrogen) and progesterone play a major part in this cycle.

At around five days into the cycle, your ovaries release the hormone oestrogen. This hormone helps thicken your uterus, which would be there to nourish an embryo if you were to concieve. At around 14 days into your cycle, an egg is released in a process called ovulation.

After ovulation, the last (luteal) phase of your menstrual cycle begins, and PMS symptoms tend to emerge. During this phase, your ovaries increase production of oestrogen and begin producing progesterone to prepare the uterus for a possible pregnancy. If the egg is not fertilized, production of estrogen and progesterone drops. It is this hormonal drop that causes the lining of the uterus to die and slough off, leading to menstruation. Once menstruation starts, PMS symptoms stop within a day or two. 

Scientists believe that these hormones interact with certain brain chemicals, specific neurotransmitters and that it is this interaction which can affect mood and contribute to PMS symptoms like depression and anxiety.

Severe mood swings associated with hormonal changes is experienced by between 3-8% of cases of PMS, and is actually considered to be different condition called premenstrual dysphoric disorder(PMDD).