One of the most common symptoms of PCOS (PolyCystic Ovarian Syndrome) is infrequent or absent menses. Infrequent menses (also called as Oligomenorrhea) is a condition where a woman has less than 8 menses in one year. Absence of menses (also called as anovulation) is a condition where a woman has no menses for months and may require the use of medication to induce their menses.
Women do not ovulate regularly will have a hormonal imbalance between estrogen and progesterone during that month which may lead to irregular heavy bleeding or no bleeding at all. Remember that just having menses every month does not necessarily mean that ovulation is occurring regularly.
Heavy bleeding is also another sign associated with PCOS and a variety of other gynecological changes such as uterine polyps, uterine fibroids. Typically a pelvic ultrasound and or a hysteroscopy (placing a telescope like probe in the uterus) can rule out most etiologies.
The normal cycle would involve ovulation, two weeks before the endometrial lining is shed (assuming that there is no successful pregnancy). Every woman has follicles in her uterus that contain eggs for the reproductive process.
The pituitary gland orders follicle-stimulating hormone (FSH) to be delivered to the ovaries every month. Follicles in the ovaries grow in response to this signal, and by day five of the cycle the body has selected a dominant follicle from one of the ovaries. This follicle will produce estrogen, thickening the endometrium. Mid-cycle, the pituitary gland will order a release of luteinizing hormone (LH) to trigger the ovulation process.
The follicle will release the egg approximately 36 hours after receiving the signal, and the fallopian tube will catch the egg. If the egg is not caught by the fallopian tube, a pregnancy will not be possible. The egg is held inside of the fallopian tube, and if intercourse is had during ovulation period, the sperm will ideally travel from the vagina, through the cervix, and from the uterus through the fallopian tubes to meet the egg within.
The fertilized egg will then travel for five more days through the fallopian tube. The egg will then be deposited in the uterus where it will attempt to attach to the endometrium, aided by the follicle, which began producing progesterone to change the properties of the endometrium, after the egg left the ovaries. Should the fertilized egg not become attached, the levels of both estrogen and progesterone will drop after two weeks, causing the endometrial lining to be shed. This is the menstrual flow, and it will usually last from anywhere between 3-5 days.