Endometriosis is a condition where the uterine lining grows on pelvic structures outside the uterine cavity.
In early stages of the disease, there is usually little, if any, visible evidence of anatomical distortion sufficient to compromise the release of an egg (ovulation) or its transportation from the ovary to the fallopian tube. In contrast, more advanced endometriosis, is characterized by the presence of pelvic adhesions sufficient to distort normal pelvic anatomy and interfere with fertilization as well as egg/embryo transportation mechanisms. Several investigators have concluded that the incidence of endometriosis is more common than appreciated. Endometriosis can only be definitively diagnosed by actually seeing the lesions at the time of a laparoscopy, unless it is very advanced and there are large ovarian lesions (called endometriomas) in the ovary.
The mechanisms by which endometriosis causes infertility have been the subject of much debate among researchers.
We can conclude that there are both chemical events as well as mechanical/anatomical distortions. It is in the milder cases with little or no anatomical distortions, that the chemical abnormalities are more significant and impact successful reproduction by releasing a variety of agents from cytokines to prostaglandins, which negatively impact the early embryo and implantation and while it is tempting to conclude that normally ovulating women with mild to moderate endometriosis would have no difficulty in conceiving if their anatomical disease is addressed surgically or that endometriosis-related infertility is confined to cases with more severe anatomical disease…nothing could be further from the truth.
The natural conception rate for healthy ovulating women in their early 30’s(who are free of endometriosis) is about 15% per month of trying and 70% per year of actively attempting to conceive. Conversely, the conception rate for women of a comparable age who have mild or moderate pelvic endometriosis (absent or limited anatomical disease) is about 5-6% per month and 40% after 3 years of trying.
The reduced conception rate in women with endometriosis can, in large part be explained by:
Toxins in the Peritoneal fluid: Women with endometriosis (regardless of severity) are believed to have” toxic factors” in their pelvic peritoneal fluid. These “toxins”, reduce the fertilization potential by a factor of 3 or 4. Only Assisted Reproductive (AR) techniques such as IVF, which involves extracting eggs before they are released from the ovary with ovulation and exposed to these peritoneal toxins, can bypass this effect. This could at least in part explain why, normally ovulating women, who have mild to moderately severe pelvic endometriosis are 3-4 times less likely to conceive of a viable pregnancy per month of trying, than their counterparts who do not have endometriosis.
Immunologic Implantation failure: It has previously been reported that ~ 66%% of women with endometriosis (regardless of severity) have antiphospholipid antibodies (APA) in their blood. Also, and perhaps much more significant is the fact that, approximately thirty percent (30%) of women who have endometriosis (regardless of severity) show evidence of increased Natural Killer Cell activity (NKa) in there peripheral blood and in their endometrial linings. In such cases there is a high likelihood of early or later immunologic implantation failure. In the case of early immunoplogic implantation failure, rejection occurs prior to embryo attachment to the uterine wall, usually even before the pregnancy hormone, HCG can be detected in the woman’s blood. Strictly speaking, rather than suffering from “true infertility” such women are experiencing “mini miscarriages “ which occur so early that they don’t even realize that they were pregnant in the first place.
Unfortunately, at the present time there is no effective cure for endometriosis, short of a hysterectomy. However, frequently, pregnancy itself will greatly improve the situation and it is not uncommon for patients to struggle to have their first child, then conceive (usually with IVF) and then conceive spontaneously. The mechanisms whereby this occurs, is that that the hormonal events of pregnancy are so profound as to markedly alter the inherent biochemical profile for the patient, that her immunologic cytokine profile has become so altered, that it is no longer detrimental to the initiation of conception.
For those patients who are not actively attempting conception at that time, birth control pills are a useful agent, especially when administered continuously to prevent menstruation. In this fashion, the “load” of endometrial cells is kept to a minimum and the disease stage can be kept stable rather than progressing. Endometriosis, remains an enigmatic condition, but is certainly responsible for significant debilitation with painful menses, painful intercourse, discomfort with bowel movements and a general sense of malaise and malcontent for many days in the month. In extreme cases, a hysterectomy can improve the situation but clearly, for those seeking to have a child, this is an option of last resort. However, for some patients, they will be best served by completing their family and then progressing to a hysterectomy for quality of life purposes, and to be able to enjoy the family they worked so hard to create! I have had many patients over the years who have commented to me “I wish I would have done it sooner”, in reference to hysterectomy. Assisted Reproductive Treatments and IVF in particular, have been a dramatic help in the management of patients with this condition.