More than half of women who have endometriosis harbor antiphospholipid antibodies (APA) that can compromise development of the embryo’s root system (trophoblast). In addition and far more serious, is the fact that in about one third of cases endometriosis, regardless of its severity is associated with NKa and cytotoxic uterine lymphocytes (CTL) which can seriously jeopardize implantation. This immunologic implantation dysfunction (IID) is diagnosed by testing the woman’s blood for APA, for NKa (using the K-562 target cell test or by endometrial biopsy for cytokine activity) and, for CTL (by a blood immunophenotype). Activated NK cells attack the invading trophoblast cells (developing “root system” of the embryo/early conceptus) as soon as it tries to gain attachment to the uterine wall. In most cases, this results in rejection of the embryo even before the pregnancy is diagnosed and sometimes, in a chemical pregnancy or an early miscarriage. As such, many women with endometriosis, rather than being infertile, in the strict sense of the word, often actually experience repeated undetected “mini-miscarriages”. Women who harbor APA’s often experience improved IVF birth rates when heparinoids (Clexane/Lovenox) are administered from the onset of ovarian stimulation with gonadotropins until the 10th week of pregnancy. NKa is treated with a combination of Intralipid (IL) and steroid therapy: Intralipid (IL) is a solution of small lipid droplets suspended in water. When administered intravenously, IL provides essential fatty acids, linoleic acid (LA), an omega-6 fatty acid, alpha-linolenic acid (ALA), an omega-3 fatty acid.IL is made up of 20% soybean oil/fatty acids (comprising linoleic acid, oleic acid, palmitic acid, linolenic acid and stearic acid) , 1.2% egg yolk phospholipids (1.2%), glycerin (2.25%)  and water (76.5%).IL exerts a modulating effect on certain immune cellular mechanisms largely by down-regulating NKa. The therapeutic effect of IL/steroid therapy is likely due to an ability to suppress pro-inflammatory cellular (Type-1) cytokines such as interferon gamma and TNF-alpha. IL/steroids down-regulates NKa within 2-3 weeks of treatment the vast majority of women experiencing immunologic implantation dysfunction. In this regard IL is just as effective as Intravenous Gamma globulin (IVIg) but at a fraction of the cost and with a far lower incidence of side-effects. Its effect lasts for 4-9 weeks when administered in early pregnancy. The toxic pelvic environment caused by endometriosis, profoundly reduces natural fertilization potential. As a result normally ovulating infertile women with endometriosis and patent Fallopian tubes are much less likely to conceive naturally, or by using fertility agents alone (with or without intrauterine (IUI) insemination. The only effective way to bypass this adverse pelvic environment is through IVF. I am not suggesting here that all women who have endometriosis require IVF! Rather, I am saying that  in cases where  the condition is further compromised by an IID associated with NKa and/or for older women(over 35y)  who have  diminished ovarian reserve (DOR) where time is of the essence, it is my opinion that IVF is the treatment of choice.