Peritoneal fluid and serum steroids in infertility patients

Peritoneal secretion of ovarian hormones and its consequences

Secretion of ovarian hormones directly into the peritoneal cavity has been repeatedly demonstrated for 25 years, but the consequences of this pathway of secretion have not been fully considered. Circumstantial evidence suggests the following hypotheses: (1) Hormones enter the endometrial cavity through the tubes and influence the endometrial cycle. (2) Androgens are absorbed into the portal venous system and are inactivated in the liver. (3) In polycystic ovary syndrome, ovarian cortical fibrosis inhibits peritoneal secretion of androgens and contributes to hyperandrogenemia. (4) Bypass of the ovarian vein by peritoneal secretion leads to underestimation of ovarian hormone production rates. (5) Peritoneally secreted hormones are absorbed into the broad ligaments of the uterus and returned to the reproductive organs by veno-arterial countercurrent transfer. Some approaches to testing the hypotheses are outlined. If any of the hypotheses are supported by more direct evidence, some aspects of reproductive endocrinology will turn out be even more complicated than they have seemed.

Biases in the endometriosis literature. Illustrated by 20 years of endometriosis research in Leuven

AIM

To review the Leuven data on endometriosis to demonstrate the shifts that occurred over the years in diagnosis of endometriosis, classification of women with endometriosis and thus in interpretation of results.

RESULTS

The contributions to the LUF syndrome, to non-pigmented endometriosis, to cystic ovarian endometriosis, to deep endometriosis, to endometriosis as an immunologic disease and to the development of an animal model of endometriosis, illustrate the persistent interest in endometriosis over 20 years. Using these data it can be shown how progressively the recognition of endometriosis caused important shifts from women who in the beginning of this period were classified as normal, to women who later became classified as having minimal or mild endometriosis. This was caused initially by the active search for small typical lesions and later by the recognition of non-pigmented lesions as endometriosis. The second important shift was caused by the recognition that deep endometriosis is not only a frequent disease, but that these women are predominantly classified as having mild to moderate endometriosis and even as women without endometriosis. The third shift is still ongoing, since the deep lesions reported become progressively smaller, by the "enthusiasm" of the surgeons, and by the introduction of a menstrual clinical exam. A fourth bias in the literature concerns the diagnosis and treatment of cystic ovarian endometriosis. Together with these shifts in recognition and treatment of endometriosis, our understanding of the physiopathology of endometriosis has changed. This is illustrated by the new concepts which have emerged over this period. These are, the focal treatment of cystic ovarian endometriosis, the concept that mild endometriosis could be a normal physiological condition and the endometriotic disease theory.

CONCLUSION

To interpret the data of the literature we should be aware of the shifts that have occurred in the classification of endometriosis over the past 20 years, and which still can hamper the comparison of results between research groups.

Peritoneal fluid volume and steroid hormone concentrations in baboons with and without either spontaneous minimal/mild endometriosis or the luteinized unruptured follicle syndrome

This study was performed to document for the first time peritoneal fluid volumes and steroid hormone levels in baboons with and without endometriosis. A laparoscopy was carried out in 19 female baboons (11 with a normal pelvis and 8 with histologically proven spontaneous minimal/mild endometriosis) during 64 cycles in the early luteal phase. Peritoneal fluid was measured and aspirated. The pelvis was examined for evidence of recent ovulation and endometriosis. Peritoneal fluid and serum were assayed for 17 beta-estradiol and progesterone. The mean volume of peritoneal fluid and its concentration of 17 beta-estradiol and progesterone were 2.6 ml, 679 pmol/l and 64 nmol/l, respectively. No differences were observed between animals with or without either endometriosis or luteinized unruptured follicle syndrome. The peritoneal fluid and serum steroid levels were comparable to those found in women. The results presented are similar to those obtained in women with endometriosis and this suggests that the baboon can be used for the study of this disease.

The origin of estrogens, progesterone, androgens and sex hormone binding globulin in peritoneal fluid in the immediate postovulatory period in normal ovulating women

In 20 women with proven fertility, one menstrual cycle was monitored by ovarian ultrasonography, laparoscopy and estimation of 17 beta-estradiol (E2), estrone (E1), progesterone, testosterone, androstenedione (Adion), dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), and sex hormone binding globulin (SHBG) in serum and peritoneal fluid. Three groups were studied, in which the peritoneal fluid was collected within 1, 3 and 5 days after ovulation. E1, E2 and progesterone levels in peritoneal fluid were highest shortly after ovulation and decreased with time. Testosterone and Adion in peritoneal fluid showed no changes, but peritoneal fluid levels were always higher than serum levels. No differences were found between the peritoneal fluid and serum levels of DHEA and DHEAS. SHBG in serum was always higher than in peritoneal fluid. The results are compared with reported steroid levels in follicular fluid from the literature and factors complicating the interpretation of steroid levels in peritoneal fluid are discussed.

Inspection of the ovaries and steroids in serum and peritoneal fluid at various time intervals after ovulation in fertile women: implications for the luteinized unruptured follicle syndrome

In 20 fertile women one menstrual cycle was monitored by ovarian ultrasonography, laparoscopy, and estimation of 17 beta-estradiol (E2) and progesterone levels in serum and peritoneal fluid (PF). Three groups were studied, performing the laparoscopy within 1, 3, and 5 days after ovulation. The results indicate that the opening in the corpus luteum remains at least during the first 1.5 postovulatory days. The process of the closure starts thereafter and has been accomplished 4 to 5 days after ovulation. Progesterone and E2 levels in PF follow a similar pattern, showing high levels in the first, decreasing levels in the second, and low levels in the last laparoscopy groups. Therefore the significance of inspection of the ovaries and hormone level estimation in PF depend on the timing of the laparoscopy in relation to the moment of ovulation, especially in the first 5 postovulatory days.

Endometriosis and infertility

The relationship of endometriosis, the most common benign gynaecological disease during reproductive life, to infertility is generally ill understood. The association between infertility and minimal to mild endometriosis, when no anatomical defect is evident, may be explained by the following possible mechanisms: alternations in peritoneal fluid (macrophages - immunoglobulins, Interleukin-1, protease inhibitors, prostanoids, an ovum capture inhibitor), ovulatory dysfunctions (anovulation, LUF syndrome), luteal phase defect, disturbed implantation, and spontaneous abortion. These possibilities are discussed. The latest prospective controlled studies offer strong evidence that endometriosis per se is not a direct cause of infertility. On the other hand, the disease usually deteriorates if not treated, and therefore medical or surgical interventions are often needed when expectant treatment or other infertility therapies, e.g., ovulation induction, fail to result in pregnancy. Women with minimal to mild endometriosis only should be diagnosed as having unexplained infertility, which today may be treated by in vitro fertilization.

Limited hormonal responsiveness of ectopic endometrium: histologic correlation with intrauterine endometrium

In order to assess the hormonal responsiveness of ectopic endometrium, 438 unselected endometrial implants and corresponding intrauterine endometrium from 196 patients were evaluated and classified by standard endometrial dating criteria. Only 13% of the endometrial implants were histologically synchronous with the corresponding intrauterine endometrium. Both proliferative and secretory implants were present in relatively constant proportions throughout the menstrual cycle, demonstrating a lack of correlation with cyclic endogenous hormones. A significant percentage (range, 25% to 49%) of endometrial implants displayed some form of local hemorrhage irrespective of the menstrual cycle timing. Sixty percent of the patients had evidence of hemorrhage in at least one implant. In women receiving hormonal therapy at the time of surgery, the proportion of endometrial implants that were histologically in concert with the corresponding endometrium ranged from 0% to 33%. In early pregnancy and menopause, 50% and 31% of endometrial implants were histologically similar, respectively. These data indicate that the hormonal responsiveness of endometrial implants is unpredictable and inconsistent.

Peritoneal fluid environment and infertility

The PF environment is one that hosts the processes of ovulation, gamete transportation, fertilization, and early embryonic development. The cellular and acellular constituents of this dynamic fluid are in a constant interactive state, being influenced by the physiologic events of the menstrual cycle and pelvic disease processes; these constituents probably influence disease manifestation and reproduction. The importance of understanding this zone of early reproductive life has been now recognized. We hope that future investigations will define the exact role(s) of known components and some yet-to-be defined substances of PF in disease processes that affect reproductive function. With better understanding of normal and abnormal events in this pelvic microenvironment, we can develop rationales for novel treatment modalities.

Oestradiol-17 beta and progesterone level changes in peritoneal fluid around the time of ovulation

In 15 women, peritoneal fluid was obtained by either culdocentesis (n = 20) or laparoscopy (n = 3), before (n = 9) and after (n = 14) ovulation. Ultrasound was used for ovulation detection. Before ovulation the mean oestradiol-17 beta level in plasma and peritoneal fluid was not essentially different; the mean progesterone level was significantly higher in peritoneal fluid. After ovulation both the mean oestradiol-17 beta and progesterone levels were significantly higher in peritoneal fluid than in plasma. In peritoneal fluid, there was a wide distribution of individual oestradiol-17 beta values before and after ovulation; no significant difference existed between the mean pre- and postovulatory oestradiol-17 beta level. More consistent changes were seen in peritoneal fluid progesterone levels; the mean level was significantly higher after ovulation. In three subjects, a low postovulatory progesterone level in peritoneal fluid was associated with a cystic luteal structure observed by ultrasound, suggesting a reduced leakage of fluid from the ovulation stigma.

Pharmacologic production of luteinized unruptured follicles by prostaglandin synthetase inhibitors

Serial ultrasonic scans of follicular development were performed throughout 46 spontaneous cycles in 20 healthy female volunteers. Human chorionic gonadotropin was then given to induce follicle rupture on a particular day. Luteinized unruptured follicles (LUFs) were seen in 10.7% of untreated cycles. When prostaglandin synthetase inhibitor drugs were administered over the ovulatory period the incidence of LUF was greatly increased (to 50% with azapropazone and 100% with indomethacin). Serum estradiol concentrations and length of luteal phase were unaltered in LUF cycles. Progesterone concentrations were lower in the first half of the luteal phase if follicles remained unruptured.

The luteinized unruptured follicle syndrome: anovulation in disguise

The luteinized unruptured follicle syndrome is a form of anovulation and a subtle cause of female infertility. The syndrome cannot be diagnosed by traditional progesterone-dependent ovulation detection methods. Without the use of invasive procedures or sophisticated equipment, the luteinized unruptured follicle syndrome may go unnoticed. The patient diagnosed as ovulatory, on the basis of traditional ovulation detection methods, who does not conceive may be experiencing the luteinized unruptured follicle syndrome, and thus infertility. The syndrome's incidence, detection, etiology, and treatment are described.

Plasminogen in peritoneal fluid: a possible nonsteroidal indicator of ovulation

Plasminogen levels in peritoneal fluid were evaluated in 40 fertile women with regular ovulatory cycles. Fifteen samples were obtained before ovulation and 25 samples after ovulation. Plasminogen content and concentration in postovulatory peritoneal fluid was 0.84 +/- 0.10 mg and 6.1 +/- 0.57 mg/dl, respectively. These values were significantly higher than in the preovulatory peritoneal fluid, which were 0.36 +/- 0.12 mg (P less than 0.005) and 3.5 +/- 0.33 mg/dl, (P less than 0.001), respectively. Estradiol and progesterone (P) concentrations in peritoneal fluid were significantly higher after ovulation (P less than 0.05 and P less than 0.01, respectively). P concentration in serum and peritoneal fluid showed a linear correlation (P less than 0.05). Peritoneal fluid plasminogen is significantly elevated after ovulation and may be a nonsteroidal marker for follicular rupture and oocyte extrusion.

Diagnosis of luteinized unruptured follicle by ultrasound and steroid hormone assays in peritoneal fluid: a comparative study

Luteinized unruptured follicle detection was carried out in 27 women by means of ultrasound scans three times per day and estimation of 17 beta-estradiol and progesterone levels in peritoneal fluid. The incidence of luteinized unruptured follicle diagnosed by ultrasound was 2 of 27 and by estimation of steroid levels was 8 of 27. In three women, a follicle-like structure appeared within 24 hours after ovulation was established by ultrasound; this was accompanied by extremely low progesterone levels in the peritoneal fluid. The disparity between these methods requires further evaluation.

Follicle growth patterns and endocrinological abnormalities in infertile women with minor degrees of endometriosis

Eighteen patients whose only demonstrable cause of infertility was a minor degree of endometriosis and whose partners were normal, were investigated prospectively for one menstrual cycle using ultrasonography and endocrine profiles. Twelve cycles appeared to be normal. A luteinized unruptured follicle (LUF) occurred in two cycles and one patient had a follicular cyst. In a further two patients there was inadequate or abnormal folliculogenesis whilst in the last patient the follicle ruptured prematurely. This study describes the variety of endocrinological abnormalities found in women with mild endometriosis, and concludes that, in this series at least, there is a low frequency of LUF.

Follicle growth curves and hormonal patterns in patients with the luteinized unruptured follicle syndrome

A prospective longitudinal and standardized study is presented, dealing with ultrasonographic and hormonal characteristics of the luteinized unruptured follicle (LUF) syndrome. Among 600 cycles monitored in 270 infertility patients, 40 cycles in 27 patients showed no evidence of follicle rupture, in spite of signs of luteinization, as reflected by basal body temperature recordings and progesterone determinations. In this study, 20 LUF cycles in 20 infertile patients were compared with 45 ovulatory cycles in 45 control women. During the follicular phase, no substantial difference in follicle growth was found, but after the luteinizing hormone peak, LUF follicles, instead of rupturing, showed a typical accelerated growth pattern. Both mean luteinizing hormone peak levels and midluteal progesterone levels were significantly lower in LUF cycles than in the control cycles. However, the duration of the luteal phase was not affected. Both central and local factors can be held responsible for the lack of follicle rupture. Ultrasound offers new possibilities as a noninvasive method in diagnosing the LUF syndrome.