Origin of peritoneal fluid in women: an ovarian exudation product

Neonatal uterine bleeding as antecedent of pelvic endometriosis

Brosens I et al., 2013 · Human reproduction (Oxford, England)

We elaborate on a new theory to explain pelvic endometriosis, including endometriosis in premenarcheal girls, based on the finding that the neonatal endometrium can display secretory activity immediately after birth and, in some cases, changes analogous to those seen at menstruation in adults. The neonatal uterus is therefore capable of shedding its endometrium. Indeed, occult vaginal bleeding occurs in a majority of neonates, although overt bleeding is estimated to occur in only 5% of neonates. This may be due to functional plugging of the endocervical canal in the neonate, which in turn would promote retrograde flux of endometrial cells contained in menstrual debris. Ectopic endometrial implantation in a newborn with hydrometrocolpos has been documented. These data, coupled with the observation of a significantly increased risk of endometriosis in adolescents with cervical outflow obstruction and patent Fallopian tubes, indicate that endometriosis, especially in children and young adolescents, may originate from retrograde uterine bleeding soon after birth.

The pathophysiology of uterine adenomyosis: an update

Benagiano G et al., 2012 · Fertility and Sterility

A role for menstruation in preconditioning the uterus for successful pregnancy

Brosens JJ et al., 2009 · Am J Obstet Gynecol

Menstruation is widely viewed as serving no purpose other than to reinitiate the endometrial cycle in the absence of pregnancy. Yet, it is striking that cyclic endometrial decidualization followed by menstrual shedding is confined to the few species, including human beings, where placenta formation entails deep trophoblast invasion of maternal tissues and its vasculature. Both menstruation and pregnancy are inflammatory conditions that cause a degree of physiological ischemia-reperfusion tissue injury, albeit much more so in pregnancy. Thus, the emergence of cyclic menstruation may not have been an evolutionary coincidence but serves to protect uterine tissues from the profound hyperinflammation and oxidative stress associated with deep placentation, a process known as preconditioning. The concept of menstrual preconditioning provides a novel paradigm for understanding how reproductive disorders impact on pregnancy outcome. For example, endometriosis could be viewed as a disorder of exaggerated menstrual preconditioning that confers protection against placentation-related disorders, such as preeclampsia.

Endometriosis is associated with a decreased risk of pre-eclampsia

Brosens IA et al., 2007 · Hum Reprod

We postulated that impaired endometrial differentiation in women with pelvic endometriosis predisposes for pre-eclampsia. A retrospective case-control study set at the University of Ghent IVF centre. The incidence of pre-eclampsia and pregnancy-induced hypertension (PIH) following the clinical and/or laparoscopic diagnosis of endometriosis-associated infertility (case group; n = 245 pregnancies) was compared with the incidence of these obstetric complications in pregnancies following treatment for male-factor infertility (control group; n = 274 pregnancies). Pregnancy data were obtained by searching electronic databases and postal questionnaires. The case and control groups were matched for age, parity and multiple pregnancies. The incidence of pre-eclampsia was significantly lower in the case group (0.8%) when compared with control group (5.8%) (P = 0.002; odds ratio (OR) = 7.5, 95% confidence interval (CI): 1.7-33.3). Analysis of obstetric outcome in the subgroup of patients with laparoscopic data confirmed the lower risk of pre-eclampsia in the case (1.2%) versus control (7.4%) groups (P = 0.032; OR = 6.6, 95% CI: 1.2-37). PIH occurred in 3.5% and 8.7% of case and control pregnancies, respectively (P = 0.018; OR = 2.6, 95% CI: 1.2-6.0). The odds of developing pre-eclampsia were 5.67 times higher in the control group than in pregnancies following endometriosis-associated infertility. In multiple pregnancies, the odds of developing pre-eclampsia increased 1.93 times per additional child, with or without endometriosis. We found no evidence that endometriosis predisposes for pre-eclampsia. Instead, the risk of hypertensive disorder in pregnancy is significantly reduced in women with endometriosis-associated infertility.

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

Scheenjes E et al., 1990 · Fertil Steril

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.

Endometrial tissue in peritoneal fluid

Bartosik D et al., 1986 · Fertil Steril

Peritoneal fluid (PF) was studied for the presence of endometrial tissue in a consecutive series of 67 women (with documented tubal patency) undergoing diagnostic laparoscopy, tubal lavage, and hysteroscopy. PF was completely aspirated from the cul-de-sac both before and after uterine irrigation. The PF was then analyzed for the presence of endometrial tissue. In native PF no significant difference in the incidence of endometrial tissue between patients with (19%) and without (11%) endometriosis (P = 0.6) was observed. Refluxed PF, obtained after uterine irrigation, showed a significantly higher incidence of endometrial tissue in women with endometriosis (76%) as compared to controls (42%) (P = 0.03). We propose two models to explain the development of endometriosis. These are not mutually exclusive, may be independent of each other, and may represent two distinct pathophysiologic disease processes.

Peritoneal fluid: its relevance to the development of endometriosis

Ramey JW et al., 1993 · Fertil Steril

To review and evaluate published studies that have examined the role of peritoneal fluid (PF) in the development of endometriosis. Important studies related to this topic have been identified through a computerized bibliographical search (MEDLINE), as well as by manually scanning the published literature of major reproductive journals over the last several years. Studies that examined the effect of PF or its components on the pathophysiology of endometriosis are discussed. These include reported effects on the histogenesis, maintenance and proliferation of endometriosis, as well as related actions on infertility. The majority of investigations into the role PF plays in the pathogenesis of endometriosis have evaluated how it may adversely affect fertility. Suggestive but inconclusive data in the literature indicate that degenerating endometrial tissue may release a biochemical factor(s) into the peritoneal environment that is capable of inducing ectopic endometrium formation. Peritoneal fluid itself contains growth factor that may play a role in the implantation and maintenance of the ectopic endometrium. The PF of women with endometriosis has been shown to contain angiogenic as well as other growth factors. These compounds may contribute to the proliferation of the ectopic endometrium.

Fluid Retention over the Menstrual Cycle: 1-Year Data from the Prospective Ovulation Cohort

White CP et al., 2011 · Obstet Gynecol Int · Free full text on PubMed Central

We report menstrual and mid-cycle patterns of self-reported "fluid retention" in 765 menstrual cycles in 62 healthy women. Self-reported "fluid retention," commonly described as bloating, is one element of the clinical assessment and diagnosis of premenstrual symptoms. These daily diary data were collected as part of an observational prospective one-year study of bone changes in healthy women of differing exercise characteristics. Ovulation was documented by quantitative basal temperature analysis, and serum estradiol and progesterone levels were available from initial and final cycles. Fluid retention scores (on a 0-4 scale) peaked on the first day of menstrual flow (mean ± 0.9 ± 0.1), were lowest during the mid-follicular period, and gradually increased from 0.22 ± 0.05 to 0.50 ± 0.09 over the 11 days surrounding ovulation. Mid-cycle, but not premenstrual, fluid scores tended to be lower in anovulatory cycles (ANOVA P = 0.065), and scores were higher around menstruation than at midcycle (P < 0.0001). Neither estradiol nor progesterone levels were significantly associated with fluid retention scores. The peak day of average fluid retention was the first day of flow. There were no significant differences in women's self-perceived fluid retention between ovulatory and anovulatory cycles.