It is estimated that 25 to 35 percent of female infertility is associated with tubal abnormalities through functional or anatomic causes [1]. Extensive emphasis is given to mechanical injury, such as through peritubal adhesions, fimbrial agglutination, and intraluminal obstruction and ciliary damage. Though there has been meaningful investigation of how peritonitis influences patency, understanding of how hormonal shifts affect tubal patency is limited.

Distinct from mechanical obstruction, it is established that androgens can affect tubal function [2, 3]. Ciliary flagellation decreases with testosterone exposure [2]. Accumulation of intraluminal secretions and cellular debris increases for testosterone-pretreated transmen with supraphysiologic hyperandrogenism [3]. In a retrospective case series of our study group, eight percent of women with PCOS (showing signs of elevated testosterone levels) were found to have occluded fallopian tubes during laparoscopy [4]. Though hormonal effects may hinder tubal patency, they have not been proven to cause complete or lasting obstruction.

With several studies suggesting that hyperandrogenism is associated with multiple risks for tubal dysfunction [2, 3], it is natural to question whether hormonal shifts increase occlusion in general when compared with otherwise healthy women. Further, the literature also lacks data regarding the incidence of tubal blockage in a general population of women without subfertility. Since laparoscopic chromopertubation is rarely performed in women without infertility, it would be of interest to study the tubal patency of a healthy population and to compare it to women with hyperandrogenism. To achieve this end, we explored the role of hyperandrogenism on tubal patency by comparing infertile, anovulatory women undergoing laparoscopy with chromopertubation for PCOS and non-subfertile women undergoing the procedure for ovarian cyst indications, excluding participants with concurrent endometriosis or pelvic inflammatory disease (PID).

No difference was observed for mean patient age at the time of surgery between women of the PCOS and women of the control group (28.3 $\pm$ 4.9 versus 29.2 $\pm$ 4.1 years, respectively; p = 0.226). PCOS women were found to have a statistically higher BMI, consistent with greater risk for the metabolic syndrome (PCOS: 25.3 $\pm$ 4.5 kg/m${}^2$; p = 0.022, controls: 23.3 $\pm$ 4.3 kg/m${}^2$). No participants in either the PCOS or in the control group had undergone previous abdominal surgery. In PCOS women, the mean LH:FSH ratio was 2.3 $\pm$ 1.3. Mean serum testosterone, androstenedione and DHEAS levels were 0.5 $\pm$ 0.2 ng/mL, 3.7 $\pm$ 2.3 ng/mL, and 2.6 $\pm$ 1.2 $\mu$g/mL, respectively.

Regarding laparoscopic chromopertubation, PCOS patients had greater need for high pressure chromopertubation to demonstrate bilateral tubal patency to an extent that statistically was significantly more often than controls (12.4% versus 2.1%; p = 0.036). There were no other differences between the groups, which also includes the total number of occluded tubes and the total number of patent tubes achieved by high chromopertubation pressure only (p $>$ 0.05; Table 2).

We also substratified PCOS women by comparing those having bilateral patency with low pressure (n = 172) to those with high pressure patency on chromopertubation (n = 25; Table 3). The latter revealed higher total testosterone levels (0.66 $\pm$ 0.17 versus 0.47 $\pm$ 0.24 ng/mL; p = 0.001) and higher DHEAS levels (3.57 $\pm$ 1.07 versus 2.51 $\pm$ 1.13 $\mu$g/mL; p 0.001), whereas there were no differences in the LH:FSH ratio or in androstenedione levels, or in estradiol levels.

In this retrospective case-control study, about seven percent of all Fallopian tubes were occluded. Of note, it is rare to see laparoscopic chromopertubation control groups where no participants have immediate procreative goals. Given that tubal factor accounts for up to thirty percent of subfertility and is one of the most common etiologies [1], it is important to know that only about four percent of women without subfertility have bilateral occlusion, emphasizing the close link between tubal disease and nonconception [1].

No differences were noted between women with PCOS or with ovarian cysts for the total number of occluded tubes or the number with bilateral blockage (Table 2). Accordingly, given the typical difficulty in obtaining control groups without subfertility, it would be reasonable to consider using clomiphene- or letrozole-resistant PCOS women without known PID, hydrosalpinges, or endometriosis as a laparoscopic control group for chromopertubation studies. However, it was more common in PCOS patients to require high chromopertubation pressure in order to achieve patency (12.4% versus 2.1%; p = 0.036; Table 2), suggesting that the Fallopian tubes may be inherently different for patients with PCOS. With multiple studies showing testosterone to influence Fallopian tube function [2, 3, 11], it seems reasonable to find differences.

Given that differences in testosterone levels do not seem to increase occlusion, two main factors may explain why PCOS patients require higher chromopertubation pressures to demonstrate patency. First, they have higher BMI, where increasing intraabdominal pressures (accentuated by abdominal adiposity) lead to a need for greater pressure to demonstrate patency. However, with a mean BMI of 25.3 relative to 23.3 in ovarian cyst controls, a two-point shift in BMI is unlikely to account for a six-fold increase in needing additional pressure. Moreover, standardization of intraabdominal insufflation pressures (12 mm Hg) may lead to less space with pneumoperitoneum in patients with a higher BMI means that the amount of pressure on the tubes still remains fifteen millimeters of mercury.

If neither obstruction nor obesity are reasons for needing higher pressures to achieve patency in PCOS women, then this may derive from shifts in the tubal lumen from hyperandrogenism. As noted in the introduction, PCOS women have slower flagellation of cilia associated with testosterone exposure [2]. Also, there is increased intraluminal accumulation of secretions and cell debris for the Fallopian tubes of testosterone-pretreated transmen [3]. Admittedly, the supraphysiologic testosterone levels in transmen do not reflect those in PCOS women, consistent with PCOS patients in our study having a mean testosterone level of 0.5 ng/mL. However, plugging of the tubes through intraluminal debris has been postulated as a reason for subfertility. Notably, it was found that women with high pressure patency was associated with significantly higher testosterone levels. Though high testosterone levels are associated with both accumulation of intraluminal debris [3] and high-pressure patency, future studies will have to directly correlate these issues, as we did not specifically track which patients had increased intraluminal contents. Moreover, this debris does not invade the tubal lumen so one would not expect a meaningful increase in pressure to be required for displacement. These findings need to be compared to fecundity, as high pressure patency has been linked with lower pregnancy rates [12].

Study limitations which need to be mentioned include the retrospective study design as well as the sample size in the control group. In detail, given a prevalence of bilateral Fallopian tube occlusion of 6.3% in the control group, a minimum sample size of 47 patients per group would have been sufficient to show a significant difference between the two groups, if the rate for bilateral occlusion was 25% in PCOS women (power 80%, alpha 0.05, after Fleiss correction). This underscores the fact that a larger sample size would be needed to completely rule out minor differences between the groups. However, 48 patients undergoing chromopertubation without subfertility is a larger control group than is readily found in the literature for chromopertubation in non-subfertile women. Another opportunity for improvement is that the pressure needed to achieve tubal patency was only measured subjectively; however, most research on tubal patency doesn’t account at all for the degree of pressure required. Studies which use a direct measurement of chromopertubation pressure are underway. Also, subjectively measured pressures may have influenced by confounding variables other than tubal function. However, since many of these possible variables were applied as exclusion criteria and since only experts in tubal surgery were responsible for chromopertubation, we consider this a minor limitation only. Additionally, for generalizability, PCOS participants were medication resistant to the point of undergoing ovarian drilling, which doesn’t reflect the majority of women with PCOS. Also, hormone levels were not available for the control group. However, since none of the women in the control group met the revised Rotterdam criteria, we would expect normal testosterone profiles even though this was not directly confirmed. Additionally, for many women hysteroscopy was performed prior to laparoscopy. Were there longer operative hysteroscopies, myometrial edema could have created a false positive for occlusion with chromopertubation when the tubes would normally be patent. However, access to the uterine cavity was easy in all patients and operative hysteroscopies had brief duration, making this consideration unlikely to meaningfully shift results. Last but not least, though pelvic inflammatory disease was an exclusion critiera, medical history about other sexually transmitted infections (STI), which could have resulted in tubal adhesions and blockage, were not available. However, when most women who have had an STI are unaware of it, not accounting for this factor may actually enhance generalizability.

This retrospective case-control study adds three central findings to the literature. First, for women without subfertility and without known risk factors for tubal disease, six percent of all Fallopian tubes are occluded and four percent of women have bilateral blockage. Second, women with medication-resistant anovulatory PCOS requiring drilling have similar rates of tubal occlusion relative to patients without subfertility, making these women a reasonable but more available control group for laparoscopic chromopertubation studies. Third, higher total testosterone and DHEAS levels were found in enrolled PCOS patients and this was associated with a need for higher chromopertubation pressures to demonstrate bilateral patency. Future studies should directly correlate accumulation of tubal debris with high pressure patency and on quantifying chromopertubation pressure objectively rather than subjectively.

DM—protocol and project development, data collection and management, manuscript writing; JPP—protocol and project development; MH—data collection and management, manuscript editing; RM—data analysis; JO—protocol and project development, data analysis, data collection and management, manuscript writing. All authors read and approved the final manuscript.

This study was approved by the Institutional Review Board (IRB) of the Medical University of Vienna (IRB number 2371/2020. Data in this retrospective study was anonymized; thus, the requirement for informed consent was waived.

Not applicable.

This research received no external funding.

The authors declare no conflict of interest. JO is serving as one of the Editorial Board members and Guest editors of this journal. We declare that JO had no involvement in the peer review of this article and has no access to information regarding its peer review. Full responsibility for the editorial process for this article was delegated to MD.

The datasets generated and analyzed during the current study are not publicly available, since the dataset will be used for other retrospective analysis. The data are available from the corresponding author upon reasonable request.