We conducted a hospital-based cross-sectional analytical study with retrospective data collection. Medical records covering a 10-year period from January 1, 2014 to December 31, 2022 were reviewed. Data collection and analysis were conducted over a five-month period from January to June 2025.

The study was conducted in the gynecology departments of three specialized healthcare facilities in Douala, Cameroon:

Douala General Hospital (HGD)Douala Gyneco-Obstetrics and Pediatrics Hospital (DGOPH)Clinique de l’Aéroport (CA)

The first two institutions are tertiary-level teaching and referral hospitals providing advanced gynecological care and specialist training. Clinique de l’Aéroport is a private healthcare facility specialized in minimally invasive gynecological surgery and assisted reproductive techniques.

All three centers are equipped with video-laparoscopy systems enabling direct visualization of pelvic structures. Laparoscopic procedures were performed by experienced gynecologic surgeons with 8 - 35 years of surgical experience.

A non-probabilistic exhaustive sampling method was used.

We included all medical records of women who underwent diagnostic and/or operative gynecological laparoscopy during the study period for indications including infertility, chronic pelvic pain, adnexal masses, or suspected ectopic pregnancy.

A diagnosis of pelvic endometriosis was retained when one of the following criteria was met:

1) Laparoscopic diagnosis: Direct visualization of typical endometriotic lesions such as powder-burn lesions, ovarian endometriomas, or deep infiltrating nodules by experienced surgeons.

2) Histological confirmation: Identification of endometrial glands and/or stroma on histopathological examination of biopsy specimens obtained during laparoscopy.

Diagnosis was primarily based on laparoscopic visualization. Biopsy with histological examination was performed when lesions appeared atypical or when diagnostic uncertainty existed.

Medical records with incomplete data (defined as missing more than 20% of required study variables) were excluded from the analysis.

Following administrative authorization and ethical approval, surgical registers were reviewed to identify eligible cases. Complete medical files were subsequently retrieved from hospital archives. Data were collected using a standardized data extraction form developed in accordance with the study objectives and relevant literature. The form was pretested on a subset of medical records not included in the final analysis and refined accordingly. Data extraction was carried out by trained physicians under the supervision of the principal investigator. To ensure data quality and consistency, a random sample of records was cross-checked, and any discrepancies were resolved through consensus.

Sociodemographic characteristics: Age, marital status, education level, and occupation.

Gynaecological and reproductive variables: Age at menarche, menstrual cycle length and regularity, gravidity, parity, and family history of endometriosis.

Medical and surgical history: History of diabetes mellitus, hypertension, prior abdominal or pelvic surgery.

Lifestyle factors: Alcohol consumption and tobacco use.

All laparoscopic procedures were performed by senior surgeons with documented expertise in minimally invasive gynaecological surgery.

An exhaustive sampling approach was adopted, including all eligible cases that met the inclusion criteria during the study period. As a result, no a priori sample size calculation was performed. The final sample size corresponded to the total number of complete medical records available and eligible across the three study sites.

Data were entered and analyzed using SPSS version 24.0.

Categorical variables were summarized as frequencies and percentages.

Bivariate analysis was performed to evaluate associations between pelvic endometriosis and independent variables using crude odds ratios (ORs) with their 95% confidence intervals (CIs).

Variables with p < 0.20 in bivariate analysis were included in a multivariate logistic regression model to identify independent factors associated with endometriosis while controlling for potential confounders.

Adjusted odds ratios (AORs) with 95% confidence intervals were reported. Statistical significance was set at p < 0.05.

Family history of endometriosis was not included in the multivariate model due to complete separation, as no cases were observed among the control group, preventing reliable estimation of adjusted odds ratios.

The study was conducted in accordance with the ethical principles of biomedical research involving human subjects. Ethical approval was obtained from the Institutional Ethics and Research Committee (2025/083/UDM/PR/CEAQ). Given the retrospective nature of the study, informed consent was waived. Patient confidentiality was strictly maintained by anonymizing all extracted data and restricting access to study files to the researchers.

During the study period, 506 women underwent gynecological laparoscopy in the three participating centres. Of these, 440 patients (87.0%) met the inclusion criteria and were included in the analysis.

Pelvic endometriosis was identified in 99 women, yielding a surgical prevalence of 22.5% among women undergoing laparoscopy.

Diagnosis was based on direct laparoscopic visualization of typical endometriotic lesions (Figures 1-3). Biopsies for histological confirmation were performed in 88 cases (20.0%), with histopathology confirming endometriosis in 81 cases, corresponding to a confirmation rate of 92.0%.

Figure 1. Bilateral endometrioma.

Figure 2. Laceration of the pelvic parietal peritoneum. Clear, reddish, and brownish endometriotic vesicles.

Figure 3. Brownish hemoperitoneum; clear endometriotic vesicles. On a hypervascularized parietal peritoneum.

In bivariate analysis, occupation in the private sector was significantly associated with pelvic endometriosis. Women working in the private sector had more than twice the odds of endometriosis compared with those in the informal sector (OR = 2.47; 95% CI: 1.20 - 5.09; p = 0.014).

Age, marital status, and level of education were not significantly associated with pelvic endometriosis in bivariate analysis (Table 1).

Table 1. Socio-demographic factors associated with pelvic endometriosis (Bivariate analysis).

Notes: 1) The reference group for Age is 45 - 54 years, 2) The reference group for Marital status is Single, 3) The reference group for Occupation is Informal, 4) The reference group for Level of education is Primary, 5) Significant result at p < 0.05: Occupation (Private) is associated with a higher odds of endometriosis (OR = 2.47, p = 0.014).

Several clinical and reproductive variables were significantly associated with pelvic endometriosis (Table 2).

Table 2. Clinical factors associated with pelvic endometriosis (Bivariate analysis).

Notes: 1) OR: Odds ratio; CI: Confidence interval, 2) Reference category indicated where applicable, 3) NA: Not applicable (cell count = 0, OR not estimable), 4) Percentages are calculated per column, 5) Statistical significance set at p < 0.05.

An age at menarche ≤ 11 years was associated with a nearly fivefold increased risk of endometriosis (OR = 4.84; 95% CI: 2.50 - 9.39; p < 0.001). Similarly, a menstrual cycle length ≤ 27 days significantly increased the odds of endometriosis (OR = 5.35; 95% CI: 3.27 - 8.77; p < 0.001).

Conversely, primigravidity (OR = 0.45; 95% CI: 0.25 - 0.82; p = 0.009), paucigravidity (OR = 0.35; 95% CI: 0.19 - 0.65; p < 0.001), and a history of pelvic surgery (OR = 0.27; 95% CI: 0.15 - 0.51; p < 0.001) were associated with reduced odds of pelvic endometriosis.

A family history of endometriosis was significantly associated with the condition (p < 0.001). Other medical comorbidities and lifestyle factors, including hypertension, diabetes, alcohol consumption, and tobacco use, showed no significant association.

After adjustment for potential confounders in multivariate logistic regression analysis (Table 3), five variables remained independently associated with pelvic endometriosis.

An age at menarche ≤ 11 years (aOR = 5.14; 95% CI: 2.49 - 10.64; p < 0.001) and a menstrual cycle length ≤ 27 days (aOR = 5.20; 95% CI: 2.91 - 9.30; p < 0.001) were independently associated with increased odds of pelvic endometriosis.

Table 3. Factors associated with endometriosis (Multivariate analysis).

In contrast, a history of pelvic surgery (aOR = 0.30; 95% CI: 0.14 - 0.61; p < 0.001), primigravidity (aOR = 0.49; 95% CI: 0.25 - 0.98; p = 0.045), and paucigravidity (aOR = 0.34; 95% CI: 0.16 - 0.70; p = 0.003) were independently associated with reduced odds of endometriosis

This study found a surgical prevalence of pelvic endometriosis of 22.5% among women undergoing gynecological laparoscopy in three hospitals in Douala between 2014 and 2022. This prevalence is consistent with the findings of Nana N. et al., who also reported a prevalence of 22.5% among women undergoing laparoscopy for chronic pelvic pain in Cameroon [10]. However, it is higher than the 3.12% prevalence reported by Bilkissou et al. [15]. These differences may reflect variations in study design and patient selection. While Bilkissou et al. included clinically diagnosed cases, the present study focused exclusively on women undergoing laparoscopy, which likely increased the detection of endometriotic lesions.

Histological confirmation was not performed systematically in our study. Nevertheless, among cases where biopsy was performed, histopathology confirmed endometriosis in 92% of cases. This high concordance between laparoscopic and histological findings may reflect the expertise of the surgeons performing the procedures. McKee et al. reported that visual diagnosis during laparoscopy has high sensitivity but moderate specificity when compared with histological confirmation [16]. In contrast, Buchweitz et al. highlighted the variability in laparoscopic diagnosis and emphasized the importance of histological confirmation when feasible [17].

Early menarche (≤11 years) and short menstrual cycle length (≤27 days) were strongly associated with pelvic endometriosis. Women with early menarche had approximately fivefold higher odds of endometriosis (AOR = 5.14; 95% CI: 2.49 - 10.64; p < 0.001), while those with shorter menstrual cycles had a similarly increased risk (AOR = 5.20; 95% CI: 2.91 - 9.30; p < 0.001). These findings are consistent with those reported by Burghaus et al., who identified early menarche and shorter menstrual cycles as important risk factors for the development of endometriosis [18]. From a pathophysiological perspective, early menarche increases lifetime exposure to estrogen, while shorter cycles increase the frequency of menstruation and the likelihood of retrograde menstruation, a central mechanism proposed in Sampson’s theory of endometriosis pathogenesis [19].

A history of pelvic surgery was inversely associated with endometriosis in the present study (AOR = 0.30; 95% CI: 0.14 - 0.61; p < 0.001). This finding contrasts with the results of Ashrafi et al., who reported pelvic surgery as a potential risk factor for endometriosis [20]. The observed inverse association should be interpreted cautiously, as it may reflect reverse causation or selection bias rather than a true protective effect. Women with prior pelvic surgery may have undergone procedures for conditions unrelated to endometriosis, or surgical history may influence referral patterns for laparoscopy.

Similarly, primigravidity and paucigravidity were inversely associated with endometriosis. This observation aligns with findings from Ashrafi et al., who reported a negative association between the number of pregnancies and endometriosis [20]. Pregnancy reduces the number of menstrual cycles and is associated with prolonged exposure to progesterone, which exerts antiproliferative effects on endometrial tissue [21]. However, the relationship between pregnancy and endometriosis remains complex. A meta-analysis by Leeners et al. did not confirm a consistent protective effect of pregnancy, suggesting that residual confounding and reverse causation may influence these associations [22].

A family history of endometriosis was strongly associated with the disease in bivariate analysis (p < 0.001). However, this variable was not retained in the multivariate model due to complete separation, as no cases were reported among the control group. This prevented reliable estimation of adjusted odds ratios. Previous studies have demonstrated that genetic susceptibility plays an important role in the development of endometriosis, with familial aggregation suggesting involvement of hormonal, inflammatory, and immune regulatory pathways [23][24].

The association observed between private-sector employment and endometriosis in bivariate analysis may reflect socioeconomic differences in access to healthcare. In many resource-limited settings, laparoscopic procedures may be more accessible to women with higher socioeconomic status, potentially leading to underdiagnosis among women in the informal sector.

This study has several strengths. It included a relatively large sample size and involved three specialized healthcare facilities performing laparoscopic surgery, which enhances the reliability of the findings. In addition, all procedures were performed by experienced surgeons trained in minimally invasive gynecological surgery.

However, some limitations should be acknowledged. The retrospective design may have introduced information bias due to incomplete documentation in medical records. Histological confirmation was not performed systematically in all cases, which may introduce some diagnostic misclassification. Furthermore, the study population consisted exclusively of women undergoing laparoscopy for specific gynecological indications, which may limit the generalizability of the findings to the broader population.