.
Study Population
This consisted of women in their reproductive age group who needed day-case laparoscopy mainly from the gynaecology clinic and gynaecology emergency unit. They included patients who presented with features suggestive of infertility or chronic pelvic pain.
Inclusion criteria
1. All the women scheduled for diagnostic laparoscopy on account of features suggestive of chronic pelvic pain and infertility.
Exclusion criteria
1. Women below 15 or above 49 years of age because they are not within the reproductive age group.
2. Women with massive haemoperitoneum.
3. Women with cardiopulmonary decompensation.
4. Women with gross pelvic or abdominal masses.
SAMPLE SIZE DETERMINATION
This was determined using the Kish formula95, n= Z2PQ where
a2
n = Minimum sample size
Z = Area under the normal curve corresponding to 95% confide interval = 1.96.
P = Prevalence of endometriosis in Enugu20.
= 4.3% = 0.043 q = 1-P
a = level of statistical significant = 0.05 n = 1.96x1.96x0.043x0.957
0.05 x 0.05
=55
CLINICAL MANAGEMENT
The participants were counseled for diagnostic laparoscopy.
Each step of the procedure was explained to the participants and written informed consent was obtained.
The patients were informed about the type of anaesthesia [conscious sedation using intravenous diazepam 10mg and 60mg of pentazocine]. They were also informed of the drowsiness following the anaesthesia, the slight pain during small incision just below the umbilicus and during blood sample collection. Discomfort during the procedure was also explained to the participants.
PRE-OPERATIVE MANAGEMENT
Pre-operative counselling which included detailed description of laparoscopic procedure was given. Laparoscopy was performed as out-patient procedure. Preparation included obtaining an informed consent, no ingestion of solid food for at least 8 hours prior to surgery, no liquids for more than 6 hours preoperatively. General examination and vital signs check were performed. Routine pre-operative investigations were done which included packed cell volume, full blood count and urinalysis.
Determination of blood group
Principle: Blood grouping system was based on the presence or absence of the inherited antigenic substances including proteins, carbohydrates, glycoprotein or glycolipid, on the surface of the red blood cells. It involves antigen/antibody reaction. Antisera contains antibodies and patient's blood contains antigens.
Method:
Blood grouping was carried out by collecting the patient's blood sample into a blood group bottle. The patient grouping was done using antisera A, B, AB and D. Tile method was used whereby a drop of each antisera was mixed with a drop of patient's blood and agglutination noted. Patient's cells were suspended in normal saline before grouping, (25% cell suspension). Rhesus grouping was confirmed by doing tube method. The patient's sample was washed 4 times with normal saline and then anti D added and incubated at 37°C for 1 hour. The mixture was then examined microscopically for evidence of agglutination.
Interpretation of the result:
Presence of agglutination on mixing patient's blood and antisera indicated the presence of the corresponding antigen which is the patient's blood group.
PROCEDURE OF DIAGNOSTIC LAPAROSCOPY
Patients were placed with their arms at their sides in the Lloyd David's position and cleaned with savlon and drapped. Conscious sedation was then given and intravenous fluid using normal saline was set up .Bladder was emptied using metal catheter. After careful bimanual examination, a tenaculum was attached to the cervix and a Sparksman's canula was inserted into the cervical canal and finally fixed to the tenaculum so that it can be used to manipulate the uterus. A 1cm transverse incision was given just below the umbilicus after infiltration with plain xylocaine through which a veres needle was inserted. A safety measure like easy instillation of 5ml of normal saline into the peritoneal cavity using a 10ml syringe through the veres needle was performed. Carbon dioxide was then introduced and monitored by the pneumatic insufflators, usually 2-3L. The maximum insufflation pressure did not exceed 20mmHg. The needle was withdrawn and the laparoscopic trocar and cannula inserted through the same port. After proper abdominal entry, the trocar was withdrawn and replaced with the fibreoptic laparoscope. The Sparksman's cannula was manipulated and pelvic organs observed. A panoramic view of the abdomen was done, and then pelvic organs were visualized for endometriotic spots among others. For those who were investigated for infertility, test for tubal patency was done.
To test for tubai patency, methylene blue solution was injected through the intrauterine cannula. Direct observation of dye spillage indicated tubal patency. Staging of endometriosis was performed using revised classification of American Society of Reproductive Medicine.
The operation was terminated by evacuating the insufflated gas through the cannula followed by removal of all instruments. The wound was closed with 3-0 subcuticular suture and dressed with small gauze soaked with iodine.
Postoperative follow-up
Postoperative review which included general examination and vital signs check was done. Participants were commenced on prophylactic antibiotics and analgesics. The participants were discharged and accompanied by an adult when fully recovered from conscious sedation and the vital signs normalized otherwise they were kept overnight.
Definitive treatment
The patients were referred to the managing consultant who was informed of laparoscopic findings for definitive management.
ETHICAL CONSIDERATION
The purposes of this study were explained to the potential participants. Patients who were willing signed an informed consent.
The participation in this study was voluntary and without prejudice to those who opted out or refused to participate.
Confidentiality was ensured by not writing the names of the patients on the consent form. However, where information was necessary for care of the patient, it was given to the managing consultant.
Ethical clearance was obtained from the University of Ibadan and University College Hospital Ethical Committee.
DATA MANAGEMENT
All participants proforma were collected at the end of each session of interview and errors corrected before collation.
Data collection
A proforma in form of a questionnaire was developed which consisted of serial number, patient's socio-demographic characteristics, obstetric and gynaecological history, presenting complaints, relevant examination findings at presentation and interventions. This was administered by the investigator (A copy of the proforma was attached. See Appendix 1).
Statistical analysis
Data was entered into a computer with the Statistical Package for the Social Science (SPSS version 18). The results were displayed in tables, percentages and pie charts. Significance level was set at p<0.05. Chi-square test was used to test associations between categorical variables. T-test was used to test difference in means between two continuous variables. Both tests were conducted at a significance level p<0.05.
In order to determine the factors that predict the presence of endometriosis in the subjects, a linear regression analysis was carried out using presence of endometriosis as a dependent variable.
Thereafter, Stepwise multivariate linear regression analysis was used to find out strongest risk factors associated with endometriosis.
RESULTS
Socio-demographic characteristics of the participants and presence of endometriosis.
Fifty five participants were recruited for this study but endometriosis was evidenced in fourteen (25.5%) of the participants. Table 1. Shows the socio-demographic characteristic data of the participants. The mean age of participants in this study was 33.1± 5.1 years. Majority (29.1%) were over 35 years of age.
Of fourteen participants that had endometriosis, two (14.3%) were between 15 and 20 years, three (21.4%) were in the age group 21-25 years, seven (50.0%) were 26-30 years, one (7.1%) was 31-35years and over 35 years respectively. There was no significant difference between the presence of endometriosis and age of the participants (X2 =7.905, P-value = 0.951).
Twenty seven (49.1%) participants were civil servants, ten (18.2%) were traders, 10 (18.2%) were housewives, one (1.8%) was a banker, three (5.4%) were students while four (7.3%) were applicants. Seven (50%) of the participants who had endometriosis were civil servants while two (14.3%), three (21.4%), were traders and housewives respectively, and one (7.1%) each was student and banker. Similarly, occupation of the participants was not statistically significant to the presence of endometriosis (x2 = 5.54, P - value = 0.477).
Most participants, 39 (70.8%) had tertiary education while thirteen (23.6%) had secondary education and only one (1.8%) had primary education. Nine (63.9%) of the participants that had endometriosis attained tertiary education while four (28.4%) and one (7.1%) attained secondary and primary education respectively.
There was no significant difference between the presence of endometriosis and educational attainment. (X2 = 3.14, P- value = 0.208).
Thirty-four participants (61.8%) were Yoruba, 17 (30.9%) were Igbo while three (5.6%) were Hausa. Out of fourteen participants who had endometriosis twelve (85.7%), were Yoruba while two (14.3%) were Igbo. There was no significant difference between the tribe of the participants and presence of endometriosis (x2 = 4.38; p-value = 0.112).
Caffeine consumption was noticed in three (21.3%) of the participants that had endometriosis while eleven (79.7%) of those participants that had endometriosis did not consume caffeine. There was no statistically significant association between caffeine consumption and presence of endometriosis (x2 = 3.459; P-value = 0.98).
Smoking was also noticed in two (14.2%) of the participants that had endometriosis while, twelve (85.8%) of them did not smoke.
There was no significant association between smoking and presence of endometriosis (x2 = 0.41; P-value = 1.000).
Among the participants that had endometriosis, alcohol consumption was noticed in two (14.2%) participants while twelve (85.8%) did not consume alcohol. Equally, alcohol consumption was not statistically significant for the acquisition of endometriosis (x2 = 1.375; P-value = 0.265).
Finally, out of fourteen participants that had endometriosis, all (100%) had mild exercise. Strength of exercise was not statistically significant for the presence of endometriosis (x 2 = 1.473; P-value = 0.562).
From the above, none of the socio-demographic characteristics was statistically significant for the presence of endometriosis (P > 0.05).
Distribution of menstrual pattern, parity and blood groups of the participants in relation to the presence of endometriosis.
Table 2 shows the distribution of menstrual pattern, parity and blood groups of the participants in relation to the presence of endometriosis. Of the fourteen participants who had endometriosis one (7.1%) menstruated for less than five days and thirteen (92.9%) menstruated for five days or more. The duration of menstrual flow was statistically significant for the presence of endometriosis (x2 = 3.83, p-value< 0.001).
Of the fourteen participants that had endometriosis, ten (71.4%) attained menarche at or less than 12 years while four (28.6%) attained menarche at or greater than 13 years. Age at onset of menarche was statistically significant (X2 = 27.1; P-value <0.001).
Out of fourteen participants that had endometriosis, eight (56.8%) had polymenorrhea while six (43.2%) did not have polymenorrhea. Menstrual irregularity (polymenorrhea) equally was statistically significant for the presence of endometriosis (x2 = 22.82, P <
0.001).
Nine (63.9%) participants who had endometriosis were nulliparous. There was no significant difference between the parity of the participants and the presence of endometriosis (X2 = 1.3, P-value = 0.355).
Out of fourteen participants that had endometriosis, three (21.4%) had A blood group, one (7.1%) had B while ten (71.4%) had 0 blood group.
Blood groups of the participants was not statistically significant risk factor for the presence of endometriosis (x2 = 3.577; P-value = 0.311).
Of fourteen people that had endometriosis, eleven (78.1%) were rhesus positive while three (21.9%) were rhesus negative.
Presence of rhesus factor was not statistically significant to the acquisition of endometriosis (x2 = 0.133; P-value = 0.715).
To determine the predictors of endometriosis, using linear regression analysis with the presence of endometriosis as dependent variable and individual factors as independent variable, age at menarche (B = 0.264, Std Error = 0.042, Beta = 0.658, t = 6.354, and Sig < 0.001), duration of menstrual flow (B = 0.281, Std Error = 0.64, Beta = 0.522, t = -4.409, and Sig. <0.001) and menstrual abnormality (polymenorrhea) (B= 0.758, Std Error = 0.124, beta = O.644, t = -6.131 and sig. = 0.000) were found to be the predictors for the acquisition of endometriosis.
To determine the strength of significance of the three predictors, stepwise multivariate linear regression analysis was used and it was found that the significance of duration of menstrual flow dropped (B= -0.105, Std Error = 0.048, Beta = -0.193, t = -2.186 and Sig.=0.034) while polymenorrhea (B = 0.474, Std Error = 0.102, Beta = 0.404, t =4.660, Sig < 0.001) and age at menarche (B
=0.483, Std error = 0.04, Beta = 0.095 , t = 5.067 and Sig. < 0.001) retained the same strength of significance. This is shown in table 3.
When these predictors [age at menarche, menstrual irregularity
(polymenorrhea) and duration of menstrual flow] and other variables ( age, blood group rhesus factor, alcohol and caffeine consumption, smoking, exercise, and parity ) were subjected to multivariate linear regression analysis using presence of endometriosis as a dependent variable, it was noticed that duration of the menstrual flow became insignificant while menstrual irregularity (polymenorrhea) and age at menarche again retained the same strength of significance. This is shown in table 4.
This therefore means that age at menarche ( B = 0.506, Std error 0.105, Beta = 0.480, t = 4.820, Sig= 0.000) and menstrual irregularity like polymenorrhea ( B=0.466, Std error= 0.113, Beta
=0.396, t=4.106, Sig= 0.000) were the strongest predictors of endometriosis.
Staging of endometriosis among the participants.
Table 5 shows that out of the fourteen participants that had endometriosis, three (21.3%), seven (49.7%) and four (28.4%) had stages 2, 3 and 4 disease respectively.
Symptomatology of endometriosis
Table 6 shows the symptomatology of endometriosis.
Pelvic pain. Twenty-eight (50.9%) respondents had pelvic pain. Of these, 4 (14.3%) had pain once a month, 4 (14.3%) had twice a month, 6 (21.4%) had pain thrice a month while 14 (50.0%) had more than thrice a month. Pelvic pain necessitated the use of analgesics in 20 (71.4%) of those who had it and this also resulted
in absence from work in 17 (60.7%) of them. Pelvic pain also disturbs performance of normal domestic chores in 19 (67.9%) of those who had it. Of fourteen participants that had endometriosis, seven (50.0%) had chronic pelvic pain ( Table 7).
Infertility: Out of thirty-four participants that presented with infertility, ten (29.4%) had endometriosis. Fig. 1 shows the distribution of the duration of infertility among participants. Out of fourteen participants that had endometriosis, ten (71.4%) had infertility ( Table 7).
Dyspareunia: Twenty-seven (49.1%) had dyspareunia which led to reduction in the rate of sexual intercourse in 13 (48.1%) of them.
Dyspareunia also necessitated use of analgesics in 11 (40.7%) of those who had it. Sex discontinuity was experienced by 14 (51.9%) of those who had dyspareunia .Out of fourteen participants that had endometriosis, six (42.9%) had dyspareunia ( Table 7).
Polymenorrhea: Out of fourteen participants that had endometriosis, eight (57.1%) had polymenorrhea ( Table 7).
Infertility (RR = 0.36, 95% CI: 0.21 – 0.64) and polymenorrhea (RR = 6.81, 95% CI: 3.12 –14.88) were statistically linked to endometriosis.
Table 1: Socio-demograhic Characteristics of Participants and Presence of Endometriosis
Socio-demographic
Characteristics Frequency
(%) Presence Endometriosis
%
Absence Endometriosis
(%)
X2 P- (Value) Age groups (yrs)
15-20 7(12.7) 2(14.3) 5(12.2)
7.905 0.951
21-25 8(14.5) 3(21.4) 5(12.2)
26-30 14 (25.5) 7(50.0) 7(17.1)
31-35 10(18.2) 1(7.1) 9(22.0)
>35 16 (29.1) 1(7.1) 15(36.6)
Occupation
Civil Servants 27 (49.1) 7 (50) 20 (48.8)
5.54 0.477
Traders 10 (18.2) 2 (14.3) 8 (19.5)
Housewives 10 (18.2) 3 (21.4) 7 (17.1)
Students 3 (5.4) 1 (7.1) 2 (4.8)
Applicants 4 (7.3) 0 (0) 4 (9.8)
Banker 1 (1.8) 1 (7.1) 0 (0)
Educational Attainment
Primary 1 (1.8) 1 (7.1) 0 (0)
3.14 0.208
Secondary 13 (23.6) 4 (28.4) 9 (23.1)
Tertiary 39 (70.8) 9 (63.9) 30 (76.9)
Tribe
Yoruba 34 (61.8) 12 (85.7) 22 (55..0)
4.38 0.112
Igbo 17 (30.9) 2 (14.3) 15 (37.5)
Hausa 3 (5.6) 0 (0) 3 (7.5)
Caffeine Consumption 3.459 0.98
Yes 5 (9.1) 3 (21.3) 2 (4.9)
No 50 (90.9) 11 (79.7) 39 (95.1)
Smoking
Yes 7 (12.7) 2 (14.2) 5 (12.2)
0.410 1.000
No 48 (87.3) 12 (85.8 36 (87.8)
Alcohol Consumption
Yes 4 (7.3) 2 (14.2) 2 (4.9)
1.375 0.265
No 51 (92.7) 12 (85.8) 39 (95.1)
Exercise
Mild 51 (92.7) 14 (27.5) 37 (90.2)
1.473 0.562
Strenuous 4 (7.3) 0 (0) 4 (9.8)
Table2: Menstrual Pattern, Parity and Blood groups of the participants in relation to the presence Endometriosis
Menstrual Pattern, Parity and Blood group
ENDOMETRIOSIS X2 P- Value
Present (%) Absence % Duration of menstrual flow (Days)
<5 1 (7.1) 27 (65.9)
3.83 < 0.001*
≥ 5 13 (92.9) 14 (34.1)
Age (yrs) at menarche
≤ 12 10 (71.4) 2 (16.7)
27.1 < 0.001*
≥ 13 4 (28.6) 39 (90.7)
Menstrual Irregularity (Polymenorrhea)
Yes 8 (56.8) 1 (11.1)
22.82 0.001
No 6 (43.2) 40 (87)
Parity
Nulliparous 9 (64.3) 19 (67.9)
1.3 0.355
Non-Nulliparous 5 (35.7) 22 (81.5)
Blood Groups
A 3 (21.4) 8 (19.5)
3.577 0.56
B 1 (7.1) 10 (24.4)
AB 0 (0) 3 (7.3)
O 10 (71.4) 20 (48.4)
Rhesus factor
Positive 11 (78.1) 34 (82.9)
0.133 0.715
Negative 3 (21.9) 7 (17.1)
Table3: Multivariate analysis to determine the influence of the covariates (predictors) with presence of endometriosis as dependent variables.
Predictors B Std.
Error
Beta t Sig.
Constant 0.445 0.386 - 1.152 0.255
Duration of menstrual flow
0.105 0.048 -0.193 -2.186 0.034
Menstrual irregularity
(polymenorrhea)
0.474 0.102 0.404 4.660 0.000
Age at menarche 0.483 0.04 0.095 5,067 0.000
Table 4: Multivariate Linear regression analysis of the predictors of endometriosis and other socio-demographic factors.
Factors B Std.
Error
Beta t Sig.
Constant 0.505 0.715 - 0.706 0.484
Age -0.007 0.009 -0.073 -0.728 0.471
Duration of menstrual flow
-0.108 0.054 -0.200 -1.993 0.054
Parity 0.025 0.27 0.096 0.899 0.374
Menstrual irregularity
(polymenorrhea)
0.466 0.113 0.396 4.106 0.000
Blood group -0.009 0.032 -0.026 `-0.278 0.783 Rhesus status -0.125 0.101 -0.111 -1.237 0.223 Alcohol consumption -0.127 0.161 -0.076 -0.788 0.435 Caffeine consumption 0.171 0.156 0.113 1.097 0.279
Smoking 0.095 0.133 0.073 0.716 0.478
Exercise 0.046 0.195 0.024 0.235 0.815
Age at menarche 0.506 0.105 0.480 4.820 0.000
Table 5: Staging of endometriosis in participants according to American Society for Reproductive Medicine Classification65.
Stage Frequency Percentages
1 (Minimal) 0 0%
2 (Mild) 3 21.3%
3 (Moderate) 7 49.7%
4 (Severe) 4 28.4%
Table 6: shows the symptomatology of endometriosis
Symptomatology Total (%)
Endome.
(%)
No
Endo(%)
RR 95%CI (lower)
Upper
Chronic pelvic pain Yes 28(50.9) 7(25.0) 21(75.0)
1.21 0.48 3.05 No 27(49.09) 7(25.9) 20(74.1)
Infertility Yes 34(61.8) 10(29.4) 24(70.6)
0.36 0.21 0.64 No 21(38.2) 17(80.9) 4(19.1)
Dyspareunia Yes 27(60.0) 6(22.2) 21(77.8)
0.50 0.21 1.20 No 18(40.0) 8(44.4) 10(55.6)
Polymenorrhoea Yes 9(16.4) 8(88.9) 1(11.1)
6.81 3.12 14.88 No 46(83.6) 6(13.0) 40(87.0)
Infertility (RR = 0.36, 95% CI: 0.21 – 0.64) and polymenorrhea (RR = 6.81, 95% CI: 3.12 –14.88) were statistically linked to endometriosis.
Table 7: Frequency Distribution of Endometriosis amongst patient according to symptomatology
Symptomatology Presence of endometriosis
Percentages
Chronic pelvic pain 7 50.0
Inferlity 10 11.4
Dyspareunia 6 42.9
Polymenorrhea 8 57.1
Fig. 1: Distribution of duration (years) of infertility among patients who presented with infertility
> 10 yrs 18%
5 - 10 yrs
< 5yrs 21%
61%
Fig. 2: Distribution of ABO blood group among participants
B 20%
A 20%
AB 6%
O 54%
Table 8: Distribution of ABO and Rhesus Blood group among participants with endometriosis
ABO AND RHESUS BLOOD GROUPS
ENDOMETRIOSIS PERCENTAGES
A 3 21.4
B 1 7.1
AB 0 0
O 10 71.4
RHESUS POSITIVE 11 78.7
RHESUS NEGATIVE 3 21.3
DISCUSSION
All the participants in this study were in their reproductive age group. This is understandable as the symptoms at presentation are mostly found in this group of patients.
The prevalence of endometriosis among women undergoing diagnostic laparoscopy for chronic pelvic pain and infertility in this study was 25.5%. The prevalence of endometriosis was known to be low as documented by Ezem et al18, Otolorin et al19 and Osefo et al20. But the prevalence was high in this study because the people recruited for this study were already the population with symptomatologies of endometriosis. Moreso, laparoscopy rather than open surgery was used. In the study with same methodology, diagnostic and selection criteria, the incidence was equally high. This study shows that endometriosis is being underdiagnosed in our environment because of poor mode of diagnosis and different methodology and selection criteria.
Ezem et al18 studied the incidence of endometriosis in hysterectomy specimens among Fulani and Hausa populations in Nigeria. Two hundred and sixty five abdominal hysterectomies were used. They concluded that the incidence of endometriosis in the two study populations was 1.6%. In that study open surgery was used and patients who had chronic pelvic pain and infertility and did not require hysterectomy were excluded in the study. The age range recruited in this study 17-70 years and uterine fibroid was the commonest indication for the surgery. Laparoscopy was not used and it was a retrospective study and some of the women recruited were postmenopausal (endometriosis regresses during the postmenopausal period). These could be the reasons for the
documented lower incidence.
Osefo et al20 conducted a retrospective study on the incidence of endometriosis among Igbos using one thousand and three hundred and eighty four women and he noted an incidence of 4.3%
in patients who underwent pelvic surgeries. These were open surgery and diagnosis of endometriosis was made visually without laparoscopy. The age distribution ranged from 19 to over 60 years, again, including postmenopausal women. The indications for the surgery were not stated. Patients who had chronic pelvic pain and infertility but did not have any surgery could have been missed. All these led to lower incidence documented.
Otolorin et al19 conducted a prospective study on the evaluation of the tubo-peritoneal factor in infertile Nigerian women using 218 diagnostic laparoscopies. The participants were women who had been infertile for 12 years or more. An incidence of 1.4%
was reported but the selection criteria were quite different. Only infertile women were selected and these were women who had been infertile for 12 years or more but most the patients used in this study were infertile for less than 5 years . Patients who had chronic pelvic pain were excluded.
The difference in the prevalence, therefore, may be due to difference in participant’s selection, methodology and diagnostic criteria. It is possible that majority of those who had endometriosis but did not present with overt symptoms were missed.
An Italian study was cited because of similar methodology and selection criteria used. The study was a multicentric study to determine the prevalence and anatomical distribution of endometriosis in women with selected gynaecological conditions.
Three thousand, six hundred and eighty four women were recruited for the study, 1069 had infertility and chronic pelvic pain while 1800 had fibroid and 735 had benign ovarian cyst. The methodology involved use of laparoscopy to identify endometriosis in women in their reproductive age. The result was that for the women who had chronic pelvic pain and infertility 380 (35.5%) had endometriosis.
This shows that using almost the same methodology and selection criteria, the incidence of endometriosis was high though lower than that of caucasians.
This could be due to lifestyle changes of women in this part of the world which is becoming similar to those of women in western countries as a result of westernization and cross-cultural civilization.
The fact that more endometriosis could be detected at laparoscopy emphasizes the importance of the use of laparoscopy in the investigation of women with infertility and chronic pelvic pain.
Several factors such as smoking, exercise, alcohol and caffeine consumption have been reported by researchers as being associated with endometriosis. This study explored the relationship between endometriosis and these factors. Cramer et al21 in their study on the epidemiology of endometriosis using women undergoing tubal ligation, infertile women and women with chronic pelvic pains and adolescents, smoking was noticed to be associated with decreased incidence of endometriosis while alcohol and caffeine consumption were noticed to be statistically significant as risk factors for endometriosis.The interpretation being that factors (smoking .exercise) that decrease estrogen level and those (caffeine and alcohol consumption) that increase estrogen level cause decrease and increase incidence of endometriosis respectively. Signorello et al28 in
their study on the epidemiologic determinants of endometriosis, a hospital based study, showed that endometriosis has an inverse association with exercise (OR=0.6; 95% Cl, 0.3-1.5). Both Cramer et al21 and Signorello et al28 also showed increased exposure to menstruation as a risk factor for endometriosis.
In contrast to the above findings, this study did not show any significant association between smoking, exercise, caffeine, alcohol consumption and endometriosis. The reason could be due to difference in the incidence of these habits among women in the two populations, giving false impression of these habits as risk factors for endometriosis in the western countries. Moreso, inclusion of adolescents in the study population could have been the cause of the misconception because these habits are commoner in this age group.
However, menstrual irregularity (polymenorrhea), duration of menstrual flow and age at menarche were the significant predictors and from the stepwise multivariate linear regression analysis, menstrual irregularity (polymenorrhea) and age at menarche were the strongest predictors. This will support the implantation theory as the cause of endometriosis which has been attributed to retrograde menstruation as a result of prolonged period of menstruation.
In this study, blood group of patients did not have any significant association with endometriosis. Matalliotakis61 in a study done in the United States of America reported that women with endometriosis had a 2.9 fold increased risk in the A blood group distribution while O was less predominant. From this study, majority of the participants with endometriosis (71.4%) have blood group O while 21.4% have blood group A. The difference in our finding may be due to difference in the distribution of ABO blood group in the two populations.
In this environment, the prevalence of blood groups O and A are 53.12%
and 21.30% respectively while presence and absence of rhesus factor are 93.32% and 6.68% respsctively96.
Presence of Rhesus factor was also not statistically associated with endometriosis in contrast to what was reported by Berfu et al59. Berfu and co-workers in a similar study conducted among Turkis population, showed that endometriosis is significantly high among patients that are rhesus positive.
It is pertinent to note that three participants were rhesus negative. This shows that about 5.5% of the participants were rhesus negative, which almost gives the same prevalence as obtainable in this environment (6.7%)96.
In this study, none of the patients reported a similar condition in their relatives. It could also be that this study is in concordance with some other researchers who have challenged the evidence of endometriosis having a genetic background.58
The three factors that were significantly associated with endometriosis in this study were menstrual related. Early age at menarche, prolonged duration of menstrual flow and presence of menstrual irregularity (polymenorrhea) were all significantly associated with endometriosis. This is in conformity with what was reported by Cramer et al21 and Signorello et al28 that factors that cause prolonged exposure to menstruation are the predisposing factor to endometriosis.
However, parity of patients was not significantly associated with endometriosis in contrast to what some authors reported.
From this study, women who in their reproductive age group, presenting with chronic pelvic pain and infertility, and have