|Year : 2016 | Volume
| Issue : 2 | Page : 74-79
Prevalence of Chlamydia trachomatis immunoglobulin G antibody in infertile women in Calabar
Patience O Odusolu, Ekpo E Edet, Cajethan I Emechebe, Thomas U Agan, Andrew E Okpe, Saturday J Etuk
Department of Obstetrics and Gynaecology, University of Calabar Teaching Hospital, Calabar, Nigeria
|Date of Web Publication||13-Jan-2017|
Patience O Odusolu
Department of Obstetrics and Gynaecology, UCTH, Calabar
Source of Support: None, Conflict of Interest: None
Background: Genital Chlamydia trachomatis infection is recognized as the single most common cause of tubal peritoneal damage leading to infertility. Knowledge of the prevalence of Chlamydia antibodies among infertile women will help determine the level of Chlamydial infection and hence its contribution to infertility. Objectives: To determine the prevalence of C. trachomatis immunoglobulin G (IgG) antibody in infertile patients and the sociodemographic characteristics and risk factors associated with infection in Calabar. Materials and Methods: This was a prospective comparative study conducted among 145 women presenting for infertility in UCTH Calabar. Another 145 women with normal pregnancies attending the antenatal clinic were used as controls. The data was analyzed using the Statistical Package for the Social Sciences (SPSS) version 18.0 (SPSS Inc, Chicago, IL, USA). A P-value of less than 0.05 was considered significant. Results: The prevalence of C. trachomatis IgG antibody was 38.6% in the infertile group and 22.8% in the pregnant controls. This difference was statistically significant (P < 0.05). Infertile women aged 30–34 years had the highest positivity rate (36.0%) for C. trachomatis antibody. Thirty-eight (42.7%) of the infertile subjects who tested positive had a history of pelvic inflammatory disease (PID) while 47 (23.4%) who tested negative had a history of PID. The difference was statistically significant (P = 0.001). Chlamydia infection was not found to be associated with any particular type of infertility (P > 0.05). Conclusion: The prevalence of C. trachomatis was higher in infertile women when compared to pregnant controls. This finding lends credence to the call for enzyme immunosorbent assay for Chlamydial IgG antibodies to be incorporated into infertility investigation in this environment.
Keywords: Chlamydia trachomatis, IgG antibody, infertility, prevalence
|How to cite this article:|
Odusolu PO, Edet EE, Emechebe CI, Agan TU, Okpe AE, Etuk SJ. Prevalence of Chlamydia trachomatis immunoglobulin G antibody in infertile women in Calabar. Afr J Med Health Sci 2016;15:74-9
|How to cite this URL:|
Odusolu PO, Edet EE, Emechebe CI, Agan TU, Okpe AE, Etuk SJ. Prevalence of Chlamydia trachomatis immunoglobulin G antibody in infertile women in Calabar. Afr J Med Health Sci [serial online] 2016 [cited 2017 Aug 21];15:74-9. Available from: http://www.ajmhs.org/text.asp?2016/15/2/74/198319
| Introduction|| |
Infertility is a worldwide problem that affects about one in 10 couples and leading to increasing number seeking specialist fertility care., The high prevalence of infertility in Africa has profound implications for women’s reproductive health. There is a high premium placed on childbearing in many African societies; infertility is therefore a social destabilizing condition for couples, and a cause of marital disharmony and physical violence against women. Tubal pathology is the most common cause of infertility in this sub-region, accounting for approximately 30–35% of infertile women. Genital Chlamydia trachomatis infection is now recognized as the single most common cause of tubal peritoneal damage., This infection, commonly unrecognized and often poorly or inadequately treated, can ascend the reproductive tract resulting in pelvic inflammatory disease (PID) and consequently infertility.
Infection with C. trachomatis results in the formation of antibodies detectable in serum. The demonstration of IgG antibody in infertile women may be useful as a marker for a subgroup of women at increased risk of tubal pathology.
Besides, there is lack of information as regards the prevalence of Chlamydia infection in women presenting with infertility in our center. Therefore, the aim of this study was to determine the prevalence of C. trachomatis immunoglobulin G antibody among infertile women in our center and to assess the sociodemographic and other risk factors associated with Chlamydia infection among infertile women.
| Materials and methods|| |
The study was a prospective comparative study to determine the prevalence of Chlamydia antibodies among patients with infertility in University of Calabar Teaching Hospital.
The study population included women presenting with infertility at the gynecological clinic. All women with infertility within the study period that met the criteria for inclusion participated in the study.
The sample size was calculated using the single proportion formula: n = (1.96)2 pq/d2; where n = sample size, p = proportion which is 10% from a study on the prevalence of developing tubal infertility after Chlamydia PID; d = margin of error which is 5% and q = 1−p.
To compensate for nonresponse, the selected sample size (ns) was calculated to be: ns = calculated sample size/anticipated response rate (0.95) ns = 138/0.95; ns = 145.
Hence, 145 subjects were studied, in each of the two groups of infertile and pregnant women. The total number of women studied was therefore 290 women. Inclusion criterion for cases was women who met the definition of infertility and gave informed consent while inclusion criterion for controls was pregnant women attending antenatal clinic who consented.
Recruitment of subjects
A structured questionnaire was used to collect information from the women and from their case records. A simple random sampling method was used until the required sample size was achieved. For each infertile woman, a pregnant control was randomly selected. The technique used was lottery. The serial number against each woman in the clinic register was copied into pieces of paper and all put into a non-transparent bag. The bag was shuffled and a piece of paper was picked from the bag blindly each time with replacement. Each time a number which has been picked and replaced was picked again, the paper was returned into the bag, shuffled, and the process of picking repeated. Women whose names were picked and also met the inclusion criteria were included in the study as cases. This was continued until the sample size of 145 was reached. For each case, a control was selected from the pregnant women who met the inclusion criteria for control.
For serology testing, 5 mL of venous blood was collected from each subject into a sterile plain specimen bottle, properly labeled, and sent to the Medical Microbiology Laboratory where they were analyzed. The blood specimen was allowed to clot, and then centrifuged to obtain clear sera. The specimen was kept at 2–8°C and analyzed in batches for serum Chlamydia antibodies. The serological assay was done using the C. trachomatis immunoglobulin G enzyme-linked immunosorbent assay (ELISA) kit (manufactured by Human Diagnostics in Germany, product no. 51228).
Results were read directly through the bottom of the microwell plate using an automated photometer (ELISA-reader). The plate was read at 450 nm. The standard curve on semi logarithmic paper was plotted with A450 nm as ordinate and log10 concentration of standard.
The data obtained was analyzed using Statistical Package for the Social Sciences (SPSS) version 18.0 (SPSS Inc, Chicago, IL, USA). Categorical data was analyzed using the chi-square (χ2) and Fischer exact test. A P-value of less than 0.05 was considered significant.
Clearance was obtained from the Ethics Committee before recruitment of subjects commenced. All women eligible to participate in the study were adequately informed and their consents obtained before they were enrolled. Participation was voluntary. They were informed that nonparticipation would not influence their care. A record of subjects was under the custody of the investigators.
| Results|| |
A total of 290 blood serum samples were screened for the presence of C. trachomatis IgG antibodies. Of these samples, 145 were from infertile women and 145 from pregnant controls. Among the infertile women, 56 (38.6%) had IgG antibody to C. trachomatis in their serum, while 33 (22.8%) of the pregnant women were positive for the antibody [Table 1]. This difference was statistically significant (P = 0.005).
|Table 1 Comparing Chlamydia trachomatis IgG in infertile women with pregnant control|
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[Table 2] shows that most of the infertile women (86%) were between the ages of 25 and 39 years, while 89% of the pregnant controls were between the ages of 20 and 34 years. Majority of the subjects in the infertile and pregnant groups had secondary and tertiary education. Of the infertile women, 65 (44.8%) were civil servants, followed closely by traders who were 50 (34.5%). The reverse was the case for the control group, as the majority, that is, 68 (46.9%) were traders and 36 (24.8%) were civil servants.
|Table 2 Sociodemographic characteristics of infertile and fertile women n (%)|
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[Table 3] shows the frequency of C. trachomatis IgG antibody in relation to the sociodemographic characteristics. This study showed that subjects aged 30–34 years had the highest positivity rate (36.0%) for C. trachomatis antibody; this was closely followed by age group 25–29 and 35–39 years having 34.8% and 16.9% positivity, respectively.
|Table 3 Sociodemographic characteristics associated with Chlamydia trachomatis IgG among infertile and pregnant women at UCTH|
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Forty-nine (55.1%) and 39 (43.8%) of those who had secondary and tertiary education, respectively, tested positive to Chlamydia IgG antibodies. This difference was statistically significant (P < 0.05).
Forty (44.9%), 28 (31.5%), and 15 (16.9%) of traders, civil servants, and unemployed subjects, respectively, tested positive to Chlamydia IgG antibodies (P = 0.05).
The mean number of life-time sexual partners in the subjects and controls was 2.59 ± 0.11; and 2.21 ± 0.098, respectively [Table 4]. The difference was not statistically significant at P = 0.255. Twenty – seven (30.3%) of those who never took OCPs tested positive. This was not statistically significant, P = 0.779.
|Table 4 Risk factors associated with Chlamydia trachomatis IgG among infertile and pregnant women at UCTH|
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Thirty-eight (42.7%) of the infertile subjects who tested positive had a history of PID while 47 (23.4%) of the infertile subjects who tested negative had a history of PID. The difference was statistically significant (P = 0.001).
Comparing C. trachomatis IgG with type of infertility as shown in [Table 5], a total of 35 (74.5%) of those with primary infertility and 12 (25.5%) of those with secondary infertility tested positive. The difference was of no statistical significance (P = 1.000).
| Discussion|| |
The prevalence of C. trachomatis IgG antibody in this study was 38.6% in the infertile women and 22.8% in the pregnant controls. This difference was statistically significant (P < 0.05). The higher proportion of Chlamydial infection among infertile women in this study population is probably a reflection of higher rate of tubal infertility that has been documented in Nigeria when compared to other developed countries. Studies in Nigeria and other West African countries show prevalence from 23.4 to 65.8% in infertile population, and 17.3% in pregnant women,, which is consistent with the result from this study for the infertile population. This is far higher than similar studies conducted in the United Kingdom and other western countries which reported figures of about 10.4%. Similar studies conducted by Okoro et al., Omo-Aghoja et al., and Jeremiah et al. reported prevalences of serum Chlamydia IgG antibodies in infertile women as 45%, 65.8%, and 74%, respectively. The wide variation of Chlamydia prevalence in above studies with this study may be due to several factors, such as study population (i.e., selection of high-risk groups), socioeconomic status, and different ELISA tests kits employed. The limitation of the study by Jeremiah et al. is that qualitative test kit was used, so results were either positive or negative for IgG antibody to Chlamydia. In this study, this limitation was overcome by using a quantitative test kit that determined the titer level of the antibody which showed the difference in titer range for the positive results in the pregnant controls and infertile women.
The high prevalence recorded in this study may be related to the poor health-seeking behavior of Nigerian women, especially on sexually transmitted infection. The fear of possible stigma and accusation of marital infidelity may be an added barrier to accessing care for sexually transmitted infections (STIs) by the womenfolk in our setting.
The demographic analysis of this study showed that most of the women with Chlamydial infection were civil servants or business women and attended higher education. This was inconsistent with analysis from similar study by Morhason-Bello et al., which showed that women with lower educational level or none are more likely to be at risk of Chlamydial infection. The reason may be because women of higher socioeconomic status are more likely to present to health facilities for health-related problems and hence detection of asymptomatic cases in this group of women.
This study showed that subjects aged 30–34 years had the highest positivity rate (36.0%) for C. trachomatis antibody; this was closely followed by age groups 25–29 and 35–39 years having 34.8% and 16.9% positivity, respectively. This finding is inconsistent with those of other studies that have shown a decline in the prevalence rate after 25 years of age., A similar study that was done in this center by Inyang-Etoh et al. where C. trachomatis antigen detection cassette was used to detect the presence of Chlamydia antigen in endocervical swabs showed that the highest rate of infection (30.4%) was observed among those aged between 18 and 25 years. The reason for the high positivity of C. trachomatis IgG antibodies in subjects aged 25–34 in this study, may be because of the frequent persistence of anti-Chlamydial IgG antibodies for prolonged periods of time, even among women who have been treated with antibiotics or due to reinfection with C. trachomatis.
A literature survey suggests that the use of hormonal contraceptive methods increases the risk of C. trachomatis infection., Hormonal contraception promotes sexual activity and frequent changes of sexual partners, thus leading to cervical ectopy. In this study, only 27 (30.3%) of those who used oral contraceptive pills were among the C. trachomatis-positive patients. This was not statistically significant as most of them were married or had one sexual partner.Thirty-eight (42.7%) of respondents with and 51 (57.3%) without history of PID tested positive to IgG, and this was statistically significant in the fertile women (P < 0.001) (odds ratio (OR) = 0.518, confidence interval (CI) = 0.374–0.718). This lends credence to the fact that clinical history is not reliable in making a diagnosis of Chlamydial infection and World Health Organization (WHO) estimates that 70–80% of women infected with C. trachomatis are symptom-free.
Comparing C. trachomatis IgG with type of infertility, 35 (74.5%) and 12 (25.5%) of those with secondary and primary infertility, respectively tested positive. The difference was of no statistical significance (P = 1.000). This compares with similar study by Inyang-Etoh et al., though is inconsistent with study by Akande et al. which showed that antibody titers were found to be significantly higher among infertile women who had previously conceived compared to those with primary infertility. This finding may be related to increased risk factors for STIs, including increased numbers of sexual partners, in those with secondary infertility, or with higher prevalence of other causes of infertility (anovulation or endometriosis) in those with primary infertility.
This study relied in part on information obtained with a precoded questionnaire and history obtained from the subjects, some important facts might not have been volunteered.
The possibility of cross-reaction of the antibody with other microorganisms leading to false-positive result and also a negative antibody result does not rule out current or recent past infection.
| Conclusion|| |
The prevalence of C. trachomatis was higher in infertile women when compared to the pregnant controls, and there was a strong association between Chlamydia antibody positivity and tubal blockage. In a resource-poor country such as Nigeria, enzyme immunosorbent assay for Chlamydial IgG antibodies should be incorporated into the routine infertility investigation and since infertility resulting from C. trachomatis is preventable, clinicians should be more aware of its deleterious effects even in asymptomatic women who will benefit from early screening and treatment.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]