3 Methods
3.9 Intrumentation
Approving Authority: The approval for the study was obtained from the research and ethical committees of Jos University Teaching Hospital, Plateau Specialist Hospital and Faith Alive Hospital Jos.
Voluntary Participation: Informed consent was obtained from the subjects before enlistment for the study after due information about the study. The subjects who wished not to participate in the research or wished to withdraw after enlistment for the study were allowed to do so. This did not by any means influence their subsequent management.
Confidentiality: The information obtained from this study was stored and analyzed without the name of the participants. The results of this research work may be published in a medical literature without revealing the identity of participants. The blood collected was not used for any other reason except for this research purpose. The remaining blood sample after the analysis was discarded appropriately.
The participants were assured of confidentiality of their information based on the Principles of Bioethics.58,59,60 Their spouses were not informed, knowing that revealing a positive test result of this research may jeopardize their marriage. A positive test does indicate previous infection and not on-going infection, therefore partner tracing was not necessary.7,23
Beneficence: This study posed minimal risk to the participants, however; during the process of blood collection participants felt pain of a needle prick at the site of blood collection. When the test result was out, some were grieved on receiving positive result and resort to self-blame for the
21
tubal ectopic pregnancy and probably reduced self-esteem. These women were properly counseled.
Non-malficence: No harm was done to the participants other than needle prick pain during blood collection and grieve or reduced self-esteem on receiving positive result of past Chlamydia trachomatis infection.
Justice: There was equitable recruitment of participants, no favoritism towards participants.
22
CHAPTER FIVE RESULTS
A total of 80 women were enrolled in this study. This comprised of 40 women who had tubal ectopic pregnancy (cases) matched for age with 40 uncomplicated parous second trimester pregnant women (control).
Table 1 below shows socio-demographic characteristics of study participants. The mean age for cases and controls were 29.45±5.66 years and 29.03±4.41 years respectively. The participants were largely (83.7%) below age 35 years; 85% of cases were married and 15% were single while the control were all married. Majority of cases (60.0%) and controls (82.5%) have had between 1-4 children.
Approximately 63% of tubal ectopic pregnancy occurred at gestational age of less than 10 weeks with average gestational age of 8.83±1.57 weeks; average gestational age for control was 20.88±3.78 weeks.
23
Table 1: Socio-demographic characteristics of study participants
Characteristics Study group χ2 p-value
Case n=40(%) Control n=40(%) Age (years)
<35 31(77.5) 36(90.0) 2.296 0.130
≥35 9(22.5) 4(10.0)
Education
Primary 4(10.0) 2(5.0) 0.908 0.635
Secondary 20(50.0) 23(57.5)
Tertiary 16(40.0) 15(37.5)
Marital Status
Married 34(85.0) 40(100.0) - 0.026*
Single 6(15.0) 0(0.0)
Occupation
Housewife 14(35.0) 21(52.5) 9.429 0.024
Business 15(37.5) 6(15.0)
Civil servant 4(10.0) 10(25.0)
Others 7(17.5) 3(7.5)
Religion
Christianity 32(80.0) 18(45.0) 10.453 0.001
Islam 8(20.0) 22(55.0)
Parity
0 14(35.0) 0(0.0) 18.199 0.001
1-4 24(60.0) 33(82.5)
≥5 2(5.0) 7(17.5)
EGA
<10 25(62.5) 0(0.0) 36.364 0.001
≥10 15(37.5) 40(100.0)
Alcohol intake
Yes 8(20.0) 0(0.0) - 0.005*
No 32(80.0) 40(100.0)
Smoking
Yes 0(0.0) 0(0.0) - -
No 40(100.0) 40(100.0)
*Fisher’s exact test p- value
24
Table 2 below shows Chlamydia IgG titre in Cases and Control, 55.0% of cases tested negative while 85.0% of controls tested negative
Table 2 : Chlamydia IgG titre in cases and control(Positive Chlamydia antibody titre ≥11.0) Chlamydia IgG titre
levels
Cases n=40(%)
Control n=40(%)
χ2 P
0-10.9 22(55.0) 34(85.0) 11.771 0.008
11-11.9 2(5.0) 3(7.5)
12-12.9 1(2.5) 0(0.0)
≥13 15(37.5) 3(7.5)
Table 3 below shows the prevalence of Chlamydia antibody and average serum levels of IgG anti chlamydial antibody in cases and controls. The overall prevalence of IgG anti Chlamydial antibody was 30.0%; prevalence of IgG anti Chlamydial antibody in cases was 45.0% and 15.0%
in controls. The difference was statistically significant (p-value<0.05). The mean serum level of IgG anti Chlamydial antibody titre for cases was 11.07±2.91 and 8.75±2.43 for controls. The difference was statistically significant (p-value<0.05).
25
Table 3: Prevalence of Chlamydial antibody And Average serum levels of IgG Chlamydial antibody in cases and controls
Chlamydial antibody Case n=40(%) Control n=40(%) χ2 p-value
Yes 18(45.0) 6(15.0) 8.571 0.003
No 22(55.0) 34(85.0)
Antibody Titre (Mean±SD)
11.07 ±2.91 8.75 ±2.43 t-test=
3.880
0.001
Overall prevalence=30.0%
Table 4 below shows the sensitivity, specificity, predictive values of Chlamydial IgG antibody testing; and positive and negative likelihood ratio of Chlamydia antibody testing (CAT) for tubal ectopic pregnancy. The positive predictive value (PPV) of tubal ectopic pregnancy using IgG anti Chlamydia antibody was 75.0%. This means that women with suspected tubal ectopic pregnancy who tested positive for IgG Chlamydia antibody have 75.0% chance of having tubal ectopic pregnancy. The negative predictive value (NPV) of IgG for tubal ectopic pregnancy was 60.7%. The sensitivity was 45% while the specificity was 85.0%. The positive likelihood ratio was 3.0, and negative likelihood ratio was 0.6. A positive likelihood ratio greater than 1 indicates the test result is associated with the disease.
26 Table 4: Sensitivity, specificity and predictive values
Chlamydial antibody Tubal Ectopic Total Yes No
Yes 18 6 24
No 22 34 56
Total 40 40 80
PPV 75.0%
NPV 60.7%
Sensitivity 45.0%
Specificity 85.0%
Positive Likelihood Ratio=Sensitivity/1-specificity=0.45/0.15=3.0 Negative Likelihood ratio=1-sensitivity/specificity=0.55/ 0.85=0.6
Table 5 below shows indicators and risk factors of past pelvic infection in cases and control, 57.5% of the cases gave history suggestive of past PID while 42.5% did not, none of the controls gave history suggestive of past PID (P<0.05). There was no significant difference in age at coitarche in both cases and controls. 57.5% of cases gave history of infertility. History of at least an episode of induced abortion was noted in 37.5% of the cases. Six of the cases has had ectopic pregnancy in the past giving recurrence rate of 15.0%. There was significant number of cases who had multiple sex partners (67.5%) than the controls (42.5%), P-value=0.025.
27
Table 5: Relationship between clinical/risk factors for pelvic infection and Chlamydia trachomatis among study participants
Characteristics Case n=40(%) Control n=40(%) χ2 p-value
Vaginal discharge
Yes 23(57.5) 0(0.0) 32.281 0.001
No 17(42.5) 40(100.0)
Lower abdominal pain
Yes 18(45.0) 0(0.0) 23.226 0.001
No 22(55.0) 40(100.0)
Fever
Yes 9(22.5) 0(0.0) - 0.002*
No 31(77.5) 40(100.0)
Dyspareunia
Yes 13(32.5) 0(0.0) 15.522 0.001
No 27(67.5) 40(100.0)
Sexual partner
1 13(32.5) 23(57.5) 5.051 0.025
≥2 27(67.5) 17(42.5)
PID
Yes 23(57.5) 0(0.0) 32.281 0.001
No 17(42.5) 40(100.0)
Age at coitarche
<18years 20(50.0) 18(45.0) 0.201 0.654
≥18years 20(50.0) 22(55.0)
Infertility
Yes 23(57.5) 0(0.0) 32.281 0.001
No 17(42.5) 40(100.0)
Used condom
No 24(60.0) 29(72.5) 1.398 0.237
Occasionally 16(40.0) 11(27.5)
Induced Abortion
0 25(62.5) 40(100.0) 18.462 0.001
≥1 15(37.5) 0(0.0)
Ectopic*
YES 6(15.0) 0(0.0) - 0.026*
No 34(85.0) 40(100.0)
*Fisher’s exact test p-value
28
Table 6 below shows levels of Chlamydial antibody according to PID status and number of sex partners among cases, IgG anti Chlamydial antibody level in those that gave history suggestive of PID was higher than those without such history but the difference was not significant (p-value=0.099). Also there was higher level of IgG in those with history of multiple sex partners than those without but the difference was not statistically significant (p-value=0.113).
Table 6: Levels of chlamydial antibody according to PID status and number of sexual partner among cases
PID Yes No t-test p-value
Chlamydial antibody 10.77±2.90 9.58±2.87 1.668 0.099
Sex partner 1 ≥ 2 t-test p-value
Chlamydial antibody 9.35±2.52 10.39±3.15 1.602 0.113
29
Table 7 below shows relationship between socio-demographic characteristics and Chlamydia trachomatis infection among cases with none of the factors showing statistical significance.
Table 7: Relationship between socio-demographic characteristics and Chlamydia trachomatis infection among cases
Characteristics Positive chlamydia antibody χ2 p-value
Yes n=18(%)
No n=22(%) Age (years)
<35 13(72.2) 18(81.8) - 0.705*
≥35 5(27.8) 4(18.2)
Education
Primary 0(0.0) 4(18.2) 4.091 0.129
secondary 11(61.1) 9(40.9)
Tertiary 7(38.9) 9(40.9)
Marital Status
Married 14(77.8) 20(90.9) - 238*
Single 4(22.2) 2(9.1)
Occupation
Housewife 3(16.6) 11(50.0) 5.974 0.113
Business 9(50.0) 6(27.3)
Civil servant 3(16.7) 1(4.5)
Others 3(16.7) 4(18.2)
Religion
Christianity 14(77.8) 18(81.8) - 1.000*
Islam 4(22.2) 4(18.2)
Parity
0 7(38.9) 7(31.8) 1.785 0.410
1-4 11(61.1) 13(59.1)
≥5 0(0.0) 2(9.1)
EGA
<10 12(66.7) 13(59.1) 0.242 0.622
≥10 6(33.3) 9(40.9)
Alcohol intake
Yes 4(22.2) 4(18.2) - 0.100*
No 14(77.8) 18(81.8)
Smoking
Yes 0(0.0) 0(0.0) - -
No 18(100.0) 22(100.0)
*Fisher’s exact test p- value
30
Table 8 below shows relationship between indicators/risk factors for pelvic infection and Chlamydia trachomatis infection among cases; none of the factors showed statistical significance.
Table 8: Relationship between clinical/risk factors for pelvic infection and Chlamydia trachomatis infection among cases
Characteristics Positive chlamydia antibody χ2 P-value
Yes n=18(%)
No n=22(%) Vaginal discharge
No 9(50.0) 8(36.4) 0.753 0.385
Yes 9(50.0) 14(63.6)
Lower abdominal pain
No 10(55.6) 12(54.5) 0.004 0.949
Yes 8(44.4) 10(45.5)
Fever
No 12(66.7) 19(86.4) - 0.253*
Yes 6(33.3) 3(13.6)
Dyspareunia
No 14(77.8) 13(59.1) 1.576 0.209
Yes 4(22.2) 9(40.9)
Sexual partner
1 6(33.3) 7(31.8) 0.010 0.919
≥2 12(66.7) 15(68.2)
PID
No 9(50.0) 8(36.4) 0.753 0.385
Yes 9(50.0) 14(63.6)
Age at coitarche
<18years 6(33.3) 14(63.6) 3.636 0.057
≥18years 12(66.7) 8(36.4)
Infertility
No 6(33.3) 11(50.0) 1.125 0.289
Yes 12(66.7) 11(50.0)
Used condom
No 10(55.6) 14(63.6) 0.269 0.604
Occasionally 8(44.4) 8(36.4)
Induced Abortion
0 10(55.6) 15(68.2) 0.673 0.412
≥1 8(44.4) 7(31.8)
Ectopic
No 14(77.8) 20(90.9) - 0.381
Yes 4(22.2) 2(9.1)
*Fisher’s exact test p-value
31
Table 9 below shows logistic regression of factors associated with ectopic gestation. The Odds ratio for Chlamydia infection was 4.636; 95% CI=1.593-13.494 , and the Odds ratio for multiple sex partners was 2.658; 95% CI=1.045-6.762.
Table 9: Logistic regression of factors associated with ectopic gestation
Factors Odds ratio 95%CI P-value
Chlamydia antibody
Yes 4.636 1.593 – 13.494 0.005
No 1
Sexual partner
≥2 2.658 1.045 – 6.762 0.040
1 1
32
CHAPTER SIX DISCUSSION
The IgG anti Chlamydial antibody was used to determine prior Chlamydia trachomatis infection in 80 women which involved 40 women with tubal ectopic pregnancy (cases) which were matched for age with 40 uncomplicated second trimester pregnant women (controls). The overall prevalence of IgG anti Chlamydial antibody in this study was 30.0%. This is comparable with prevalence of 30.0% in UK24 and 38.5% in Zaria.26 However, it is lower than 56.1% reported in an earlier study in Jos,3 and that reported in Lagos 51.0%,9 South Eastern Nigeria 40.7%25 but higher than the prevalence in Benin 13.3%.27
In this study the seroprevalence of IgG anti Chlamydial antibody was significantly higher (45.0%) in women with tubal ectopic pregnancy (cases) than women with intrauterine pregnancy (15.0%), P-value <0.05. This is in keeping with the findings of Adewumi et al in Lagos ( 62.4%
versus 29.0%),19 Agholor et al in Benin (48.0% versus 16.3%)16 and Ibe et al in Port Harcourt (53.1% versus 28.1%).61
The serum level of IgG anti Chlamydial antibody of ≥ 11 was said to be positive in this study.
The average IgG anti Chlamydial antibody for cases (women with tubal ectopic pregnancy ) was 11.07±2.91 and that of controls (intra-uterine pregnant women) was 8.75±2.43. This was statistically significant (p-value<0.05), and this was in keeping with several reports on tubal ectopic pregnancy with respect to IgG anti Chlamydial antibody level.16,19,32,33,61
There was no significant difference in anti Chlamydial IgG antibody level between those with history suggestive of PID and those without such history. This may be explained by genital Chlamydia infection being asymptomatic in 80% of cases.3
33
The factors found to be associated with tubal ectopic pregnancy in this study were Chlamydia antibody positivity and having two or more sex partners. These factors were subjected to logistic regression and Chlamydia antibody positivity was found to be associated with tubal ectopic pregnancy, Odds ratio=4.636 (1.593-13.494; P-value=0.005). The finding of an association between prior Chlamydia trachomatis infection and tubal ectopic pregnancy is in keeping with the findings in a number of reports.16,19,32,33,61 The Benin16 and Portharcourt61 studies did not show strong association between Chlamydia infection and tubal etopic pregnancy.
The Scandinavian studies34,35 had divergent results concerning the association of tubal ectopic pregnancy and prior Chlamydia trachomatis infection, reduced risk of tubal ectopic pregnancy was found in a Denmark study,34 and no association was found in a Swedish study.35 In this study having two or more sex partners was associated with tubal ectopic pregnancy; Odd ratio=2.658(1.045-6.762; P-value=0.04), this finding was corroborated by the Benin study.16 Multiple sex partners is a risk factor for Chlamydia trachomatis infection so as other sexually transmitted infections.1,3,4,7
Chlamydia antibody level could be of predictive value in detection of tubal damage and is quantitatively related to the severity of damage.62,63,64 The sensitivity and specificity of Chlamydia antibody testing (CAT) in this study were 45.0% and 85.0% respectively, while the positive predictive value (PPV) and negative predictive value (NPV) were 75.0% and 60.7%
respectively. A positive predictive value of tubal ectopic pregnancy of 75.0% means that for women with suspected tubal ectopic pregnancy who tested positive to IgG anti Chlamydia antibody have 75% chance of having tubal ectopic pregnancy due to tubal damage, and a negative predictive (NPV) of 60.7% means that women with suspected tubal ectopic pregnancy
34
who tested negative to IgG anti Chlamydia antibody have 60.7% chance of not developing tubal ectopic pregnancy due to tubal damage.65
The positive predictive value of Chlamydia antibody testing for tubal ectopic pregnancy of 75.0% in this study is higher than 66% noted by Olaleye et al62 for tubal damage, but lower than 80.7% by Gharajeh et al63 and 100% by Singh et al.64 The negative predictive value of 60.7% is lower than 89% by Olaleye et al,62 86.7% by Gharajeh et al63 and 100% by Singh et al.64 The positive likelihood ratio of 3.0 was noted with a negative likelihood ratio of 0.6. A positive likelihood ratio greater than 1 indicates the test is associated with the disease.65
CONCLUSION
This study has shown that a greater proportion of women with tubal ectopic pregnancy had serological evidence of prior Chlamydia trachomatis infection than women with uncomplicated intrauterine pregnancy. It also demonstrated a 4.6 fold risk association between prior Chlamydia trachomatis infection and tubal ectopic pregnancy. Further more, having two or more sexual partners was positively associated with tubal ectopic pregnancy.
LIMITATION OF STUDY
IgG Chlamydia trachomatis Antibody Test (CAT) is a marker of a previous Chlamydia trachomatis infection, but does not reflect the course of the infection and neither the eventual extent of the resulting tubal damage. Further studies may be required to evaluate these limitations.
The result would be more representative if polymerase chain reaction (PCR) and, or ligase chain reaction (LCR) were assayed alongside anti Chlamydia trachomatis antibody.
35
Neisseria gonorrhea and other microorganisms such as Mycoplasma genitalium that can cause tubal ectopic pregnancy were not ruled out.
RECOMMENDATION
There is a need to re-address safe practices through sex education, and prompt and effective treatment of sexually transmitted infection will likely contribute in reducing the burden of tubal ectopic pregnancy.
36
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