Participant characteristics
Between January 1st, 2012 and December 31st, 2017, 626 446 pregnant women were screened for syphilis and 1302 were identified to be syphilis-seropositive. A total of 1299 syphilis-seropositive pregnant women with complete available information were enrolled.963 male partners of syphilis-seropositive pregnant women presented to clinic and received screening for syphilis. Data of 1299 syphilis-seropositive pregnant women and 963 male partners were included for analyses.
Characteristics of 1299 syphilis-seropositive pregnant women are presented in Table 1. The pregnant women had a mean age of 28.81 (SD=5.85, range: 16–49).Most pregnant women presented to the clinics for routine antenatal care at their first ANC visits (n=936, 72.1%), and the rest presented for emergency services, including being parturient (n=165, 12.7%), spontaneous abortion (n = 43, 3.3%), stillbirth (n = 25, 1.9%), ectopic pregnancies (n =120, 9.2%), and artificial abortions or inductions (n = 10, 0.8%). The number of early syphilis, latent syphilis and syphilis after adequate treatment were 10 (0.8%), 870 (67.0%) and 419 (32.3%), respectively. TRUST titer ranged from 1:1-1:256, with the majority under 1:8 (n=954, 73.4%). 418(32.2%) of pregnant women had first sex at the age of 20 and younger, and 652(50.2%) reported more than one lifetime sex partners.
Characteristics of 963 male partners are presented in Table 1. The male partners had a mean age of 31.50 (SD= 6.53, range: 17–56).429(44.5%) of male partners had first sex at the age of 20 or younger, and 377(39.1%) reported more than one lifetime sex partners.
Table 1 Characteristics of syphilis-seropositive pregnant women and male partners
Characteristics
|
Pregnant women
n (%)
|
Male partners
n (%)
|
Age (Years)
|
|
|
≤ 20
|
94(7.2)
|
22 (2.3)
|
21-30
|
308(53.5)
|
443 (46.0)
|
31-40
|
387(37.2)
|
403 (41.8)
|
>40
|
334(2.1)
|
95 (9.9)
|
Ethnicity
|
|
|
Han
|
1252(96.4)
|
939 (97.5)
|
Minority
|
47(3.6)
|
24 (2.5)
|
Marital status
|
|
|
Unmarried
|
203(15.6)
|
-
|
Divorced
|
32(2.5)
|
-
|
Married
|
1064(81.9)
|
-
|
Occupation
|
|
|
Employment
|
463(35.6)
|
923(95.8)
|
Unemployment
|
836(64.4)
|
40 (4.2)
|
Education level
|
|
|
Secondary school or below
|
895(68.9)
|
489 (50.8)
|
Senior high school
|
301(23.2)
|
326 (33.9)
|
College or above
|
103(7.9)
|
148 (15.4)
|
Service at first ANC visit
|
|
|
Routine antenatal care
|
936(72.1)
|
-
|
Emergency services
|
363(27.9)
|
-
|
Source of syphilis infection on pregnant women's reports
|
Current partners
|
379(29.2)
|
-
|
Someone other than current partner
|
296(22.8)
|
-
|
Unknown
|
624 (48.0)
|
-
|
Age of first sex (Years)
|
|
|
≤20
|
418(32.2)
|
429 (44.5)
|
>20
|
881(67.8)
|
342 (35.5)
|
Unknown
|
0 (0.0)
|
192 (19.9)
|
Number of lifetime sex partners
|
|
|
1
|
478 (36.8)
|
311 (32.3)
|
≥2
|
652 (50.2)
|
377 (39.1)
|
Unknown
|
169 (13.0)
|
275 (28.6)
|
History of APOs
|
|
|
Yes
|
302(23.2)
|
-
|
No
|
997(76.8)
|
-
|
History of drug abuse
|
|
|
Yes
|
20(1.5)
|
18 (1.9)
|
No
|
1279(98.5)
|
945 (98.1)
|
History of other STD
|
|
|
Yes
|
14(1.1)
|
8 (0.8)
|
No
|
1285(98.9)
|
955 (99.2)
|
Contact tracing and associated factorsAmong the 1299 syphilis-seropositive pregnant women, 1205(92.8%) stated willingness to notify their male partners, and 94 (7.2%) reported that they did not want to notify their male partners. The barriers to partner notify reported by the pregnant women included fear of relationship breakdown (n=82, 87.2%), lack of contact information because of having divorced or separated with partners (n=10, 10.6%), fear of social discrimination (n=1, 1.1%), and distrust of the diagnosis (n=1, 1.1%). 1191 (91.7%) of the syphilis-seropositive pregnant women selected patient referral, 66 (5.1%) selected provider referral and 42 (3.2%) selected contract referral. Finally, 1155(88.9%) pregnant women reported that their partners were notified, 985 (75.8%) partners presented to the clinics and 963 (74.1%) male partners received screening for syphilis, resulting in a contract tracing rate of 74.1% (95% CI, 72.9%-75.3%).
Factors independently associated with contact tracing in a multivariate regression model are showed in Table 2. Pregnant women being divorced (adjusted odds ratio [AOR] =0.39; 95%CI: 0.17-0.87), seeking for emergency services at their first ANC visits (AOR =0.58; 95%CI: 0.44-0.77), reporting willingness to notify partner (AOR=7.65; 95%CI: 4.69-12.49), multi-partners (AOR= 1.38; 95%CI: 1.03-1.86) and having a history of drug abuse (AOR = 0.37; 95%CI: 0.14-1.00) were independently and significantly associated with successful contact tracing.
Table 2 Multivariate logistic model for associated factors for contact tracing among syphilis-seropositive pregnant women
Characteristics
|
Pregnant women
|
Pregnant women whose male partner received syphilis screening n (%)
|
Adjusted OR(95%CI)
|
P values
|
Marital status
|
|
|
|
|
Married
|
1064
|
817(76.8)
|
reference
|
-
|
Unmarried
|
203
|
131(64.5)
|
0.83(0.55-1.25)
|
0.374
|
Divorced
|
32
|
15(46.9)
|
0.39(0.17-0.87)
|
0.021
|
Service at first ANC visit
|
|
|
|
|
Routine antenatal care
|
936
|
735(78.5)
|
reference
|
-
|
Emergency services
|
363
|
228(62.8)
|
0.58(0.44-0.77)
|
<0.001
|
Willingness to notify partner
|
|
|
|
|
No
|
94
|
30(31.9)
|
reference
|
-
|
Yes
|
1205
|
933(77.4)
|
7.65(4.69-12.49)
|
<0.001
|
Number of lifetime sex partners
|
|
|
|
|
1
|
478
|
345(72.2)
|
reference
|
-
|
≥2
|
652
|
501(76.8)
|
1.38(1.03-1.86)
|
0.034
|
Unknown
|
169
|
117(69.2)
|
1.01(0.67-1.53)
|
0.969
|
History of drug abuse
|
|
|
|
|
No
|
1279
|
953(74.5)
|
reference
|
-
|
Yes
|
20
|
10(50.0)
|
0.37(0.14-1.00)
|
0.049
|
Syphilis infection status among male partners and associated factors
Among the 963 male partners screened for syphilis, 779 (80.9%) were negative in both TRUST and TPPA,155 (16.1%) were positive in both TRUST and TPPA, 29 (3.0%) were positive only in TPPA, leading to a syphilis prevalence of 19.1% (184/963).
Factors independently associated with syphilis infection among male partners in a multivariate regression model are shown in Table 3.For pregnant women, TRUST titer ≥1:8 (AOR = 2.81; 95%CI: 1.87-4.21), syphilis infection from the current partner (AOR = 5.05; 95%CI: 2.82-9.03), multi-partners (AOR = 0.43; 95%CI: 0.29-0.64), history of APOs (AOR = 1.70; 95%CI: 1.14-2.53) were all independently and significantly associated with syphilis-infection of their male partners. For the male partners themselves, of minority ethnicity (AOR = 4.15; 95%CI: 1.66-10.34), age of first sex > 20 years old (AOR = 0.57; 95%CI: 0.37-0.87), multi-partners (AOR= 1.60; 95%CI: 1.04-2.46), and history of drug abuse (AOR =4.07; 95%CI: 1.31-12.64) were all independently and significantly associated with their own syphilis-infection.
Table3 Multivariate logistic model for associated factors for syphilis-infection among male partners
Characteristics
|
Male partners
|
Syphilis-infected
n (%)
|
Adjusted OR (95%CI)
|
P values
|
Pregnant women
|
|
|
|
|
TRUST titer
|
|
|
|
|
<1:8
|
712
|
115(16.2)
|
reference
|
-
|
≥1:8
|
251
|
69(27.5)
|
2.81(1.87-4.21)
|
<0.001
|
Source of syphilis infection on pregnant women's reports
|
Someone other than the current partner
|
225
|
20(8.9)
|
reference
|
-
|
Current partner
|
284
|
97(34.2)
|
5.05(2.82-9.03)
|
<0.001
|
Unknown
|
454
|
67(14.8)
|
1.61(0.91-2.88)
|
0.105
|
Number of lifetime partners
|
|
|
|
|
1
|
345
|
91(26.4)
|
reference
|
-
|
≥2
|
501
|
62(12.4)
|
0.43(0.29-0.64)
|
<0.001
|
Unknown
|
117
|
31(26.5)
|
1.01(0.59-1.73)
|
0.976
|
History of APOs
|
|
|
|
|
No
|
728
|
125(17.2)
|
reference
|
-
|
Yes
|
235
|
59(25.1)
|
1.70(1.14-2.53)
|
0.009
|
Partners
|
|
|
|
|
Ethnicity
|
|
|
|
|
Han
|
939
|
174(18.5)
|
reference
|
-
|
Minority
|
24
|
10(41.7)
|
4.15(1.66-10.34)
|
0.002
|
Age of first sex (Years)
|
|
|
|
|
≤20
|
429
|
93(21.7)
|
reference
|
-
|
>20
|
342
|
51(14.9)
|
0.57(0.37-0.87)
|
0.009
|
Unknown
|
192
|
40(20.8)
|
0.76(0.46-1.23)
|
0.256
|
Number of lifetime sex partners
|
|
|
|
|
1
|
311
|
52(16.7)
|
reference
|
-
|
≥2
|
377
|
81(21.5)
|
1.60(1.04-2.46)
|
0.033
|
Unknown
|
275
|
51(18.5)
|
1.26(0.79-2.03)
|
0.336
|
History of drug abuse
|
|
|
|
|
No
|
945
|
177(18.7)
|
reference
|
-
|
Yes
|
18
|
7(38.9)
|
4.07(1.31-12.64)
|
0.015
|