INTRODUCTION
In sub-Saharan Africa, female sex workers (FSWs) living with HIV represent a key population for targeting HIV treatment and prevention efforts(1,2). This programming focuses on condom use, sexually transmitted infections (STI), and antiretroviral therapy (ART), but rarely incorporates comprehensive family planning (3). Female sex workers experience high unintended pregnancy rates(4). Contributing factors include a higher frequency of sex compared to women not engaged in transactional sex, gender-based violence, and inconsistent contraceptive use(5–8). HIV-seropositive FSWs face additional challenges to preventing unintended pregnancy, including discrimination(7) and ART-associated drug interactions that may reduce hormonal contraceptive efficacy(9).
There are limited data describing pregnancy incidence among FSWs (4). Incidence data for HIV-seropositive FSWs would provide important information to inform programs addressing unmet contraceptive need and optimizing prevention of maternal-to-child transmission (PMTCT) of HIV. This study examined the incidence and correlates of pregnancy in Kenyan FSWs living with HIV.
METHODS
Study Population & Procedures
The Mombasa Cohort, an open-cohort study of FSWs in Mombasa, Kenya, was established to study HIV/STI acquisition and transmission among women reporting transactional sex (cash or in-kind payments). Participants can remain in the cohort regardless of current involvement in transactional sex, as many FSWs enter and leave sex work in response to economic needs(10). Since 1993, HIV incidence in the cohort has fallen from 11.4 to less than 1/100 woman-years (11). Between October 2012 and April 2017, HIV-seropositive women in the Mombasa Cohort were eligible for a nested study assessing the relationship between reproductive life course events and HIV treatment (12). Participants eligible for this incident pregnancy analysis were 18–49 years old and enrolled in the life course study; women were excluded if they were pregnant, post-menopausal, reported a tubal ligation or hysterectomy, or contributed <2 pregnancy tests.
Procedures for the life course cohort have been described(12). At enrollment, women participated in a standardized interview assessing socio-demographic characteristics, sexual behavior, and menopause status (standardized tool)(13). Genital swabs, blood, and urine were collected for STI screening, CD4 cell count and HIV viral load, and β-hCG pregnancy testing, respectively. Participants received a package of care including risk-reduction education, free contraception, STI treatment, and ART (14).
Participants completed monthly interviews on sexual behavior. Pregnancy and STI testing were repeated quarterly. Every six months, blood samples were collected for CD4 cell count and HIV viral load. Menopausal status was re-assessed annually. The Kenyatta National Hospital and University of Washington ethics committees approved this study. All participants provided written informed consent.
Laboratory Procedures
Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis were detected using nucleic acid amplification based assays (Aptima, Hologic Corporation). Gram stained vaginal swabs were assessed for bacterial vaginosis (BV)(15). Quantification of CD4 lymphocytes (FACSCount, Becton Dickinson) occurred in real time, while HIV viral load (Hologic Corporation) was assessed in batches.
Planned, Mistimed, Unwanted, and Unintended Pregnancy
At enrollment and quarterly, participants were asked about fertility desire (Do you want to have any/more children?) and pregnancy intention (Are you trying to become pregnant?)(16). Pregnancies were defined as planned (desired and intended), mistimed (desired, not intended), and unwanted (not desired and not intended) based on responses at the visit prior to pregnancy testing. Unintended pregnancies included mistimed and unwanted pregnancies.
Statistical Methods
Because data were collected at monthly, quarterly, 6-month, and annual frequencies, correlate response data were carried forward from most recent measurement and time-updated at each response. For time-varying characteristics, exposure was defined as status prior to each pregnancy test to reflect exposure during the potential fertile window (Supplemental Table 1). Cox proportional hazard models with robust standard errors were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) comparing women who did and did not become pregnant during follow-up. Only the first pregnancy was included. Time was defined as days from enrollment into the study to the first day of last menstrual period for women with a positive pregnancy test, to the date of last pregnancy test for women without a pregnancy, or date of censoring. Women were censored at age 50, menopause, tubal ligation or hysterectomy, and when lost to follow-up. If >6 months elapsed between visits, women were censored at the visit prior to the gap to exclude intervals with potential for undetected pregnancy. A sensitivity analysis was conducted excluding women ≥45 years old.
Correlates of pregnancy included in univariate analyses included age, education, sexual behavior (condomless sex, frequency of sex, number of sex partners, vaginal washing); transactional sex in last year, substance use (smoking, Alcohol Use Disorders Identification Test), depressive symptoms (Patient Health Questionnaire-9), intimate partner violence in last year, clinical factors (body mass index, BV, STIs, CD4 count, HIV viral load), parity, and partnership factors (non-paying, regular partner in last three months; partner’s fertility desire). Fertility desire and pregnancy intent were combined to define a potential incident pregnancy as planned, mistimed, or unwanted. Contraceptive method (none, condoms only, oral contraceptive pills (OCP), depo medroxyprogesterone acetate (DMPA) injectable, implant, other) was assessed. Many FSWs reporting no contraceptive method use condoms for STI prevention(17). Correlates of pregnancy were considered for inclusion in the multivariable model if they were associated with pregnancy (p<0.1) in univariate analysis and were not mediators of the relationship between other correlates and pregnancy.
RESULTS
This study included 279 HIV-positive FSWs. At enrollment, participants were a median of 38 years old (interquartile range [IQR] 32–42) and most had a non-paying, regular partner (83.2%, 232/279) (Table 1). Half of the women were on ART (56.3% 157/279) and 36.8% had a detectable viral load (71/193). Almost a third (29.4%, 82/279) reported fertility desire. Of these, 41.5% (34/82) were trying to conceive. Among women without pregnancy intent, 67.4% (165/245) were not using modern non-barrier contraception.
Table 1.
Enrollment characteristics for 279 HIV-positive female sex workers in Mombasa, Kenya
| Characteristic | N | n (%), median (IQR) | |
|---|---|---|---|
| Demographic | |||
| Age | 279 | 38 | (32,42) |
| Age categories | 279 | ||
| <25 | 14 | (5.0) | |
| 25–29 | 31 | (11.1) | |
| 30–34 | 48 | (17.2) | |
| 35–39 | 78 | (28.0) | |
| ≥40 | 108 | (38.7) | |
| Education | 278 | ||
| None or some primary (1–8 years) | 153 | (55.0) | |
| Some secondary (9–11 years) | 63 | (22.7) | |
| Completed secondary (≥12 years) | 62 | (22.3) | |
| Contraception | |||
| Method of contraception | 279 | ||
| None | 84 | (30.1) | |
| Condoms Only | 110 | (39.4) | |
| OCP | 10 | (3.6) | |
| DMPA | 47 | (16.9) | |
| Copper IUD | 7 | (2.5) | |
| Implant | 21 | (7.5) | |
| Any modern non-barrier methodi | 279 | 85 | (30.5) |
| Sexual Risk Behavior | |||
| In the last week: | |||
| Sexual abstinence | 279 | 97 | (34.8) |
| Any condomless sex | 279 | 26 | (9.3) |
| Among those reporting sex: | |||
| Frequency of sex | 182 | 2 | (1,3) |
| Any condom use | 182 | 163 | (89.6) |
| 100% condom use | 182 | 156 | (85.7) |
| Number of sex partners | 182 | 1 | (1,3) |
| Vaginal washing | 279 | 230 | (82.4) |
| Transactional sex in last year | 278 | 168 | (60.4) |
| Substance Use | |||
| Current smoking | 278 | 22 | (7.9) |
| Alcohol use disorder riskii | 278 | ||
| Non-drinkers | 130 | (46.8) | |
| Minimal risk | 80 | (28.8) | |
| Moderate risk | 55 | (19.8) | |
| Severe risk/possible alcohol use disorder | 13 | (4.7) | |
| Depression & Intimate Partner Violence | |||
| Depressive symptom screeniii | 279 | ||
| None (0) | 111 | (39.8) | |
| Minimal (1–4) | 87 | (31.2) | |
| Mild (5–9) | 56 | (20.1) | |
| Moderate/severe (≥10) | 25 | (9.0) | |
| IPV by non-paying, regular partner in past 12 months | 232 | 56 | (24.1) |
| Clinical | |||
| BMI (kg/cm2)iv | 278 | ||
| Underweight (<18.5) | 8 | (2.9) | |
| Normal (18.5–24.9) | 112 | (40.3) | |
| Overweight (25–29.9) | 100 | (36.0) | |
| Obese (≥30) | 58 | (20.9) | |
| Vaginal microbiota | 279 | ||
| BV (Nugent ≥7) | 66 | (23.7) | |
| Intermediate microbiota (Nugent 4–6) | 34 | (12.2) | |
| Normal (Nugent 0–3) | 179 | (64.2) | |
| Trichomonas vaginalis | 274 | 21 | (7.7) |
| Neisseria gonorrhoeae | 274 | 8 | (2.9) |
| Chlamydia trachomatis | 274 | 7 | (2.6) |
| Cervicitisv | 279 | 63 | (22.6) |
| PSA detected in vaginal secretionsvi | 275 | 38 | (13.8) |
| On ART | 279 | 157 | (56.3) |
| CD4 | 279 | 444 | (305, 604) |
| CD4 category (cells/mm3) | 279 | ||
| <200 | 41 | (14.7) | |
| 200–350 | 49 | (17.6) | |
| >350 | 189 | (67.7) | |
| Detectable HIV viral load (≥180 c/ml)vii | 193 | 71 | (36.8) |
| Pregnancy History, Fertility Desire, Pregnancy Intention, & Partnership | |||
| Parity | 266 | ||
| 0 | 12 | (4.5) | |
| 1 | 75 | (28.2) | |
| 2 | 80 | (30.1) | |
| 3+ | 99 | (37.2) | |
| Fertility desire (ever)viii | 279 | 82 | (29.4) |
| Current pregnancy intentionix | 279 | 34 | (12.2) |
| Non-paying, regular partner | 279 | 232 | (83.2) |
| Non-paying, regular partner’s fertility desire | 230 | ||
| Very excited | 93 | (40.4) | |
| Somewhat excited | 37 | (16.1) | |
| Would not care | 55 | (23.9) | |
| Very upset | 45 | (19.6) | |
Abbreviations: OCP-oral contraceptive pills; DMPA-depo medroxyprogesterone acetate; IUD-intrauterine device (copper); IPV-intimate partner violence; BMI-body mass index; BV - bacterial vaginosis; PSA – prostate specific antigen
Modern non-barrier contraceptive method – No=no contraception, condoms, diaphragm; Yes = implant, copper IUD, DMPA, OCP, spermicide
Alcohol Use Disorders Identification Test (AUDIT) scores – score 0=non-drinkers, score 1–6=minimal, score 7–15=moderate, score ≥16 = severe/possible alcohol use disorder
Patient Health Questionnaire-9 Depression Severity Scores
If weight values were missing, the value was imputed from the visit prior.
Average of ≥10 cervical polymorphonuclear leukocytes per high powered field
Testing for prostate specific antigen in vaginal samples was performed with a commercially available assay (ABAcard, Abacus Diagnostics).
Detectable plasma viral load was defined as ≥180 copies/mL, which is higher than the assay’s lower limit of detection of <30 copies/mL. This was due to some 100mL samples requiring a dilution of 6-fold (600mL) before testing.
Fertility desire - Do you want to have any/more children?
Pregnancy intention - Are you trying to become pregnant?
Participants contributed 5,963 follow-up visits totaling 591 person-years (p-y). Participants attended a median of 15 visits (IQR 7,27) and visits were a median of 30 days (IQR 28,35) apart. During follow-up, 65.6% (183/279) of participants had consistent fertility desire and pregnancy intention. There were 34 first incident pregnancies (5.8/100 p-y, 95%CI 4.1–8.0). Incidence ranged from 2.6/100p-y (95%CI 1.3–5.1) among women 40–49 years old to 22.2/100 p-y (95%CI 5.6–88.8) among women <25 (Table 2). Ninety-one percent (31/34) of pregnancies were unintended (incidence=5.8/100 p-y, 95%CI 4.0–8.2). The incidences of planned (n=3, 5.7/100 p-y, 95%CI 1.8–17.7), mistimed (n=9, 10.4/100 p-y, 95%CI 5.4–20.1), and unwanted pregnancies (n=22, 4.9/100 p-y, 95%CI 3.2–7.4) were similar (log rank p-value=0.15. Among women <45 years old, the pregnancy incidence was similar (n=33, 6.8/100p-y, 95%CI 4.8–9.6, Supplemental Table 2).
Table 2.
Incidence and correlates of 34 pregnancies
| Characteristic* | Pregnancy | Univariate Analysis | Primary Multivariable Analysis† | Secondary Multivariable Analysis‡ | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| n | Incidence per 100 p- years (95%CI) | HR (95% CI) | p-value | HR (95% CI) | HR (95% CI) | |||||
| Demographic | ||||||||||
| Age | ||||||||||
| <25 | 2 | 22.2 | (5.6, 88.8) | REF | <0.001§ | REF | REF | |||
| 25–29 | 6 | 13.5 | (6.1, 30.1) | 0.73 | (0.14, 3.74) | 0.71 | 0.72 | (0.12, 4.24) | 0.61 | (0.10, 3.62) |
| 30–34 | 11 | 17.7 | (9.8, 31.9) | 0.92 | (0.19, 4.34) | 0.92 | 0.77 | (0.14, 4.18) | 0.60 | (0.11, 3.22) |
| 35–39 | 7 | 4.3 | (2.0, 9.0) | 0.25 | (0.05, 1.26) | 0.09 | 0.26 | (0.04, 1.50) | 0.21 | (0.03, 1.25) |
| 40–49 | 8 | 2.6 | (1.3, 5.1) | 0.14 | (0.03, 0.71) | 0.02 | 0.15 | (0.03, 0.89) | 0.13 | (0.02, 0.75) |
| Education | ||||||||||
| None or some primary (0–8 years) | 20 | 5.8 | (3.8, 9.0) | REF | 0.90§ | |||||
| Some secondary (9–11 years) | 7 | 5.7 | (2.7, 11.9) | 0.91 | (0.39, 2.13) | 0.82 | ||||
| Completed secondary (≥12 years) | 7 | 5.7 | (2.7, 11.9) | 0.81 | (0.32, 2.03) | 0.65 | ||||
| Method of Contraception | ||||||||||
| None | 9 | 4.5 | (2.3, 8.7) | REF | <0.01§ | REF | REF | |||
| Condoms Only | 18 | 8.0 | (5.0, 12.7) | 1.96 | (0.83, 4.61) | 0.13 | 0.84 | (0.25, 2.83) | 1.55 | (0.40, 6.00) |
| OCP | 4 | 34.4 | (12.9, 91.6) | 6.66 | (1.95, 22.72) | <0.01 | 2.58 | (0.59, 11.2) | 4.39 | (0.99, 19.5) |
| DMPA | 2 | 2.0 | (0.5, 7.9) | 0.46 | (0.10, 2.17) | 0.32 | 0.28 | (0.05, 1.70) | 0.42 | (0.07, 2.41) |
| Copper IUD | 0 | 0 | - | - | - | - | - | - | - | |
| Implant | 1 | 2.9 | (0.4, 20.5) | 0.68 | (0.08, 5.53) | 0.72 | 0.33 | (0.03, 3.68) | 0.34 | (0.03, 4.11) |
| Other | 0 | 0 | - | - | - | - | - | - | - | |
| Sexual Risk Behavior** | ||||||||||
| Frequency of sex in last week | ||||||||||
| 0 | 5 | 2.2 | (0.9, 5.3) | REF | <0.001§ | REF | ||||
| 1 | 5 | 3.5 | (1.5, 8.4) | 1.68 | (0.49, 5.81) | 0.41 | 2.38 | - | ||
| 2 | 11 | 11.4 | (6.3, 20.7) | 4.78 | (1.68, 13.62) | <0.01 | 7.01 | (2.13, 23.05) | ||
| ≥3 | 13 | 10.4 | (6.1, 18.0) | 4.28 | (1.55, 11.80) | <0.01 | 7.08 | (1.61, 31.20) | ||
| Any condomless sex in last week | ||||||||||
| No | 23 | 4.4 | (2.9, 6.6) | REF | REF | |||||
| Yes | 11 | 17.3 | (9.6, 31.2) | 3.75 | (1.79, 7.84) | <0.001 | 3.16 | (1.20, 8.29) | ||
| Number of sex partners in last week | ||||||||||
| 0 | 5 | 2.2 | (0.9, 5.3) | REF | 0.03§ | REF | REF | |||
| 1 | 16 | 7.5 | (4.6, 12.3) | 3.26 | (1.21, 8.81) | 0.02 | 2.10 | (0.57, 7.53) | 0.27 | (0.06, 1.24) |
| ≥2 | 13 | 8.6 | (5.0, 14.9) | 3.71 | (1.34, 10.25) | 0.01 | 1.44 | (0.33, 6.21) | 0.13 | (0.02, 0.95) |
| Vaginal washing in last week | ||||||||||
| No | 3 | 2.7 | (0.9, 8.4) | REF | REF | REF | ||||
| Yes | 31 | 6.5 | (4.5, 9.2) | 3.79 | (0.91, 15.89) | 0.07 | 2.30 | (0.58, 9.19) | 2.16 | (0.53, 8.85) |
| Transactional sex in last year | ||||||||||
| No | 7 | 3.4 | (1.7, 7.1) | REF | REF | REF | ||||
| Yes | 27 | 7.0 | (4.8, 10.3) | 2.76 | (1.12, 6.79) | 0.03 | 1.89 | (0.72, 4.92) | 1.69 | (0.63, 4.51) |
| Substance Use | ||||||||||
| Current smoking | ||||||||||
| No | 32 | 5.8 | (4.1, 8.2) | REF | ||||||
| Yes | 2 | 5.1 | (1.3, 20.3) | 0.86 | (0.22, 3.44) | 0.84 | ||||
| Alcohol use disorder risk†† | ||||||||||
| Non-drinkers | 16 | 4.6 | (2.8, 7.6) | REF | 0.52§ | |||||
| Minimal risk | 8 | 5.2 | (2.6, 10.4) | 1.13 | (0.49, 2.61) | 0.78 | ||||
| Moderate risk | 8 | 10.2 | (5.1, 20.4) | 1.92 | (0.82, 4.53) | 0.14 | ||||
| Severe risk/Possible alcohol use disorder | 1 | 7.2 | (1.0, 51.0) | 1.34 | (0.19, 9.66) | 0.77 | ||||
| Depression & Intimate Partner Violence | ||||||||||
| Depressive symptom screen‡‡ | ||||||||||
| None (0) | 20 | 5.1 | (3.3, 8.0) | REF | <0.001§ | REF | REF | |||
| Minimal (1–4) | 7 | 5.6 | (2.7, 11.8) | 0.91 | (0.37, 2.25) | 0.83 | 0.92 | (0.36, 2.35) | 0.86 | (0.33, 2.21) |
| Mild (5–9) | 7 | 12.8 | (6.1, 26.8) | 1.85 | (0.77, 4.43) | 0.17 | 1.65 | (0.68, 3.99) | 1.82 | (0.73, 4.53) |
| Moderate/severe (≥10) | 0 | 0 | - | - | - | - | - | - | ||
| IPV by non-paying, regular partner in past 12 months | ||||||||||
| No | 21 | 5.4 | (3.5, 8.2) | REF | ||||||
| Yes | 12 | 8.6 | (4.9, 15.1) | 1.77 | (0.86, 3.64) | 0.12 | ||||
| Clinical | ||||||||||
| BMI (kg/cm2) | ||||||||||
| Underweight or Normal (≤24.9) | 17 | 7.5 | (4.7, 12.0) | REF | 0.41§ | |||||
| Overweight (25–29.9) | 9 | 4.1 | (2.2, 8.0) | 0.59 | (0.26, 1.32) | 0.20 | ||||
| Obese (≥30) | 8 | 5.4 | (2.7, 10.9) | 0.72 | (0.30, 1.75) | 0.47 | ||||
| BV (Nugent ≥7 vs 0–6) | ||||||||||
| No | 21 | 5.1 | (3.3, 7.8) | REF | ||||||
| Yes | 13 | 7.6 | (4.4, 13.0) | 1.58 | (0.78, 3.21) | 0.21 | ||||
| CD4 Category | ||||||||||
| <200 | 2 | 3.9 | (1.0, 15.7) | REF | 0.32§ | |||||
| 200–350 | 9 | 8.7 | (4.5, 16.7) | 2.48 | (0.54, 11.33) | 0.24 | ||||
| >350 | 23 | 5.3 | (3.5, 7.9) | 1.48 | (0.35, 6.33) | 0.59 | ||||
| Detectable HIV viral load (≥180 c/ml) | ||||||||||
| No | 17 | 4.3 | (2.7, 6.9) | REF | ||||||
| Yes | 7 | 4.8 | (2.3, 10.0) | 1.13 | (0.49, 2.67) | 0.76 | ||||
| Pregnancy History & Partnership | ||||||||||
| Parous | ||||||||||
| No | 2 | 10.7 | (2.7, 42.8) | REF | ||||||
| Yes | 32 | 5.9 | (4.1, 8.3) | 0.63 | (0.15, 2.67) | 0.53 | ||||
| Non-paying, regular partner in last 3 months | ||||||||||
| No | 3 | 1.7 | (0.5, 5.1) | REF | REF | REF | ||||
| Yes | 31 | 7.6 | (5.3, 10.8) | 4.84 | (1.41, 16.60) | 0.01 | 4.04 | (1.16, 14.07) | 3.88 | (1.11, 13.6) |
| An incident pregnancy would be§§: | ||||||||||
| Planned | 3 | 5.7 | (1.8, 17.7) | REF | 0.15§ | |||||
| Mistimed | 9 | 10.4 | (5.4, 20.1) | 1.84 | (0.50, 6.85) | 0.36 | ||||
| Unwanted | 22 | 4.9 | (3.2, 7.4) | 0.86 | (0.26, 2.91) | 0.82 | ||||
| Non-paying, regular partner’s fertility desire | ||||||||||
| Very excited | 8 | 4.9 | (2.4, 9.8) | 0.67 | (0.25, 1.82) | 0.44 | ||||
| Somewhat-excited | 11 | 12.4 | (6.9, 22.4) | 2.02 | (0.80, 5.10) | 0.14 | ||||
| Would not care | 7 | 6.9 | (3.3, 14.5) | REF | 0.03§ | |||||
| Very upset | 7 | 6.0 | (2.9, 12.6) | 0.83 | (0.28, 2.44) | 0.74 | ||||
| No regular partner | 1 | 0.8 | (0.1, 5.9) | 0.13 | (0.02, 1.08) | 0.06 | ||||
Exposure was defined as status prior to each pregnancy test to reflect exposure during the potential fertile window.
Condomless sex and frequency of sex were excluded from the primary multivariable models since they are mediators in the relationship between the potential independent correlates and pregnancy. The model also excluded partner fertility desire, since it was correlated with having a current partner.
Condomless sex and frequency of sex were added to the multivariable model.
Joint-p value describing the overall significance across categories compared to the reference category.
Sexual behavior in the last week data were lagged from the monthly visit prior to pregnancy testing to reflect sexual behavior preceding positive pregnancy testing.
Alcohol Use Disorders Identification Test (AUDIT) scores – score 0=non-drinkers, score 1–6=minimal, score 7–15=moderate, score ≥16 = severe/possible alcohol use disorder
Patient Health Questionnaire-9 Depression Severity Scores
Future pregnancy category defined by responses to fertility desire and pregnancy intent questions at visit prior to each pregnancy test.
In univariable analysis, several characteristics were associated with pregnancy (Table 2). Compared to women who reported no contraceptive method, women using OCPs had a 6.7-fold higher risk of pregnancy (95%CI 2.0–22.7). Women with a non-paying, regular partner in the last 3 months had a 4.8-fold increased risk of pregnancy (95%CI 1.4–16.6). Any condomless sex, increasing frequency of sex, higher number of sexual partners, vaginal washing, and transactional sex in last year were also significantly associated with pregnancy (Table 2). Compared to women <25 years old, women ≥40 were significantly less likely to become pregnant (HR: 0.1, 95%CI 0.0–0.7).
The primary multivariable model excluded condomless sex and frequency of sex, which were considered mediators in the relationship between other characteristics and pregnancy. Age remained significantly associated with pregnancy, with women ≥40 years old (versus <25) having a significantly lower risk of pregnancy (adjusted HR (aHR) 0.2, 95%CI 0.0–0.9). Women with a non-paying, regular partner in the last 3 months continued to have a higher risk of pregnancy (aHR 4.0, 95%CI 1.2, 14.1). Results were similar when restricting to women< 45 years old (Supplemental Table 2). When frequency of sex and condomless sex were added to the primary multivariable model, the association between OCP use and pregnancy was strengthened (aHR 4.4, 95%CI 1.0–19.5) (Table 2).
Characteristics at the visit prior to pregnancy were similar between women with planned (n=3), mistimed (n=9), and unwanted (n=22) pregnancies (Supplemental Table 3). At the preconception visit, 29.2% (7/24 with viral load data) of women had a detectable HIV viral load, including 66.7% (2/3) of women with planned pregnancies, 40.0% (2/5) with mistimed pregnancies, and 18.8% (3/16) with unwanted pregnancies.
Of 31 women with unintended pregnancies, 7 (22.6%) reported using modern non-barrier contraception at the visit prior to their positive pregnancy test (DMPA=2, implant=1, OCP=4). One of the women conceiving on DMPA reported DMPA use for 14 monthly visits, while the second reported switching from no contraception to DMPA two months prior to pregnancy. The participant who conceived on the implant reported implant use for more than one year prior to pregnancy. Participants conceiving on OCPs reported using OCPs for a median of 5.5 monthly visits (range 5–7).
DISCUSSION
Among these HIV-positive Kenyan FSWs, >90% of pregnancies were unintended. Several characteristics, including increased sex frequency, OCP use, having a non-paying regular partner, and age, were associated with pregnancy in univariate analysis. In multivariable analysis, having a non-paying, regular partner in the last 3 months and age ≥40 years remained significantly associated with a higher and lower pregnancy risk, respectively. Among women who became pregnant, a third had a detectable HIV viral load during the preconception period, representing a period of increased MTCT risk.
A meta-analysis of unintended pregnancy rates among FSWs in low and middle income countries reported an incidence range of 7.2–59.6/100 person-years(4). There is a lack of published unintended pregnancy incidence estimates among HIV-positive FSWs. In this study, most pregnancies were unintended, with an incidence of 5.8/100 person-year. The low overall pregnancy incidence is likely due to the older age, lower frequency of sex, lower prevalence of recent transactional sex, and higher use of long-acting reversible contraception reported by participants compared to other FSWs(4). The older age of this cohort of FSWs living with HIV may be reflective of the broader trend in aging of the HIV epidemic in Africa(18), and is likely relevant to other populations of FSWs living with HIV in the context of this demographic shift.
Non-use of modern non-barrier contraceptives has been associated with increased pregnancy among FSWs (5,19). Surprisingly, in this cohort, there was some evidence that OCP use might be associated with higher pregnancy risk compared to no contraception. This finding should be interpreted cautiously given the small number of OCP users and pregnancies and no adjustment for multiple comparisons. The result may also reflect the challenge of pill adherence or social desirability bias influencing contraception and condom use reporting.
This study had important strengths. First, quarterly fertility desire and pregnancy intention questions allowed typing of pregnancies as planned or unintended (mistimed or unwanted). Second, behavioral and clinical characteristics were collected frequently which allowed for time-varying modeling (ex: sex frequency). Third, this study assessed menopause status annually to exclude infecund women.
There were also several limitations. While data were collected monthly, it was not possible to definitively ascertain a woman’s precise preconceptual exposure status. For example, frequency of sex and condom use were ascertained for only the prior week, which could lead to residual confounding by sexual behavior. Many characteristics were collected via self-report and subject to social desirability bias. In addition, while loss to follow-up was reduced in this cohort since the FSWs received HIV care at the study clinic, it is possible there was differential loss to follow-up with respect to pregnancy incidence. Moreover, this study of older HIV-positive FSWs receiving frequent counseling and STI testing through a research project may not be representative of all HIV-positive FSWs, particularly younger or more marginalized FSWs. Lastly, the fertility desire and pregnancy intention questions included binary responses, which did not allow women to express ambivalence or unknown desire/intent (20).
In the context of comprehensive care for HIV-positive FSWs, regular ascertainment of fertility desire and pregnancy intention could increase effective contraceptive use in women not trying to conceive and facilitate uptake of safer conception strategies for pregnancy planners. Importantly, prevention of unintended pregnancies makes up a key pillar of the World Health Organization’s strategy for PMTCT(21). While this call for integrating comprehensive family planning into HIV care for FSWs is not new(3,22), this study further demonstrates an immediate need for action.
Supplementary Material
ACKNOWLEDGEMENTS
The authors acknowledge the support from the clinic, laboratory, and administrative staff in Mombasa and Seattle. We are grateful to Mombasa County for their support of our research and for providing clinical and laboratory space at Ganjoni Clinic and Coast Provincial General Hospital. Finally, we thank the women in the Mombasa Cohort, whose participation and commitment made this research possible.
This work was supported by a National Institutes of Health grant (R01 HD072617 - RSM). EML was supported by a pre-doctoral fellowship (T32 AI07140 - Lukehart). RSM received support for mentoring (K24 HD88229). Infrastructure and logistical support for the Mombasa research site was provided by the University of Washington’s Center for AIDS Research (CFAR), a National Institutes of Health funded program (P30 AI027757) which is supported by the following research centers: National Institute of Allergy and Infectious Diseases, National Cancer Institute, National Institute of Mental Health, National Institute on Drug Abuse, Eunice Kennedy Shriver National Institute of Child Health and Development, National Heart, Lung and Blood Institute, and National Center for Complementary and Integrative Health. The content of this paper is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Conflict of Interest & Sources of Funding: RSM receives research funding, paid to the University of Washington, from Hologic Corporation, and has received honoraria for consulting from Lupin Pharmaceuticals.
Footnotes
Presentation Information: This research was presented, in part, as a poster (#1006) at the 2019 Conference on Retroviruses and Opportunistic Infections March 4–7, 2019 in Seattle, WA.
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