Hormonal Contraceptives and the Acquisition of Sexually Transmitted Infections: An Updated Systematic Review

Contraceptive effects on the cervicovaginal microbiome: Recent evidence including randomized trials

BACKGROUND

Until recently, most data regarding the effects of non-barrier contraceptives on the mucosal microbiome have derived from observational studies, which are potentially biased due to behavioral confounders that may mask their true biological effects.

METHOD OF STUDY

This narrative review summarises recent evidence of the effect of contraceptives on the cervicovaginal microbiome, emphasising data obtained through randomized trials.

RESULTS

Good quality data describe that initiation of long-acting progestin-only contraceptives, including levonorgestrel (LNG)-implant and the injectables depot-medroxyprogesterone acetate (DMPA-IM) and norethisterone enanthate (NET-EN) do not alter the mucosal microbial environment. Likewise, no strong evidence exists that the use of oral contraceptive pills (OCPs) is associated with alterations of the vaginal microbiome or increased risk of bacterial sexually transmitted infections (STIs). Limited data on the effect of intravaginal rings (IVRs) on the mucosal environment exist and show conflicting effects on the vaginal microbiota. Copper intrauterine device (Cu-IUD) initiation has been associated with bacterial vaginosis (BV) acquisition, including in a randomized trial. LNG-IUDs may have similar affects but need to be evaluated further.

CONCLUSION

Different synthetic hormones have divergent effects on the microbiome and therefore novel hormonal methods need to be rigorously evaluated. Furthermore, the addition of antiretrovirals into multipurpose technologies may alter the effects of the hormonal component. There is thus a critical need to improve our understanding of the biological effects of contraceptive hormones and delivery methods with different pharmacokinetic and chemical properties on the mucosal microbiome in rigorous trials, to inform the development of novel contraceptives and improve individual family planning guidance.

Update on the Impact of Depot Medroxyprogesterone Acetate on Vaginal Mucosal Endpoints and Relevance to Sexually Transmitted Infections

PURPOSE OF REVIEW

The long-acting reversible intramuscularly-injected contraceptive depot medroxyprogesterone acetate (DMPA-IM) is widely used by cisgender women in Africa. Although DMPA-IM provides reliable contraception, potential effects on the female genital tract (FGT) mucosa have raised concern, including risk of HIV infection. This review summarises and compares evidence from observational cohort studies and the randomised Evidence for Contraceptive Options in HIV Outcomes (ECHO) Trial.

RECENT FINDINGS

Although previous observational studies found women using DMPA-IM had higher abundance of bacterial vaginosis (BV)-associated bacteria, increased inflammation, increased cervicovaginal HIV target cell density, and epithelial barrier damage, sub-studies of the ECHO Trial found no adverse changes in vaginal microbiome, inflammation, proteome, transcriptome, and risk of viral and bacterial STIs, other than an increase in Th17-like cells. Randomised data suggest that DMPA-IM use does not adversely change mucosal endpoints associated with acquisition of infections. These findings support the safe use of DMPA-IM in women at high risk of acquiring STIs, including HIV.

Biological, demographic, and health factors associated with HPV infection in Ecuadorian women

Objectives

The study aims to identify the correlation between human papillomavirus (HPV) infection and sociodemographic and sexual reproductive health factors in Ecuadorian women from March to August 2019.

Methods

120 women were randomly selected from two gynecological clinics to complete a questionnaire and provide a biospecimen. PCR-Hybridization was used to genotype 37 HPV serotypes in samples obtained by endo-cervical brushing for liquid-based cytology. Sociodemographic and sexual health data were collected through a validated questionnaire during a medical consultation. Mathematical modeling of HPV infection was done using bivariate logistic regression.

Results

65.0% of the women sampled had an HPV infection; 74.3% of these women had co-infections with other HPV genotypes. Out of the women who were HPV positive, 75.6% were diagnosed with high-risk genotypes from HPV strains 18, 35, 52, and 66. Parity, immunosuppression, and use of oral contraception/intrauterine devices (IUDs) were identified as associated variables. The explanatory model had a sensitivity of 89.5% and a specificity of 73.8%.

Conclusion

The predominant strains of HPV among Ecuadorian women are diverse. The risk of HPV infection is a complex phenomenon where biological and psychosocial variables are integrated into a model. In populations with limited access to health services, low socioeconomic status, and negative sociocultural beliefs about sexually transmitted infections (STIs), surveys can be used as a pre-screening step for HPV infections. The diagnostic value of the model should be tested in multicenter studies that include women from all over the country.

2gether: A Clinic-Based Intervention to Increase Dual Protection from Sexually Transmitted Infections and Pregnancy in Young African American Females

Background: To determine whether the 2gether intervention increases use of a dual protection (DP; concurrent prevention of pregnancy and sexually transmitted infections [STIs]) strategy and decreases pregnancy and STIs among young African American females, who disproportionately experience these outcomes. Materials and Methods: We conducted a randomized clinical trial comparing the 2gether intervention to standard of care (SOC). Participants were self-identified African American females aged 14-19 years who were sexually active with a male partner in the past 6 months. Participants were followed for 12 months; 685 were included in the analytic sample. The primary biologic outcome was time to any incident biologic event (chlamydia, gonorrhea, trichomonas infections, or pregnancy). The primary behavioral outcomes were use of and adherence to a DP strategy. Results: 2gether intervention participants had a decreased hazard of chlamydia, gonorrhea, trichomonas infections, or pregnancy during follow-up, hazard ratio = 0.73 (95% confidence interval [CI] 0.58-0.92), and were more likely to report use of condoms plus contraception, generally, adjusted risk ratio (aRR) = 1.61 (95% CI 1.15-2.26) and condoms plus an implant or intrauterine device (IUD), specifically, aRR = 2.11 (95% CI 1.35-3.29) in the prior 3 months compared with those receiving SOC. 2gether participants were also more likely to report use of condoms plus an implant or IUD at last sex and consistently over the prior 3 months. Conclusions: 2gether was efficacious in increasing use of condoms with contraception and decreasing pregnancy or selected STIs in our participants. Implementation of this intervention in clinical settings serving young people with high rates of pregnancy and STIs may be beneficial. ClinicalTrials.gov, No. NCT02291224 (https://clinicaltrials.gov/ct2/show/NCT02291224?term=2gether&draw=2&rank=5).

Hormonal contraceptive use and the risk of sexually transmitted infections: a systematic review and meta-analysis

There are 150 million women worldwide using combined or progestogen-only hormonal contraceptive methods who may be at risk of sexually transmitted infections (STIs). Previous systematic reviews that have sought to establish whether there is an aetiological association between hormonal contraceptive methods/use and STIs have been limited in their methods and have mixed findings. We sought to update these reviews using appropriate control groups. We undertook a systematic review following the PRISMA guidelines and meta-analysis to examine the association between the use of all hormonal contraceptive methods and the acquisition of STIs (Neisseria gonorrhoeae, syphilis/Treponema pallidum, Chlamydia trachomatis, herpes simplex virus, and Trichomonas vaginalis) and/or bacterial vaginosis in literature published between 2005 and 2020. We analysed the effect of hormonal contraceptive methods/use separately on the prevalence, incidence and recurrence of STIs. A total of 37 studies were included in this review that reported 61 associations, in which 27 prevalence, eight incidence and two recurrence studies provided 43, 16, and two associations, respectively. We observed a positive association between hormonal contraceptive methods/use and the risk of chlamydia and herpes but a negative association for trichomoniasis and vaginosis. A negative but statistically insignificant association was observed between hormonal contraceptive methods/use and gonorrhoea. Hormonal contraceptive methods/use influences a woman's risk of STIs/ bacterial vaginosis, but the risk may differ depending on the type of STI. These findings should be contextualized carefully, particularly when formulating practice guidelines and policy, as the effects of hormonal contraceptive methods/use on the risk of STIs varied in direction when analysed separately by STI.

The relationship between hormonal contraception and cervical dysplasia/cancer controlling for human papillomavirus infection: A systematic review

OBJECTIVE

Studies on the effect of long-term use of combined oral contraceptives (COCs) on cervical dysplasia and/or cancer risk have been inconsistent. Less is known about the effects of other forms of hormonal contraception (HC). We examine whether HC use increases the risk of incident cervical intraepithelial neoplasia (CIN) 2, 3 and/or cancer after accounting for preexisting human papillomavirus (HPV) infection.

STUDY DESIGN

Systematic review of prospective studies on HC use as risk factor for cervical dysplasia with HPV infection documented prior to outcome assessment including PubMed and EMBASE records between January 2000 and February 2020 (Prospero #CRD42019130725).

RESULTS

Among nine eligible studies, seven described recency and type of HC use and therefore comprise the primary analysis; two studies limit comparisons to ever versus never use and are summarized separately. All seven studies explored the relationship between oral contraceptive (OC) use and cervical dysplasia/cancer incidence: two found increased risk (adjusted odds ratio, aOR = 1.5-2.7), one found no association but decreased risk when restricted to women with persistent HPV (adjusted hazard ratio = 0.5), and four found no association. None of the seven studies differentiated between COC and progestin-only pills (POPs) by use recency or duration. The only study that included injectable progestin-only contraception (DMPA) found increased CIN3 incidence among current versus never users (aOR = 1.6). The one study that included Norplant found no association. Two studies included intrauterine device (IUD) use, but did not differentiate between hormonal and copper IUDs, and found no association.

CONCLUSION

We found no consistent evidence that OC use is associated with increased risk for cervical dysplasia/cancer after controlling for HPV infection. There were too few studies of progestin-only injectables, implants or IUDs to assess their effect on cervical dysplasia/cancer risk.

IMPLICATIONS

Use of single self-reported HC measures and insufficient distinction by hormonal constituent cloud our understanding of whether some HCs increase risk for cervical cancer. Methodologically rigorous studies with distinct HCs measured as time-varying exposures are needed to inform cervical cancer prevention efforts and improve our understanding of cervical cancer etiology.

Incidence of Herpes Simplex Virus Type 2 Infection Among African Women Using Depot Medroxyprogesterone Acetate, a Copper Intrauterine Device, or a Levonorgestrel Implant for Contraception: A Nested Randomized Trial

BACKGROUND

Globally, women have higher herpes simplex virus type 2 (HSV-2) prevalence than men; data from observational studies suggest a possible association of HSV-2 acquisition with use of intramuscular depot medroxyprogesterone acetate (DMPA-IM).

METHODS

Within a randomized trial of the effect of 3 contraceptive methods-DMPA-IM, a copper intrauterine device (IUD), and a levonorgestrel (LNG) implant-on human immunodeficiency virus (HIV) acquisition, we assessed HSV-2 acquisition. HSV-2 and HIV seronegative women, aged 16-35 years, and seeking effective contraception were followed for 12-18 months at 12 sites in Eswatini, Kenya, South Africa, and Zambia from 2015 to 2018. HSV-2 serologic testing was done at enrollment and final study visits. Intention-to-treat analysis using Poisson regression with robust standard errors compared HSV-2 incidence by contraceptive method.

RESULTS

At baseline, 4062 randomized women were HSV-2 seronegative, of whom 3898 (96.0%) had a conclusive HSV-2 result at their final study visit. Of these, 614 (15.8%) acquired HSV-2, at an incidence of 12.4/100 person-years (p-y): 10.9/100 p-y among women assigned DMPA-IM, 13.7/100 p-y the copper IUD, and 12.7/100 p-y the LNG implant. Incidence rate ratios (IRR) for HSV-2 acquisition were 0.80 (95% confidence interval [CI], .65-.97) for DMPA-IM compared with copper IUD, 0.86 (95% CI, .71-1.05) for DMPA-IM compared with LNG implant, and 1.08 (95% CI, .89-1.30) for copper IUD compared with LNG implant. HSV-2 acquisition risk was significantly increased among women who also acquired HIV during follow-up (IRR 3.55; 95% CI, 2.78-4.48).

CONCLUSIONS

In a randomized trial, we found no association between HSV-2 acquisition and use of 3 contraceptive methods.

TRIAL REGISTRATION

ClinicalTrials.gov number NCT02550067.

Long-Acting Reversible Contraception, Condom Use, and Sexually Transmitted Infections: A Systematic Review and Meta-analysis

INTRODUCTION

Given mixed findings regarding the relationship between long-acting reversible contraception and condom use, this systematic review and meta-analysis synthesizes studies comparing sexually transmitted infection‒related outcomes between users of long-acting reversible contraception (intrauterine devices, implants) and users of moderately effective contraceptive methods (oral contraceptives, injectables, patches, rings).

METHODS

MEDLINE, Embase, PsycINFO, Global Health, CINAHL, Cochrane Library, and Scopus were searched for articles published between January 1990 and July 2018. Eligible studies included those that (1) were published in the English language, (2) were published in a peer-reviewed journal, (3) reported empirical, quantitative analyses, and (4) compared at least 1 outcome of interest (condom use, sexual behaviors other than condom use, sexually transmitted infection‒related service receipt, or sexually transmitted infections/HIV) between users of long-acting reversible contraception and users of moderately effective methods. In 2020, pooled ORs were calculated for condom use, chlamydia/gonorrhea infection, and trichomoniasis infection; findings for other outcomes were synthesized qualitatively. The protocol is registered on the International Prospective Register of Systematic Reviews (CRD42018109489).

RESULTS

A total of 33 studies were included. Long-acting reversible contraception users had decreased odds of using condoms compared with oral contraceptive users (OR=0.43, 95% CI=0.30, 0.63) and injectable, patch, or ring users (OR=0.58, 95% CI=0.48, 0.71); this association remained when limited to adolescents and young adults only. Findings related to multiple sex partners were mixed, and only 2 studies examined sexually transmitted infection testing, reporting mainly null findings. Pooled estimates for chlamydia and/or gonorrhea were null, but long-acting reversible contraception users had increased odds of trichomoniasis infection compared with oral contraceptive users (OR=2.01, 95% CI=1.11, 3.62).

DISCUSSION

Promoting condom use specifically for sexually transmitted infection prevention may be particularly important among long-acting reversible contraception users at risk for sexually transmitted infections, including adolescents and young adults.

Sexually Transmitted Infections Treatment Guidelines, 2021

These guidelines for the treatment of persons who have or are at risk for sexually transmitted infections (STIs) were updated by CDC after consultation with professionals knowledgeable in the field of STIs who met in Atlanta, Georgia, June 11–14, 2019. The information in this report updates the 2015 guidelines. These guidelines discuss 1) updated recommendations for treatment of Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis; 2) addition of metronidazole to the recommended treatment regimen for pelvic inflammatory disease; 3) alternative treatment options for bacterial vaginosis; 4) management of Mycoplasma genitalium; 5) human papillomavirus vaccine recommendations and counseling messages; 6) expanded risk factors for syphilis testing among pregnant women; 7) one-time testing for hepatitis C infection; 8) evaluation of men who have sex with men after sexual assault; and 9) two-step testing for serologic diagnosis of genital herpes simplex virus. Physicians and other health care providers can use these guidelines to assist in prevention and treatment of STIs.

Sexually transmitted infections among women randomised to depot medroxyprogesterone acetate, a copper intrauterine device or a levonorgestrel implant

Objectives

Reproductive aged women are at risk of pregnancy and sexually transmitted infections (STI). Understanding drivers of STI acquisition, including any association with widely used contraceptives, could help us to reduce STI prevalence and comorbidities. We compared the risk of STI among women randomised to three contraceptive methods.

Methods

We conducted a secondary analysis to assess the risk of chlamydia and gonorrhoea in a clinical trial evaluating HIV risk among 7829 women aged 16–35 randomised to intramuscular depot medroxyprogesterone acetate (DMPA-IM), a copper intrauterine device (IUD) or a levonorgestrel (LNG) implant. We estimated chlamydia and gonorrhoea prevalences by contraceptive group and prevalence ratios (PR) using log-binomial regression.

Results

At baseline, chlamydia and gonorrhoea prevalences were 18% and 5%, respectively. Final visit chlamydia prevalence did not differ significantly between DMPA-IM and copper IUD groups or between copper IUD and LNG implant groups. The DMPA-IM group had significantly lower risk of chlamydia compared with the LNG implant group (PR 0.83, 95% CI 0.72 to 0.95). Final visit gonorrhoea prevalence differed significantly only between the DMPA-IM and the copper IUD groups (PR 0.67, 95% CI 0.52 to 0.87).

Conclusions

The findings suggest that chlamydia and gonorrhoea risk may vary with contraceptive method use. Further investigation is warranted to better understand the mechanisms of chlamydia and gonorrhoea susceptibility in the context of contraceptive use.

Hormonal contraception and risk of STIs and bacterial vaginosis in South African adolescents: secondary analysis of a randomised trial

OBJECTIVES

Young women in sub-Saharan Africa are at high risk of STIs and unintended pregnancies, yet hormonal contraceptive (HC) use may affect STI risk. We compared the influence of three HCs on the incidence and prevalence of STIs and bacterial vaginosis (BV) in South African adolescents.

METHODS

One hundred and thirty adolescents between 15 and 19 years were randomised to the injectable norethisterone enanthate (Net-En), combined oral contraceptives (COC) (Triphasil or Nordette) or a combined contraceptive vaginal ring (CCVR; NuvaRing) for 16 weeks (clinicaltrials.gov/NCT02404038). Vaginal samples were collected at baseline and 16 weeks post contraceptive initiation for STI and BV testing.

RESULTS

In an intention-to-treat analysis, no significant differences in BV prevalence were found between study arms. The overall incidence of any STI at follow-up was high: 16.2% in the COC arm; 25.7% in the Net-En arm; and 37.1% in the CCVR arm. The incidence rate (IR) of any STI was similar between Net-En (IR 0.74 (95% CI 0.34 to 1.41)) and the oestrogen-containing contraceptives (IR 0.78 (95% CI 0.47 to 1.22)). A lower IR of Chlamydia trachomatis (incidence rate ratio (IRR) 0.68 (95% CI 0.19 to 1.99)) and Neisseria gonorrhoeae (IRR 0.25 (95% CI 0.01 to 1.35)) but a higher IR of Mycoplasma genitalium (IRR 16.0 (95% CI 2.96 to 400)), was observed in the Net-En arm compared with the oestrogen-containing contraceptives, although the overall incidence of M. genitalium was low (4.7%). In an exploratory analysis, the risk of any STI and N. gonorrhoeae was lower in the COC arm compared with CCVR. A per-protocol analysis yielded similar results.

CONCLUSION

Our results suggest that use of Net-En may be associated with increased risk of M. genitalium compared with oestrogen-containing contraceptives but not with overall STI risk. COC use may decrease STI risk relative to CCVR.

The complexity of interactions between female sex hormones and Chlamydia trachomatis infections

PURPOSE OF REVIEW

This review focuses specifically on the mechanisms by which female sex hormones, estrogen and progesterone, affect Chlamydia trachomatis infections in vivo and in vitro.

RECENT FINDINGS

Recent data support previous work indicating that estrogen enhances chlamydial development via multiple mechanisms. Progesterone negatively impacts Chlamydia infections also through multiple mechanisms, particularly by altering the immune response. Conflicting data exist regarding the effect of synthetic hormones, such as those found in hormonal contraceptives, on chlamydial infections.

SUMMARY

Numerous studies over the years have indicated that female sex hormones affect C. trachomatis infection. However, we still do not have a clear understanding of how these hormones alter Chlamydia disease transmission and progression. The studies reviewed here indicate that there are many variables that determine the outcome of Chlamydia/hormone interactions, including: 1) the specific hormone, 2) hormone concentration, 3) cell type or area of the genital tract, 4) hormone responsiveness of cell lines, and 5) animal models.

Medroxyprogesterone Acetate Decreases Th1, Th17, and Increases Th22 Responses via AHR Signaling Which Could Affect Susceptibility to Infections and Inflammatory Disease

A synthetic progestin, medroxyprogesterone acetate (MPA), was used in a novel study to determine progestin effects on human purified macrophages and Th1, Th2, Th17, Th22 cells. MPA concentrations were equivalent to those in the serum of women after 6 and 9 months of progestin use. MPA has no effect on the proliferation of PBMCs and CD4+ T cell clones induced by immobilized anti-CD3 antibodies or by antigen (streptokinase). However, MPA decreases production and mRNA expression of IL-5, IL-13, IFN-γ, T-bet, RORC, and IL-17A but increases production and mRNA expression of IL-22 by CD4+ Th22 cell clones and decreases IL-22 production by Th17 cells. MPA inhibits RORC, but not T-bet and AHR, by Th17 cells but increases AHR mRNA and T-bet expression of established CD4+ Th22 cell clones. This suggests that MPA, at concentrations equivalent to those found in the serum of women after treatment for contraception and hormone replacement therapy, can directly inhibit Th1 responses (against intracellular bacteria and viruses), Th17 (against extracellular bacteria and fungi), Th2 (against parasites) but MPA therapy increases IL-22 produced by Th22 cells mediated by an increased expression of AHR and T-bet controlling inflammation. MPA could be responsible for the tissue damage limited by IL-22 in absence of IL-17A.