The effect of different contraceptive methods on the vaginal microbiome

ABSTRACT

Introduction: Following a historical overview, the effect of different contraceptive methods on vaginal microbiome has been reviewed and summarized.

Areas covered: Effects of combined hormonal contraceptives (oral or vaginal) and of progestin only (injectable and implantable), intrauterine devices/systems (copper- or levonorgestrel-releasing), on vaginal microbiome. In addition, mention is made of vaginal rings releasing antiviral drugs and lactic acid.

Expert opinion: The vaginal microbiota (VM) is unique in that it is normally dominated by Lactobacillus species providing a degree of protection against infections; this however may vary, depending on the species and strains of Lactobacillus. Bacterial Vaginosis represents the most common dysbiosis of the VM and its prevalence can be influenced by use of contraception. Available evidence indicates that, under the influence of oral or systemically administered female sex hormones, there is apromotion of vaginal eubiosis, with aprevalence of ahealthy VM in which Lactobacilli predominate.

KEYWORDS:

• Combined hormonal contraceptives
• intrauterine devices
• progestin-only contraceptives
• vaginal microbiome
• vaginal rings

List of Abbreviation

3TC-TP: Emtricitabine Triphosphate

95%CI: 95% confidence interval

aOR: Adjusted Odds Ratio

AV: Aerobic Vaginitis

AVR: Antiretroviral-releasing Vaginal Rings

BV: Bacterial Vaginosis

CAVR: Contraceptive and Antiretroviral-releasing Vaginal Rings

COC: Combined Oral Contraception

CT: Chlamydia Trachomatis

Cu-IUD: Copper-releasing Intra Uterine Device

CVR: Contraceptive-releasing Vaginal Rings

DMPA: Depot-Medroxyprogesterone Acetate

E₂: Estradiol-17β

ECHO: Contraceptive Options and HIV Outcomes

EE: Ethinyl-Estradiol

ENG: Etonogestrel

FDA: Food and Drug Administration

HIV: Human Immunodeficiency Virus

HRT: Hormonal Replacement Therapy

HVR: Hydroxychloroquine-releasing Vaginal Rings

IUD: Intra Uterine Device

LNG-IUS: Levonorgestrel-releasing Intra Uterine System

LNG: Levonorgestrel

LVR: DL-Lactic acid-releasing Vaginal Rings

mL: Milliliters

NET-EN: Norethisterone Enanthate

pHR: Pooled Hazard Ratio

POP: Progestogen-Only Pills

RR: Relative Risk

SGSA: Segesterone Acetate (Nestorone)

STI: Sexually Transmitted Infections

TMG: Trimegestone

TVF-DP: Tenofovir Diphosphate

TVF: Tenofovir

VM: Vaginal Microbiome

VNAB: Vaginosis-Associated Bacteria

VR: Vaginal Rings

WHO: World Health Organization

Article Highlights

• The fundamental role of lactobacilli in vaginal physiology has been documented by a variety of studies.

• The ability to produce lactic acid seems conserved in all vaginal bacterial communities of healthy women.

• There is good evidence that the use of COC and condom is associated with a significant protective effect against BV.

• Under the influence of oral or systemically administered female sex hormones there is a promotion of vaginal eubiosis, with a prevalence of a healthy VM in which lactobacilli predominate.

• Estrogens are the main contributor to the maintenance of a normal vaginal ecosystem in women of reproductive age.

• CVR cause no substantial changes in the VB.

• There seems to be no evidence that intrauterine contraception (Cu-IUD or LNG-IUS) can alter vaginal microbiota composition.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper did not receive funding.