The goal of this clinical trial is to definitively determine whether copper intrauterine device (IUD) or hormonal intrauterine system (IUS) results in greater vaginal microbial diversity after 1 year in women (n= approximately 120) aged 18-40 years, who desire to use a copper IUD or hormonal IUS as contraception, are HIV-negative and could benefit from STI prevention.

The main questions it aims to answer are:

1. Whether women assigned to copper IUD vs hormonal IUS have differences in vaginal microbial diversity after 1 year of use
2. Whether women randomized to Copper IUD have reduced genital mucosal barrier integrity as indicated by proteomic signatures
3. Whether women randomized to Copper IUD have greater incidence of high-risk HPV or curable STIs (Ct, Ng, Tv)

Participants will be assigned to have either the copper IUD or the hormonal IUS inserted as contraception. After that, they will have blood and vaginal fluids collected every 3 months for one year to look at the bacteria in their vagina, test for sexually transmitted infections, and examine markers of vaginal health.

After enrolment, each participant will be followed for 12 months, and at the end of the trial, the participant can continue to use the IUD/IUS or the study clinician can remove it.

Through this protocol, the investigators will recruit and follow a novel cohort of young women in the Thika, Kenya area. Enrolled women (approximately 120 aged 18-40 years who may benefit from STI prevention) will be randomized to use either Cu-IUD or LNG IUS and followed for 1 year. Through periodic genital sampling and metagenomic sequencing of vaginal wall swabs, the study will definitively determine whether Cu-IUD use (relative to levonorgestrel-containing hormonal IUD use) results in greater vaginal microbial diversity after 1 year. In addition, the study will conduct periodic testing for human papilloma virus (HPV), Chlamydia trachomatis (Ct), Neisseria gonorrhea (Ng), and Trichomonas vaginalis (Tv) to determine whether Cu-IUD users experience greater incidence of high-risk HPV or curable STIs. Finally, the study will conduct proteomic analyses to determine whether Cu-IUD users experience reduced integrity in genital mucosal barriers.

Inclusion Criteria:

• Willing and able to provide written informed consent for screening and trial participation
• Desire and willingness to use either IUD or IUS for contraception for at least one year
• Clear understanding of study randomization and commitment to use the assigned IUD
• Between 18 and 40 years of age (inclusive)
• Willing and able to actively participate in the study for 12 months
• Willing to be tested for HIV
• Sexually active
• HIV-negative
• Would benefit from STI prevention

Exclusion Criteria:

• Living with HIV or HIV screening results that are not definitively negative

• Currently pregnant or planning to become pregnant within the next 12 months

• Documented or known history of infertility or sterilization

• Prior history of ectopic pregnancy

• Use of contraceptive implant, IUD or injectable progestin in the past 3 months

• Use of oral contraceptives in the past 30 days

• Planning to use alternative contraception except condoms for the trial duration

• 0-6 weeks postpartum

• Has had a hysterectomy or sterilization

• History of challenges using and IUD/IUS, including frequent expulsion

• Medical contraindications (Category 3 or 4 criteria as detailed in the WHO MEC1 to copper IUDs or LNG-IUS, including:

  • Endometrial, ovarian, or cervical cancer
  • Unexplained vaginal bleeding between menstrual periods or bleeding after intercourse
  • History of pelvic tuberculosis
  • Anatomical abnormality of the uterus incompatible with IUD insertion
  • A recent septic abortion
  • Untreated mucopurulent cervicitis on exam, untreated pelvic inflammatory disease (PID), or untreated known gonorrhoea or chlamydia

• Has any condition (social or medical), which in the opinion of the investigator, would make study participation unsafe or complicate data interpretation