Pregnancy and Contraceptive Use among Young Women Who Inject Drugs in a Hepatitis C Virus Vaccine Preparedness Study

Author: White B, Day C, Black K, Maher L

Theme: Epidemiology & Public Health Research Year: 2015

Background: Efficacy trials of preventive HCV vaccine candidates require recruitment of large numbers of HCV-uninfected people who inject drugs (PWID). Women who inject drugs (WWID) are at higher risk of HCV infection and have elevated rates of unplanned pregnancies compared to the general population. While pregnancy is an exclusion criterion for vaccine trials, little is known about pregnancy incidence among WWID. This study aimed to estimate pregnancy history and intention and contraception use among HCV-uninfected WWID in Sydney.

Methods: Women were enrolled in HITS-c, a prospective cohort of anti-HCV antibody negative PWID. Participants completed quarterly follow-up visits with pregnancy intention and contraception use documented biannually.

Results: Between November 2008 and November 2013, 23% (n=44) of the 188 participants enrolled in HITS-c were women. The median age of women who completed ≥1pregnancy-related follow-up assessment (n=38) was 26 years (range 16-37). Thirty-one (82%) women reported ≥1prior pregnancy at baseline with a median of 3 (range 1-9) pregnancies and a median of 1 (range 0-6) live births. Eighteen women (47%) indicated future pregnancy intention. Of the 17 women (45%) not any using contraception, only 9 (52%) expressed pregnancy intention. The most common method currently used by the 21 (55%) women using contraception were condoms (n=11) and oral contraceptives (n=6). Use of long-acting reversible contraceptive (LARC) methods was rare with 2 women each reporting use of implants and intra-uterine device. Three women had taken the morning-after pill for post-coital contraception.

Conclusion: The high prevalence of previous pregnancy (84%), future pregnancy intention (47%) and low prevalence of LARC suggest a need to consider the impact of pregnancy on study power in sample size estimates for trials involving WWID. Results are also relevant to new HCV treatments given most DAAs will require contraception use throughout treatment with regimens containing ribavirin also requiring contraception 6 months post-treatment.

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