National Partnership for Women & Families

Monthly Women's Health Research Review

Study examines efficacy, acceptability of LARC among women seeking short-term contraception

Summary of "Long-acting reversible contraceptive acceptability and unintended pregnancy among women presenting for short-acting methods: a randomized patient preference trial," David Hubacher et al., American Journal of Obstetrics & Gynecology, August 2016.

"One of the most startling reproductive health statistics in the United States is that 48 percent of unintended pregnancies occur in the same month when contraception is used," Hubacher, senior epidemiologist at the not-for-profit FHI 360, and colleagues wrote.

They noted that despite research showing the "superior effectiveness of long-acting reversible contraception (LARC)," such as intrauterine devices and implants, data show that the use of short-acting reversible contraception (SARC) methods is "about four times higher than LARC use." While SARC "methods such as oral contraceptives provide tremendous reproductive health benefit when used consistently and correctly, they can be unforgiving" when used inconsistently, the researchers wrote. They added that although wider LARC use is recommended, "scientific evidence of acceptability and successful use is lacking.'

As a result, for the study, the researchers sought "to isolate the role that LARC may have in preventing unintended pregnancy in a high-risk population and to assess general satisfaction with the products."

Methods

Between December 2011 and December 2013, the researchers recruited 916 women ages 18 to 29 seeking oral contraception or an injectable contraceptive at three Planned Parenthood South Atlantic-operated health centers in North Carolina. Participants were "sexually active, [had] no previous use of an intrauterine device, no previous use of a subdermal implant, not currently pregnant or seeking a pregnancy termination on the day of screening, and good follow-up prospects."

Participants chose to be either randomly assigned a contraceptive method at no cost or to use their preferred method and follow normal payment procedures. Those who agreed to randomization were placed in one of two categories -- LARC or SARC -- and were able to choose a specific method within that category. During the study period, women were allowed to change or stop their method of contraception.

At six and 12 months, the researchers followed up with all participants via a questionnaire "to measure primary outcomes of method continuation and unintended pregnancy." Participants who voluntarily returned to the clinic before the 12 month survey were asked about their reason for the visit and "any contraceptive method provision, method switching, or LARC removal."

The researchers also estimated the probability of the women continuing to use their contraceptive method, compared the incidence of unintended pregnancy and assessed participants' satisfaction with their contraception.

Results

Of the 916 study participants, 57 percent "chose to be in the preference cohort of the study" and 43 percent "asked for random assignment." Ultimately, the researchers enrolled at least 150 participants in the three study groups: preference SARC, randomized SARC and randomized LARC. According to the researchers, "Two participants chose LARC in the preference cohort, but this quantity was insufficient for further analysis."

Overall, 896 participants initiated a contraceptive regimen. Participants in the three study groups "were similar in terms of age, marital status, race, ethnicity, education, pregnancy history, and other variables; approximately 25 percent had a previous abortion," the authors wrote. They added, "Nearly half of women in the randomized groups did not have health insurance, compared with 36 percent in the preference SARC group."

At the end of the study, 95 percent of participants completed the 12-month questionnaire.

The researchers found that the 12-month probabilities that the women would continue the method for each group were 63 percent for preference SARC, 53 percent for randomized SARC and 77.8 percent for randomized LARC. When considered by specific contraceptive product, the researchers found that injectable contraceptive users "had the lowest continuation probabilities," while the implant and IUD users "had the highest."

"SARC users in the randomized group had a higher incidence of unintended pregnancy compared with the LARC cohort," the researchers wrote. They found that the 12-month cumulative probabilities for unintended pregnancy were 6.4 percent among the preference SARC group; 7.7 percent for the randomized SARC group; and 0.7 percent for the randomized LARC group.

The secondary comparisons of just SARC users showed "the continuation probability was higher in the preference group compared with the randomized group." However, the authors found that the two SARC groups had "statistically equivalent rates of unintended pregnancy." When considered by specific contraceptive product, the researchers found that injectable contraceptive users "had the lowest continuation probabilities," while the implant and IUD users "had the highest."

In a separate analysis controlling "for age, Hispanic ethnicity, education, motivation to opt for randomization, and desire for more children" the researchers found SARC users were more likely than LARC users "to discontinue from the assigned contraception ... and also more likely to experience unintended pregnancy."

Further, the researchers found that "78 percent of randomized [LARC] users were happy/neutral with their initial method, compared with 89 percent of randomized [SARC] users." According to the researchers, "LARC users who had the product removed were disproportionately unhappy compared with other discontinuers." Among participants who were still using their contraceptive method at 12 months, "all groups were equally happy/neutral (>90%)."

Discussion

"Our research found scientific evidence that typical users of SARC can find LARC highly acceptable," the researchers wrote, adding, "The forces and factors that lead many typical SARC users to eventually experience unintended pregnancy were demonstrably suppressed and overcome by random assignment and the decision to try LARC."

They continued, "The initial decisions to try LARC, regardless of any subsequent decisions to stop using it, provided substantially higher protection from unintended pregnancy than short-acting alternatives. The random assignment and intention-to-treat analysis confirmed commonly accepted benefits attributed to LARC that have been based on observational studies."

In terms of acceptability, the researchers wrote that their study found high levels of happiness with LARC among a "population who was initially seeking SARC." They explained, "Our overall estimate of happy (71 percent), combined with neutral feelings (7 percent), is somewhat consistent with high levels of satisfaction with LARC (79-86 percent) from observational studies of women seeking LARC." Nonetheless, they noted that "it certainly bears acknowledging that not all women want LARC, and it is clear that not all women will be satisfied with LARC."

Taken as a whole, the researchers wrote, "Our results provide additional evidence for policy recommendations calling for wider access to LARC to improve reproductive health in the United States." However, LARC access is still limited through the United States, the researchers wrote, noting that product availability ranges from 32 percent to 56 percent in office-based facilities and 36 percent to 60 percent in Title X clinics. Further, while patient cost barriers "are fading with Medicaid expansion and with passage and more complete implementation of the Affordable Care Act," the researchers noted that "many states are still underperforming in terms of removing the cost barriers."

However, they noted the study's "main weakness" is that "complete interchangeability of contraceptive regimens at a family-planning consultation is not a practical concept," adding, "Clients should always make final decisions about what product to use, and for many, LARC and SARC are not substitutable." The researchers also wrote that their "estimates of probabilities of unintended pregnancy should not replace standard measures of contraceptive effectiveness."

They concluded, "More voluntary uptake of LARC will help avert many unintended pregnancies and the negative consequences. LARC appears highly acceptable and beneficial, even for women who are not initially interested in trying it."