Aside from the immediate health risks of injecting drug use (IDU), such as overdose or transmission of blood-borne infections, IDU often leads to dependence, incarceration, and potentially premature death [1–3]. While a “comprehensive package of interventions” is recommended by the World Health Organization, the United Nations Office on Drugs and Crime, and the Joint United Nations Program on HIV/AIDS, gender-specific needs of women are often ignored or overlooked in the development and delivery of prevention and treatment services [4]. However, the proportion of women among people who inject drugs (PWID) ranges from 10 to 30% and is increasing [5]. Unfortunately, IDU is most prevalent during late adolescence and early to mid-adulthood, coinciding with a woman’s childbearing years [4]. Despite this alignment of risks, only a few studies have assessed the utilization of female-specific contraceptive use among females who inject drugs (FWID) nor have they quantified a higher incidence of pregnancy and abortion of undesired pregnancies [6–9]. Although research exists for condom use among PWID, little is known of non-condom contraception use in women currently injecting drugs, and scarce data are available related to the gender-specific needs for harm reduction services and preferences for contraceptive methods.

The complexities of PWID reproductive life are not limited to the contraceptive challenges.

While the diagnosis of the neonatal abstinence syndrome (NAS) is often dependent on physician bias [10], the rise in NAS incidence has been documented in the USA and Europe [11–13]. A recent assessment indicates that treatment for NAS is often of poor quality across the USA [14]. Further, reviews on effects of opioid agonist treatment for pregnant opioid-dependent women concluded that the evidence base was of very low quality, yet documented an increased risk of NAS among newborns of mothers receiving medication-assisted treatment [15]. Importantly, positive outcomes of the treatment are higher birth weight and parental custody [16]. It has been acknowledged that the opioid epidemic in the USA has brought along an alarming number of children placed into foster care [17].

Eastern Europe and Central Asia have the fastest growing HIV epidemic, initially driven in large part by injection drug use [18], and it is noteworthy that PWID account for 51% of new HIV infections in this region. According to a global review, Estonia has one of the highest concentrations of PWID among those 15–64 years (1.5% in 2007) and a very high HIV prevalence among PWID [1]. Several studies have examined sociodemographic factors and behaviors associated with IDU in Estonia [19–23]. One such study documented that females who inject drugs and who have started injecting recently are in high risk of becoming infected with HIV via sexual transmission, even before IDU initiation, highlighting the need for gender-specific interventions [24]. In this report, we examine the prevalence of and factors associated with the use of non-condom contraceptives among FWID with the focus on effective contraception.

There were 265 FWID with a mean age of 28.5 (range 18–50) years. The mean age for the first illicit drug injection was 19.5 years (range 11–40) years, and the mean number of injections in a typical day was 2.

Of the recruited FWID, 85.6% were of non-Estonian ethnicity (Russian speaking) (n = 233), 43.6% reported less than 10 years of education, and 37.0% were previously incarcerated. In terms of income, 39.1% reported government/social subsistence, and 23.3% reported employment as their main source of income. Just over half (50.8%) were married, 36.9% single, 10.6% divorced, and 6.6% widowed. In our study, about two thirds (63.0%) of the women who participated were mothers. Of those with a child, the mean number of children was 1.8 (range 1–6); one in four (25.7%) mothers lived with minor child(ren) younger than 18 years. Most (68.6%) women reported Health Insurance Fund coverage and average health; 35.4% reported excellent or good health and 15.0% reported poor or very poor health.

Half of the participating women were HIV-infected (50.1%, 95% CI 39.0–61.2%); of those HIV-infected, 46.9% were on ART. Of note, ART coverage rose dramatically from 19.2% in 2007 to 56.8% in 2013.

For the more detailed analysis of contraception methods and factors associated with choice of method, we focused on sexually active women who reported having a main partner (n = 196). Those not meeting these criteria were 28 women who were not sexually active, 35 who were sexually active but did not have a main partner, and 6 who were trying to conceive.

Sexually active women with a main partner who were retained for analysis were more likely to be married than those who were excluded (57.9 vs 10.3%, respectively, p < 0.001). They also had more sexual partners during the previous 12 months (mean 2.5 vs 2.0, p < 0.001), and a higher proportion with more than three sexual partners (23.5 vs 10.8%, p < 0.001). The women with a main sexual partner also tended to report employment as a main source of income more frequently than their counterparts (28.0 vs 10.2%, p = 0.054).

This study of factors associated with contraceptive use among FWID in Tallinn, Estonia, revealed that needed effective contraception (hormonal contraception/intrauterine device/sterilization) use among women (sexually active, with a main sexual partner and not trying to conceive) was exceedingly low—less than 5% benefit from adequate contraception. Half of women (47%) were not using any contraception at all.

A systematic review of contraceptive use among women with substance use disorders also found that these women have an unmet need for contraception [34]. Comparable to our findings, very low (effective) contraception use among current FWID (not recruited from treatment settings) has been reported (Russia [9]; USA [6, 7]); France [35]). Clearly, work remains to reach this group.

Women’s attitudes towards contraception may be affected by several factors, including amenorrhea [36], low knowledge [37], barriers (particularly stigma) related to seeking health/care services, financial constraints, and generally, a challenging life. In our study, education did emerge as an important factor positively associated with effective contraception use. We consider it noteworthy that none of the women lacking health insurance were using effective contraception.

Contraceptive behavior among FWID significantly differs from that of the general population. Compared to the Estonian general population, FWID are more than six times less likely to use effective contraception and over three times more likely to not use any method of birth control [38]. However, this trend diverges importantly among FWID in this study in that they did report condom use for contraception (46.7% compared to 31% in the Estonian general population). While condoms are the only contraceptive choice that will also prevent HIV transmission, this is largely within male control. The discordant pair condom use rates found in the study are noteworthy (HIV+ men with HIV− female partners had low condom use). Evidently, women in these partnerships are not only placing themselves at risk for undesired pregnancy but also importantly at great risk for HIV.

Research on opioid (the most frequently injected substances) use during pregnancy has documented the negative effects on the pregnant woman, fetus, and neonate [39, 40]. Infants born to women chronically using an opioid are at risk for neonatal abstinence syndrome. In spite of lack of clarity and consistency in how the syndrome is defined, there are clear signs of growing number of newborns diagnosed with this condition in the USA and in Europe [12, 41]. Further, Cornford et al. [42] noted that 64% of children aged < 16 years born to opioid drug-using women in drug treatment did not live with their mother. In our study, about two thirds of the women were mothers but fewer than a third were living together with their child(ren). Taking care of children while living with the stigma of IDU creates another layer of complexity for the FWID and their family members. Clearly, the relationship between child protection issues and contraception remains complex and poorly described [42]. It has been questioned, whether women who use drugs are too readily separated from their children, temporarily or permanently [43]. Whether the potential premature separation of IDU mothers from their children may predispose the mothers to continue IDU and other risky relationships and behaviors warrants more attention.

We concur with other researchers in the assertion that targeted interventions are warranted to meet the specific (highly effective) contraceptive needs of FWID. The challenging lifestyle of FWID may hinder their access or commitment to medical and social services. However, a study conducted in Australia among women who inject drugs found that FWID strive to control their fertility and express individual contraceptive preferences and concerns for their children (both born and unborn). Women’s drug use should not be automatically associated with an inability to make informed health care choices nor a lack of desire to care for their children [44]. Any efforts to decrease unintended pregnancy will need to include elimination of the everyday barriers which preclude access among at-risk women, such as stigma, lack of insurance, or inadequate coverage. Alternative providers and settings should also be considered, such as during antenatal care and after delivery, at prisons upon release, and drug treatment and needle exchange programs. About 40% of FWID in our study have been imprisoned at some point, and previously incarcerated women are at high risk for unintended pregnancy upon release [45]. Finally, while it does not confer any disease transmission protection, emergency contraception is likely to prevent an unintended pregnancy and should be considered as part of a panel of services provided.

Of the limitations inherent to any study, the cross-sectional design used mostly affects and limits our ability to draw causal inferences. The modest sample size (especially for the FWID using effective contraception) increases the likelihood of type II error. While the fact that we found so few FWID who were using effective contraception that we could not do standard multivariable logistic regression is a limitation, this is an important finding in its own regard. Regression analysis attempts to discern between causal and confounding factors; we propose that in this study, there are probably multiple important causal factors, such as lack of health insurance. Many factors may be necessary but not sufficient causes. Last but not the least, our study focused on women in a main partnership, therefore omitting relevant and needed information on women with casual partnerships.

This study benefits from a carefully selected target population, focusing on only those women who are at risk of becoming pregnant and are not trying to conceive, thus at greatest need for effective contraception. Second, we selected the recall period of 6 months for contraception and partnership measures to be able to capture meaningfully current practices and to lower recall bias. Finally, we described each contraceptive method separately and, for further analysis, grouped the methods with regard to effectiveness.

A recent review detailed research gaps on HIV in women who use drugs [46] highlighted potential vulnerability of FWID for HIV, HCV and other co-morbidities, and access to care for HIV treatment and prevention. Our study highlights the exigency of providing FWID with a range of gender-specific sexual and reproductive health services, including contraception and pregnancy services, in addition to prevention of mother-to-child HIV transmission.

With the continued high prevalence of HIV among PWID, promoting condom use among drug users remains important for preventing sexually transmitted infections. However, the extremely low rate of effective contraception use in Estonia specifically, and notably so in HIV-discordant pairs, underscores the urgent need to promote the use of effective contraceptives (such as hormonal contraception or IUD) for females who are not seeking to become pregnant.

Reproductive health service including contraception should be considered essential components of harm reduction and of comprehensive prevention and care for HIV among persons who use drugs. Programs that aim to provide free, integrated needle exchange, drug treatment and non-stigmatizing reproductive advice, and parenting assistance would greatly improve access to reproductive health services and expand choices available to women.