Recently, I viewed an infographic in the offices of the Population Foundation of India that read: “Family planning saves women’s lives.” This simple slogan captures the profound impact that birth spacing has on preventing death in the developing world, where 479,000 women die each year because of postpartum hemorrhage. This slogan explains the reason that government support for birth spacing is so important. Birth spacing or optimal interpregnancy intervals (IPIs) is also a crucial issue in the United States, where the maternal and fetal consequences of short IPI are well-documented. Short IPIs of <6 months are at higher risk of small-for-gestational-age, preterm, and low birthweight infants, as well as maternal morbidity and death. IPIs of <12 months are at higher risk for fetal death, stillbirth, and early neonatal death. As a source of health disparities, short IPIs are associated disproportionately with being African American, Latino, <25 years old, less educated, unmarried, of higher parity, smokers, and/or without adequate or any prenatal care. Short IPIs contribute to an estimated 8% of low birthweight and preterm infants among African American and Latino mothers. The adverse consequences of short IPIs have made reducing the number of IPIs of <18 months a “Healthy People 2020: objective. Thus, family planning saves lives.

These observational studies that describe the benefits of birth spacing are not new; however, helping all women achieve optimal birth intervals remains an elusive goal. In 2014, Thiel de Bocanegra et al published an article in the American Journal of Obstetrics and Gynecology that showed that contraceptive coverage through California Family Planning Access, Care, and Treatment (Family PACT) was associated with a decreased rate of IPI. Thus, a policy-level intervention led to an increased IPI. In this issue of the Journal, Rodriquez et al, and members of the previous team, take this analysis 1 step further to describe the effect of contraceptive coverage on decreasing rates of preterm birth, which in turn could prevent poor neonatal and infant outcomes.

The current study actually is a study of access to insurance—a study of a supply-side intervention. Indeed, the lack of uptake of insurance and contraception might explain the small-effect size. The average length of coverage was only 5.1 months for all women in this study and only 7.7 months for women who had insurance coverage, which is far from the optimal IPI. One-third of the women in this study did not adopt any method. In another study on this topic by members of this team among 117,644 California enrollees in Family PACT, only 41% of the women had a contraceptive claim within 90 days after birth. More than one-third of the women in these studies did not use a method within 3 months of delivery. Further, on the whole, women adopted less effective methods of contraception, predominately oral contraceptives and barrier methods, which have been associated with shorter IPIs.

Viewing this study as a study of insurance coverage is highly relevant because the Affordable Care Act (ACA) contains the contraceptive mandate that allows women to obtain contraception without copay. Despite the small-effect size that is seen in this study, multiplied over many states and many pregnancies, a lot of a little effect can be a whole lot of effect. It will be important to stay tuned to see, as this study suggests, whether rates of preterm delivery will decrease in states that have accepted the ACA.

Similarly, the impact of this study may be amplified by additional policy changes. Few women in this study used highly effective methods of contraception. A growing body of research describes postplacental intrauterine device (IUD) placement and postpartum contraceptive implant placement. Regarding postplacental IUD placement (within 10 minutes of placenta), Chen et al demonstrated similar IUD use at 6 months postvaginal delivery vs delayed (6-week postpartum) placement. In another study, hormonal IUD use at 12 months was similar with postplacental cesarean delivery placement vs delayed placement. The safety of immediate postpartum implant placement is well-established. Despite higher expulsion rates, postplacental IUD placement may be ideal for patients who are challenged by postpartum follow up. The presence of a global fee for obstetrics, in practice, has limited the implementation of immediate postpartum IUDs and the contraceptive implant. Currently in approximately one-quarter of states, Medicaid has agreed to separate billing for postpartum placement of the intrauterine device and contraceptive implant.

Insurance interventions are imperfect. First, the availability of insurance coverage does not necessarily guarantee that people actually will be insured or that they will have access to contraception. Not all companies have accepted the Medicaid expansion through the ACA. Within states that have accepted it, not all insurance plans cover all methods of contraception. New rules that have been issued by the Department of Health and Human Services have described the importance of offering access to a wide range of contraception. Another major issue in considering whether access to insurance will lower preterm birth rates is that the ACA does not cover women who are not citizens of the United States. Thus, a sizeable number of babies who are born to reproductive-age women who are at risk for preterm delivery may not reap the benefits of birth spacing.

This study has a number of limitations. First, it was conducted in a single state. The very presence of Family PACT suggests that California may differ from other states and that findings from this study may not translate to other states. Second, the sample is predominately Latina, and 45% of the sample was born outside of the United States. Lower rates of preterm delivery for Latinas who were born outside of the United States have been well-described and are attributed to factors other than contraceptive use, such as social support and cultural factors. Despite the authors’ statement, controlling for race and ethnicity does not make the results generalizable to the rest of the country. Third, as a cohort study, the analysis is quite limited. Preterm delivery is a multifactorial problem, and a more rigorous design is needed to control for confounders. The absence of a control condition greatly limits these intriguing findings. Fourth, although the authors state that it is a study of contraception, one might argue that it is a study of insurance coverage; because of the many confounders, the mechanism by which insurance coverage limits preterm delivery actually is not clear. Although it would be logical to assume that the decrease in preterm delivery is due to increased contraceptive use, the mechanism cannot be determined by this study. It is possible that the adoption of contraception is a marker for another behavior that also is associated with decreased rates of preterm delivery (eg, education, social support). Finally, although the impact on Latinas is encouraging, rates of preterm delivery for African American women in this study persisted, which suggests that more is needed to prevent preterm delivery among these women.

Ultimately, the relationship between family planning and maternal child health is well described. Yet, understanding how to address this knowledge through policy and clinical care continues to be a vexing problem. This study that connects insurance coverage to hard outcomes (such as preterm delivery) helps to compel the argument for all women to have access to insurance coverage. Thus, we know that family planning saves lives. The question remains how to support families in achieving the promise of family planning.