The ACA mandated Essential Health Benefits (EHBs) that all plans sold on the marketplaces and in the small group market must cover, including maternity care, mental health services, and prescription drugs.

Before the ACA, the scope of coverage offered by health insurance plans could vary dramatically, leaving consumers vulnerable to unexpected costs for critical services. Many plans lacked coverage for essential services like maternity care, mental health, or prescription drugs, or imposed annual and lifetime limits on benefits, potentially leaving individuals with catastrophic medical bills. To address this, the ACA established ten categories of 'Essential Health Benefits' (EHBs) that most health insurance plans must cover. These include ambulatory patient services, emergency services, hospitalization, maternity and newborn care, mental health and substance use disorder services, prescription drugs, rehabilitative and habilitative services, laboratory services, preventive and wellness services, and pediatric services. This standardization ensures a minimum level of comprehensive coverage, protecting consumers and improving overall health outcomes by making vital services universally accessible within covered plans.