The legislators who drafted the Affordable Care Act wrestled with cosmic issues of health and spending, but here’s one consequence they didn’t foresee.

Tucked within the new law is a provision requiring insurance companies to cover breast pumps and visits to lactation consultants at no cost to the patient.

Other mandated benefits, including the requirement to pay for contraceptives, drew far more attention and controversy. But when health insurance plans began resetting Jan. 1 under the new terms, it was the breast-pump clause that took off with consumers.

Insurance companies are figuring out the best way to navigate the federal regulation and provide a benefit that, until now, they had not routinely covered.

The government does not bear the costs of providing breast pumps. Instead, insurers will have to pay for the new benefit, likely with a slight increase to the premiums they charge their members.

Administrators of insurance plans still have questions about how to best implement the rule. No state has ever required insurance companies to cover the benefit, although Louisiana did convene a study panel on the issue in 2002, according to the National Center for State Legislatures.

Thirty-one states already require Medicaid, for the low-income, to cover breast pumps.

The health care law’s requirement does not specify whether insurance companies must cover certain brands or types of breast pumps. It directs health plans to pay for “the costs of renting breastfeeding equipment” in conjunction with each birth. The breast pumps available for rental tend to be larger and more durable than those sold commercially, which are not intended for long-term use.