Childbirth is the leading reason for hospitalization in the United States.¹ For both private insurers and Medicaid, hospital maternity and newborn charges exceed those for any other condition.² In US hospitals, vaginal and caesarean deliveries cost approximately $8000 and $11,000 respectively.³ High-deductible health plans (HDHPs) have expanded rapidly in recent years, with 27% of workers having a deductible of at least $1000.^4,5 Between 2006 and 2010, enrollment in HDHPs tripled to 10.0 million members,⁶ and analysts predict an “explosion” in growth due to the recent health reform legislation.⁷

Although HDHPs are intended to decrease escalating health costs and discretionary care, they have generated controversy.^8-12 High cost sharing can reduce appropriate  healthcare utilization, including hospitalizations, preventive services, and essential medicines.^13-15 Therefore, HDHPs often fully cover preventive services, including prenatal care.^16-19 No previous studies have measured the impact of HDHPs on the costs and use of maternity care.^20,21

Our study examined this question among women insured by a large Massachusetts-based health insurance program (Harvard Pilgrim Health Care) that predominantly insures members through HMO plans and began offering HDHPs in April 2002. We anticipated that HDHP membership would increase out-of-pocket maternity expenditures, shift costs to members, and possibly reduce total maternity care expenditures, consistent with the cost-containment goal of consumer-directed healthcare.²²

Although use of exempted services might be expected to remain stable, we hypothesized 3 mechanisms that could decrease utilization. (1) Cost sharing for nonexempt services (such as laboratory tests) ordered during prenatal visits could discourage subsequent visits. (2) The intricacy of maternity benefit design in HDHPs (eg, deductible exemptions based on clinical conditions) combined with uncertainty regarding costs of anticipated services could cause confusion and reduced care even for exempt services.^9,23 (3) Experiencing a previous large deductible payment (eg, an emergency department visit) might induce “sticker shock” and broadly reduce utilization.²⁴

The objective of this study was to evaluate the impact of transition from an HMO to an HDHP on the costs and utilization of maternity and delivery care services within the 6 months before and 3 months following delivery.

METHODS

The Office for Sponsored Programs (Harvard Pilgrim Health Care Institute) reviewed this study and granted institutional review board approval.

Research Design

We used a pre–post study design with matched control group and a difference-in-differences analysis to measure changes in study outcomes.

Setting

Harvard Pilgrim Health Care is a health plan serving approximately 1 million individuals in New England. On April 1, 2002, Harvard Pilgrim began offering HDHPs with annual deductible amounts of $500 to $2000 for individuals and $1000 to $4000 for families. Members of family plans also had individual deductibles equal to half of the family deductible. Of Harvard Pilgrim’s commercially insured members, approximately 70% have HMO plans, 20% have preferred provider organization (PPO) plans, and 10% have HDHPs, compared with corresponding national rates of 58%, 19%, and 13%.⁴ Although PPO plans are more common than the HMO plans we study, cost-sharing requirements for services such as preventive tests, hospitalizations, and specialist visits are quite similar4; the primary differences between HMO and PPO plans are the more limited provider network, the need for specialist referrals, and the inclusion of high deductibles in approximately 40% of PPO plans.⁴

Insurance coverage for maternity care in Harvard Pilgrim HMO plans includes full coverage of prenatal and postpartum care, with no cost sharing beyond office visit and  hospitalization copayments. Outpatient visit copayments among HMO members in our study ranged from $5 to $25 (median $15) while hospitalization copayments ranged from $0 to $1000 (median $250).

In the HDHPs we studied, many maternity care services are exempt from the deductible, having either first dollar coverage or low copayments. First dollar coverage applies to routine prenatal and postpartum visits, fetal ultrasounds (sonograms),  routine urinalysis, Papanicolaou tests, and screenings for sexually transmitted infections. All hospital delivery charges and many outpatient procedures are subject to the deductible, but are covered in full after the deductible has been met. Copayments of $20 apply to non–maternity care outpatient visits, urgent care visits, and specialist consultations. These copayments apply regardless of whether the member has exceeded the deductible spending level. However, the HDHPs have an out-of-pocket maximum (including copayments and deductibles) of $2000 to $4000 for individuals and $4000 to $8000 for families. After a member reaches the out-of-pocket maximum, all services are covered in full. Provider networks for women in HDHPs and HMO plans are identical.

The HDHPs we studied were not eligible to be paired with health savings accounts (HSAs); all were eligible to be combined with health reimbursement accounts (HRAs). Although we could not account for HRA purchases from other companies, only 3% of the HDHPs we studied had HRAs through Harvard Pilgrim. Nationally, fewer than half of HDHPs with deductibles over $1000 are paired with HSA or HRA accounts,⁴ so our analysis is relevant for the predominant type of HDHP.

Study Population

Using previously established methods,²⁴ we created a cohort of health plan members enrolled through employers who exclusively offered insurance through Harvard Pilgrim Health Care. We defined 2 cohorts: an HDHP group and an HMO control group. The HDHP group included members enrolled in traditional HMO plans during a 1-year baseline period prior to an employer-mandated switch to an HDHP. The date of this switch was defined as the index date. For each HDHP member, we identified 8 contemporaneous members who  were continuously enrolled in traditional HMO plans during the same time period. We assigned HMO controls the same index date as their HDHP counterparts, and the distribution of index dates was similar in the HDHP and HMO control groups in the final study population. We selected only HMO members whose employers did not offer an option to enroll in an HDHP or any other plan types. Therefore, no study members were able to self-select their health insurance plan or benefits structure.