The fund is designed to assist investors in saving for future eligible medical expenses. Because the time horizon of such expenses is inherently uncertain, the fund pursues an asset allocation strategy that is designed to balance growth and downside market protection through different market environments. Investing primarily in a combination of both actively and passively managed Fidelity bond and equity funds and affiliated and unaffiliated exchange-traded funds (collectively, underlying funds). Investing approximately 30% of the fund's assets in underlying equity funds, 60% of the fund's assets in underlying bond funds, and 10% in short-term and/or money market funds. The Adviser may vary the fund's exposure to the underlying funds within the following ranges: 20-40% of the fund's assets in underlying equity funds , 50-70% of the fund's assets in underlying bond funds, and 0-20% of the fund's assets in underlying short-term and/or money market funds.   Allocating the fund's assets among bond funds (including domestic, international , U.S. inflation-protected debt, and short-term bonds), equity funds (including domestic, international, and emerging markets equities), and short-term and/or money market funds to manage the fund's risk across asset classes over time. Emerging markets include countries that have an emerging stock market as defined by MSCI, countries or markets with low- to middle-income economies as classified by the World Bank, and other countries or markets that the Adviser identifies as having similar emerging markets characteristics. Investing up to 25% of assets in underlying high income (including funds that invest in high yield debt securities (also referred to as junk bonds)), leveraged loan, country specific equity, real estate equity, U.S. long term treasuries, emerging market debt, and commodities funds. Investing in Fidelity's Central funds (specialized investment vehicles used by Fidelity® funds to invest in particular security types or investment disciplines) consistent with the asset classes discussed above. Buying and selling futures contracts (both long and short positions) in an effort to manage cash flows efficiently, remain fully invested, or facilitate asset allocation.