The Maryland General Assembly, which was to adjourn at midnight last night, considered the following major issues during its 1985 session: BUDGET.

The legislature enacted a $7.5 billion operating budget containing more than $200 million in new programs. It included 4 percent raises for most state employes and increases in welfare grants. It also approved a $220 million capital budget, funding local programs in Montgomery and Prince George's counties and other jurisdictions. PRISONS.

Funds were approved to begin planning the renovation of the Maryland Penitentiary in Baltimore. HEALTH CARE.

A package of bills designed to slow the growth of health care costs won enactment in the final hours of the session. It would stop new hospital construction until October, encourage hospitals to merge and even force them to close, require hospitals to review practices to eliminate unneeded inpatient care. BANKING.

Citicorp, the giant New York bank, and other out-of-state banks would be allowed to set up limited branches in Maryland when they meet certain job creation requirements. A related bill establishing regional banking among Maryland, D.C. and 14 states by 1987 would allow banks in those states to merge or acquire Maryland banks. SEAT BELTS.

Legislation requiring motorists to wear seat belts died in a House committee. GAMBLING.

Limited use of slot machines by nonprofit groups on the Eastern Shore was legalized after a 22-year hiatus. The bill, passed following several raids on fraternal organizations, now goes to the governor, who has not said whether he will veto it. Another effort to restrict gambling by nonprofit groups throughout the state died. EDUCATION.

Baltimore got a $7.7 million grant for schools and several million dollars were added for community colleges. RACING.

Maryland's thoroughbred race tracks got a $12 million break when the General Assembly cut the state tax on each dollar wagered from 4.09 cents to half a cent. Track owners had argued they needed the boost in order to meet stiff competition from tracks in neighboring states. ENVIRONMENT.

The assembly sent to the governor a measure to ban the sale of phosphate detergents, with some exceptions. Environmentalists won a battle earlier in the session when the legislature refused to allow utility interests to construct a coal slurry pipeline from West Virginia to the Chesapeake Bay. The legislature bowed to coal interests, however, when it approved strip mining of coal on mountain slopes above 20 degrees. YOUTH.

The legislature voted to spend about $11 million for programs to attack problems including child abuse and foster care. Other measures passed included a bill that would allow a child to testify against an alleged abuser over closed circuit television rather than in the courtroom. ABORTION.

The House rejected Hughes' efforts to liberalize funding guidelines for abortions for poor women, and the Senate sidestepped the issue completely.