Lobbyists for the Catholic Church and right-to-life organizations today strongly supported proposed legislation that would prohibit doctors, nurses and midwives in Maryland from withholding food, water or other "things required for sustenance" from a newborn child in their care.

Sponsors of the House bill, introduced by Del. Joan B. Pitkin (D-Prince George's), say it is intended to prevent a so-called "Baby Doe" case such as the one last April in Bloomington, Ind., in which a severely retarded newborn boy died in a hospital after his parents decided to withhold food and treatment.

At a hearing before the House Environmental Matters Committee here today, however, representatives of Maryland's doctors and nurses opposed the legislation, saying that the law would interfere with medical judgments made within hospitals. The opponents also were concerned that the bill's language about the type of care required was vaguely worded and would result in medical officials taking "extraordinary" steps beyond feeding because they feared reprisals connected with the law.

The bill is one of a number of controversial social questions that have come up during this legislative session, including Medicaid funding of abortion, parental consent for abortions for minors, and the issue of whether a dying person should be able to write a "living will" telling doctors that no extraordinary means should be taken to extend their lives.

The bill today, called the "Infant Protection Act," would require medical staffs to report immediately to the state court's juvenile services office any cases in which food, nutrients or other "sustenance" was denied. The courts could then immediately order that care necessary to "maintain the life and health of the child" be provided. The court could also appoint a guardian for the child.

The court would have the authority to suspend, temporarily or permanently, the health care license of medical personnel if it found after a hearing that information about withholding such care was not reported to authorities.

The Maryland Catholic Conference said in a statement submitted today that "infants in our society are too often the victims of abusive and neglectful behavior on the part of health care providers and others having responsibility for their care." While current Maryland law protects abused and neglected children, the conference said, it does not provide similar protection for newborns in hospital care.

Dr. John Hawkinson, chairman of the Maryland Medical Society's maternal welfare committee, told the delegates yesterday, "I seriously question where and in what circumstances there is a specific need" for this law.

"In a rare instance a baby is born with a serious problem and from a medical standpoint we all have difficulty dealing with it," said Hawkinson, who practices obstetrics in Easton, Md. Hawkinson said it would be his practice to feed and care for a distressed infant as well as possible.