If the newborn baby is a girl, she will be named Kimberly. If her mother's prayers are answered, she will be virtually normal.

With luck, there will be few telltale signs -- no excessive sweating and crying, no violent seizures, no brain damage -- of the teaspoonful of heroin that her mother Del, 33, shot herself up with each day during the fetus' first three months of development. Nor of the cocaine that Del had used intravenously each week.

Del, a heroin addict for about seven years, is among a rapidly growing number of District women who are using cocaine, PCP, heroin and methadone during their pregnancies. These women, some of them in their teens, have added a disturbing new dimension to the area's drug epidemic, created life-threatening risks for their fetuses and newborns, and filled hospital nurseries with hundreds of babies who, because of a grab bag of symptoms, require special and more lengthy care.

It is a relatively new phenomenon, for which comprehensive statistics are lacking. But hospitals and research centers here and nationwide have reported an explosion in the incidence of infant drug addiction and intoxication.

The trend appears to be concentrated in areas of heavy drug activity and at hospitals that treat large numbers of indigent patients or those receiving public assistance.

From January through November of last year, 142 drug-addicted babies were born at Greater Southeast Community Hospital, compared with 16 in 1983, 18 in 1984, 19 in 1985 and 55 in 1986. At D.C. General Hospital, there were 195 births of babies whose mothers admitted to drug abuse. They accounted for 11 percent of births at the hospital last year, up from 3.2 percent in 1982, 5 percent in each of the following two years and 8 percent in 1985 and 1986.

Counting the babies born of drug-abusing mothers, however, is an imprecise process and the numbers may be much higher, neonatologists say. The women frequently fail to tell their doctors that they are using drugs. Some of the women will not allow doctors to test their urine. And urine testing of a newborn may be inconclusive if performed too long after birth.

Even when a newborn's urine tests positive for drugs, some women continue to insist they have not used anything, doctors say.

For those reasons, Dr. John Grausz, chairman of neonatology at the Washington Hospital Center, said any attempt to accurately record the number of drug-addicted babies born there would be futile. "It may be as high as 10 percent. That's a wild guess. It could even be higher," he said.

Doctors and nurses who work with drug-abusing mothers say they also are seeing women, particularly young cocaine users, who do not seem to care about their newborns.

"When people used to be heroin abusers, those mothers seemed pretty concerned about their babies and they wanted the babies off and they would give the babies the medication," Grausz said.

"My impression with cocaine is that the cocaine abusers don't care. The heroin mothers would come and they'd relate to their babies and learn how to take care of their babies. The coke mothers, they don't come. We often have to go out and really chase them down so they'll come and take the babies home. I have a real concern that when these babies get home, there are going to be many neglected babies because coke makes them not care."

Some doctors speculate that perhaps the insidious effects of cocaine put the women on a cycle of drug-seeking behavior that leaves little room for concern about the fetus, for which many seek little or no prenatal care, and the newborn.

In addition, doctors say, many expectant mothers are using more than one drug. "We're seeing more mothers who are using combinations of heroin, cocaine and PCP," said Dr. Yvette Reid, a neonatologist at D.C. General. "Two or three years ago, we didn't see that."

Public health workers say some women are shocked and ashamed when they learn about the effects that drugs can have on their unborn children. In the best-case scenario, such as Del's, a woman's pregnancy is diagnosed early enough for her to stop using drugs and begin bolstering her health.

Del, a Congress Heights resident who asked that her last name not be used, is expecting her third child next month. She said she did not use drugs during her other two pregnancies. In August, when she was arrested on heroin possession charges, she learned that she was three months pregnant. For three months, she had been giving heroin and cocaine to her baby. "I had a lot of different feelings," she said. "One of them was abortion, and fear that my baby wouldn't be normal."

Del was placed in the Pregnancy Substance Abuse Program at D.C. General. She stopped using heroin and cocaine. But because the withdrawal symptoms from heroin were considered too risky for the fetus to go through, she was placed on methadone, a heroin substitute used in drug treatment.

"The fetus can go through withdrawal and the fetus can die in utero," said Dr. Howard Wood, director of the clinic.

So far, Wood said, he has not detected any problems for Del's baby, such as retarded fetal growth. Del's methadone dosage will be reduced progressively as her delivery date approaches. The newborn likely will go through some degree of methadone withdrawal, but its chances of suffering neurological damage will be reduced.

Heroin addicts who continue using the drug without any treatment during pregnancy "have babies that have a failure to thrive," Wood said. The babies are listless and often have no suck and swallow reflexes. They have poor breathing ability and little or no motor control, he said. "If the baby's brain is so depressed from these drugs, they can't do these things on their own," he said.

Withdrawal for a newborn is the same as for an adult addict, Grausz said. Such babies are irritable and sweaty; their noses run. Some go through violent seizures that could cause them to asphyxiate.

Del says that had she known she was pregnant, she would have stopped using heroin and cocaine. "A lot of times, when you're out there in the life style, the last thing you think is that you're pregnant," she said. She was accustomed to disruptions in her menstrual cycle caused by intravenous drug use.

Del's baby may also have to contend with some effects of her mother's cocaine use, doctors say. Although use of more than one drug makes it difficult for neonatologists to attribute specific symptoms to specific drugs, researchers have provided a road map.

According to Dr. Ira Chasnoff, director of the Perinatal Center for Chemical Dependence at Northwestern University near Chicago, cocaine has been linked to incidence of fetal strokes, which can cause paralysis and brain damage. In some cases, cocaine use has led to genital, urinary tract and kidney malformations in babies.

Cocaine use may result in premature births through early separation of the placenta, researchers say. And even if a fetus reaches full term, it often is much smaller than normal.

Research also has established a strong link between cocaine and sudden infant death syndrome. At Children's Hospital, babies whose mothers used cocaine during pregnancy are at the top of the hospital's priority list for being sent home on breathing monitors, said Dr. Mhairi MacDonald, vice chairman of neonatology.

Cocaine-addicted babies do not experience the same withdrawal symptoms as those addicted to heroin. Instead, doctors say, they suffer intoxication from the drug's stimulatory effects on their brains. They tend to be extremely cranky and hyperactive. Their cries are high pitched, and they suffer from fine but persistent tremors.

PCP produces effects similar to that of cocaine, researchers say. In addition, PCP babies experience extreme behavior swings that may be caused by brain damage. "Those children are very labile, meaning that they can be very quiet and sleepy and suddenly be startled awake and become agitated and disoriented, then suddenly drop off into a deep sleep," Chasnoff said.

Because PCP is stored in fat and brain cells, researchers believe that the mood swings may be triggered years down the road. Long-term damage to the nervous system also is suspected. Cocaine and PCP can be transmitted to babies through breast feeding, researchers add.

At times, Del says, the stress of being a single parent, a recovering addict and pregnant gets to her. "I get the thoughts of wanting to pick up," she said.

But she has found a support network that includes the clinic and frequent Narcotics Anonymous meetings. Running away, she said, is often the first thing an addict wants to do when someone tries to help.

"But I told Dr. Wood I'm not going to run. I'm going to have my baby here . . . . I know that if there is a problem I still have the pediatric clinic, also the social workers, the public health workers. So I know that I can still get help if it happens that there is something wrong with my baby.

"If it's a girl," she said, "I want to name her Kimberly."