Yesterday Reatha Manning did what only about one in a million mothers has done before. She gave birth to four babies at one time - and without the aid of fertility drugs.

Joseph W. Manning III and his three still-unnamed sisters are the third set of quadruplets born in Washington in about 40 years, and the second set in four months.

The four were born between 9:24 and 9:30 a.m. and weighed a total of slightly less than 10 pounds at Washington Hospital Center. They were pronounced in "good" condition despite the fact that they arrived nine weeks prematurely.

Joseph W. Manning Jr., who drove his wife to the hospital, expecting twins, professed to be calm while hospital staff members who witnessed the wonder became excited.

"I just stood there, I couldn't believe it," said Manning, a federal protection officer with the General Services Administration. "All the nurses ran to the X-ray machine. The staff was more excited than I was."

Manning was describing what happened shortly after he brought his wife to the hospital about 4:30 a.m. in premature labor. X-rays showed four fetuses instead of the two predicted last April.

The quads were delivered by cesarrian section with about 20 doctors, nurses and assorted staff on hand, more than six times the normal complement for a single premature birth.

"We did marshal our forces and I conducted the orchestra," said Dr. Milton Werthmann, chief of the hospital's neo-natalogy department.

Leaning against a wall, with his wristwatch attached to his shirt with two diaper pins and a satisfied smile on his face, Werthmann displayed the four birth weights, inked on his trousers for the curious.

"It's been a very busy morning, to put it mildly," the doctor said.

The babies, red and angry faces behind the cover of isolettes because of "mild respiratory problems," were stabilizing and in increasingly good condition by yesterday afternoon, Werthmann said.

The father, a GS-5 worker, showed off his new son and daughters, and insisted that he was calm - far more so than he had been on the speeding predawn trip from the couple's Suitland home.

"There's nothing to get excited about, nothing's going to change by getting excited," Manning said.He said the couple's preparations for everything in doubles - including the names Joseph III and Kristy - will have to be repeated. Numerous relatives are standing by to help when the babies are brought home in about five weeks, Manning said.

At home, Manning said, his older daughter, Kimberly, 7, was having trouble convincing her sister Katina, 4, that four new babies would be coming home, instead of two.

Mrs. Manning, a secretary at Washington Technical Institute, understandably, just wanted to sleep. She said she had not decided whether one of the girls would be named Kristy. Werthmann said Mrs. Manning would be hospitalized for about a week.

Both grandmothers of the quads, Novella Cook and Louise Manning, marveled at the father's demeanor.

"He's standing up pretty good," Manning's mother remarked, as he walked dazedly among the four isolettes in the intensive-care unit for newborns.

The maternal grandmother said she asked. "What are you going to do with four babies?" and Manning answered, "We'll work something out."

"I don't know, I had eight, but they all came one at a time," Mrs. Cook said.

A hospital spokeswoman said the hospital center, delighted to have delivered the new little Mannings, will pay for all costs of the births beyond the family's insurance coverage.