The teen-age girls who gathered around a conference table at Greater Southeast Community Hospital yesterday were speechless as their instructor told the story of parents who learned of their daughter's pregnancy when the girl collapsed in the kitchen. She was getting milk for the child she had just delivered in her bedroom.

Each of the 12 girls in the conference room was pregnant or holding an infant. They met for the hospital's teen-age pregnancy class and were getting advice about prenatal care and a dose of reality from straight-talking nurse Gloria Rankin.

Under a program funded by the March of Dimes, Rankin has met with more than 200 girls since 1984 and is determined that they have smooth deliveries and the wisdom to face the difficulties created when children have children.

Rankin, reminding the girls of the District's rising infant mortality rate -- up 16.5 percent last year from the year before -- said she is convinced that teen-agers who have a second child are part of a high-risk group because they fail to get the proper care. When these girls become pregnant a second time, she said, they are usually more afraid to tell their parents and delay seeking prenatal care.

Eight girls attending the class said they knew teen-agers who had tried to hide their second pregnancy.

"I know a girl and it was six months before she told anyone she was pregnant," one teen-ager said. "She was not going to the doctor because it was hard for her to get to the doctor without her mother knowing."

Rankin begins her class by giving out her home phone number and telling the students to call when they have a problem or when they think that no one else will listen. She gives them a list of do's and don'ts about taking care of themselves.

Yesterday, she warned them to stay away from alcohol and drugs and anyone who is using drugs. She told them to cut down on the use of salt and to avoid drinking sodas.

"The girls come in here with a lot of misinformation," said Rankin. "No one tells them not to eat a lot of salt and not to drink sodas. A lot of them come in thinking they are having their babies when what they actually have are contractions caused by urinary infections."

During the class, Rankin tries to make the girls, parents and boyfriends comfortable by serving refreshments and giving them an opportunity to talk to one another.

Sherri Lane, a 17-year-old whose son Toney is 4 months old, said she attended the pregnancy class because she was frightened about what she would face during delivery. Yesterday, she gave the class a step-by-step account of her delivery and said she felt comfortable around her doctors thanks to Rankin's instructions.

Rankin makes it clear that she expects the girls to become independent and to realize that having a baby does not mean that somone else will take care of the child.

"You all are the most important group to me," she told yesterday's class. "And I want you to remember that Medicaid didn't get any of you pregnant and Medicaid shouldn't support you. You can go to college and you can get a good home."

Most of the girls said they plan to raise their children.

But at the front of the room, a 13-year-old girl remained silent. She sat beside her mother, who had had two children as a teen-ager and found out only last month that her daughter was six months pregnant.

The woman said she plans to put her daughter's baby up for adoption.

"I'm dealing with whether or not I want to be a mother again," said the 13-year-old's mother. "I've been there and I'm trying to make her understand because I don't want her to hate me for life. These kids in this room are excited and they will be happy when the children first come. But reality hits later. My daughter is entirely too young and she's bright."

The 13-year-old frowned and merely said, "I want to keep it."