Victoria Perez had her head buried in a textbook as her Northwestern High School technology class studied in silence.

Two floors below, down a hallway where students rarely venture, Perez’s nearly 2-year-old son, Christian, noisily shook a musical instrument while Sandra Cruz, a day-care aide, sang “Mary Had a Little Lamb.”

For the past two decades, teen parents such as Perez and their babies have quietly slipped into a side entrance of the Prince George’s County high school campus to a nursery room inside. They exit the “baby bus” and enter the day-care program with their children cradled in one arm, their book bags slung across another.

For the kids who have kids, such day-care centers offer a chance to stay in school and earn a diploma while getting help with the daily responsibilities of parenthood.

Although the number of teen pregnancies has dropped across the country, proponents of the day-care programs say they hope to prevent teens from leaving school to care for babies, with the added bonus of offering their young kids early childhood development. Critics say the centers promote unprotected sex by teens.

“A lot of people think we are enabling pregnancy,” said Maxine Thompson-Burroughs, who operates the Early Head Start program at Northwestern. “We are not a babysitting service. The mission of the program is to help them graduate from high school.”

The Northwestern program, which is paired with a required teen parenting class, is one of two in Prince George’s and similar to others in about a half-dozen high schools across the Washington region and in high schools in cities such as Detroit; Worcester, Mass.; and Portland, Ore. The District has child-care centers at Ballou and Dunbar high schools, Columbia Heights Educational Campus and Luke Charles Moore Academy.

Some teen parents in Arlington County, who are referred by social services and school counselors, are moved off campus to a county building where they learn parenting skills and earn a high school diploma.

Most of the nursery programs care for about 10 children while their parents attend classes.

Ten high school students, including two boys, recently sat in a parenting class at Northwestern, where they discussed what to expect and how to adjust to parenthood. The project of the day: clipping pictures from a magazine to create of collage that represents their future.

Next door to the class is the nursery, where seven children of teen parents are cared for along with about 25 children of staff members and Hyattsville residents.

“I was scared when I first found out,” said Charles Ragland, 18, a senior whose daughter was born in November.“I’ve calmed down, but I’m still nervous. . . . Taking care of her is what I’m thinking about most.”

The teen birthrate reached a historic low at 34.3 births per 1,000 females aged 15 to 19 in 2010, a 9 percent decline from 2009, according to the Centers for Disease Control and Prevention. Still, school systems across the country continue to try to figure out ways to address the issue.

Nearly one-third of teen girls who have dropped out of high school cite pregnancy or parenthood as a reason, and only 40 percent of teen mothers graduate from high school, according to the National Campaign to Prevent Teen and Unplanned Pregnancy.

Thompson-Burroughs said her program has a 95 percent graduation rate. But, she said, budget cuts caused about five students to drop out of the program last year after they didn’t receive the state vouchers that offset part of the cost of the services. She is hoping that the state will restore such subsidies.

“It is critical to help young mothers stay in school, get their degrees and achieve their goals for the future,” said Bill Albert, a spokesman for the National Campaign to Prevent Teen and Unplanned Pregnancy. “One of the ways to do that is to provide the assistance where they need it most.”

Leroy Pointer, whose mother dropped out of school after having him at 17, said he sees the benefits of programs such as the one his teenage daughter, Naomi, and grandson, Jeremiah, have been able to use at Northwestern.

“It’s a place where I trust, know the staff and where they hold the students accountable,” Pointer said.

Brenda Gonzalez, 20, who graduated from Northwestern in 2011, said she doesn’t know where she would be if the school did not offer the day-care service and parenting classes.

“I was scared,” Gonzalez said. “I didn’t know what I was going to do. . . . It was very helpful to me. It still is.”

Since graduating, Gonzalez continues to come back to Northwestern. Now, she is an aide in the day care that her 21 / 2-year-old son, Anderson, attends.

Gonzalez pays $400 a month for day-care services. The rest — an additional $450 — is covered with a state voucher.

Perez, a senior who turned 18 in December, pays about the same. Thompson-Burroughs said her concern is that without vouchers to help offset the cost of the program, the students will not be able to participate.

Two years ago, vouchers and day-care services were not something Perez was thinking about. She gave birth at 16 and said her mother, Rita, “was happy, but disappointed.” Perez’s mother later told her: “Everyone makes mistakes, but you can always overcome them.”

As Perez recently walked past a glass-enclosed case with the names of honor roll students for the first marking period, she pointed to the list and beamed.

“I made the honor roll,” she said as she smiled, showing off her mouthful of braces.

It’s one of the many goals she’s set for herself. She wants to become a medical assistant and then a nurse. For now, she juggles homework, a part-time job and caring for Christian.

“I wouldn’t say it’s hard, but it’s not easy,” she said. “I have to do my homework. I have to take care of the baby. I have everything timed. Right now, I’m studying for my SAT, applying for colleges and scholarships. I have to organize my time.”

The one thing that Perez is happy she doesn’t have to worry about is who is caring for her son while she is in school.