When a teenager gets pregnant in Ramsey County, she can generally expect a knock on her door. It's not a diaper service or someone selling infant formula — it's a public health nurse dropping by to give her a checkup, offer advice and make sure she's on track to having a healthy baby.

The county's visiting nurse program, which has been around for more than a century, has been shown to reduce premature births, cut the number of low-birthweight babies, lead to fewer ER visits, and has even been linked to lower rates of child maltreatment.

That track record explains why Gov. Mark Dayton is asking the Legislature for $60 million over the next three years to expand the visiting-nurse concept to more homes across the state, with a goal of serving an additional 4,100 families.

"We know that there's a lot of strong evidence for strong outcomes," said Dawn Reckinger, manager for the family home visiting section at the Minnesota Department of Health. "We hope legislators take a look at the need."

Many teen parents lack parenting skills, family support and a high school diploma, and many live in poverty — all factors that have been linked to poverty, health problems and other liabilities for their children. A visiting nurse will give the woman a prenatal checkup, direct the family to classes and community services and even give them parenting tips.

"Teens are in their own developmental process," said St. Paul-Ramsey County Public Health Director Marina McManus. "So it's even more complicated because you have women going through their own maturation."

Nurses sometimes visit clients as often as once a week and continue seeing the mother until her child is around 2 years old.

Because of the intimacy of home visits, a nurse can often make observations about a woman's health and home environment that would not be revealed during a clinic visit, said Jamie Stang, an associate professor in the division of epidemiology and community health at the University of Minnesota.

"Very few women are going to admit to you that there isn't enough food in the house because there's a lot of shame in asking for help," Stang said. "If you have [a patient] come into a clinic, you just can't pick that up."

Stang said she found a high degree of food insecurity in patients she saw while working as a visiting dietitian for Ramsey County in the late 1990s.

Poor nutrition during a woman's pregnancy and her child's early years can increase the likelihood of heart disease, depression, obesity and hypertension later in the child's life, she said.

Reckinger said the Dayton administration plans to offer home visits to all pregnant teens, with the expectation that about two-thirds would voluntarily participate.

In Ramsey County, where visiting nurses reach more than 1,200 women each year, the funding would increase that number by about 400 families, McManus said.

Aside from long-term health consequences for children, child maltreatment costs the health care system an estimated $210,000 per child over the course of a lifetime, according to the U.S. Centers for Disease Control and Prevention.

"We see it as the earliest form of intervention," Reckinger said.

Youssef Rddad is a University of Minnesota student on assignment for the Star Tribune.