California’s infant mortality rate has reached a record low, state health officials reported on Tuesday.

The California Department of Public Health said that in 2010, the most recent year data are available, the rate was 4.7 infant deaths per 1,000 live births, down from 4.9 infant deaths per 1,000 live births in 2009.

Infant mortality is defined as the number of deaths in infants under one year of age.

The findings give California the fourth-lowest infant mortality rate among all 50 states.

“Optimal infant health outcomes are influenced by a woman’s health even before she becomes pregnant, including avoiding tobacco, alcohol and drugs, maintaining a healthful weight, and taking folic acid supplements,” said Dr. Ron Chapman, state health officer and director of the California Department of Public Health.

“Early entry into prenatal care, genetic testing to identify health risks at birth, breastfeeding, immunizations, and continuing proper nutrition through a baby’s developing years all contribute to improving infant health outcomes,” Chapman said.

In Lake County in 2010 there were 721 live births and three infant deaths. Because there were less than five deaths a rate was not assigned to Lake County, according to the agency's report.

For 2009, Lake County had 726 live births and five deaths, and that year also was not assigned a rate, based on the available data.

African Americans in California experienced the largest decline in infant mortality in 2010, from 10.6 infant deaths per 1,000 live births in 2009 to 9.5 in 2010, the agency reported.

While this is a significant improvement, health officials said racial/ethnic disparities in infant mortality persist. African-American infant deaths occurred 2.3 times more frequently than Caucasian infant deaths in 2010.

The infant mortality rate among Caucasians remained unchanged between 2009 and 2010 (4.1 deaths per 1,000 live births) and dropped from 5.0 to 4.9 among Hispanics, according to the data.

Among the factors that may have contributed to the declining infant mortality rate is the decline in the percent of births born prematurely (less than 37 weeks’ gestation). The percent of births born prematurely in California declined from 10.4 percent in 2009 to 10.0 percent in 2010.

Optimal health of women before pregnancy and during pregnancy is likely to contribute to fewer babies born prematurely and to better survival rates of babies overall, the agency's report suggested.

State data showed that the United States ranked No. 31 worldwide for infant mortality; had California been its own nation, it would have ranked No. 27.

Lowest mortality is found in Luxembourg, 1.8; Slovenia, 2.1; Sweden, 2.5; Iceland, 2.5; and Finland, 2.6, according to the report.

Many California Department of Public Health programs and initiatives target reduction of infant mortality as a goal.

For information on these programs, as well as resources that can help pregnant women or women who are considering pregnancy, visit one of the Web sites listed below.

Maternal health before, during and after pregnancy: http://www.cdph.ca.gov/programs/mcah/Pages/MaternalHealth.aspx

Nutrition needs for pregnant women, nursing women and infants: http://www.cdph.ca.gov/programs/wicworks/pages/default.aspx

Immunization needs of pregnant women and infants: http://www.cdph.ca.gov/programs/immunize/Pages/default.aspx

Maternal, Child and Adolescent Health Program: http://cdph.ca.gov/programs/mcah/Pages/default.aspx

Genetic Disease Screening Program: http://www.cdph.ca.gov/programs/gdsp/pages/default.aspx