Worldwide, "roughly one child out of every 10 does not live to see its first birthday," according to a Washington-based international research group.

While most advanced industrial countries have witnessed "a continuing steady decline" since World War II in infant death rates, the progress is "mixed" among developing countries, writes Kathleen Newland in a new report released today by the Worldwatch Institute.

"The disparity between the world's highest and lowest rates is probably greater now than ever before," she warns, particularly since the infant death rates in some of the least developed countries are "as high as any in history."

The infant death rate is usually expressed as the number of babies out of each 1,000 born alive who die before the age of 1. Worldwide, this is estimated to be 97 per 1,000.

Newland says the low end of the range can be found in the "most deprived" people in the world, particularly in sub-Saharan Africa, where infant mortality rates are as high as 200--or a death in one out of every five babies.

In contrast, she says, in the "wealthy and egalitarian societies" such as Sweden and Japan, fewer than 10 per 1,000 babies die.

In North America and most of western Europe, infant death is slightly higher, with the United States' rate, which has been declining in recent years, now falling below 13 per 1,000 births.

However, says Newland, the highs and lows do not simply reflect poverty and affluence. Poor countries such as Sri Lanka and China have relatively low infant mortality rates while richer ones, such as Libya and Saudi Arabia, have high levels.

In addition, U.S. cities such as the District of Columbia and countries such as Brazil and the Soviet Union recently have recorded increases in their infant death rates--signs, she contends, of "a development process gone astray."

In the District, the infant mortality rate increased from 22.2 deaths per 1,000 births in 1979 to 24.6 in 1980, a rate about twice the national average and the worst for any metropolitan area in the country.

While gross national product and average income reflect economic health, Newland says, infant death rate better measures the "overall level of well-being in a country" and a society's ability to meet "the needs of its people."

"High infant mortality is associated with certain social problems that may persist even in the face of rising per capita income: environmental contamination, lack of education, discrimination against women, poor health services," Newland says.

Because there are so many possible causes, "there is no quick fix for reducing infant mortality," she concludes, particularly since the dominant problems do not easily yield to direct medical action. But "health education, more even distribution of food resources, improvements in sanitation, enhancement of the status of women and restructuring of priorities in public spending can all pay handsome dividends in infant survival," she says.

Smoking and drinking by pregnant women are of particular danger to their unborn infants.

Women who have large families--particularly more than four children--in a short time frame also experience more infant deaths. An El Salvador study found that infant death rates were three to five times higher than normal when the interval between births was particularly short.

Discrimination against women in education is "a recipe for higher infant mortality," maintains Newland. She says the level of education directly affects the child's chance of survival, with the poorly educated woman less able to respond to threats posed by the physical environment.

She also cited studies, including one in Bangladesh, showing that women, even when pregnant, continue to be underfed, for their size, relative to men.