Teen-age pregnancy, a specter of broken dreams that haunts many American families, is no less a growing worry in the suburbs of Moscow or the neighborhoods of Tokyo. Thirteen million women around the world who bore children in 1977 became mothers before they became adults. In most nations children born to women under 20 years of age represent a growing share of all births. The U.S Department of Health, Education and Welfare, now under fire from parenthood planning groups to improve its contraceptive education and service programs for teens, may have something to learn from efforts to cope with teen pregnancy in other societies.

As birth rates among most other age groups slowly begin to fall, teen birth rates remain visibly high. In England and Wales, the number of births to girls under the age of 16 has grown from nearly 200 a year in the 1950s to nearly 2000 in the 1970s.

In the U.S.S.R., births to teens rose in a decade from 3 percent to 9 percent of all births. In 1963 one in eight babies born in East Germany had a teen-age mother; by 1973 it was one in four. Sexual activity amont the unmarried young is increasing, only exacerbating the problem.

Teen pregnancies are, in part, due to the biological fact that women are reaching sexual physical maturity at a younger and younger age. In Europe that threshold age has decreased about 10 months with each of the last several generations. In developing countries, wherever there are nutritional improvements, the age at which sexual maturity begins is falling gradually. Many doctors expect that eventually the age of menarche will level off at about the age of 12.

But reprodutive biology is not the only reason more teens are having babies. Many coples, especially in poorer societies, marry young and have one or two children while still in the second decade of life. While raising the legal age of marriage might help delay childbearing in some places, custom often defies law. Common-law marriage and premarital childbearing, widely accepted practices in Latin America for example, contribute to adolescent pregnancy. The dissolution of traditional communities and the flight from the countryside to cities have weakened many traditional moral injunctions against premarital sexual relations.

Most important, today's teen-agers are ushered into a world of tempting sexual freedom that all too often becomes a trap because family planning programs are inadequate. For adults, the sexual revolution came after the contraceptive revolution. For adolescents, the sexual mores of the society around them have changed, but they still face nearly insurmountable barriers in their efforts to obtain information about contraceptives and to protect themselves from unwanted pregnancies.

Contraceptive ignorance is widespread. A recent survey in Kenya among sexually active 15- to 19-year-old women showed that seven out of 10 could not name one contraceptive method. Such lack of information often ends in abortion. Women in their teens have one of every four abortions in Great Britain, Sweden and Australia.

Formal family-planing programs have been slow to serve the young. Contraceptives are prohibited for unmarried adolescents in China, Taiwan, the Philippines and Indonesia. In many nations, abortions for teen-agers still require parental consent. Indeed, few countries teach the young about reproduction and sexual responsibility, and only in Sweden is sex education deeply entrenched in the curriculum.

Fortunately, this discrimination against teens is gradually changing. In 1974, the French eliminated parental consent requirements for access to contraception and now permit free government services to minors. Other governments are removing many of the legal barriers to contraceptives facing sexually active adolescents,

New, innovative family-planning programs have begun to reach out to teen-agers. Grapevine, Britain's community sex-education project for adolescent, trains young volunteers to work with people their own age in coffee bars, in pubs and on the streets. Teen counselors distribute condoms to those who request them and refer interested young woment to teen clinic where they can get medical advice and contraceptive. This program, which started in London, has expanded to other British towns and has recently been replicated in West Germany.

Similar, innovative programs are in a pilot stage in the United States. Since 1974, Woodson High School in Washington has had the only school-based contraceptive clinic in the United State. Peer counseling goes on during class hours, and students can have physical examinations and obtain contraceptive from the clinic in the school at the close of the school day.

Despite the rising tide of teen pregnancies, HEW is still more willing to fund programs to help teen-age mothers than to help teens who want to avoid becoming mothers. HEW Secreatry Joseph Califano, who balks at pregnancy-prevention programs for the young, seems caught up in the moral debate over who should provide contraceptive information and services - the community or the family. While most observers acknowledge that parents are often best in handling this sensitive issue, the global epidemic of adolescent pregnancy is forceful evidence that that is no longer an option in many families. Experience in Europe and in some U.S. cities suggests teens working to educate other teens is the best way to ensure the young have contraceptive responsibility commensurate with their sexual maturity.