Mom’s 1st Day Back on the Job : As they kiss their babies goodby, many ask, ‘Am I doing the right thing?’

Martha Duffley leans over her son’s crib, stretching the silent moment.

Too soon, it’s the 6 a.m. feeding, the scrambling to get the 5-month-old dressed and packed for day care. In no time, it’s the first goodby.

“No tears,” the new mother promises herself, swinging her compact car away from suburbia and into the commuter traffic surging toward downtown Boston. “No time for tears.”

It’s Martha’s first day back.

She is just one of about 1.9 million women who return to jobs each year after having a child. Some mothers prefer to work; others have no choice.

Regardless of financial circumstances, fewer than 10% of Americans live in what once was the traditional family headed by a male breadwinner. Sixteen percent of women with infants worked in the early 1960s, compared with more than 50% today.

“Women are still asking themselves: ‘Am I doing the right thing?’ ” said Barbara Reisman, executive director of the national Child Care Action Campaign. “Our mothers led a different life, and theirs is the only model we have.”

But that nuclear, 1950s model is, for many mothers, far out of date. The rules have changed, the days grown longer and more complicated.

* Martha, a Boston postal supervisor, fears her son’s care-giver seems more a mother to him than she does.

* Pam Salazar, a television reporter in Dayton, Ohio, wonders whether continuing to breast-feed after returning to work seems unprofessional.

* Vicki Sugarman, who shares a job managing promotions for a Stoughton, Mass., company, frets over finding convenient and reputable day care.

* Her partner, Janet Aikens, worries that their job-sharing experiment at Reebok International Ltd. may be tokenism rather than the start of a common option for working mothers.

* Sheila Michelli, an Army captain in Fort Lee, Va., struggles to negotiate shared responsibilities with her semi-workaholic husband.

* Cynthia Sartin, a nurse in downtown New Orleans, feels guilt’s stab each time she tucks her sad-eyed baby girl into bed and slips out the door.

* Amanda Wallis, a San Francisco bank executive, realizes time for herself has disappeared amid the crazy scramble that is modern motherhood.

These and millions of other moms are exhausted. Yet despite their daily race, “having it all” still too often means living with the uncomfortable sense that everything is only half-done.

No simple “how-to” manual exists to ease the dueling pressures or explain away irrational guilt. Working parents still are experimenting, making errors and veering off track.

“If I were giving the nation a report card, I would have to give us a C,” said Joseph Pleck, a family issues researcher at Wheaton College in Norton, Mass. “You can expect a little more help from your husband, but don’t expect much from your employer.”

One in five men now pitch in at home and, Pleck said, their increased participation in flexible hours, paternity leave and other child care programs has helped debunk employers’ perception that these are special women’s benefits.

Still, less than half of working women receive paid maternity leave, and only 11% of companies with more than 10 employees offer on-site day care, subsidies, counseling or referrals, according to the U.S. Census Bureau.

The United States is the only industrialized nation besides South Africa that has no family leave policy. Meanwhile, the 1990 federal budget of $7 billion for child-care subsidies and tax credits lags far behind most other developed countries, according to the Children’s Defense Fund.

“Our expectations aren’t realistic. Because the career system hasn’t been modified, women are always doing two things at once,” said sociologist Arlie Hochschild, whose “The Second Shift” examines two-career families.

“That’s not liberation,” she said. “That’s just bad for our kids.”