It was April, and Judith Helfand was dreading her first motherless Mother's Day. Since her mother died in September, the award-winning filmmaker had a hole in her heart. Compounding the hollowness, she was en route to her first parentless Passover seder.

A casualty of a pharmaceutical time bomb, Helfand could not have biological children. After her mother, Florence, miscarried in 1963, the doctor prescribed the "miracle drug" diethylstilbestrol (DES) so it wouldn't happen again. The next year, she gave birth to Judith, who grew up and - like one in every 1,000 DES daughters - developed cervical cancer.

In 1990, Helfand had a radical hysterectomy that radicalized her in other ways, as well.

Camera in one hand and catheter in the other, she made A Healthy Baby Girl, which aired on PBS in 1997. Funny, sad, and inspirational, the film chronicled how the fallout from DES transformed her relationships. On the downside, her boyfriend told her she was like "a tree that can't bear fruit." On the upside, mother and daughter grew closer, unburdening themselves of guilt and pain. They met other DES daughters, and mobilized with them to get federal support for research into the drug's effects.

As Helfand, now 49, drove to the seder April 15, her cellphone rang. The Sundance Institute had just announced that A Healthy Baby Girl was available on iTunes, and she expected the call to be about that. She had it half right. It was Joy Goldstein from Forever Families Through Adoption. The agency had a healthy baby girl available. Could Helfand let her know later that night whether she was ready to adopt? The baby was to be delivered by C-section the next morning.

Suddenly, it was possible that Helfand would spend her first motherless Mother's Day as a new mom. How fitting that the call came on Passover, the holy week celebrating spring and rebirth. Since 2009, she had waited for a baby, and what seemed like the world's longest gestation would have the world's shortest delivery.

The agency had matched Helfand once before. But at the time, her mother was in hospice, in the end stages of colon cancer. Florence had delivered Helfand's older brother on the same day her own mother had died.

"Hard to take care of a baby when your mother has just died," Florence advised. "Take care of me, and your baby will come."

The next day, Florence became incontinent. Struggling with her mom's adult diapers, Helfand thanked her for her training in how to care for a newborn.

It was winter - Feb. 28, 1990 - when Helfand got the cancer diagnosis. She was 25. Tears in her eyes, she walked home. "I'm trying to assimilate this news, and I realize it's 3:15 - child pickup time. I'm thinking, 'All these women are picking up their children. This will never happen to me.' "

She saw an acquaintance hand-in-hand with her son. Noah had Esther's eyes. Later, Helfand sobbed on a friend's shoulder, "Esther Cohen has a son with her eyes. I'm never going to have a baby with my eyes."

Her friend disagreed. "What you're seeing is the love they have for each other. Noah is adopted." It was a sign.

The National Institutes of Health estimates that as many as 10 million pregnant women and babies were exposed to DES - a synthetic estrogen prescribed to prevent miscarriage and short-term delivery - from 1941 to 1971.

Thanks to a product-liability lawsuit against Eli Lilly, the manufacturer of DES, Helfand received an undisclosed settlement. She called it her "uterus money" and used it to turbocharge her career. She completed A Healthy Baby Girl, and then Blue Vinyl (2002), a documentary on the pernicious effects of polyvinyl chloride common in house siding. In her disarmingly funny narration of these films about the serious personal and environmental impacts of chemicals, Helfand comes off as the Erin Brockovich of documentary.

"I'd always known, if I was going to be a mother, I would adopt," she said by phone last week from New York, "or co-parent with a husband and raise his children."

She was waiting for the right person. But wasn't that putting her motherhood in another's hands?

Meanwhile, she channeled maternal energy into teaching filmmaking at the New School and New York University.

Then, in 2005, with colleagues Wendy Ettinger and Judith Parker-Benello, Helfand cofounded Chicken & Egg, a hybrid film fund and nonprofit production company that gives grants and mentors female documentary filmmakers. In a measure of its success, Helfand has producer or executive-producer credits on a range of award-winning films, including The Barber of Birmingham, Brooklyn Castle, Pariah, and Semper Fi.

"You can say the Chicken & Egg experience," she reflected, "has been a way to mother and nurture."

More than half a year had gone by since her mother died, at 84. Yet when Helfand arrived last month at her brother Alex's home for the seder, she told him, "I don't know if I'm ready to adopt."

"No one's ever really ready to become a parent," he said.

During the meal, Alex held up the Passover plate and looked at her when he talked about how the holiday symbolized renewal and new life. Helfand thought, "Mom's fingerprints are all over this."

Reading from (billed as "the Haggadah that blends brevity with tradition"), Alex told the story of Shifra and Puah, midwives who found ways to have Jewish infants, like Moses, adopted and saved from death at Pharaoh's hands. Helfand looked at her best friends, Marsha and Rhoda, and thought, "These are my midwives."

When Goldstein called at 9:30, Helfand said yes.

She met the birth mother - and the new baby girl - the next day at the hospital. "The birth mother took a picture of the baby and me and sent it to my phone with the subject line, 'Your daughter.' "

On Saturday, April 19, the girl with the lustrous dark hair and beautiful tapered fingers came home to Helfand's apartment on New York's Upper West Side. To honor her parents, she named her Theo, short for Theodora Feyge. Her father was Ted; her mother's Hebrew name was Feyge, meaning "bird."

In the welcoming committee was Helfand's cousin, Molly, 16, adopted from Cambodia. She took a picture with her cellphone. "Theo's first selfie!" Molly exclaimed.

When Helfand and Theo are alone, "I hold her on my lap," she said, "and feel my mother holding us."