Mother’s Day brings to mind fresh flowers, blueberry pancakes and homemade cards. It’s a day to be spoiled and fêted by family. But for me, an adoptive mother, it’s never as simple as the Hallmark holiday it’s touted to be.

Don’t get me wrong: I feel deep joy in my role as mom to my two-and-a-half-year-old son, and I marvel at his giddy joie de vivre. But the way I arrived at motherhood will always be bittersweet. In order for me to become a mom, another mother had to lose a child.

My husband and I met our son’s birth mother three years ago on a dazzling spring day bursting with new life. But I hardly noticed the sun sparkling on the water or the lush rhododendrons that surrounded the adoption agency that May afternoon – the day our lives would change forever. I was too busy tapping my feet nervously and focusing on my breath. We’d been waiting more than a year to adopt internationally when the agency called to say that a local expectant family wanted to meet us. So there we were at the agency waiting for a pregnant 15-year-old girl and her parents.

When the agency door swung open, the birth mother went from abstract idea to real person. She was seven months pregnant, petite, with flawless, coffee-coloured skin. She seemed calm, with a sense of purpose, and so sure about her future and that of the baby she carried. If she was a rock, I was shifting sand. I felt shaky, dizzy, and off-kilter. My mind was fuzzy. I jumped wildly from topic to topic trying to make sense, to make a connection. Then out of the blue, she told us that she was carrying a boy. And the room went silent. “A boy? A boy! A BOY!” I thought, my mind reeling with visions of soccer games and toy trains. Suddenly, the possibility of motherhood was so close – and so was the potential for heartbreak.

Fast-forward two months to the stickiest summer on record in Vancouver. My husband and I were pacing around the house sipping icy lemonades and pausing in front of our only fan when we got The Call. The birth mother had delivered a healthy baby boy – 7 lbs 7 oz – and she was ready for us to come and take him home.

We raced to the hospital with our hearts in our throats, sweat dripping off our noses, and our arms laden with flowers, gifts and a car seat. The maternity room was a blur of family – including the birth father and three of the biological grandparents – but all I registered was the birth mother, whose grief hit me like a wave of tears. I stood frozen, staring helplessly as she sobbed, and a tiny baby wearing giant blue slippers emitted little cries from the end of the hospital bed. What should have been a joyous celebration felt like a funeral. I felt awkward and confused in the eye of this emotional storm. I ached as I watched her walk out of the hospital with empty arms, while mine were full.

Almost three years have passed since that intense day, and now, with an open adoption, we see our son’s birth parents regularly for holidays, or sometimes just to catch up. My son’s birth mother is thriving as she prepares for university, while I chase my happy toddler around the house. His coffee-coloured skin, brightness and beauty bring his biological mom to mind whenever I look at him.

While there won’t be cards and calls to my son’s birth mother this year on May 13, there will be humble thoughts of gratitude to the young woman who made me a mother. Without her I wouldn’t be surrounded by fresh flowers, blueberry pancakes and one amazing little boy this Mother’s Day.

Harriet Fancott is an adoptive mom, blogger, communications specialist, and Senior PR Associate at Limelite PR. This article originally appeared pseudonymously in Today’s Parent in April 2012. Reprinted with permission.