Not every birth has a professional photographer standing by to capture the moment, and not every birth comes with a shock so huge it makes a photo go viral all over the world.
She told the story to Essential Baby, of how this incredible image came about.
"Nancy was expecting her third baby girl last December and hired me to document her labor and birth. She and her husband, Will, had chosen to wait until birth to find out the sex of their first two babies - both girls. This time, Will wanted some heads up if they were going to be welcoming another girl, so they decided to find out."
Nancy had been ill with gastro in the week leading up to the birth and sadly, on the day she went into labour, Will also came down with "two strains of the flu", Nancy recounted in a blog post. Just days beforehand their town had experienced a huge snowstorm which threatened to snow them in.
Under these challenging circumstances, Lauren arrived at the hospital with only moments to spare.
"I got the call and arrived at the birth centre just in time to photograph baby's speedy arrival. She delivered the baby in the tub and they then carried her [the baby] over to the bed."
After 10 minutes, the medical staff prepared the baby to cut the umbilical cord. It was then that Nancy noticed her daughter was actually a son!
""What is THAT? Is this a boy baby?!" she exclaimed.
Nancy wrote that she "...looked at the midwifes with wide eyes and they smiled so big and said, "YES! We have been waiting for you to discover him!"
"I looked at Will and he quickly came over and lifted the baby's leg to see for himself! Then he proceeded to fall on the floor!"
"It's a BOY! We have a SON!"
"I kept saying it over and over. I couldn't believe it!"
Lauren said, "We were all in shock and couldn't stop laughing" said Lauren of the experience. "I'm so glad I was there to capture this moment - that's the magic of birth photography!"
They named him Beaufort William. If he had been the expected girl, she would have been called Rosie.
"All the pain, weakness, and desperation of the hours leading up to his birth vanished", wrote Nancy.
"Will was unbelievably strong, and says that he felt horrible the day before and the day after his birth, but that he felt supernaturally sustained the day Beaufort was born.
If you'd like to read more about Beaufort's birth from Nancy's perspective, see her blog post here.