At one of the saddest times of her life, Gillian Brockell kept seeing ads on social media that twisted the knife in her wound.

In an open letter posted to Twitter and addressed to "Tech Companies," the Washington Post opinion video editor says she continued to be targeted with motherhood ads after learning that her baby would be stillborn.

At a time when the public is questioning tech companies' hyper-specific ad targeting, Brockell's letter highlights the damaging emotional effects this practice can have when these companies fail to adjust their targeting to new information about someone's altered life situation.

Tweet

"I know you knew I was pregnant," Brockell wrote in the letter and tagged with Twitter, Facebook, Instagram and Experian's handles. "It's my fault, I just couldn't resist the hashtags - #30weekspregnant, #babybump. And, stupid me!, I even clicked once or twice on the maternity-wear ads Facebook served up."

She continues the letter, revealing topics she searched for when she learned her baby would be stillborn.

"But didn't you also see me googling 'is this braxton hicks?' and 'baby not moving'? Did you not see the three days of silence, uncommon for a high-frequency user like me? And then the announcement with keywords like 'heartbroken' and 'problem' and 'stillborn' and the two-hundred teardrop emoticons from my friends? Is that not something you could track?"

Brockell wrote in her letter that even when she opted to not see the ads she was served for products to prepare her for her new baby, the companies misinterpreted her motivation. After answering a prompt about why she didn't want to see the ad with "it's not relevant to me," she began being served ads for nursing bras and strollers, according to the letter. She said she then received what she called a "spam email" asking her to "finish registering your baby" in order to track his credit through Experian.

The average person is becoming increasingly more aware of the amount of data tech companies store on them. A New York Times investigation earlier this week showed that many seemingly mundane apps can actually track your location throughout the day to a specific spot in a room, and on Tuesday, Google CEO Sundar Pichai was questioned by the House Judiciary Committee about his company's location-tracking policies. Brockell's letter raises the question of why these companies still can't adjust fully to the realities of people's lives.

In a statement, a Twitter spokesperson said, "We cannot imagine the pain of those who have experienced this type of loss. We are continuously working on improving our advertising products to ensure they serve appropriate content to the people who use our services."

Experian did not respond to requests for comment. Brockell pointed CNBC to tweets from a Facebook advertising executive, Rob Goldman, who explained how to turn off ads related to parenting. Facebook also pointed CNBC to Goldman's tweets.

"I am so sorry for your loss and your painful experience with our products," Goldman wrote. "We have a setting available that can block ads about some topics people may find painful — including parenting. It still needs improvement, but please know that we're working on it & welcome your feedback."

Tweet

Brockell thanked Goldman for responding and suggested Facebook add a keyword like "stillborn" that would turn off ads automatically instead, saying the process of turning off ads is "too confusing when you're grieving."

Tweet

Brockell also told CNBC she wished Experian would respond.

"Please, Tech Companies, I implore you: If you're smart enough to realize that I'm pregnant, that I've given birth, then surely you're smart enough to realize that my baby died, and can advertise to me accordingly," Brockell wrote, "or maybe just maybe, not at all."

Subscribe to CNBC on YouTube.