NBC News' Kristen Welker, who is expecting her first baby via surrogate, opened up about infertility in a letter to her unborn child

• NBC News journalist Kristen Welker and her husband are welcoming a child via surrogate.
• Welker opened up about her infertility in a letter addressed to her unborn child.
• She wrote about going through IVF for three years before being told she couldn't carry a child.

NBC News Chief White House Correspondent Kristen Welker announced Friday that she and her husband are welcoming their first child together this summer with the help of a surrogate after a years-long journey trying to get pregnant.

Welker, 44, a longtime journalist, moderated the final presidential debate between former President Donald Trump and now-President Joe Biden in October 2020.

On Friday, Welker shared a picture of her hand on the baby bump of the person who's presumably her surrogate and wrote: "After years of really tough infertility struggles, my husband, John, and I are so thrilled to share that, with the help of a surrogate, we will welcome a baby girl and become a family of three in June."

-Kristen Welker (@kwelkernbc) April 23, 2021

Welker appeared live on the "Today" show to share her pregnancy news and also published a letter addressed to her unborn child. In it, she detailed her infertility and her and her husband's decision to have their child via surrogate.

"Even before your daddy and I met, we both dreamed about becoming parents," Welker wrote in her letter, which is published on the "Today" website. "When we got married, we couldn't wait for you to join our family! When you didn't arrive at first, we worried something might be wrong. So, we went to a doctor to ask for help. She was so smart and explained that I might need some extra help to bring you here."

Welker wrote about trying in vitro fertilization (IVF) for three years and later turning to surrogacy.

She then recalled the day a doctor told her that she wasn't able to carry a baby.

"I would need a special helper to carry you inside her belly. That person is called a 'surrogate.' On that day, I cried so many tears that I didn't think they would ever stop. I felt as though I had let you down because I couldn't carry you myself," Welker wrote.

She also wrote about her surrogate, who she described as a "special helper and hero" and "a young mom who says being a helper is her purpose."

In the fall of 2020, Welker said, she and her husband "received the greatest news of all."

"Your daddy and I were on the road driving to New York where I was working on a big project. We pulled over when the call came in and when the doctor said you were on your way, we cried again, only this time they were tears of joy," Welker wrote.

"There will be heartbreaks in life; some won't ever fully heal, others will make you stronger. It is OK to ask for help; in fact, it can be empowering. Families are made in all different ways, come in all different shapes and sizes, and all families should be celebrated," she added.

"And, finally, while I didn't carry you in my body, I have always carried you in my heart and I will always be your mommy," Welker wrote.

Welker and her husband, John, are expecting their baby in June.