Heidi Montag gets candid about fertility struggles

Heidi Montag has opened up about her struggles to have a second child.

Taking to Instagram on Tuesday, the 35-year-old reality star got candid about her fertility journey as she and husband Spencer Pratt try for another baby.

"So thankful for my angel," the Hills: New Beginnings star wrote beneath a photo of the couple's four-year-old son, Gunner. "I never thought it would be so hard trying to have another. I am trusting God's plan and if we only have one I am so thankful for this miracle!"

Last year, the reality star told fans about their desire to have a second child via their Speidi Podcast on YouTube.

In August, she described undergoing a hysteroscopic polypectomy, which removes benign polyps from the uterus.

"I was feeling nervous last night about it, but I'm excited today," she said in a video. "And I'm hoping that the surgery works and that this is the only reason I haven't been able to get pregnant ... Hopefully after this, I can get pregnant right away."