WELLINGTON (REUTERS) - Two-time Olympic shot put champion Valerie Adams is to have a second child, with the news coming just weeks after she opened up about her problems with infertility.

She used social media on Sunday (Oct 14) to announce her pregnancy with a photograph of her one-year-old daughter Kimoana holding a sign stating "I'm going to be a sister".

The 34-year-old, however, also told TVNZ that the pregnancy would not stop her plans to end her glittering career at the 2020 Olympics in Tokyo.

It was, however, due to her issues with fertility she felt she could not wait until after the Games to add to her family.

"I don't want to come end of Tokyo, look back and have any regrets," Adams said. "That's what I didn't want to happen because realistically, my fertility situation isn't great and this was my only chance.

"My time frame was limited and I knew that. I'm 34 now and basically I'm going to menopause by the time I'm 43.

"The risk of completing our family and training for the Olympics... I don't want that. First and foremost for me was actually giving Kimoana a sibling and completing a family. For us this is it.

"I don't want to be one of those should've, would've, could've. I've got the opportunity now, I need to take it. It's the same with sport, if you've got the opportunity, take it."

Adams, who battled numerous injuries and surgeries on her shoulder, elbow, knee and ankle after the 2012 London Games, was pipped to a third successive Olympic shot put gold by a mammoth last-round throw from Michelle Carter of the United States at the 2016 event in Rio de Janeiro and finished with silver.

She told New Zealand's TV3 last month that she had attempted to get pregnant immediately following the Rio Games, but discovered she had fertility problems and had to undergo in-vitro fertilisation treatment.

"I think people underestimate just how hard fertility is," she said. "Our wants were there, but nothing was happening."

Adams, however, became pregnant and had her daughter last October. She only returned to training in January and claimed silver at the Commonwealth Games on the Gold Coast in April.

The baby is due in April, giving Adams more than a year to prepare for the Tokyo Games.