Australian model Miranda Kerr has posed nude for W magazine's latest issue, showing off her six-and-a-half months baby bump.

Kerr, 27, who spoke about Fistula, a complicated prolonged birth delivery without sufficient access to proper medical care, was photographed caressing her baby bump.

"For me, family is life. The decision to start one wasn't complex at all," News.com.au quoted her as saying.

The model also explained that she was in Paris shooting an ad campaign for the minimalist German designer Jil Sander when she discovered she was pregnant.

"I was wondering why I'd been so sick," she added.