The 37-year-old supermodel - who already has three-year-old son George with long-term boyfriend Gregorio Marsiaj - is seven months pregnant with her second child and doesn`t understand why some celebrities opt to have their babies via an elective Caesarean.
She said: "I wanted to give birthnaturally at nine months.
"I`ve heard some women book delivery by Caesarean early before their due date. I think a lot do it because of the fear of pain."
The Czech-born beauty also spoke of her delight at the changes pregnancy has brought on her body, admitting she feels more "feminine".
She told the new issue of Harper`s Bazaar magazine: "Being pregnant is less about being sexy than being sensual. You feel very feminine. There are all these special hormonal enhancements.
"It`s amazing refinding the body that you used to have in your 20s."
Eva and businessman Gregorio have been in a relationship since 2001.