Marlowe, who is Sienna's only child with fiancé Tom Sturridge, was born in July 2012.
Speaking to Time Out, Sienna, 33, said Marlowe's birth 'went all wrong', and, having her heart set on a water birth, her daughter was instead delivered by emergency C-section after 27 hours of labour.
"My birth went all wrong. I had my heart set on this natural water birth and I ended up, after 27 hours, having an emergency C-section," Sienna told the magazine.
"I spent so much time thinking about the birth and not realising that you take a baby home at the end of it.
"It's a shock, of course it is, and some people find it really easy, but for me I found it really hard."
In another recent interview with the Guardian, Sienna also touched on motherhood, saying: "I think having a baby really changed everything, if I'm honest.
"The stakes are higher. You have someone that you want to be proud of you eventually. You're aware of your own mortality. For me, as soon as I had a baby I had a vision of my life – and what was left of it."
Sienna isn't alone in needing changes to her birth plan on the big day. In her piece 'Why I'm not writing a birth plan', Parentdish writer Paula Greenspan talks about the feeling of being a 'failure' when things don't go to plan in the delivery room:
"Instead of the soothing water birth with little pain relief that I'd hoped for, I wound up spending weeks trying to coax my body into labour before being induced, loaded up with more drugs than a chemist's shelf and, in the end, having an emergency Caesarean.
"And for a long time afterwards, despite having a healthy baby boy, I felt like I'd failed. All because I hadn't been able to stick to my plan."
Have you experienced the same?
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