Sarah Jessica Parker worries about the surrogate carrying her twins "on an hourly basis."
The 'Sex and the City' actress is appalled at the attention the woman carrying her daughters has received - she is followed by photographers and has reportedly had her phone tapped - and is concerned the scrutiny could cause difficulties in the pregnancy.
Sarah said: "On a daily basis, on an hourly basis, I am greatly concerned for her health and safety and the safe delivery of our children. Obviously there are those that don't care about her, or her health, or safety, or my children's health and safety, and that they should go to term and not go into an early labor and, god forbid, suffer all the things that can happen - that is a real possibility."
"It keeps me up every night. It's really incredibly upsetting to think of her so far away and me not being able to do something."
The 44-year-old actress - who already has a six-year-old son, James Wilkie, with her husband Matthew Broderick - decided to use a surrogate after struggling to get pregnant over the last few years.
Sarah and Matthew were amazed to discover they will be parents to twins, and James is also looking forward to his role as older brother.
She added to TV show 'Access Hollywood': "We didn't expect it. I think after a certain amount of time, you tend to hold your hopes at bay a bit so as not to be disappointed. One really would have been thrilling and we would've felt incredibly lucky. And two was a comedy!"
"James is really excited. He's very much ready to be an older brother. I think it gives him a great sense of pride. It's wonderful and I just hope for their safe arrival."