Narrator: This is Science Today. Women over forty who give birth for the first time have a higher rate of caesarian sections than first-time mothers half their age. Dr. William Gilbert of the University of California, Davis found this was largely due to the higher risk of pregnancy complications in older women. But Gilbert says other possible factors their study did not cover are maternal and physician anxiety levels.

Gilbert: Obviously if you're a woman having a first child over forty and you either paid the money with infertility drugs to get pregnant or you were pregnant spontaneously, this is what we would call a premium, quote/unquote, pregnancy. We actually think all pregnancies are premium but if you're twenty-two and you have a miscarriage, you still have time where if you're forty-two, you're chance of getting pregnant is even less and less.

Narrator: This may cause anxiety amongst health care providers and lead to delivering a patient earlier than normal.

Gilbert: By delivering earlier, they may have an increased risk of induction or outright caesarian section and this could be part of the cause for the increase in caesarian section rate.

Narrator: For Science Today, I'm Larissa Branin.