Women with preeclampsia are more likely to have complications such as low birthweight, premature birth or placental abruption, where the placenta separates from the wall of the uterus before birth, according to the March of Dimes.

CNN: Eclampsia: 5 things you need to know

Novartis hopes to show that Prexige avoids nasty ulcers better than the older compounds without increasing cardiovascular complications, even in patients who are taking low-dose aspirin to prevent heart attacks.

FORBES: Novartis Study Could Affect Pfizer, Merck

There was also a lack of awareness of signs and symptoms of complications in children whose weight had dropped to seriously low levels.

BBC: Doctors 'miss' underweight children, UCL study suggests

But given that most patients, especially those with low risk operations, fly through anesthesia without any complications, nurse anesthetists are able to handle most of the care without a hitch.

FORBES: Solving the Primary Care Physician Shortage by Turning PCPs into Anesthesiologists

Complications such as pre-eclampsia were hard to predict so it was not possible to decide which women were "low risk" cases and therefore suitable for birth at midwife-led units, he said.

BBC: NEWS | Health | Hospital overhaul 'under attack'