The use of assisted reproductive technologies to conceive has been linked to a greater risk of premature birth.
An Italian study published in journal Ultrasound in Obstetrics and Gynecology found in-vitro fertilisation (IFV) and intra cytoplasmic sperm injection (ICSI) was associated with an overall 80 per cent increased risk of spontaneous pre-term birth - that is a baby born before 37 weeks - compared with natural conception.
The meta-analysis involved the review of 15 studies involving 62,000 patients and about 3800 preterm births.
"Placental development may play a key role in the pathogenesis of spontaneous preterm birth in IVF pregnancies," said lead author Dr Paolo Cavoretto, of the IRCCS San Raffaele Hospital, in Milan, Italy.
"We recommend ultrasound cervical screening in this high-risk group in order to apply timely preventive strategies".
Leading reproductive expert Laureate Professor John Aitken at The University of Newcastle was not surprised by the findings and says previous evidence has raised concerns about the use of ICSI.
"There is quite good data showing that miscarriage is elevated when ICSI is used as the insemination technology rather than IVF," Prof Aitken told AAP.
This particular technology involves taking a single sperm cell from the teste and directly injecting it into the female egg to achieve conception.
It was originally developed to treat very severe male infertility, however increasingly clinics have been using it more as a "routine default measure", says Prof Aitken.
One of the reasons for this, he says, is because it can guarantee conception.
While it may be considered more efficient, there can be adverse consequences of using "un-selected" sperm, Prof Aitken warns.
"In normal life, at the moment of insemination roughly 200 million sperm cells are released into the female tract and they have to find just one other cell in the body," he said.
"Out of 200 million probably about 50 to 100 are going to make it to the surface of the egg, one of those will get through the outer layers of egg and achieve fertilisation."
"The trouble with ICSI is that you take any old cell and you inject into the egg, so it's not selected at all and not surprisingly we are now beginning to see adverse consequences of unselected spermatozoa in conception."
Prof Aitken said ICSI had also been linked to an increased risk of autism.
"The data for these things is incontrovertible now and I think a consequence of using unselected gametes."
The reproductive biologist says the new study highlights that assisted reproduction measures like IVF/ICSI should not be used "thoughtlessly" and only used when appropriate.
"What's happening now is because we have many more IVF babies coming through we are beginning to see things at a population level you would never have seen by just considering the fate of IVF at a single couple level," Prof Aitken said.
