Pregnancy scans inquiry
Concerns that pregnant women are receiving more scans than ever has sparked a government investigation.
And some health professionals fear the sharp rise could be leading to more women having their labours induced, which carries added risk.
It has become the norm for pregnant women to receive three or four ultrasounds, up from the recommended two scans a decade ago.
The Government's maternity adviser, who reported the statistics, says some women are requesting scans to feel more connected to their babies or discover the gender.
Midwifery adviser Lesley Dixon, from the New Zealand College of Midwives, said the longer term risk of more frequent scans is unknown.
"We like to err on the side of caution. If you don't need to do it, why would you do it?"
A woman with a low-risk pregnancy should have two scans to detect foetal abnormalities, around 12 weeks and 20 weeks.
But the average number of pregnancy scans has leapt from 2 to 3.4 since 2005.
"We need to connect with our bodies more," Dixon said. "If you're concerned because the baby is not moving as it should be, that is when you might have a scan."
Some health professionals were concerned the increase in scans had led to more labours being induced, according to the maternity advisory report.
A Ministry of Health spokeswoman said there was no evidence of this, but they were looking at a national tool for measuring the growth of foetuses. Induction numbers vary between hospitals.
Concerns over the slow growth of a foetus can be a reason to induce labour.
But one health campaigner said ultrasounds were safe and could pick up life-threatening conditions.
"No baby has died because of a scan. There's harm when you don't have enough scans," maternity campaigner Jenn Hooper said.
Aged in her 40s and pregnant, she has already had 10 ultrasounds due to her age and being diagnosed with cancer.
"Scans don't hurt you. There's zero evidence in all this time that multiple scans can hurt you."
She said a move against rising scan numbers could put pressure on mums-to-be not to be checked out.
"Even if it just reassures the mum. It's not going to harm and at its worst it's going to cost the Government money. Let women make informed decisions."
Wellington mum Maria Milmine had four scans during her first pregnancy.
At the 20-week scan doctors discovered her son's kidney was abnormally large.
"We were told a number of times there was no need to worry and that nothing could be done until he was born."
However, in a follow-up scan doctors found her amniotic fluid was low - a potentially serious problem.
This can increase the risk of complications, including the baby's movements or contractions compressing the umbilical cord.
Milmine decided to have her labour induced at 37 weeks.
"They said it's better to be safe than wait to see what happens. We preferred to err on the side of caution. Inducing was the best decision."
Mum Michelle Robinson decided against the 12-week ultrasound to check for defects such as Down syndrome.
"If we had the scan and it showed a risk for Down syndrome, we weren't prepared to have the riskier follow-up test to confirm this and none of these tests would be enough to change our minds about keeping our baby."
She waited for the 20-week scan to see her active, thriving baby. Her pregnancy went smoothly so there was no need to go for other ultrasounds.
"I felt confident as I kept track of my baby's movements each day - and night - and loved the sound of his heartbeat at each appointment with my midwife."