Midwives say some women are having trouble giving birth because of the stress from the Canterbury earthquake.
This is despite a record 21 babies being born on the day of the quake, 4 September.
Suze Keys from the suburb of Mairehau in Chirstchurch says she has been deliberately trying not to have her baby because of the uncertainty and anxiety caused by the aftershocks.
The College of Midwives says it is well known that large shakes bring on labour for many women.
But chief executive Karen Guilliland says there are probably just as many who are now finding it hard to give birth, even though they want to, because of the need mothers feel to protect their babies.