Babies will not do what they are told, especially when it comes to being born. Anyone seeking to compare a maternity hospital to a factory production line misses an important point.

Babies will not do what they are told, especially when it comes to being born. Anyone seeking to compare a maternity hospital to a factory production line misses an important point. Ask any midwife. One day a unit can be disturbingly empty and quiet, while the next it will be overflowing. There are predictably busy times, such as during heatwaves and the annual September rush (nine months after New Year) and others that crop up for no particular reason.

There are additional factors that render predicting future requirements for maternity services something of a planner's nightmare. If more women opt for Caesareans, more maternity beds are required because recovery times are longer. Then there are the population figures. For years we were told that the birthrate, especially in Glasgow, was going down. Then, unexpectedly in 2004 and 2005, Scotland's population saw its first substantial increases for many years and as a result, the target date for Scotland's population slipping below five million has shifted from 2009 to 2035. Since the most recent enlargement of the EU, large numbers of east European migrants have come to Scotland, in addition to many families of asylum-seekers. Some eventually put down roots. And, as in countries such as France and Russia, the government's family-friendly policies can be expected to feed through to more births. All these changes are welcome but they have implications for the planning of our public services. In Glasgow, there is the extra unknown factor of some mothers-to-be in outlying areas that are subject to the centralisation and downgrading of consultant units to midwife-led ones, opting to have their babies in the city.

There is little that can be done to adjust demand other than by dissuading women from having Caesareans, sending them home earlier or redirecting elsewhere women from outwith Glasgow: all likely to be unpopular. When the Queen Mother's maternity hospital at Yorkhill closes within the next two years, the city will have the capacity to deliver just 12,000 babies a year at the Princess Royal and Southern General. Glasgow is already handling 11,800 births annually. Is there enough slack? Some senior clinicians do not think there is.

We accept that there is an issue about finding and paying for doctors to keep the current three Glasgow units open, especially given the new training regime. However, with some obstetricians convinced that current demand projections are unrealistic, should the board and the Scottish Executive be thinking again? In particular, rather than closing the Queen Mother's and moving patients from the north and west of the city to the 1970s-built unit at the Southern, it might make more sense to incorporate a new, enlarged maternity unit in the major rebuilding programme being planned for the Southern campus. Meanwhile, the Queen Mother's would need to be patched up and serve a few more years until it is ready. This issue has been mired in NHS politics for too long. Some fresh thinking is needed or we risk the prospect of women queuing up to give birth and babies not prepared to wait.