Older Women and Twins

This week the Office of National Statistics released their birth statistics for 2011, the latest figures that will be released until the 2012 stats come out next year. There were 723,913 live births in England and Wales in 2011, and interestingly the rate of multiple births increased to around 16.1 per 1000 births from 15.7 in the previous year. There are various reasons for this, some may be natural variance, but there is no doubt that the fact that women are falling pregnant at older and older ages has dramatically altered the statistics. The table below shows us how multiple births were spread across the ages in the UK in 2011:

In 2011 it is interesting to point out that women aged 45 or over had the highest multiple maternity rate, with almost 1 in 10 pregnancies resulting in multiples, and of course that doesn’t necessarily mean twins! We could be talking about triplets, or even more babies. Imagine the surprise that people have when they discover that the pregnancy they were looking forward to results in more than one baby!

Statistics show that the likelihood of twins in pregnancies involving older women is more likely, this is due to many factors, but mainly because as we got older our cells deteriorate. The same goes for eggs stored in the ovaries, they slowly become less and less productive, and less well formed, which is why older women sometimes struggle to fall pregnant. This consequently means that the eggs once fertilised separate and form multiple pregnancies on a more frequent basis.

What we also know is that more women are falling pregnant through IVF, and this has enabled women of an older age to fall pregnant when they may have struggled naturally. As the table above shows, multiples in those who go through IVF are more common, although with changing technology these numbers are decreasing. It is important to remember that IVF success in those over 38 is still low, in fact only 1.5% of IVF cycles are successful for those over 45. Interestingly whilst 1 in 10 pregnancies of those over 45 ended up with multiples, for those taking part in IVF, 28.1% of live births produced multiples. This is a staggering increase in multiple rates, and no doubt due to the process that women have to go through to give birth via IVF.

Undoubtedly the age at which women fall pregnant has a strong correlation with the likelihood that they will have multiples. The statistics show that women who are over 45 are more likely to have twins, and the fact that IVF is used more frequently at this age plays a key role. All of the statistics point to twins being more likely when you are an older woman, so be prepared, it might not just be Jimmy you’re welcoming into your home, but Jennie too!

About the author

James Brighton

Since 2011 James has been in charge of working with and organising all our writers to put together Pregnancy.co.uk and Babies.co.uk. Anna, his girlfriend, knows he will be an encyclopaedia of knowledge if she ever falls pregnant!

Click here to read my full biography.