A woman’s biological clock ticking is a pretty universally understood metaphor. And while true that women have a limited number of years where they can conceive children if they wish, there’s an even more important clock that they should be paying attention to if they’re trying – the one on the wall.
It’s no secret that keeping irregular hours can wreck havoc on a person. Jet lag, sensory deprivation, playing slots in windowless casinos – your body would much rather prefer to stay on a regular schedule. The circadian rhythm isn’t just something that we get used to once we’re brought into the world, it’s encoded in our DNA.
Now, Fred W. Turek of Northwestern University has shown that keeping these regular hours is even more important for a woman trying to have a child than your average Joe.
Turek took three groups of mice and had them mate. Afterwards, the first group was left alone to see their pregnancies to term in peace. But the other two had their internal clocks messed with. One group had their days and nights shifted forward six hours every five days while the other had theirs shifted backwards every five days. During the course of the pregnancies, there were a total of four time shifts.
The results were kind of startling. The control group saw 90 percent of their knocked-up mice come to full term without any problems. However, the phase-delay group had only a 50/50 shot at giving birth. While significantly lower, it was still much better than the phase-advanced group, which fell all the way to 22 percent.
It seems pretty clear – at least in mice – that messing with your biological clock can cause difficulties in pregnancies. What’s more frightening is that this sort of temporal shifting isn’t all that uncommon. Flight stewardesses, nurses or anyone who travels the world a lot on business can easily see these sorts of disruptions on a regular basis.
So if you’re one of them and trying to have a child, you might consider sticking to a regular shift for a little while.