This article first appeared in New Scientist, 26.06.2017
Living near a noisy road seems to affect couples who are trying get pregnant, increasing the likelihood that it will take them between six to 12 months.
That’s according to an analysis of 65,000 women living in Denmark. Jeppe Schultz Christensen of the Danish Cancer Society Research Center in Copenhagen and his team made this discovery by analysing data from the Danish National Birth Cohort, a project that ran from 1996 to 2002. They selected women who had tried to get pregnant during the project if traffic noise data was available for where they lived.
Previous research has suggested that 80 per cent of women who are actively trying to get pregnant usually do so within six menstrual cycles. But Christensen’s team found that for every 10 decibels of extra traffic noise around a woman’s home, there was a 5 to 8 per cent increased chance of it taking six months or longer.
This link persisted even when factors like poverty levels and nitrogen oxide pollution were taken into account. However, their statistical analysis showed that this association did not hold for women who took more than 12 months – perhaps because these couples may have had other factors affecting their fertility. “Road traffic noise may affect reproductive health,” says Christensen.
Him or her?
It is unclear whether traffic noise may be affecting women or their partners. Previous research has found a link between sleep disturbance and decreased fertility in women, as well as lower quality of semen in men. A 2013 study showed that consistent exposure to aircraft traffic noise activates a system in the brain that is known to disrupt the rhythm of ovulation.
Rachel Smith of Imperial College London says the link between traffic noise and health is worrying. Because traffic noise is common, even a small effect on health could feasibly have a large impact across a population, she says.
Europe’s roads are getting noisier. In the UK alone, an extra 2 million cars hit the road between 2011 and 2015. Christensen says traffic noise and fertility need to be investigated further before drawing up any recommendations for couples hoping to get pregnant, but Smith suggests that anyone who is worried could try to choose bedrooms away from the road, and close windows at night.
Marie Pedersen at the University of Copenhagen says traffic issues should be tackled by society as a whole, through better town planning and alternative transport. “It is a matter for urban planners and politicians,” she says.
Journal reference: Environment International, DOI: 10.1016/j.envint.2017.05.011