There could be a link between high levels of pollution and miscarriage, according to new research.
Experts found that levels of pollution just above the "safe" amount could increase the risk of miscarriage.
The study was carried out by the University of Sao Paulo in Brazil and looked at the effect of diesel exhaust particles on embryos in mice.
Apparently diesel disrupted the development of cells, which can trigger a miscarriage.
Scientists say women should avoid getting pregnant when there are high levels of pollution in the air.
I'm not sure that's terribly helpful advice though - how are we supposed to know? Should we be testing pollution levels before we get it on? Should we only be trying to get pregnant on mini-breaks in the countryside?
Dr Paulo Marcelo Perin, from the University of Sao Paulo, said: "Our latest study found that air pollution significantly decreased the cell population (of embryos).
"When you have a decrease in cell mass you compromise embryo viability. Because diesel is a major component of air pollution we can assume most of the effect is from diesel."
Another study found that high levels of air pollution can cut the chances of successful IVF.
The Telegraph reports that scientists at Penn State College of Medicine in Pennsylvania found that high levels of traffic pollution had the same effect as a woman being a year older.
Apparently previous studies have found that there is more chance of fertility treatment succeeding in the summer when there is less pollution than the winter.
The studies were both presented at the American Society of Reproductive Medicine annual conference in Atlanta.
Air pollution levels in the UK have been highlighted recently by the European Commission, which is prosecuting the government for breaking the law.
The UK has failed to sufficiently reduce levels of particles known as PM10s, which mainly come from industry and traffic.
More than 20 UK cities had dangerous levels of these particles between 2005 and 2007.
Perhaps we should be campaigning for cleaner air if we want safer pregnancies.
Source: AOL News
Source: The Telegraph