Childbirth risk when yellow sand clouds roll into Japan

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Pregnant women exposed to dust clouds of yellow sand run a higher risk of placental abruption, which can jeopardize the life of the unborn child, Japanese researchers say.

The condition in which the placenta separates before childbirth occurs in 1 percent of expectant mothers.

Such cases can require an emergency caesarean section or induced delivery. Why it occurs is not fully understood.

Researchers mainly from Kyushu University and Toho University examined the correlation between placental abruption and sand dust, as well as microorganisms and pollutants in the air carried by prevailing westerly winds from inland Asia to the Japanese archipelago.

As it is already known that yellow sand dust clouds cause bodily inflammation, the team wondered if stimuli associated with sand-derived inflammation could increase the risk of early placental separation.

The researchers studied yellow sand cloud concentrations in the air over nine prefectures, among them Tokyo, Osaka and Nagasaki, where data from real-time monitoring systems is available for 2009 through 2014.

They then looked at the delivery conditions of 3,000 women at 113 medical centers on and around days when the airborne pollutant rate reached a certain level.

The results showed those who give birth within one or two days after exposure to sand clouds were 1.4 times more likely to undergo caesarean sections or other emergency operations due to placental abruption.

No increase in the placental separation risk was observed on the day of the sand cloud arrival.

The team noted that concentrations of PM2.5, a measurement of particulates, and other airborne pollutants rise when yellow sand clouds blow over.

Takehiro Michikawa, a lecturer of environmental health at Toho University’s Faculty of Medicine, said the team will continue to study the causes of placental abruption.

“Placental separation may be attributed to yellow sand, microorganisms in it or other airborne particles,” said Michikawa. “We hope to pinpoint the cause through more research and other efforts.”

The team’s findings have been published in the British obstetrics and gynecology journal BJOG.

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