Negative birth outcomes linked to air pollution exposure early in pregnancy, study finds

July 27, 2017
Credit: CC0 Public Domain

Exposure to air pollution early in a pregnancy could increase risk for preterm birth and low birth weight, according to a study led by researchers at NYU School of Medicine, and published on July 27 in Environmental Health Perspectives.

The study, conducted in mice, found that to air during the equivalent of the first or second trimester in humans was linked to more negative outcomes than exposure later in .

Researchers studied the effects of fine particulate air pollution, which is made up of particles less than one ten-thousandth of an inch in diameter, or PM2.5. Inhalable and almost invisible to the eye, this type pollution comes from car exhaust, , and other industrial processes. PM2.5exposure has previously been linked to risk for asthma and heart disease.

According to the US Centers for Disease Control and Prevention, preterm birth and low birth increase risk for vision and hearing problems, learning problems and even death.

Using PM2.5 levels comparable to those found in highly-polluted urban environments, researchers examined obstetric outcomes based on exposures during different stages of pregnancy in mice. The findings, according to the study's authors, could have both implications for physicians as they advise women during pregnancy, as well as for air pollution policy.

"This first study of this problem in mice adds to the growing body of evidence that inhalation of particulate matter from implantation through the second trimester of pregnancy is potentially dangerous," says lead author and investigator Jason Blum, PhD, MS, assistant professor in the Department of Environmental Medicine at NYU School of Medicine.

Implications for Clinical Care and Policy

Past studies had linked high levels particulate matter exposure to low birth weight, but impact of the timing of maternal exposure on birth weight had been debated. The new findings suggest that exposure during the first two trimesters has the greatest affect, say the study authors.

In the study, pregnant mice were randomly assigned to one of two groups— one exposed to filtered air and a second to concentrated PM2.5. The mice exposed to particles were also randomly assigned for exposure during one of four gestational periods designed to mirror the stages of human pregnancy: period 1(0.5-5.5 days); period 2(6.5-14.5 days); period 3(14.5-16.5 days); or period 4(0.5-16.5 days).

Researchers measured both the duration of pregnancy and birth weight of the offspring to identify the effects of concentrated PM2.5 over the time periods. Their results show that exposure to during period one resulted in preterm birth for about 83 percent of exposed mouse litters. Similarly, exposure to PM2.5 from conception to the end of the second trimester—periods one, two and three—resulted in an 11.4 percent decrease in birth weight for 50 percent of the litters.

Exposure during the first and second trimester also came with decreased body length, decreased placental weight, and decreased anogenital distance, which can reflect abnormal hormone levels, says Blum.

"These findings could lead physicians to advise women to avoid high pollution areas or use air filtration systems during the early stages of pregnancy," says senior study author Judith Zelikoff, PhD, a professor in the Department of Environmental Medicine at NYU School of Medicine. "With and having such serious health consequences, the need for further research in this area is greater than ever."

Explore further: Extreme temperatures may increase risk for low birth weight at term, study suggests

Related Stories

Extreme temperatures may increase risk for low birth weight at term, study suggests

February 28, 2017
Extreme hot or cold temperatures during pregnancy may increase the risk that infants born at term will be of low birth weight, according to a study of U.S. women by researchers at the National Institutes of Health. The study ...

Exposure to high levels of air pollution associated with higher risk of preterm birth

January 26, 2016
Exposure to high levels of small particle air pollution is associated with an increased risk of preterm birth - before 37 weeks of pregnancy, according to a new study published online in the journal Environmental Health.

Birth weight affected by warm temperatures during pregnancy

June 9, 2015
Ben-Gurion University of the Negev (BGU) and Harvard University researchers have developed a technique that measures the correlation between air temperature and birth weight. They evaluated the relationship between birth ...

Weight gain greater, less than recommended during pregnancy linked with increased risk of adverse outcomes

June 6, 2017
In an analysis that included more than 1.3 million pregnancies, weight gain during pregnancy that was greater or less than guideline recommendations was associated with a higher risk of adverse outcomes for mothers and infants, ...

Air pollution linked to higher risk of preterm birth for mothers with asthma

March 1, 2016
Pregnant women with asthma may be at greater risk of preterm birth when exposed to high levels of certain traffic-related air pollutants, according to a study by researchers at the National Institutes of Health and other ...

Study finds variation of the interval between first and second pregnancy

February 2, 2015
In a study to be presented on Feb. 5 in an oral concurrent session at the Society for Maternal-Fetal Medicine's annual meeting, The Pregnancy Meeting in San Diego, researchers will report that the variation of interval from ...

Recommended for you

Population health impact of infants born small for gestational age in low- and middle-income countries

August 18, 2017
In low-and middle-income countries, it is common for babies to be born of low birth weight, due to either inadequate growth in utero (fetal growth restriction) and/or preterm birth, (birth before 37 weeks gestation). Maternal ...

Hormone from fat tissue can give protection against polycystic ovary syndrome

August 10, 2017
Obesity and reduced insulin sensitivity are common in polycystic ovary syndrome, PCOS. New research based on animal studies, and to be published in the journal PNAS, reveals that the hormone adiponectin can protect against ...

Study in mice may reveal insights into causes of miscarriages for some women

August 9, 2017
Researchers at St. Michael's Hospital have identified how natural killer cells in the mouse placenta can cause a fetus to fail to grow in the womb or cause miscarriages.

Insomnia, sleep apnea nearly double the risk of preterm delivery before 34 weeks

August 9, 2017
Pregnant women who are diagnosed with sleep disorders such as sleep apnea and insomnia appear to be at risk of delivering their babies before reaching full term, according to an analysis of California births by researchers ...

Elective freezing of IVF embryos linked to higher pregnancy rates in some cases

August 1, 2017
A delay in transferring embryos to the mother improves the success of in vitro fertilization in certain cases, according to a study by scientists at the Stanford University School of Medicine, Celmatix Inc. and several other ...

Negative birth outcomes linked to air pollution exposure early in pregnancy, study finds

July 27, 2017
Exposure to air pollution early in a pregnancy could increase risk for preterm birth and low birth weight, according to a study led by researchers at NYU School of Medicine, and published on July 27 in Environmental Health ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.