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December 1, 2017
Digest
Air Pollution Exposure in Early Pregnancy Linked To Miscarriage, Study Suggests

IMAGE: THINKSTOCK/MYKOLALVASHCHENKO
IMAGE: THINKSTOCK/MYKOLALVASHCHENKO

Exposure to common air pollutants, such as ozone and fine particles, may increase the risk of early pregnancy loss, according to a study conducted by NIH. The study appears in the journal Fertility and Sterility.

Ozone is a highly reactive form of oxygen that is a primary constituent of urban smog. Researchers followed 501 couples attempting to conceive between 2005 and 2009 in Michigan and Texas. The investigators estimated the couples’ exposures to ozone based on pollution levels in their residential communities.

The researchers do not know why exposure to air pollutants might cause pregnancy loss, but it could be related to increased inflammation of the placenta and oxidative stress, which can impair fetal development. The findings suggest that pregnant women may want to consider avoiding outdoor activity during air quality alerts, but more research is needed to confirm this association.

The study was led by Dr. Pauline Mendola, an investigator at NICHD. Her team previously found that ozone increased the risk of stillbirth. Mendola and her colleagues have also examined the effects of air pollution and extreme temperatures on other adverse outcomes of pregnancy.

Opioid Treatment Drugs Have Similar Outcomes

A study comparing the effectiveness of two pharmacologically distinct medications used to treat opioid use disorder—a buprenorphine/naloxone combination and an extended release naltrexone formulation— shows similar outcomes once medication treatment is initiated.

Among active opioid users, however, it was more difficult to initiate treatment with the naltrexone. Study participants were dependent on non-prescribed opioids, 82 percent of them on heroin and 16 percent on pain medications.

The research, published in The Lancet, was conducted at 8 sites within the National Institute on Drug Abuse Clinical Trials Network.

Five hundred and seventy opioid-dependent adults were randomized to the buprenorphine combination or the naltrexone formulation and followed for up to 24 weeks of outpatient treatment. Study sites differed in their detoxification approaches and in their typical inpatient length of stay. Buprenorphine/naloxone (brand name Suboxone) was given daily as a sublingual film (under the tongue) while naltrexone (brand name Vivitrol) was a monthly intramuscular injection. Adverse events, including overdoses, were tracked.

“Studies show that people with opioid dependence who follow detoxification with no medication are very likely to return to drug use, yet many treatment programs have been slow to accept medications that have proven to be safe and effective,” said NIDA director Dr. Nora Volkow. “These findings should encourage clinicians to use medication protocols, and these important results come at a time when communities are struggling to link a growing number of patients with the most effective individualized treatment.”

Scientists conducting the research expected that it would be more difficult to initiate treatment with naltrexone because it requires a full detoxification and patients often drop out of that process early. However, both the extent of the detoxification “hurdle,” and how the medications would compare once they were initiated, was not known.

Methadone, a third FDA-approved medication for treating opioid use disorders, was not studied in this project. Methadone is a synthetic opioid agonist usually given in liquid form that has been used successfully for more than 40 years. It must be dispensed through specialized opioid treatment programs, whereas buprenorphine/naloxone and naltrexone can be offered from a doctor’s office with a prescription.

Methadone has also been prescribed as a treatment for chronic pain.

Overdose deaths linked to opioid pain medicines nearly quadrupled from 2000 to 2014, to nearly 19,000. There is now also a rise in heroin use and heroin addiction as some people report shifting from prescription opioids to heroin because it is cheaper and easier to obtain. In 2015, nearly 600,000 people in the United States had a heroin use disorder and close to 13,000 Americans died of a heroin overdose.

Obesity During Pregnancy May Lead Directly to Fetal Overgrowth

Obesity during pregnancy—independent of its health consequences such as diabetes—may account for the higher risk of giving birth to an atypically large infant, according to researchers at NIH. Their study appears in JAMA Pediatrics.

IMAGE: THINKSTOCK/ADRIAN825
IMAGE: THINKSTOCK/ADRIAN825

“Our results underscore the importance of attaining a healthy body weight before pregnancy,” said the study’s lead author Dr. Cuilin Zhang, a researcher in NICHD’s Division of Intramural Population Health Research. “They also suggest that clinicians should carefully monitor the pregnancies of all obese women, regardless of whether or not they have obesity-related health conditions.”

Macrosomia—large body size at birth—is common among children born to obese women, particularly those who have gestational diabetes (high blood sugar during pregnancy). Macrosomia increases the risk that an infant will experience bone fracture during delivery. It also increases the likelihood that the infant will need to be delivered by cesarean section.

Having a large infant also increases a mother’s risk for postpartum hemorrhage, or excessive bleeding at birth.

The authors pointed out that earlier studies have indicated that the higher risk of overgrowth seen in newborns of obese women may predispose these infants to obesity and cardiovascular disease later in life. They called for additional studies to follow the children born to obese women to determine what health issues they may face.

Study Finds Donor Corneas Can Be Safely Preserved for Longer Period

Results from a large, national clinical trial show that corneal donor tissue can be safely stored for 11 days without negatively impacting the success of transplantation surgery to restore vision in people with diseases of the cornea. The cornea is the eye’s clear outer covering. Currently, donor corneas are generally not used for surgery in the United States if they have been preserved for longer than 7 days.

Two reports from the Cornea Preservation Time Study, which was funded by the National Eye Institute, appeared online Nov. 10 in JAMA Ophthalmology.

Expanding the window in which donor tissues can be considered suitable by even just a few days should help safeguard quality donor tissue and access to vision-saving transplantation procedures.

The study’s lead investigator was Dr. Jonathan Lass of Case Western Reserve University School of Medicine and University Hospitals Eye Institute, Cleveland.

Patients were randomly assigned to 1 of 2 treatment groups. The first received corneas preserved up to 7 days and the second received corneas preserved for 8 to 14 days.

The Food and Drug Administration has approved the use of solutions to preserve donated corneas for 14 days. “The current practice of surgeons to use corneas preserved for no longer than 7 days is not evidence-based,” said Lass, “but rather a practice based on opinion, which hopefully will change with this new evidence.”

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