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January 29, 2015
Digest

Trying to Conceive Soon After a Pregnancy Loss May Increase Chances of Live Birth

Couples who attempt to conceive within 3 months after losing an early pregnancy, defined as less than 20 weeks gestation, have the same chances, if not greater, of achieving a live birth than those who wait for 3 months or more, according to an NIH study.

The finding, published Jan. 11 in Obstetrics & Gynecology, questions traditional advice that couples should wait at least 3 months after a loss before attempting a new pregnancy. The World Health Organization, for example, recommends waiting a minimum of 6 months between a pregnancy loss and a subsequent attempt.

“Couples often seek counseling on how long they should wait until attempting to conceive again,” said Dr. Enrique Schisterman, chief of NICHD’s Epidemiology Branch and senior author of the study. “Our data suggest that women who try for a new pregnancy within 3 months can conceive as quickly, if not quicker, than women who wait for 3 months or more.”

Previous studies of pregnancy spacing have focused on when women should become pregnant after experiencing a loss, but few have addressed the question of when couples should start trying to conceive.

“While we found no physiological reason for delaying attempts at conception following a pregnancy loss, couples may need time to heal emotionally before they try again,” said Dr. Karen Schliep, a postdoctoral fellow in the NICHD Epidemiology Branch at the time of the study and primary author of the study. “For those who are ready, our findings suggest that conventional recommendations for waiting at least 3 months after a loss may be unwarranted.”

Three Glaucoma-Related Genes Discovered

An analysis funded by the National Eye Institute has identified three genes that contribute to the most common type of glaucoma. The study increases the total number of such genes to 15.

An eye exam can help in the diagnosis of glaucoma, a common cause of vision loss.
An eye exam can help in the diagnosis of glaucoma, a common cause of vision loss.

PHOTO: NEI

“Just in time for Glaucoma Awareness Month, this unprecedented analysis provides the most comprehensive genetic profile of glaucoma to date,” said NEI director Dr. Paul Sieving. “These findings open avenues for the pursuit of new strategies to screen for, prevent and treat glaucoma.”

Glaucoma is a group of conditions that damage the optic nerve, the bundle of nerve fibers connecting the eye to the brain. Primary open angle glaucoma, the most common type, was studied in this analysis. In the majority of cases, pressure inside the eye is increased. Glaucoma affects side vision first, often going unnoticed for years. If detected early, vision loss can often be prevented with surgery or eye drops to lower pressure. The most common culprit of irreversible vision loss, glaucoma affects about 2.7 million Americans and 60 million people worldwide.

Some rare types of glaucoma are inherited via a single gene. The underlying causes of primary open angle glaucoma remain poorly understood, but likely involve the interaction of many genes with environmental influences.

The report appeared online Jan. 11 in Nature Genetics.

Diet, Exercise Improve Exercise Capacity in Certain Heart Failure Patients

A randomized clinical trial of 100 patients found that diet and exercise—alone or combined—improved exercise capacity in obese older patients with a particular type of heart failure. The trial is the first to show that this dietary intervention was effective in improving exercise capacity and reducing symptoms in patients with heart failure with preserved ejection fraction (HFPEF). The results appeared in the Jan. 6 issue of the Journal of the American Medical Association. The study was supported primarily by NIA.

HFPEF is the most rapidly increasing form of heart failure, especially in older adults. It occurs primarily in overweight and obese older women and is associated with high rates of morbidity, mortality and health care expenditures. Exercise intolerance—fatigue and shortness of breath with exertion—in HFPEF patients was recently shown to be associated with increased body weight.

Dr. Dalane Kitzman and colleagues at Wake Forest University School of Medicine randomized trial participants to four groups: diet alone, exercise alone, diet and exercise together or control. After 20 weeks, people in the three intervention groups showed improved exercise tolerance, measured by peak exercise oxygen consumption. The diet and exercise groups both showed improvement; however, the combination group had almost twice the improvement in oxygen consumption. In addition to improving exercise capacity, diet and exercise decreased the amount of fat cells within the leg muscle, the researchers found; fat, which infiltrates leg muscle, contributes to reduced exercise capacity in heart failure.

This is the first randomized controlled trial of calorie restriction in this patient population. While the researchers noted that follow-up studies are needed to investigate the loss of muscle mass associated with weight loss, this research supports a treatment for heart failure that relies on diet and exercise, unlike previous treatments which focused on regulating heart function through medication.

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