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The first study to compare the effectiveness of the birth control pill in women with marked weight differences has found that the pill works equally well in women with obesity and thinner women. This new finding by physician-scientists at NewYork-Presbyterian Hospital/Columbia University Medical Center refutes a long-held conviction among many doctors that the pill may not reliably prevent pregnancy in women who are overweight or obese. With obesity a significant health issue in the United States — the U.S. government estimates that nearly 65 percent of adult women ages 20 and older are overweight or obese — the reliability of the birth control pill in this population is critical, especially since pregnancy itself is riskier among women with obesity.
In the study, published in the August issue of the journal Obstetrics & Gynecology, principal investigator Dr. Carolyn Westhoff, and her colleagues did not rely, as previous studies had, on women’s recollections of how much they may have weighed at a time when the pill had failed and they became pregnant.”We wanted to study what was actually happening in the ovaries of women and not depend on memory, which is notoriously faulty,” Dr. Westhoff says.
Dr. Westhoff and her colleagues designed a prospective study where 226 women of normal weight or who were overweight, and between the ages of 18 and 35, were randomly assigned to take either a lower- or higher-dose version of the pill. The researchers purposely used the different dose levels to assess whether heavier women required higher dosing, as has been previously believed.  After three or four months of using the oral contraceptives — the time it usually takes for a woman’s body to acclimate to the pill — the women had multiple ultrasounds and blood tests to determine if ovulation was being suppressed. The goal of oral contraception is to suppress ovulation.
Of the 150 women who used the pill consistently, three of the 96 women with normal weight ovulated, as did one of the 54 women with obesity. The researchers also found that when women were not taking the pill regularly, they ovulated with greater frequency.”Our findings strengthen the message to patients that the pill will only work if it is taken every day. Weight does not seem to have an impact on suppression of ovulation, but consistency of pill-taking does,” Dr. Westhoff says.
Importantly, the lower-dose pill seemed to be as effective as the higher-dose pill in suppressing ovulation in women with obesity. This is a crucial finding because women with obesity are at greater risk for developing blood clots from taking either type of pill, although the overall risk is small. “For a woman to fear relying on her oral contraceptive to prevent an unwanted pregnancy is a huge burden. This study should put those fears to rest,” Dr. Westhoff says.
Source:   New York Presbyterian Hospital/Columbia University Medical Center
Click here to see full press release.
Note from the Institute for Women’s Health Research:   Expect debate on this issue until the findings are replicated by other researchers and further analyzed.   The Institute will continue to track this issue and put updates on this blog site.

All living organisms have a circadian clock, sometimes called a biological clock, that is an important part of maintaining optimal health.   The circadian rhythm is a roughly 24-hour cycle in the biochemical, physiological, or behavioral processes of living things.   Although  circadian rhythms originate from within our bodies, they are synchronized to the environment by external cues, including the day-night cycle caused by the Earth’s rotation.  Researchers are looking more closely at the role circadian rhythms play in the development of diseases such as breast cancer and also how factors such as hormones affect this biological clock.
Carla Finkielstein, a molecular biologist at Virgina Tech, has launched a research project to study how changes in circadian rhythms may contribute to the development of breast cancer in women.   According to Finkielstein, “There are a number of epidemiological studies that show women working night shifts have a higher incidence of breast cancer.”  The question she asks is:   Can working odd hours actually alter a women’s body chemistry–turning healthy cells into cancer cells?
With support from the National Science Foundation, she is using frog embryos to help figure out on a molecular basis the physiological changes in women who work night shifts.   She says studies show that night workers have abnormal levels of specific protein in their cells, which act by turning on and off genes that regulate how cells grow and divide.  Proper timing of cell division is a major factor contributing to the regulation of normal cell growth and is a fundamental process in the development of most cancers.  She explains,” Our research explores ways in which the loss of circadian function impairs the death of cells in the cell cycle and leads to the accumulation of damaged, or cancerous, cells.”
Where is this leading us, what is the clinical application?   “If we were to generate a panel of markers that we can follow regularly for women who works night shifts, it would enable us to record changes in circadian-controlled genes and thus predict whether a person is at risk of developing breast cancer, ” Finkielstein said.   “If we see abnormal changes, all we may need to do is to alter this person’s work schedule.”
This study reinforces the important role circadian rhythm plays in sex and gender-based research.  In another example,  researchers at Northwestern University who are working in the lab of Dr. Fred Turek have determined that sex differences in hormone status in female mice are critical to better understanding stress or sleep deprivation.  There is growing evidence that circadian rhythm may play a part in other health issues like cardiovascular disease and diabetes.

Postmenopausal women have an increased risk of hypertension (high blood pressure), and among older adults, more women than men have hypertension.   As with many other health issues, hypertension research has been conducted predominately in males, and little is known about how women’s bodies manage blood flow.   Research conducted by Heidi A. Kluess at the University of Arkansas is focusing on a  better understanding of hypertension in women by using a new technique to examine the release of a neurotransmitter in small blood vessels.
Kluess, an exercise scientist, believes the answer seems to be in the “synapse”.  The synapse is the space between the nerve and the vascular smooth muscle, the place where the nerve and blood vessel interact.   A neurotransmitter crosses the “synapse” to activate a receptor, which then causes the artery to constrict.   “There’s been a little evidence to say that some of the neurotransmitter breakdown is different in women.   It suggests that when we’ve been looking at receptors on the smooth muscle, we may have been missing a big part of the story, particularly in women,” Kluess said.
The team measured the neurotransmitter adenosine triphosphate (ATP) coming from the small blood vessels (arterioles).  ATP plays a key role in controlling blood flow and blood pressure by causing the diameter of blood vessels to change.   Thus, the constriction of veins associated with hypertension could be related to relatively high levels of ATP in arterioles. So this raises the questions:   Where is the ATP coming from, what tissues are releasing it and how does this change with aging?
To study this,the researchers had to overcome the difficulty of working with very small blood vessels that produced minute amounts of ATP.   A biosensor that was only previously used in brain researcher was utilized that uses a set of enzymes to indirectly measure ATP as it is released.
The research findings suggest that ATP from small arterioles can be measured and that the arteriole wall plays an important role in release and management of ATP. The researchers found that ATP is released mostly from the sympathetic nerves in the arteriole wall and that only a small part comes from the smooth muscle. Considerable research suggests that having a lot of ATP floating around in the blood vessels is not a good thing. The upside of this finding is that the nerve releases ATP in response to nerve signals. However, the mechanisms involved in the release of ATP by smooth muscles are less well understood, Kluess explained, and may result in chronically high ATP release.
The researchers found that the ATP overflow varied considerably with age. Because ATP is associated with vascular growth, it is important during early development when blood vessels are growing, but levels generally decline when people reach their twenties. Elevated levels can be a bad sign during aging when the body is no longer growing and may be a predictor of vascular changes that can be detected years before hypertension is a problem.
Some previous research had suggested that the endothelium – the outer layer of the smooth muscle – produced ATP. However, Kluess’ research showed that the endothelial tissue did not produce ATP. Rather, it decreased levels of ATP and potentially plays a positive role in controlling ATP levels.
“That’s an interesting finding because we know that as people age or develop disease that their endothelium doesn’t work as well,” Kluess said. “That may be a way that ATP increases during aging because the endothelium doesn’t function as well and so can’t buffer ATP quite as well.”
More research is needed to investigate the factors that control ATP overflow and metabolism to reveal the mechanisms associated with age-related change. “We are very much at the beginning of this story,” Kluess said.
Source:   University of Arkansas
Kluess HA, Stone AJ, Evanson KW. ATP overflow in skeletal muscle 1A arterioles. J Physiol.

The most recent statistics on the women who participate in our Illinois Women’s Health Registry, indicate that sleep is a significant issue in their lives.  Among the most current women who are enrolled in our registry, 11% report difficulties getting to sleep, 12% have a hard time staying asleep, 15% wake up feeling fatigued, 13% report they are getting too little sleep for what they need, and 8% wake too early and cannot get back to sleep.

Our limited knowledge in sex differences is due to the fact that women are underrepresented in studies of sleep and its disorders.  The National Sleep Disorders Research Plan, released in 2004 by the National Center on Sleep Disorders Research reported that 75% of sleep research has been conducted in men.   While more recent sleep studies have included women, the small sample sizes limit sex comparisons.  However, there is a growing body of evidence that sex hormones influence sleep and circadian rhythms, and further neuroendocrine studies are needed.
To read more on women and sleep on the Institute for Women’s Health Research, click here.