Effects of tobacco smoke exposure on hormones and fertility
Creators: name: University Of California Office Of The President
Publisher: name: University of California Office of the President
publisherIdentifier: https://ror.org/00dmfq477
publisherIdentifierScheme: ROR
Year: 2024

description: Cigarette smoke is known to contain a large number of compounds, some of which are suspected to cause damage to the reproductive system. Smoking is one of the most preventable causes of low birth weight in exposed babies and has also been associated with pregnancy loss, infant death and infertility. Some evidence also suggests that smoking may affect hormone levels, which in turn could affect pregnancy and other hormone-dependent conditions. For example, women who smoke tend to reach menopause earlier than non-smokers. We previously conducted a study that looked at different aspects of the menstrual cycle. Women kept track of their periods and collected urine daily during several cycles. From the urine , the levels of two hormones which are secreted from the ovaries during each "normal" menstrual cycle, namely estrogen and progesterone, were measured. We found that menstrual cycles of heavy smokers tended to be shorter and more irregular than those of non-smokers. There also appeared to be some differences in hormone patterns by smoking status. Shorter cycles (in general) have been linked to earlier menopause and to higher risk of breast cancer. The timing of events in the menstrual cycle, including release of progesterone and estrogen, may affect the ability to get and stay pregnant, so these findings are important for reproductive fitness. This is one of the first studies to look at smoking and menstrual function in this way and the exact means by which smoke exposure may cause these changes is not clear. Therefore, we plan to pursue these findings further in this valuable database.
 
 
 
 
 
 The release of hormones by the ovary is under the control of messages from other organs, such as the pituitary and the brain. To learn more about how smoke exposure may act on this system, we will measure one of the pituitary hormones, called follicle stimulating hormone (FSH). FSH is important in preparing for ovulation (release of the egg in the middle of the cycle) and thus may be a marker of ovarian function. Two prior studies found some increase in FSH among smokers, but FSH was measured on only a few days. We will measure FSH on each day of a sample of menstrual cycles, so we can examine patterns throughout the cycle. FSH production will be compared by smoking status and to other menstrual cycle characteristics to determine whether it is involved in the changes in menstrual function we noted among smokers in this study.
 
 
 
 
 
 This study is directly relevant to the goals of the TRDRP to understand the biomedical effects of smoking. It is cost-effective because it uses information from a database of over 400 women and 2,000 menstrual cycles which was already collected at considerable cost and time. From this study, we expect to learn more about how smoking affects hormone systems and reproductive function. These hormone system, in turn, are critical for many other aspects of women's health.