Excerpt From: The Endocrine System
Alcohol Alters Critical Hormonal Balance – Studies in Women
NICHOLAS EMANUELE, M.D., AND MARY ANN EMANUELE, M.D.
Studies in Women
Even moderate drinking in healthy women can lead to significant reproductive problems. (For a review, see Mello et al. 1993). Mendelson and Mello (1988) studied a group of healthy, well nourished women during a 35-day stay on a clinical research unit. The first and last 7 days were alcohol-free. During the middle 21 days, each participant could drink alcohol as desired. At the end of the 35 days, the women classified themselves as heavy drinkers (7.8 ± 0.7 drinks/day, n = 5), moderate drinkers (3.8 ± 0.2 drinks/ day, n = 12), or occasional drinkers (1.2 ± 0.2 drinks/day, n = 9). Each woman’s alcohol intake within the clinical research unit was similar to her reported level of consumption for the previous 6–8 years. Sixty percent of the heavy drinkers and 50 percent of the moderate drinkers who consumed more than three drinks per day had significant problems, including delayed ovulation and failure to ovulate (i.e., anovulation). Shortening of the luteal phase also was observed. Menstrual problems did not appear to occur in the women who were occasional drinkers or who were moderate drinkers consuming fewer than two drinks per day. A dose-response relationship appears to exist between alcohol consumption and the frequency of menstrual problems. This notion also is supported by epidemiological surveys showing that prevalence of menstrual disturbances grows with increasing alcohol consumption.
The mechanism of these problems is not entirely clear. However, it is of interest that acute alcohol administration has been reported to raise estrogen levels. Whether this rise is due to an increased estrogen secretion, enhanced conversion of estrogen from precursor substances, decreased metabolism, or a combination of these factors is uncertain. Nonetheless, it has been demonstrated that estrogen administration can disrupt the reproductive cycle, at least in part because estrogen can suppress FSH (Mello et al. 1993). Recall that a rise in FSH early in the follicular phase of the reproductive cycle is crucial to the proper maturation of the dominant ovarian follicle, from which ovulation will occur and the corpus luteum will develop. This knowledge gives rise to the idea that alcohol intake could lead to increased estrogen, inhibiting FSH and disrupting folliculogenesis and subsequent corpus luteum function. In addition, alcohol has been shown to suppress progesterone, the main secretory product of the corpus luteum. Thus, even moderate amounts of alcohol may cause infertility (through suppressing ovulation) and an increased risk for spontaneous abortion (through interfering with the pregnancy-maintaining function of the corpus luteum).
Careful longitudinal studies of the effects of abstinence from alcohol on reproductive abnormalities are not available. Anecdotal evidence, however, indicates that alcohol-induced reproductive abnormalities are reversible upon discontinuing alcohol intake. Not all drinkers have reproductive abnormalities, indicating either variable susceptibility to the effects of alcohol and/or the development of tolerance to its effects. Therefore, some women who consume alcohol will continue to have regular menses and become pregnant.
Women who have ingested alcohol long enough and frequently enough to develop liver cirrhosis are ill and malnourished, putting them in a different category from the otherwise healthy, well-nourished women discussed above. Nonetheless, whether from alcohol or the attendant sickness, women with alcoholic cirrhosis, too, have reproductive and menstrual abnormalities. Their hormonal profiles are somewhat different from those of social drinkers, however. Women with alcoholic cirrhosis tend to have low, rather than high, estrogen and elevated levels of LH and FSH. This pattern is similar to what is normally seen in menopause and suggests that over the long term, alcoholic women may have premature ovarian failure. This area requires further study.