The November 30 2003 edition of Decanter suggested that “wine-drinking women have [a] better chance of becoming pregnant, research finds”. This headline refers to a paper entitled Intake of wine, beer and spirits, and waiting time to pregnancy by Juhl et al. in 2003. The paper suggested that sexually active women who consumed wine had a slightly shorter waiting time to pregnancy than consumers of beer and spirits and non-consumers, but whether this was an effect of wine itself or the characteristics of the wine drinker was unknown. The differential effect of wine compared to beer and spirit consumers was, however, small. This paper followed from a previous paper, which suggested that light to moderate consumers of alcohol has a slightly shorter waiting time to pregnancy than those who abstained (Juhl et al. 2001), and is purportedly the first paper to examine the relationship between the consumption of specific types of alcoholic beverages and fecundity.
Fertility (reproductive ability) and fecundity, which is the waiting time to pregnancy, are positively correlated.
Infertility is often multi-factorial and common causes of infertility include ovulatory factors such as anovulation, cervical factors and endometriosis. In the past decade there has been an increased demand for fertility treatment in the western world (Olsen et al. 1997), and an increased awareness of environmental or external causes, including an association with alcohol consumption.
The relationship between alcohol consumption and fertility and fecundity is an issue of controversy. The results of research studies are conflicting and have shown both positive and negative effects of alcohol on fertility and fecundity, which may merely reflect a combination of different study designs and confounding factors. Grodstein et al. (1994), for example, suggested that any amount of alcohol decreased fertility while Olsen et al. (1997) Jensen et al. (1998) and Hakim et al. (1998) linked only heavy alcohol consumption to decreased fertility. The latter two studies also suggested that the chances of successful conception decreased as alcohol consumption increased. Neither study analysis included anovular women, however, nor did they consider the pattern of alcohol consumption across the days of the menstrual cycle. Other studies by Florack et al. (1994), Zaadstra et al. (1994), Curtis et al. (1997) and Parazzini et al. (1999) did not observe an effect of any amount of alcohol consumption on fertility. Other confounding factors include: age of women studied as fertility and fecundity are negatively correlated with female age, reproductive inability, which may reflect failure of endometrial implantation rather than a failure in fertilization (West 1987, Hull et al. 1994); and the timeframe of alcohol consumption, that is whether alcohol was consumed during, prior to and/or following attempts to conceive. Indeed, prior chronic or long-term alcohol consumption may be an independent risk factor for fertility and fecundity (Tolstrup et al. 2003).
In general for women, heavy alcohol consumption, which is generally defined as greater than two 10 g drinks of alcohol per day, has been consistently associated with anovulation and increased endometriosis (Grodstein et al. 1994). It has also been associated with a change in level of female reproductive hormones, for example, an increase in the level of oestrogen (Mendelson et al. 1987, Gavaler et al. 1993, Muti et al. 1998) and a decrease in the level of progesterone (Sarkola et al. 1999), although changes in the ratio of these hormones may be more biologically significant (Gill 2000). In addition, heavy alcohol consumption has been associated with an increased risk of spontaneous abortion (Windham et al. 1997, Kesmodel et al. 2002).
An association, however, between fertility and fecundity with light to moderate alcohol consumption remains inconsistent and hence controversial. The study by Juhl et al. in 2003 did, however, observe that a higher proportion of those sexually active women who waited more than 12 months to become pregnant were heavier consumers of alcohol than those who waited less than 12 months. Interestingly, the definition of heavier alcohol consumption was greater than seven 12 g alcoholic drinks per week, which is only approximately one drink per day, and this is defined as low-risk consumption in Australia for women (NH&MRC 2001).
In conclusion, there are too few studies that consistently show an association between light to moderate alcohol consumption and fertility and fecundity to draw any conclusions as to whether women of childbearing age should not consume alcohol when planning to conceive, especially when different study designs and confounding factors are considered. There can be no doubt, however, that the chronic heavy consumption of alcohol during conception may compromise fertility and fecundity and that during pregnancy such alcohol consumption can have detrimental effects on the development and growth of the foetus (Abel and Hannigan 1995).
Furthermore, as Juhl et al. (2003) added in the concluding comments of their paper “the association between wine drinking and waiting time to pregnancy was not very strong and there was no clear dose-response pattern. We encourage other to check available data to see whether they find a similar beneficial effects of wine drinking”.
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