The first report of the fetal alcohol syndrome (FAS) was made in 1973 by Jones and Smith. A lot of focus and advice since has been given to expectant mothers. But what about fathers? Does men’s health and behavior pre-conception impact on fetal development? Specifically, does paternal alcohol consumption pre-conception affect fetal development? Short answer, yes.
A recent WHO report “Global alcohol action plan 2022-2030” caused quite a stir last week. There were some click-baity headlines going around with the Irish post writing “World Health Organization wants to BAN all women aged 18-50 from drinking alcohol,”
These news stories were a little sensationalistic. The report by the WHO only mentions alcohol consumption in pregnant women and women of childbearing age once (shown below for you to read yourself). WHO have also clarified that they did not mean to imply they want to prevent alcohol consumption in women of childbearing age. BUT, the backlash to this report did raise some very interesting points. Why is the responsibility of fetal development placed almost entirely at the feet of the mother? Can the fathers’ lifestyle (e.g. alcohol consumption) affect fetal development?
“Appropriate attention should be given to prevention of the initiation of drinking among children and adolescents, prevention of drinking among pregnant women and women of childbearing age, and protection of people from pressures to drink, especially in societies with high levels of alcohol consumption where heavy drinkers are encouraged to drink even more.”WHO “Global alcohol action plan 2022-2030
Because fathers do not have a womb?
The mother carries the developing fetus within their womb for the duration of the pregnancy. Therefore, their lifestyle choices will clearly affect the fetus. Everybody knows this is true. From smoking, to drinking, to what foods you eat while pregnant, prospective mothers have this information drilled into them by the medical community. However, what is not talked about is how the fathers’ lifestyle pre-conception CAN affect fetal development.
In this article I will attempt to examine the evidence for alcohol consumption pre-conception (but there is other evidence for smoking and even exposure to chemicals in plastic – see our article about the effects of plastic on human health here). Basically, the quality of the sperm matters, and that will be affected by the fathers lifestyle.
Alcohol consumption and male fertility
Effects of alcohol in mice
Our previous article showed conclusively the effect of chemicals in plastic on male sperm counts and fertility (see here). That got me thinking about the potential effects of alcohol consumption. The results are a little mixed. There is clear evidence in mouse models that alcohol impacts testicular size, prostate size and sperm cells (1). However, the doses used in these studies appear quite high and mice are clearly not humans. Humans have evolved over thousands of years with alcohol as part of our diet and culture. In population studies in humans, the effect of alcohol consumption on fertility is less clear.
Effects of alcohol in human male fertility
Some studies have reported that long-term, heavy alcohol use causes reduction in testicular size, decreased testosterone and decreased sperm production (2). Worrying, but the majority of us wouldn’t drink enough for that data to apply to us. What about a mild-moderate amount of alcohol? A Danish study investigated 1221 young men undergoing military service recruitment. They found that habitual alcohol consumption was associated with lower sperm concentration, lower sperm count and increased percentages of sperm with abnormal morphology (appearance) (3). However, a larger study with 8344 healthy men from Europe and the USA found that mild-moderate alcohol consumption was NOT associated with sperm count (4).
From the current studies it is probably safe to say that mild-moderate alcohol use does not cause a large effect on male fertility. If it did, these studies and others would have found a clearer association. However, that does not mean that alcohol use is advisable for men wanting to become fathers. It may not affect your fertility but there are effects on fetal development. See below.
Fathers’ alcohol use and child development
In a paper published in Alcoholism: Clinical and Experimental Research, researchers investigated the effect of alcohol exposure in male mice on the development of their offspring (who were not exposed to alcohol). They reported that alcohol exposure in male mice led to significant deficits in the brain development of their offspring (5). You may have heard of fetal alcohol spectrum disorders (FASDs). FASDs are a group of disorders caused by maternal drinking during pregnancy. The mice in the study with fathers exposed to alcohol had brains which showed changes consistent with FASDs. This demonstrates that paternal drinking may cause similar affects in offspring as maternal drinking.
So what about in humans?
Large Chinese study shows paternal alcohol exposure prior to conception increases risk of birth defects
China makes a good population to study the effect of paternal alcohol consumption on fetal development. This is because only ~3% of mothers in China drink alcohol prior to pregnancy. A large study across 31 provinces in mainland China found that paternal alcohol consumption led to an increased risk of birth defects. They also found this was especially true with cleft defects. In their statistics they accounted for other factors such as maternal age, medical history, folic acid timing, exposure to harmful substances, maternal alcohol consumption, and paternal smoking (6).
Unfortunately in this study they defined paternal alcohol consumption as drinking at least once per week. They did not show the effects of drinking varying amounts. More studies could show what level of alcohol consumption causes these effects. E.g. whether drinking more alcohol per week has more of an effect.
Paternal alcohol use and congenital heart disease
Congenital heart diseases (CHDs) are defined by abnormal development of the heart and/or the large veins/arteries going into and out of the heart. CHDs are the most common defects presenting at birth with an estimated prevalence of ~1% of all live births. They are considered the leading non-infectious cause of infant mortality. A large meta-analysis* combined 55 studies involving 41,474 CHD cases. This breakthrough paper showed paternal alcohol exposure was associated with an increased risk of total CHDs. They even found a dose-dependent relationship (i.e. the higher the alcohol consumption the higher the risk of CHD) (7).
*Meta-analysis: A study that combines results from multiple smaller studies that are all trying to answer the same question. This gives the researchers more data to investigate than any of the individual studies alone and can be very useful to find small effects that are hard to find with small studies.
These studies provide clear evidence that there are negative effects of paternal alcohol consumption on child development. I wish I could tell you how much alcohol is too much, or give a clear timeline of how long before conception paternal alcohol has an affect but the science is not there yet. We need WAY MORE STUDIES on the effect of paternal alcohol consumption pre-conception (and other factors) on fetal development.
The science is clear though that both parents health impacts on fetal development, not just the mothers. If you are thinking of having a baby maybe you should consider reducing alcohol consumption prior to conception and improving your health overall. This will definitely have benefits for you and potentially for your future children. I can’t see any downside to getting yourself healthier.
Society places more responsibility on mothers. From fertility, to child development, to raising children. I am hopeful we are seeing a culture shift towards society giving equal responsibility to both parties. Although we are obviously nowhere near there. The science has shown that men are equally responsible for fertility (something which is not talked about enough!). Now these studies show the importance of paternal health on child development.