Pregnancy comes with a lot of dos and don’ts. Some of them make good sense but others just seem like arbitrary rules and rules that are made to be broken, right? Rules that involve the avoidance of alcohol and tobacco products may seem like rules that can be safely bent from time to time but there are sound scientific reasons why these rules exist. Basically, they’re bad for the baby.

Historically, scientific studies reveal a link between consumption of alcohol and tobacco during pregnancy. This link may seem obvious, but for a long time medical science did not understand the mechanism that forms the link in the first place. More recent research is pointing to the process of epigenetics to solve the mystery.

Epigenetics works like an on-and-off switch on the genes of a cell. Epigenetics signals a single cell to divide into two identical cells and then divide again and again. Soon, it tells genes in some cells to become heart cells and others brain cells. It tells still other cells to become cells of the knee, nose, and funny bone. Eventually, the process of epigenetics constructs a baby.

When exposed to certain chemicals and hormones, the epigenetics signal may switch a gene off when the developing fetus would be healthier if the switch had been left on. It might turn one on that would be better left off.

Diseases such as diabetes and some forms of cancer are linked to epigenetic changes. Some of these diseases affect children but epigenetic changes are also associated with diseases usually not seen until adulthood, such as schizophrenia and type 2 diabetes.

As the study of epigenetics advances, it’s becoming clear that the first few weeks after conception are “a particularly vulnerable time where environmental influences can directly affect an epigenetic outcome,” says Dani Fallin. Fallin specializes in the study of genetics of mental disorders at the Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland.

Fallin’s research indicates the epigenetic mechanism is influenced by exposure to specific environmental factors such as consumption of alcohol and tobacco, exposure to toxic chemicals, and good old everyday stress.

Perhaps Fallin’s own children are a driving force behind her interest in the study of epigenetics. She lost a young son to a rare liver cancer linked to epigenetic alterations in the 1990s. She has an autistic son and a daughter with ADHD, both diagnoses linked to epigenetics.

Fallin hopes further study in epigenetics will establish safe thresholds of exposure that will allow a pregnant woman to enjoy a guilt-free glass of wine with dinner without fear of harming her developing baby.

In the meantime, the awareness of epigenetic influences is a true, identifiable, scientific reason to obey the rules for avoiding tobacco, alcohol, undue stress, and exposure to toxic chemicals during pregnancy. And there is hope that awareness will be a strong enough deterrent for expectant mothers who might be tempted to ignore or bend the rules.

Source: Hamilton, Jon. "How a Pregnant Woman's Choices Could Shape a Child's Health." NPR National Public Radio. 23 Sep 2013. Web. Retrieved 16 Nov 2013.