University of Virginia Health System

Some Birth Defects Linked to Mothers Who Smoke

One of the first things every new parent does is count their baby's fingers and toes. But women who smoke during pregnancy may be in for an unhappy surprise, because smoking increases the odds that their baby will be born with finger or toe deformities.

"One of the things that smoking does is interfere with oxygen delivery to cells at very key moments in development," explains Dr. Manuel Alvarez of Hackensack University Medical Center. "If cells are deprived of oxygen, they don't proliferate as they should. If cells don't proliferate, you can have limb deformities.

Risk Increases With Every Cigarette

About one out of every nine expectant mothers smokes, according to the March of Dimes. If no pregnant woman smoked, the rate of stillbirths would drop 11 percent and newborn deaths would decrease about 5 percent.

Mothers who smoke also increase the risk of several other problems for their baby, says Stephen Braddock, M.D., a Professor of Pediatrics at the University of Virginia Health System.

For instance, smoking also increases the risk of preterm birth, a low birth-weight baby, and cerebral palsy in the baby.

Limb defects are not uncommon. Missing toes or fingers is known as adactyly. About 1 in 600 babies is born with an extra finger or toe - a condition known as polydactyly. A baby born with webbed toes or fingers - syndactyly - occurs in about 1 in every 2,000 to 2,500 births.

Webbed fingers or toes are more common in white babies, while excess digits are more common in black babies.

Most of the time, these deformities occur in babies with no family history of such birth defects, which led researchers to suspect environmental causes.

After sifting through almost 7 million birth records from 2001 to 2002, researchers from the University of Pennsylvania found almost 5,200 babies with deformed fingers or toes born to women who smoked.

None of the women who smoked had other medical conditions, such as high blood pressure or diabetes.

The researchers found that the more a woman smoked, the greater the likelihood of finger or toe anomalies.

Women who smoked more than a pack a day had a 78 percent increased risk of having a baby with deformed toes or fingers, while women who smoked 11 to 20 cigarettes daily had a 38 percent increased risk.

Those who smoked 10 or fewer cigarettes a day upped their babies' risk by 29 percent.

"This is another reason to stop smoking," says Dr. Alfred Robichaux III of Ochsner Health System. "The problems with smoking during pregnancy are increased bleeding, miscarriage, premature deliveries, and low birth weight.

“Babies born to mothers [who are] smokers have higher respiratory illnesses and lower IQs," says Robichaux. "They also have a higher rate of SIDS [sudden infant death syndrome]. And, now we have evidence that they have up to a 30 percent increase in limb defects. Thankfully, surveys are showing that the rate of smoking during pregnancy is on the decline. It looks like the word is getting out."

Doctors Want to Help Women Quit

Dr. Robert Welch of Providence Hospital in Southfield, Mich., says he was not surprised by this study's findings, since previous research has linked smoking to an increased risk of cleft lip and palette.

He says the best thing a woman can do is quit smoking before she gets pregnant.

"If you're contemplating pregnancy, that's when you want to stop," advises Welch.

UVA's Braddock tells pregnant women he treats to quit smoking, though he realizes that can be a tough change to make.

"I also counsel women to quit smoking, but realizing that to one who is addicted, that can be difficult," Braddock says. "I encourage them to cut back as much as possible. Quitting is still the ideal message."

Welch and Alvarez say nicotine replacement products are not recommended for pregnant women, but that many women have success quitting smoking using acupuncture.

Both Welch and Alvarez say it is key for the woman's partner to also quit smoking or stay away while smoking.

What is most important, says Alvarez, is to be upfront with your doctor about your smoking habit.

"I would rather know the truth, so I know why the baby isn't growing adequately," says Alvarez. "Tell me that you're having major difficulty quitting, and we can work on breaking the habit."

To learn more about pregnancy or other women's health topics, visit www.uvahealth.com.

Women can learn more about their unique risks for heart disease - and how to better manage those risks - through Live Red, a new UVA heart-health initiative. You'll learn how heart attack symptoms can be different for women than for men, and you can take an online risk assessment to learn your personal heart disease risk factors.

There, you can sign up for Club Red, our free heart-healthy club for women. Benefits include tips from UVA healthcare providers and a gift package to help you live red in style.

Always consult your physician for more information.