Another Reason Not to Smoke While Pregnant: Birth Defects

FRIDAY, Aug. 17, 2007 (HealthDay News) -- One of the first things every new parent does is count the baby's fingers and toes. But, women who smoke during pregnancy may be in for an unhappy surprise, because smoking increases the odds that a baby will be born with finger or toe deformities.

Just a half a pack a day increased the risk of having a baby with extra, missing or webbed fingers or toes by nearly 30 percent, according to a study in a recent issue of the journal Plastic and Reconstructive Surgery.

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

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 by 11 percent, and newborn deaths would decrease by about 5 percent, according to the March of Dimes. Smoking also increases the risk of preterm birth, a low birth-weight baby and cerebral palsy in the baby.

Limb defects aren't uncommon. About one 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 one in every 2,000 to 2,500 births. Missing toes or fingers is known as adactyly. 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 born to women who smoked who also had deformed fingers or toes. 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," said Dr. Alfred Robichaux III, chairman of obstetrics and gynecology at Ochsner Health System in New Orleans. "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. They also have a higher rate of SIDS. 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," Robichaux added.

Dr. Robert Welch, chairman and program director of obstetrics and gynecology at Providence Hospital in Southfield, Mich., said he wasn't surprised by this study's findings, since previous research has linked smoking to an increased risk of cleft lip and palette.

He said 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," Welch advised. However, both Welch and Alvarez pointed out that it's never too late for a pregnant woman to stop -- or at the very least cut down -- on her smoking.

"We encourage women with each prenatal visit and may shorten the time between prenatal visits for extra support. We recommend smoking reduction with the idea that it will lead to cessation," Welch said.

Both experts said nicotine replacement products aren't recommended for pregnant women, but that many women have success quitting smoking using acupuncture. Both Welch and Alvarez said it's key for the woman's partner to quit smoking as well or stay away while smoking.

What's most important, said 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. Tell me that you're having major difficulty quitting, and we can work on breaking the habit," Alvarez said.

More information

To learn more about the effects of smoking during pregnancy, visit the March of Dimes.