Trusted Information for Healthy Pregnancies
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Smoking moms tied to lasting kids’ sleep woes
May 10th
Mothers who smoke during pregnancy are more likely to have children with sleep problems from birth all the way through age 12, new research shows.
"The more cigarettes that mothers smoked during pregnancy, the more sleep problems the children had," Dr. Kristen Stone of Women and Infants Hospital in Providence, Rhode Island, one of the study's authors, told Reuters Health.
What's more, while most of the women who smoked during pregnancy used at least one other drug, Stone and her team found that nicotine was the only substance associated with sleep problems.
Stone and colleagues from centers in Miami, Detroit, and Memphis are following nearly 1,400 children born in 1993, 1994 or 1995 to investigate the long-term effects of exposure to substances during pregnancy.
The current study included children for whom data was available up to age 12. Among the 808 study participants, 374 had been exposed to cocaine or opiates such as heroin before birth, while 434 had not.
Children's mothers or other caregivers reported on whether a child had difficulty falling asleep and staying asleep during three periods: one month to four years of age; five to eight years, and nine to 12 years. Being exposed to cocaine, opiates, marijuana, or alcohol in the womb had no effect on a child's risk of having sleep problems, but nicotine did, and problems were seen at each of the three time points.
The researchers do not report what percentage of children had sleeping problems, but used a common measure of such problems that assigns points for items such as talking in one's sleep, sleepwalking, and having trouble falling asleep.
The link remained even after the researchers took into account factors such as socioeconomic status, whether or not a child had been abused, and whether the mother or caregiver smoked after the child was born.
The findings shouldn't be seen as showing that prenatal use of alcohol and drugs aside from cigarettes isn't as harmful to a child's sleep as smoking in pregnancy, Stone noted. Cigarettes are different from other substances, she explained, in that a person who smokes will typically do so much more frequently than a drug abuser uses cocaine or opiates.
Further, she said, many of the mothers in the study were using multiple substances while they were pregnancy. "When those substances are inside of us at the same time, they basically become a whole new substance because of their interactions with each other," she added. All of this makes it difficult to tease out the effects of nicotine and other drugs, according to the researcher.
When a child does have sleep problems, Stone said, "early and careful attention" to these issues can go along way toward helping that child sleep better.
"Even an emphasis on basic behavioral sleep education could serve those children well," she added. "Doing that would then likely improve the daytime experience for those children as well."
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Antidepressant tied to risk of newborn heart defect
May 4th
Women who use the antidepressant bupropion during early pregnancy may have an increased risk of having a baby with a particular type of heart defect, a new study suggests.
Researchers caution that it is not clear whether the medication, marketed as Wellbutrin, is the cause. And even if it is, they say, the absolute risk of the heart defect would be small -- affecting just 2 out of every 1,000 infants born to women who used bupropion during the first trimester.
But the findings, published in the American Journal of Obstetrics & Gynecology, do add to questions about the risks of using antidepressants during early pregnancy.
Some studies have already linked other antidepressants -- including some of the commonly used selective serotonin reuptake inhibitors (SSRIs) -- to higher-than-average, though small, risks of certain birth defects.
A study last year, for example, found that among nearly half a million Danish children born between 1996 and 2003, the risk of heart defects was elevated among those whose mothers had used SSRIs such as fluoxetine (Prozac), sertraline (Zoloft) and citalopram (Celexa) during early pregnancy.
In this latest study, researchers found that among more than 12,700 U.S. infants born between 1997 and 2004, those whose mothers used bupropion during early pregnancy had more than double the risk of heart defects known as left outflow tract defects, compared with infants whose mothers had not used the drug.
Left outflow defects affect the flow of blood from the heart's left chambers to the rest of the body. In this study, the most common type of this defect was coarctation of the aorta -- a narrowing in the body's main artery that, in children, typically requires surgical repair.
The findings do not mean, however, that depressed women on bupropion should stop taking it if they are planning a pregnancy, according to the researchers.
"I think it's important that women understand that they should not just stop taking their medication," said Dr. Jennita Reefhuis, a senior epidemiologist at the U.S. Centers for Disease Control and Prevention and one of the researchers on the study.
Instead, she told Reuters Health, women should talk with their doctors, ideally when they are planning a pregnancy rather than after they conceive.
The potential risk of birth defects from using antidepressants must be weighed against the risks of a woman stopping her current depression therapy, Reefhuis said.
"This study needs to be replicated before we can say anything conclusive," Reefhuis said, noting that the findings point to an association between bupropion and left outflow defects, but cannot by itself prove cause-and-effect.
If the association is causal, she said, the absolute risk to any one woman would be small. For every 1,000 births, there are an estimated 0.8 cases of left outflow tract heart defects; based on the current findings, that rate would be 2 per 1,000 among women who use bupropion in the first trimester.
Reefhuis also pointed out that with any pregnancy, the overall risk of having a baby with some form of birth defect is 3 percent.
Guidelines released last year by the American Psychiatric Association and the American College of Obstetricians and Gynecologists state that psychotherapy may be an effective alternative to antidepressants for pregnant women with mild to moderate depression.
However, the guidelines say, women with a history of more severe depression, or other major psychiatric disorders, may need to continue with their medication.
Bupropion is also prescribed for smoking cessation, under the brand-name Zyban. In the case of smoking cessation, Reefhuis said, it may be easier for women to find an effective alternative to the drug.
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Third-hand smoke a danger to babies, toddlers
Feb 10th
Add a new health threat to smoking: In addition to the harm caused by actually smoking and exposure to second-hand smoke, so-called third-hand smoke may also pose a threat, particularly to babies and toddlers.
A new study reveals that the residue of nicotine that lingers on surfaces can react with another chemical in the air to form potent carcinogens - chemicals linked to various cancers. While first-hand smoke is that inhaled directly by the smoker and second-hand is the smoke exhaled (and inhaled by others), third-hand smoke is the residue from second-hand smoke.
Anyone who has entered a confined space — a room, an elevator, a vehicle, etc. — where someone has recently been smoking, knows that the scent lingers for an extended period of time.
"The burning of tobacco releases nicotine in the form of a vapor that adsorbs strongly onto indoor surfaces, such as walls, floors, carpeting, drapes and furniture. Nicotine can persist on those materials for days, weeks and even months," said Hugo Destaillats, a chemist with Lawrence Berkeley National Laboratory in San Francisco, and one of the authors of the study.
Scientists have been aware for several years that tobacco smoke sort of sticks to surfaces where it can react with other chemicals. But reactions of residual smoke constituents with molecules in the air have been overlooked as a source of harmful pollutants, the researchers of the new study say.
"Our study shows that when this residual nicotine reacts with ambient nitrous acid it forms carcinogenic tobacco-specific nitrosamines or TSNAs," Destaillats said. "TSNAs are among the most broadly acting and potent carcinogens present in unburned tobacco and tobacco smoke."
Unvented gas appliances are the main source of nitrous acid indoors.
The researchers used cellulose as a model of indoor material, and exposed it to cigarette smoke. They then exposed it to a "high but reasonable" concentration of nitrous acid for three hours. The levels of newly formed TSNAs were 10 times higher after the nitrous acid exposure. The TSNAs also formed quickly, the researchers found.
"Given the rapid absorption and persistence of high levels of nicotine on indoor surfaces, including clothing and human skin, our findings indicate that third-hand smoke represents an unappreciated health hazard through dermal exposure, dust inhalation and ingestion," said lead author Mohamad Sleiman, also of Berkeley Lab.
Since most vehicle engines emit some nitrous acid that can infiltrate the passenger compartments, tests were also conducted on surfaces inside the truck of a heavy smoker, including the surface of a stainless steel glove compartment. These measurements also showed substantial levels of TSNAs.
Individuals are most likely exposed to these TSNAs through either inhalation of dust or the contact of skin with carpet or clothes, suggesting third-hand smoke might pose the greatest hazard to infants and toddlers.
And the study's findings, detailed in the Feb. 8 issue of the journal Proceedings of the National Academy of Sciences, indicate that opening a window or deploying a fan to ventilate the room while a cigarette burns does not eliminate the hazard of third-hand smoke.
"Smoking outside is better than smoking indoors but nicotine residues will stick to a smoker's skin and clothing," said study co-author Lara Gundel, also of Berkeley Lab. "Those residues follow a smoker back inside and get spread everywhere."
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Mom’s Lifestyle in Early Pregnancy Affects Baby’s Size
Feb 10th
The lifestyle habits you bring into pregnancy can have lasting effects on your baby's health, new research shows.
A Dutch study found that women who smoked, had high blood pressure or low folic acid levels in early pregnancy had babies that were smaller in the first trimester of pregnancy and had a higher risk of complications later.
"Our study demonstrates that several maternal physical characteristics and lifestyle habits, such as smoking and non-use of folic acid supplements, affect first-trimester fetal growth," said study senior author Dr. Vincent Jaddoe, a pediatric epidemiologist at Erasmus Medical Center in Rotterdam, the Netherlands.
"First-trimester growth restriction is associated with higher risks of adverse birth outcomes and accelerated postnatal growth rates. Thus, the first trimester of pregnancy seems to be a very critical period for fetal growth and development. This is important, since it suggests that the fetus is already affected before pregnant women visit their midwife or obstetrician," he said.
For the study, published in the Feb. 10 issue of the Journal of the American Medical Association, the researchers followed 1,631 pregnant women from their first trimester through their pregnancies. The growth of their offspring was assessed until the children were 2.
The average age of the mothers was 31, and 71 percent were white. More than half had a higher than high school education. The average body mass index was 23.5, which is normal (over 25 is considered overweight). About one-quarter smoked at the start of the study.
The researchers found that certain factors affected the likelihood that a fetus would have a small crown to rump length (a standard way to measure babies using ultrasound). Babies whose mothers smoked or had higher diastolic blood pressure readings (diastolic is the bottom number in blood pressure) were more likely to be smaller. Women who didn't use folic acid supplements and those with higher levels of red blood cells also had smaller babies, according to the study.
A small size during the first trimester translated to a higher risk of certain complications later in the pregnancy, such as preterm birth and low birth weight.
Babies that had first-trimester growth restriction had 7.2 percent odds of being born preterm compared to 4 percent for babies who weren't growth-restricted. Odds of low birth weight were 7.5 percent for growth-restricted babies compared to 3.5 percent for other babies. And, the odds of being born small-for-gestational-age were 10.6 percent for babies who were growth-restricted compared to 4 percent for babies who grew normally during early pregnancy.
Jaddoe and Dr. Gordon Smith, author of an accompanying editorial in the same issue of the journal, believe that when a woman is exposed to poor lifestyle habits in early pregnancy, it may affect development of the placenta, which then affects the fetus' ability to survive and thrive.
The bottom line for women is that it's important to go to the doctor before getting pregnant to find out what steps to take to ensure that you're in the best shape possible before you get pregnant, such as quitting smoking and taking folic acid supplements.
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Birth planning leads to surprising increase in premature births
Feb 8th
The rising trend of expectant mothers being involved in every aspect of planning their births has had an unintended consequence - a rise in pre-term deliveries.
"It never would have occurred to me or anyone I knew to think you had any kind of control over when the baby would come out," said Laura Crawford, who gave birth more than a decade ago.
Crawford, producer of the Kentucky Educational Television documentary "Born too Soon," said the increasing incidence of what is called late pre-term births is among the topics explored in the film.
Prematurity rates in the nation have increased quietly over the past two decades, according to public health officials. The premature-birth rate in Kentucky is 15.2 percent, and it's rising faster than the national rate, which is 12.7 percent. Kentucky has one of the highest rates of pre-term births, trailing only Louisiana, Alabama, Mississippi and South Carolina.
Some of Kentucky's rise is related to some not-so surprising subjects, including the rate of maternal smoking (more than twice the national average), poverty and environment.
Other reasons are more surprising. They include the rise in scheduling births.
It's just within the last three or four years that the scope of the problem of late pre-term births - babies born between 34 and 36 weeks' gestation - has become apparent, said Dr. Ruth Shepherd, division director for maternal and child health in Kentucky's Department of Public Health. Roughly 10 percent of all babies born in Kentucky fall into the late pre-term category.
Ideally, she said, babies shouldn't be delivered before 39 weeks.
Often, there are legitimate reasons for early delivery, especially if the health of mother or child is at risk.
Increasingly, choices are made for reasons other than health. Delivery might be scheduled to coincide with grandparents' dates of arrival from out of town, or before Dad must ship out for Iraq.
There are several complicating factors, Crawford said. The documentary states that people tend to underestimate the impact of premature births, especially late pre-term births. They tend to overestimate how accurately a due date can be determined.
Shepherd said there can be real consequences. They can include immediate physical challenges, including underdeveloped lungs and long-term problems involving learning and behavioral disabilities, for example.
And even if a mother gets an ultrasound within the first 16 weeks - the best way to accurately determine the due date - the date can be off by two weeks either way.
Those two weeks can be crucial, she said.
"It's an issue of planning and control," she said. Planning is good. The Centers for Disease Control and Prevention recommends that mothers have a birth plan. But, Shepherd said, "you can take it too far if you don't pay attention to the science."
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Healthy Baby Campaign Uses Texts to Reach Mothers
Feb 4th
Expectant mothers are getting a new tool to help keep themselves and their babies healthy: pregnancy tips sent directly to their cell phones.
The so-called text4baby campaign is the first free, health education program in the U.S. to harness the reach of mobile phones, according to its sponsors, which include Johnson & Johnson, Pfizer, WellPoint and CareFirst BlueCross and Blue Shield. Wireless carriers including AT&T, Verizon and Sprint have agreed to waive all fees for receiving the texts.
Organizers say texting is an effective means of delivering wellness tips because 90 percent of people in the U.S. have cell phones.
"Especially if you start talking about low-income people, cell phones are the indispensable tool for reaching them and engaging them about their health," said Paul Meyer, president of Voxiva, a company which operates health texting programs in Africa, Latin America and India.
Studies in those countries have shown that periodic texts can reduce smoking and other unhealthy behaviors in pregnant mothers.
Meyer said the U.S. program, run by Voxiva, will be the largest health-related texting program ever undertaken.
Under the new service, mothers-to-be who text "BABY" to 511411 will receive weekly text messages, timed to their due date or their baby's birth date. The messages, which have been vetted by government and nonprofit health experts, deal with nutrition, immunization and birth defect prevention, among other topics. The messages will continue through the baby's first birthday.
Text4baby is expected to be announced Thursday morning by officials from the White House's Office of Science and Technology Policy. Government officials will be publicizing the campaign in speeches and promotional materials.
Organizers hope the effort can curb premature births, which can be caused by poor nutrition, excessive stress, smoking and drinking alcohol. About 500,000 babies are born prematurely in the U.S. each year, and 28,000 infants die before their first birthday, according to the Healthy Mothers, Healthy Babies Coalition. The nonprofit is among the sponsors of the campaign.
"The real scary thing is that we're an industrialized nation and we're not doing very well on infant mortality, and we know prematurity is a big part of that," said the group's director, Judy Meehan.
Currently the U.S. ranks 30th worldwide for infant mortality, according to Meehan, behind most Western European nations.
Researchers at the George Washington University have agreed to evaluate the effectiveness of text4baby by measuring health trends for mothers and newborns.
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Childhood asthma in premature babies linked to pregnancy bug
Feb 2nd
A common complication during pregnancy may predispose children born prematurely to asthma, a large study reports today.
The condition, chorioamnionitis, is inflammation of the fetal membranes and amniotic fluid from a bacterial infection. It is thought to be linked to more than half of all preterm births, before 37 weeks' gestation, scientists write in today's Archives of Pediatric and Adolescent Medicine.
The infection may have ascended to the uterus from the mother's genital tract or traveled through her bloodstream from a more remote site, such as her gums or upper respiratory tract, says lead author Darios Getahun, a scientist at Kaiser Permanente Southern California's Department of Research and Evaluation in Pasadena.
In animals, chorioamnionitis has been shown to cause lung and brain damage in offspring, Getahun says. Scientists also have found lung scarring in infants who died after pregnancies complicated by the condition.
Getahun and his co-authors analyzed electronic health records for all singleton children born at Kaiser's Southern California hospitals in 1991 to 2007, a total of 397,852. Of those, 28,869 were preterm.
Among children born full-term, chorioamnionitis wasn't linked to an increased risk of being diagnosed with asthma by age 8. But among those born prematurely, the condition was associated with double the risk of childhood asthma in blacks, a 70% increase in Hispanics and a 66% increase in whites. The researchers observed these differences even after accounting for other possible risk factors such as whether the mother smoked or had asthma herself. Only in Asian/Pacific Islanders preemies did chorioamnionitis not seem to make a difference in childhood asthma risk.
Getahun speculates that chorioamnionitis wasn't related to asthma risk in full-term children because their mothers might not have had it as long as those born prematurely. But, he adds, his team didn't have information about how early in their pregnancy women were diagnosed.
Diagnosing the condition is tricky, Getahun says, because symptoms — fever in the mother, tenderness or pain in the uterus, foul-smelling amniotic fluid — aren't definitive, and some women never exhibit symptoms. Getahun's team is now trying to find a marker in the mother's blood that would signify her symptoms are because of chorioamnionitis.
A study of 1,096 children published in 2008 found a higher risk of wheezing by age 2 in preemies whose mothers had had chorioamnionitis.
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Newborns of Smokers Have Abnormal Blood Pressure
Jan 25th
Babies of women who smoked during pregnancy have blood pressure problems at birth that persisted through the first year of life, a new study finds.
"What is of concern is that the problems are present at birth and get worse over time," said Gary Cohen, a senior research scientist in the department of women and child health at the Karolinska Institute in Stockholm, and lead author of a report in the Jan. 25 online edition of Hypertension.
The study led by Cohen compared 19 infants of nonsmoking couples with 17 infants born to women who smoked an average of 15 cigarettes a day during pregnancy. At one week of age, the infants of nonsmoking mothers experienced a 2 percent increase in blood pressure when tilted upright, with a 10 percent increase at one year. The pattern for the children of smoking mothers was reversed: a 10 percent blood pressure increase at one week, a 4 percent increase at one year.
And the heart rate response to tilting of the children of mothers who smoked was abnormal and exaggerated, the report said.
It's not possible to say whether the abnormalities seen in the babies will lead to trouble later in life, Cohen said. But, he noted, "the extent of the condition at one year suggests that it is not going to disappear quickly."
The reason why exposure to tobacco in the womb affects blood pressure is not clear, Cohen said. A leading possibility is that "smoking might damage the structure and function of blood vessels," he said, mainly by damaging the endothelium, the delicate layer of cells that line the interior of blood vessels.
Whether that damage will persist is not known. "We're only up to 12 months at the moment," he said. "We plan to follow them."
The damage seen in the Karolinska study is similar to that observed in babies born to mothers whose pregnancies were marked by such abuses as drug use, said Barry M. Lester, a professor of psychiatry and pediatrics at Brown Medical School, and director of the Brown Center for the Study of Children at Risk.
"Early kinds of natal insults can cause reprogramming of brain circuitry," Lester explained. He has led studies of the long-term effects of cocaine and amphetamine use during pregnancy. Many women who take such drugs also smoke, Lester added.
"When we isolated tobacco effects, we showed that there are inborn neural effects of tobacco exposure similar to what we see in cocaine and methamphetamine abuse," he said.
Some research has connected such problems to overproduction of cortisol, a "stress hormone" that plays an important role in regulation of blood pressure and the immune system, Lester said. "Cortisol overexposure is one hypothesis," he said. "There is a lot of evidence showing that too much cortisol is damaging."
It is a reasonable hypothesis, Cohen said. Babies born preterm have problems with blood pressure that have been linked to overproduction of cortisol by the adrenal glands, he noted, "and there are some parallels between tobacco smoke exposure and preterm babies of the same age."
Whatever the mechanism of damage, treatment to eliminate the problems after birth does not seem possible, Cohen added.
"What we know from studies in older kids is that even if you remove them from an environment of exposure to tobacco smoke, it is unlikely you will get full restoration of normal function," he said. "The best intervention to solve these problems is prevention. Women who are pregnant need to avoid exposure to tobacco smoke in the air. Passive smoke exposure can be as bad as being an active smoker."
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Pot smoking during pregnancy may stunt fetal growth
Jan 22nd
Women who smoke marijuana during pregnancy may impair their baby's growth and development in the womb, a new study suggests.
Poor fetal growth and reduced head circumference at birth are linked to an increased risk of problems with thinking, memory and behavior in childhood. Cigarette smoking during pregnancy is known to impair fetal growth, but studies on the potential effects of marijuana have been inconclusive.
For the new study, researchers in the Netherlands followed more than 7,000 pregnant women, 3 percent of whom acknowledged smoking marijuana at least during early pregnancy. They found that babies born to marijuana users tended to weigh less and have smaller heads than other infants.
What's more, the study found, the longer a woman had used marijuana during pregnancy, the stronger the impact on birth size - suggesting that the drug itself was to blame.
And while most marijuana users in the study also smoked cigarettes, the drug appeared to have effects over and above those of tobacco. In fact, marijuana showed stronger effects on birth size than tobacco, the investigators report in the Journal of the American Academy of Child and Adolescent Psychiatry.
The findings suggest that marijuana use, even restricted to early pregnancy, may have irreversible effects on fetal growth, write the researchers, led by Hannan El Marroun of Erasmus University Medical Center in Rotterdam.
The study included almost 7,500 pregnant women who were surveyed on their use of alcohol, tobacco and drugs, and had ultrasounds to chart fetal growth during the first, second and third trimesters.
Overall, 214 women said they had used marijuana before and during early pregnancy; 81 percent quit after learning they were pregnant, but 41 women continued to smoke marijuana throughout pregnancy.
The researchers found that, on average, marijuana users gave birth to smaller babies, particularly those who had used throughout pregnancy.
Women who had smoked only during early pregnancy had babies who were 156 grams -- about 5.5 ounces -- lighter than infants born to women who had not used the drug. Women who had continued to smoke past early pregnancy had babies who were 277 grams, or nearly 10 ounces, smaller.
Based on ultrasound, marijuana use only in early pregnancy impaired fetal growth by about 11 grams per week, while use throughout pregnancy slowed fetal growth by roughly 14 grams per week. That compared with a deficit of 4 grams per week with tobacco use, the researchers found.
Similar patterns were seen when the researchers looked at fetal head circumference.
According to El Marroun's team, mothers' marijuana use could stunt fetal growth for several reasons. Like tobacco smoking, it may deprive the fetus of oxygen. It is also possible that the byproducts of marijuana directly affect the developing nervous and hormonal systems of the fetus.
Finally, the researchers note, pregnant women who use marijuana may have other factors in their lives - such as a less-than-healthy diet or chronic stress -- that could contribute to poor fetal growth.
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Birth Weights Are Falling in U.S.
Jan 21st
Mothers are giving birth to lighter babies in the U.S., and no one is quite sure why.
This finding, published Thursday in the Journal of Obstetrics and Gynecology, has potentially troubling public-health implications, if the trend continues. Low-birth-weight babies are at higher risk for a host of health problems.
Between 1990 and 2005, the birth weight of full-term babies in the U.S. declined nearly two ounces to an average of seven pounds and 7.54 ounces, a reversal of a trend that had seen birth weights climb steadily since the 1950s, according to the study. They were also born 2.5 days earlier on average in 2005 than in 1990, the study said.
The decrease in weight—based on an analysis of nearly 37 million non-multiple births from a national database—isn't likely to affect the health of the average baby in the study, according to researchers. But the data showed a 1% increase in the number of the lowest-weight babies and suggested the birth-weight decline didn't stop in 2005.
These data suggest that it may be important for medical professionals to pay attention to the weight of babies born around 37 weeks and 38 weeks, as well as those considered pre-term, or less than 37 weeks, according to Joann Petrini, senior adviser at the March of Dimes and assistant research director at Danbury Hospital in Connecticut, who wasn't involved in the study.
Researchers also found a 2% decrease in the number of babies considered large—those over the 90th percentile of weight for gestational age—which is a positive, according to Dr. Oken. Large babies can experience more birth trauma and cause more birth injury to the mother.
The lower-birth-weight trend could not be explained by common factors like how much weight mothers gained during pregnancy, whether the delivery was induced or by cesarean section, prenatal care, or common maternal-health issues such as smoking and hypertension, researchers said.
Researchers also repeated their analysis in a sample of low-risk women—healthy, educated Caucasians in their mid-to-late 20s—and found that the decrease in birth weight was even more pronounced, suggesting that the trend isn't the result of changes in the population of mothers.
Other investigators also have begun to note the same trend. "There's no question" about the change in birth-weight pattern, said Michael Kramer, scientific director of the Institute for Human Development and Child and Youth Health at the Canadian Institutes of Health Research, who wasn't involved in the study.
"It is a new trend," he said. "We really don't know why the birth weight has decreased." A similar pattern has been observed in Canada, he said.
Some potential factors that weren't examined in this study include better control of gestational diabetes—when a mother develops diabetes during pregnancy—and more physical activity during pregnancy, said Dr. Kramer.
Babies considered too large, as well as too small, tend to have more health problems in the long run. The optimal size for a newborn is around 4,000 grams, or roughly 8.8 pounds, according to Dr. Kramer. The average baby in the study was found to be smaller than optimal. In 1990, the average birth weight was 3,441 grams, and in 2005 it fell to 3,389 grams, according to the study.
Babies born too small tend to have higher blood pressure and a greater risk of diabetes in the long run, said Dr. Oken.
From the 1950s until the 1980s, birth weights had increased as a result of increases in mothers' weight and how many pounds they gained during the pregnancy, as well as reduced smoking and older maternal age, according to Dr. Kramer.
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