Trusted Information for Healthy Pregnancies
preterm
Ultrasound Reveals Breastfeeding Mechanics
May 12th
Although it might look like a baby is chewing on the mother's nipple, ultrasound images show that the infant actually removes milk by creating a vacuum - also known as sucking.
The finding is important, as it could explain why some babies fail to take to the breast. It may also shed new light on why - for a minority of women - breastfeeding really can be a painful experience.
"There have been two theories about how breast milk is expressed," says Donna Geddes of the University of Western Australia in Crawley.
"One is that the baby uses a peristaltic or compression motion to actually push the milk out of the nipple and breast. The other theory is that vacuum is primary in removing the milk."
Until now, most studies examining the mechanics of breastfeeding have focused on bottle-feeding infants, or on old X-rays that were of poor quality.
Instead, Geddes and her colleagues combined ultrasound imaging of infants suckling on the breast with measurements of the strength of the vacuum created by the baby's mouth in 20 infants aged 3 to 24 weeks as they breastfed.
"What we see is that when the tongue is lowered and the vacuum is applied, that's when the milk is coming out of the breast, and that doesn't involve any compression of the nipple," says Geddes. "It's not a milking action at all."
They also found that infants who struggled to breastfeed generated much weaker vacuums than successful breastfeeders. This may explain why babies with a cleft palate often fail to breastfeed, as do premature babies: preterm infants don't have strong enough mouth muscles to suck hard enough.
The next step is to devise a simple and universal test that could be used to assess babies' ability to suck. This could reassure mothers whose infants are struggling to feed that it's not their fault. "Currently there are no measurements to assure the mother or the clinician that things [in the breast] are working," says Geddes.
For such women, keeping the milk flowing using a breast pump and using this to top up breastfeeding until the baby is strong enough to suck effectively may be a better option than giving up on breastfeeding altogether.
The team also looked at women who found breastfeeding painful and discovered that their infants had a particularly vigorous action.
"They're strong suckers," says Geddes. Some were also distorting or crushing the nipple. Further study of these infants may aid the development of better nipple shields to reduce pain during breastfeeding.
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High-dose vitamin D safe during pregnancy
May 3rd
Taking high doses of vitamin D during pregnancy is safe and appears to reduce the risk of preterm birth and infections, say the authors of a study that compared different amounts of supplementation in expectant mothers.
But their recommendation that pregnant women should take 4,000 international units of vitamin D daily -- at least 10 times the standard recommended amount -- is sure to generate controversy.
"When we first proposed the study in 2002, it was heresy to even think about giving more than 400 international units a day of vitamin D," co-principal investigator Dr. Carol Wagner said from Vancouver, where the two-part study is being presented at an international pediatrics meeting.
"Diet doesn't provide enough vitamin D, and we don't go in the sun as much as we need (to)," said Wagner, adding that her research team set out to determine the optimal dose of vitamin D supplements for pregnant women that would promote health without doing harm.
The researchers enrolled 494 pregnant women at 12 to 16 weeks' gestation in the study and assigned them to three groups: one group received 400 IUs of vitamin D a day until delivery; the second got 2,000 IUs; and the third 4,000 IUs. The women were tested monthly to ensure they were not suffering any negative effects.
Neither the women nor the researchers knew what dose of vitamin D they were receiving in the study, a "blinded," randomized controlled trial whose methodology is considered the gold standard of medical science.
"What we found was that 2,000 was better than 400, and 4,000 was the best, without any adverse events that were associated with vitamin D," said Wagner. "And then ... we found fewer infections in the 4,000 group and fewer preterm labors and-or preterm birth deliveries in the 4,000 group compared to the 400 group."
Analysis of the data also showed that the women taking 4,000 units of vitamin D had half the rate of pregnancy-related disorders, such as gestational diabetes and preeclampsia, compared to expectant mothers taking 400 units.
However, Wagner conceded that the notion of pregnant women taking a daily dose of 4,000 IUs of vitamin D will likely stir some debate, especially within the medical community. The current recommended daily dose is 200 to 400 IUs daily.
Dr. Gideon Koren, head of the Motherisk Program at Toronto's Hospital for Sick Children, said the study is too small to provide such a definitive recommendation and to "declare therapeutic superiority" of 4,000 units of vitamin D.
"I think for now women should be sure that they get the recommended dose. I don't know that this study by itself should send women to buy 4,000. No, no way. I don't think this is sufficient."
"The study's important to show that it doesn't cause side-effects, but I think to tell women that they need 4,000 - to go from 400 to 4,000 - is huge."
However, Dr. Reinhold Vieth, head of the Bone and Mineral Laboratory at Mount Sinai Hospital in Toronto, has long argued that recommended daily amounts (RDAs) for vitamin D are outdated and woefully inadequate.
Vieth, who has conducted numerous studies on vitamin D in different patient populations, said the Canadian Pediatric Society has been advocating 2,000 units during pregnancy since 2007.
"The next step, 4,000, well, I bet you they'll come up with that in a couple of years, because this (the Wagner-group study) has to get published first," he said, adding that he agrees that pregnant women should be taking that level of vitamin D daily.
Dr. Robert Gagnon, a spokesman for the Society of Obstetricians and Gynecologists of Canada (SOGC), said the study was well-designed and its findings are important.
The Montreal specialist said SOGC is in the process of reviewing the medical literature before deciding on its official recommendation for expectant mothers.
"We need to see all the details of the study before we come to the recommendation," he said. "To say (pregnant women) should take 4,000, I think it's a little premature for that."
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Excess weight raises pregnancy risks: study
Feb 12th
Being overweight or obese increases a woman's chances of having an extra-big baby, even after the effects of pregnancy-related, or "gestational," diabetes are taken into account, new research shows.
Excess weight in and of itself also sharply increased a woman's risk of pre-eclampsia, a potentially deadly pregnancy complication, Dr. Boyd E. Metzger of Northwestern University Feinberg School of Medicine in Chicago and his colleagues found.
Women have more difficulty delivering very large babies, while these newborns are also at risk of suffering injury during birth, including shoulder dislocation. While women who are overweight or obese are known to run a greater risk of having very large babies and experiencing other pregnancy complications, it has been difficult to separate out the effects of a mother's weight from those of gestational diabetes, Metzger and his colleagues note in the British Journal of Obstetrics and Gynecology.
This led them to investigate whether body mass index (BMI) -- a standard measure of weight in relation to height used to gauge how fat or thin a person is -- might influence pregnancy risks and fetal and newborn health, independently of a woman's blood sugar levels.
The study involved 23,316 women from 15 different medical centers in nine different countries. All had undergone an oral glucose tolerance test, which is used to identify women with, or at risk for, pregnancy-related diabetes; at that time, their height and weight were measured, too.
The researchers then used statistical techniques to control for women's oral glucose tolerance test results. Even after this adjustment, they found that the women with BMIs of 42 or greater, denoting severe obesity (for example, a 5-foot-5-inch tall woman weighing at least 250 pounds), were at more than triple the risk of having an excessively large baby, compared to the thinnest women in the study, who had BMIs of 22.6 or less (a 5'5" woman weighing less than 138 pounds).
The heaviest women's risks of having a C-section were more than doubled, while their likelihood of pre-eclampsia was 14-fold greater than for the leanest women. However, the heaviest women's risk for delivering a preterm baby was actually cut in half.
These findings help sort out the role BMI and gestational diabetes each play in the risk of complications of pregnancy and delivery, Metzger told Reuters Health in an interview.
He noted that recent studies have shown that dietary changes can effectively treat gestational diabetes for more than 90 percent of women with the condition.
"We're pretty confident that treating gestational diabetes going forward is going to continue to be beneficial," the researcher said. "We have much less evidence at this point as to how to neutralize or reduce the impact of overweight on pregnancy outcome."
What is becoming clear, he added, is that it's probably a woman's weight before she gets pregnant, rather than how much she gains during pregnancy, that's important in determining risk.
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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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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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Omega-3 Supplements Don’t Reduce Risk of Preterm Birth
Jan 28th
Omega-3 fatty acid supplements are believed to have many health benefits, but the one thing they can't do is help women with a history of delivering their babies early carry their next child to full term, new research finds.
"The omega-3 did not add any benefit," said study author Dr. Margaret Harper, an associate professor of obstetrics and gynecology at Wake Forest University School of Medicine, Winston-Salem, NC. The study appears in the February issue of Obstetrics & Gynecology.
Harper and her colleagues randomly assigned 852 pregnant women with a history of a preterm birth either to get a daily omega-3 supplement or a placebo beginning about week 16 to 22 and continuing through week 36 of gestation.
All women also received weekly intramuscular hormone injections of hydroxyprogesterone caproate, which has been shown to improve the chances of carrying a baby to term, Harper said.
Her team followed up to see which women delivered before 37 weeks. Full-term is defined as 37 weeks of completed gestation.
Delivery before 37 weeks occurred in 37.8 percent of those taking omega-3, and 41.6 percent of those in the placebo group, a small difference.
Prematurity is the leading cause of newborn death, the authors write in the report, and it is increasing in the United States. A woman who delivers one baby before term is more likely to deliver future babies early.
Harper's team decided to study the value of the omega-3 supplements after conflicting findings about the value of the supplements for women at high risk of premature delivery. For those at low-risk, she said, the findings seem to agree that omega-3 supplements don't further reduce the risk of preterm birth.
A recent large review of published studies found only one that showed benefit of the supplements in high-risk women, she said.
According to Harper, omega-3 fatty acids, when metabolized, are converted to much less potent biochemicals called prostaglandins, which make the uterus contract, than are omega-6 fatty acids -- also essential fatty acids but typically over-eaten in Western diets. Adding omega-3s to an omega-6-heavy diet, so the thinking went, might result in better chances of carrying the baby to term.
Omega-3 supplements, in other research, have been found to help heart health, to lower blood pressure and to reduce the risk of abnormal heartbeats.
But in Harper's study, she also noted that women getting omega-3 supplements were more likely to give birth to a baby with respiratory distress syndrome (RDS). While 59 babies (13.9 percent) of those in the omega-3 group had RDS, only 35 (8.7 percent) of those in the placebo group did. In other words, the omega-3 mothers' babies were 1.6 times more likely to get RDS than infants born to mothers taking placebo. It's the first time such a finding has been reported in clinical trials, the authors wrote.
"While the study's results showed no difference, there is early evidence that omega-3 fatty acids are beneficial for fetal brain development, so women should still consider taking them, in conjunction with their doctor's advice, despite what seems to be little benefit for the reduction of spontaneous preterm birth."
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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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Mothers with Celiac Disease Face a Higher Risk of Underweight and Early-term Births
Jan 25th
Women with celiac disease face greater risks for adverse pregnancy outcomes. A team of researchers recently set out to examine the effects of treated and untreated maternal celiac disease on infant birthweight and preterm birth. Among their findings are that expectant mothers with celiac disease face a higher risk of underweight and early-term birth than those without celiac disease.
For their data, researchers used a population-based cohort study of all live births in Denmark between 1 January 1979 and 31 December 2004. During that period, 836,241 mothers gave birth to a total of 1,504,342 babies. Mothers with diagnosed celiac disease gave birth to 1105 of those babies, while 346 were born to women with undiagnosed celiac disease.
The team considered mothers with diagnosed celiac disease to be following a gluten free diet, and those with undiagnosed celiac disease to be on a gluten-inclusive diet. The team measured outcomes based on birthweight, small for gestational age, very small for gestational age and preterm birth. They then compared the results for the treated and untreated celiac disease mothers with those of a celiac-free reference group.
The research team found that mothers with untreated celiac disease gave birth to smaller babies [difference = –98 g (95% CI: –130, –67)], with a higher risk of SGA [OR = 1.31 (95% CI: 1.06, 1.63)], VSGA [OR = 1.54 (95% CI: 1.17, 2.03)] and early birth [OR = 1.33 (95% CI: 1.02, 1.72)] compared with women with no celiac disease.
The good news is that mothers with treated celiac disease showed no increased risk of reduced mean birthweight, or of delivering SGA and VSGA infants or preterm birth compared with mothers with no celiac disease.
From the results, the research team concluded that untreated maternal celiac disease increases the risk of low birthweight, SGA and VSGA, and preterm birth.
Diagnosis and treatment of maternal celiac disease with a gluten-free diet seems to return the birthweight and preterm birth rate to one comparable to women without celiac disease.
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Stress, Anxiety Can Up Risk of Depression in Pregnancy
Jan 22nd
Stress, history of depression, lack of social support and unintended pregnancy are among the major factors that contribute to increased risk of depression in pregnant women, a new study shows.
Other important factors are maternal anxiety, domestic violence and having public insurance coverage, said the University of Michigan researchers, who reviewed 159 studies conducted between 1980 and 2008.
The study appears in the January issue of the American Journal of Obstetrics & Gynecology.
Depression, which occurs in about 12.7 percent of pregnant women, can cause problems for mothers and babies, including pre-term delivery, preeclampsia, sleep disturbances and disrupted mother-infant bonding.
It's important for physicians to know how to identify depression in pregnant women, said the study authors, who noted that not all women who test positive on depression screening tests have or will develop clinical depression.
"We are hoping that [health-care] providers can use the presence or absence of risk factors such as those identified in our study to enhance their assessments for depression in addition to the information they obtain from the screening test," study author Dr. Christie A. Lancaster, a clinical lecturer in the obstetrics and gynecology department at U-M, said in a news release.
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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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