Trusted Information for Healthy Pregnancies
39 weeks
Very premature twins do just as well as singletons
Feb 18th
Overall, very premature twins fare just as well as single babies born very early, and they may even face a lower risk of certain complications, new research shows.
But for twin pairs of the same sex but sharply different sizes who are born before 28 weeks, the risks of death and bleeding on the brain are higher than they are for single babies born at the same time, Dr. Jennifer Zeitlin of the Hopital Saint-Vincent de Paul in Paris and her colleagues found.
Premature birth is much more common among twins than singletons, Zeitlin and her team note; while one in every 10 twin pairs is born before 32 weeks' gestation, just one in 100 singletons is born this early. There is evidence that preemie twins do better than singles of the same gestational age, they add.
A full-term pregnancy lasts for 39 weeks, while babies born between 28 and 31 weeks are considered "very preterm." Babies born between 24 and 27 weeks' gestation are "extremely preterm."
To investigate outcomes for very premature and extremely premature twins compared to those of singletons born equally early, Zeitlin and her colleagues looked at births and stillbirths in nine European countries in 2003. Their analysis included 1,254 twins and 3,586 singletons born between 24 and 31 weeks' gestation.
The women carrying twins were less likely to develop high blood pressure during pregnancy than those with singletons, the researchers found: about 8 percent of those carrying twins, compared to about 22 percent of those carrying single babies.
They also found that severe bleeding and restrictions on the growth of the fetus were also less common in twin pregnancies.
Twins' mothers were also more likely to have been given corticosteroids before delivery; these drugs are administered to speed up premature newborns' lung development.
Among the very premature babies, the likelihood of dying in the first few weeks of life was lower for twins, who were also less likely to need oxygen. But once the researchers took factors such as mother's age, pregnancy complications, and infant health problems into account, the difference disappeared.
For the extremely premature infants, however, the researchers calculated that the risk of death or serious bleeding in the brain was about 1.5 times higher for twins than it was for single babies. While about 17 percent of singletons suffered from such bleeding, roughly 24 percent of twins did.
The greater risks were only seen for same-sex twins in which one twin weighed at least 15 percent more than the other twin at birth.
"Why the effects of these twin-specific complications were so much more pronounced for extremely preterm births is an area for further study," the researchers conclude.
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Inducing labor may lead to more C-sections
Jan 7th
Dr. J. Christopher Glantz at the University of Rochester School of Medicine found that inducing labor introduces a risk of 1 to 2 cesareans per 25 inductions that might have been avoided by waiting for spontaneous labor to begin.
While this risk to individual women is not particularly large, Glantz told Reuters Health that 1 to 2 cesareans per 25 inductions can quickly add up to tens of thousands of unnecessary cesareans over the course of millions of inductions.
While the procedures have become more common, C-sections are major surgeries, and carry risk of infection, bleeding, blood clots, and injury to other organs, Glantz emphasizes in a report in the journal Obstetrics and Gynecology.
The researcher analyzed birth certificate data for some 38,000 women from 13 hospitals in the Finger Lakes region of New York State from January 2004 to March 2008. He excluded women with scheduled or previous cesarean deliveries, or who had come to the hospital with ruptured membranes.
While previous studies have already shown that induced labor increases the risk for cesarean, Glantz examined how that risk might shift given a redefined comparison group.
He examined C-section rates after induction using three comparison groups: a week-by-week comparison of women induced to labor compared with those delivering spontaneously; women induced at a chosen week compared with women who delivered spontaneously after that week; and women induced at a chosen week compared with women who delivered spontaneously on or after that week.
In a nutshell, the study found that all labor induced groups faced increased risk for C-section, except for those women delivering after 39 weeks.
Glantz advises that pregnant women and their doctors may be better off waiting for spontaneous labor. "Try to reserve interventions for situations where risk outweighs benefit," said Glantz, such as in cases of diabetes, high blood pressure, problems with the placenta, a baby that is not growing well, or a woman being 10 days past her due date.
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Hormone testing may help doctors predict abnormal childbirth
Dec 31st
Testing for low levels of a thyroid hormone shortly before childbirth may help physicians identify women who will require special care during delivery, new research indicates.
Specifically, a study published in the December 23 issue of Clinical Endocrinology, sought to examine whether thyroid hormone levels in the late stages of pregnancy are associated with the head position of a fetus shortly before childbirth, Health Day News reports.
The team of researchers examined the thyroid levels of 960 expectant Dutch mothers and found that those with higher levels of the hormone T4 about 9 months into pregnancy were more likely deliver a baby in the normal delivery position - head first with the fetus facing the mother's back at the start of labor.
Women with lower levels of the hormone more commonly needed assisted delivery because of an abnormal fetal head position, according to the news source.
"We believe that the relationship between thyroid hormone levels and fetal presentation at birth may be explained by recent findings that motor development in children is related to low maternal thyroid hormone concentration during pregnancy," Victor Pop, professor at the University of Tilburg in the Netherlands, told HealthDay News.
According to the Coalition for Improving Maternity Services, almost 32 percent of U.S. births in 2007 took place via cesarean section - a 50 percent increase since 1996.
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Pregnant women develop emotion-reading superpowers
Dec 14th
Raging hormones during pregnancy prompt mood swings, but may also lead to a heightened ability to recognize threatening or aggressive faces. This may have evolved because it makes future mothers hyper-vigilant, yet it could also make them more vulnerable to anxiety.
Previous studies have suggested that a woman's ability to correctly identify fearful or disgusted facial expressions varies according to her stage of the menstrual cycle, with perception heightened on days associated with high levels of the hormone progesterone. Since levels of progesterone and other hormones rise dramatically in late pregnancy, Rebecca Pearson and her colleagues at the University of Bristol in the UK investigated whether the ability to read faces varies during pregnancy.
They asked 76 pregnant women to assign one of six emotions to 60 computer-generated faces before the 14th week of pregnancy, and again after the 34th week. Faces expressing happiness and surprise tended to be correctly assigned at both stages of pregnancy, but for faces expressing fear, anger and disgust, the accuracy rates were higher in late pregnancy.
This may increase the chance that the woman will spot potential threats to her and her fetus, and prime her to be hyper-vigilant once she becomes a mother. But it could have a downside. Pearson points out that people with clinical anxiety are also better at identifying negative emotions in faces. Pregnant women aren't clinically anxious, but "they might interpret negative or emotional things around them in a slightly more sensitive way", she says.
The finding builds on a recent study by Ben Jones of the University of Aberdeen in the UK who found that pregnant women - and women in stages of the menstrual cycle where progesterone levels spike - are better at identifying faces showing signs of sickness. "It's preventing them from becoming sick by interacting with people who are ill," he says.
The next step will be to examine whether pregnant women and new mothers are also more sensitive to emotional cues in babies' faces, Jones says.
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