March 2nd, 2010 
Women whose water has broken early may want to wait at least 18 months before having their next child, new research shows.
Known by doctors as preterm premature rupture of membranes, this complication, in which a woman’s water breaks before her pregnancy has reached full term and before labor has begun, occurs in up to 5 percent of pregnancies, Dr. Darios Getahun of Kaiser Permanente Southern California Medical Group in Pasadena and colleagues note in their report.
The complication accounts for one in every four premature births, they report in the American Journal of Obstetrics & Gynecology, and puts mother and fetus at risk of infection.
While the reasons why some women’s water breaks early are “elusive,” Getahun and his team say, there are likely many factors involved. Women who have had the complication previously, they add, are known to be at greater risk in subsequent pregnancies. And the risk is also known to be higher for black women compared to whites.
To investigate whether the length of time between pregnancies might also influence this risk, the researchers reviewed data from the state of Missouri on nearly 200,000 women who had two or three children between 1989 and 1997. Around 3 percent of black women and 1 percent of white women’s water broke early during their first or second pregnancies.
Among white women whose water broke early, 6 percent had the complication in their subsequent pregnancy, compared to 2 percent of women who hadn’t suffered premature membrane rupture.
The rates for black women were 10 percent and 4 percent, respectively. This translated to a nearly nine-fold increased risk of subsequent early water breaking for white women, and a seven-fold greater risk for black women.
The risk was even further increased if a woman got pregnant again within 18 months, and was particularly high for African-American women. For example, a black woman who got pregnant again within three to six months would be nearly nine times more likely to have the complication than a woman who waited at least 18 months.
The risk of early water breaking for white women who got pregnant again this soon was tripled.
This suggests, the researchers say, that the complication may be related to inflammation, and that a longer interval between pregnancies is needed to allow for full recovery. “We think that it might be a chronic inflammation that may persist from one pregnancy to another pregnancy,” Getahun told Reuters Health.
Women whose water has broken early should be watched closely in subsequent pregnancies, he added, so that if infection does develop they can receive prompt antibiotic treatment, which could help prevent the complication from recurring.
Related
- Childhood asthma in premature babies linked to pregnancy bug
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.
- Nicotine Patches and Gum Seem Safe During Pregnancy
Nicotine patches and gum seem to be safe and effective in pregnant women, according to a new study.
Such patches and gum have been shown to help non-pregnant adults stop smoking, study co-author Dr. Geeta K. Swamy told Reuters Health. However, women and their obstetricians have been uncertain about their safety and effectiveness during pregnancy.
Dr. Swamy, from Duke University Medical Center in Durham, North Carolina, and colleagues took another look at data on pregnant smokers who had participated in a study comparing psychological treatments with nicotine patches or gum to help them quit.
Adding nicotine patches or gum tripled the number of women who quit, from 8 percent to 24 percent.
Almost a third – 31 percent — of the women who used the patch or gum had pregnancy complications, compared to 17 percent of the women who did not use it.
However, there was a much higher risk of such complications in black women, those with complications in previous pregnancies, and use of painkillers. The use of the patch did not seem to have a direct effect, the researchers note.
Based on the findings, although the patch is not “absolutely safe,” it may still be worth using in heavy smokers, given the known association between smoking and bad pregnancy outcomes, particularly premature birth and low birth weight, they conclude.
- High blood pressure in pregnancy a heart risk
Women who had an increase in blood pressure during pregnancy are likely to develop heart disease at an earlier age than women who maintained normal blood pressure while they were pregnant, Chilean researchers report.
Dr. Gloria Valdes of Pontificia Universidad Catolica, Santiago and colleagues studied 217 women with an average age of about 61 years, who underwent a coronary artery examination about 30 years after their last pregnancy.
As reported in the medical journal Hypertension, 146 women had had normal blood pressure during their pregnancies while 71 women had hypertension during at least one pregnancy.
About half of all the participants were found to have significant coronary artery disease. Valdes told Reuters Health that women with hypertensive pregnancies developed significant narrowing in their coronary arteries about three years sooner than women with normal blood pressure during pregnancy.
Furthermore, during 10 years of follow-up, there was a significantly greater increase in the number of clogged arteries in the hypertensive group (28 percent) than in the normal blood pressure group (22 percent).
“Gestational hypertension represents a positive stress test for future cardiovascular risk, which should prompt early management of cardiovascular risks,” Valdes commented.
She added, “Obstetricians need to identify women with a family history of premature cardiovascular disease, as this doubles the risk of a hypertensive pregnancy.”
- High blood pressure in pregnancy a heart risk
Women who had an increase in blood pressure during pregnancy are likely to develop heart disease at an earlier age than women who maintained normal blood pressure while they were pregnant, Chilean researchers report.
Dr. Gloria Valdes of Pontificia Universidad Catolica, Santiago and colleagues studied 217 women with an average age of about 61 years, who underwent a coronary artery examination about 30 years after their last pregnancy.
As reported in the medical journal Hypertension, 146 women had had normal blood pressure during their pregnancies while 71 women had hypertension during at least one pregnancy.
About half of all the participants were found to have significant coronary artery disease. Valdes told Reuters Health that women with hypertensive pregnancies developed significant narrowing in their coronary arteries about three years sooner than women with normal blood pressure during pregnancy.
Furthermore, during 10 years of follow-up, there was a significantly greater increase in the number of clogged arteries in the hypertensive group (28 percent) than in the normal blood pressure group (22 percent).
“Gestational hypertension represents a positive stress test for future cardiovascular risk, which should prompt early management of cardiovascular risks,” Valdes commented.
She added, “Obstetricians need to identify women with a family history of premature cardiovascular disease, as this doubles the risk of a hypertensive pregnancy.”
- Too little weight gain risky in twin pregnancy
Women pregnant with twins should be sure to gain the recommended amount of weight, according to a new study, which shows that gaining less weight than recommended during a twin pregnancy ups the risk of early birth and low weight babies.
“A woman should gain about a pound a week; less than that, and we had smaller babies and more pre-term births,” Dr. Nathan Fox of Maternal-Fetal Medicine Associates of New York City told Reuters Health.
Fox and his partners wanted to know if the twin pregnancy weight gain guidelines updated by the Institute of Medicine in 2009 made a difference in pregnancy outcomes.
These recommendations suggest a range of weight gain depending on a woman’s weight at the start of her twin pregnancy. A normal weight woman should gain 37 to 54 pounds; an overweight woman, 31 to 50 pounds; and an obese woman, 25 to 42 pounds.
In looking at 281 mostly normal weight women pregnant with twins, Fox and colleagues found that women who gained the recommended amount of weight did much better in regards to the pregnancy outcomes.
Women who gained less than the recommended amount of weight were more likely to give birth early (before 32 weeks of pregnancy) than women who gained the correct amount of weight (14 percent versus 5 percent). They were also more likely to give birth to smaller babies.
Unlike in singleton pregnancies, gaining enough weight in twin pregnancies can be Herculean task. “It’s often not easy,” Fox said. “We send our patients to nutritionists and have them on high calorie diets a lot to have them gain the right amount of weight. It’s not easy for many (women).”
About 3 in every 100 pregnancies is a twin pregnancy, the investigators note, and preterm births occur about 60 percent of the time, making the issue of correct weight gain even more important.
The strong link between inadequate weight gain in twin pregnancies and increased rates of pre-term birth “has not been conclusively demonstrated previously,” the investigators point out in the journal Obstetrics & Gynecology.
Their findings, they say, shed light on the importance on what “could be a correctable cause of prematurity in twins,” they conclude.
