Facts You Need to Know About Preterm Labor
From Bed Rest to Muscle Relaxants, What Works to Stop Early Delivery
Dec 15, 2008
For some mothers, getting labor started at 42 weeks of pregnancy is their biggest challenge. Others have the opposite struggle of trying to prevent their babies from being born too early. While complications can occur with babies who arrive two weeks or more late, the risks from preterm birth are often more serious and can have long-term consequences for the baby's health.
What do we know about preterm labor? Are there risk factors that will make it more likely for you to have preterm labor? What options for treatment are available? Are those treatments effective?
Preterm Labor Statistics
In the US today, about 12.5% of babies, or a half a million will be born prior to 37 weeks of gestation. In the last 25 years, the rate of preterm birth has increased by more than 30%. About 70% of preterm babies are born between 34 and 36 weeks of pregnancy. Babies who are born prior to 32 weeks have the biggest risk of serious complications since their organs are still immature.
Causes of Preterm Labor
25% of preterm births are due to an induction of labor or a recommended cesarean because of health problems with mother or baby. It is crucial that mothers in this category exhaust every possible option and confirm the medical necessity of giving birth at this stage of pregnancy before agreeing to an induction or cesarean prior to 37 weeks.
The remaining 75% of preterm births occur spontaneously and often without much warning. Some evidence shows that other causes of preterm labor may be related to infection, carrying multiples, or physical problems such as fibroids or a weak cervix .
Preterm Labor Risk Factors
Mothers who have very stressful work environments or are on their feet for long periods of time are more at risk for preterm labor. In addition, smoking, alcohol, physical or emotional abuse as well as a lack of social support have all been associated as risk factors of preterm birth. If you have already had one baby arrive before 37 weeks, it is also more likely to have another preterm birth.
Detecting Preterm Labor with Fetal Fibronectin
Some evidence shows that the presence of fetal fibronectin (fFN) between 22 and 34 weeks in the mother's vaginal discharge may be a possible indicator of preterm labor. In cases where the mother may be experiencing symptoms such as regular contractions, the care provider may advise the fFN to outrule the possibility of preterm labor.
Options for Treatment of Preterm Labor
One of the most common treatments has been for the mother to restrict her activity, also called "bed rest." Bed rest can involve reducing the mother's hours at work all the way to restricting her activity to bathroom trips only. The idea is that if the mother rests, her uterus will respond by slowing down contractions and thus slowing the progress of labor. Some mothers can be on bed rest for only a short time during pregnancy and others may have months of bed rest in order to prevent preterm labor. Unfortunately there are no studies that show conclusively that bed rest is an effective treatment to slow or stop preterm labor.
Another method of treatment to prevent preterm labor is hydration. One study showed that when mothers with symptoms of preterm labor received IV fluids, 75% of them whose cervix was dilated less then 5 centimeters upon admission responded positively to the hydration.
The use of muscle relaxants as a treatment for preterm labor is common. New research on certain muscle relaxants (nifedipine), also known as tocolytics, indicates that they may be no more effective than a placebo drug in preventing preterm labor. Even those muscle relaxants that have shown to prolong pregnancy by about a week have some serious downsides. One sytemic review published in the Green Journal in 1999 examined 18 studies for benefits versus risks of tocolytics for preterm labor. The reviewers discovered that "tocolytics were not associated with improved perinatal outcomes. Maternal side effects significantly associated with tocolytic use were palpitations, nausea, tremor, chorioamnionitis, hyperglycemia, hypokalemia,and need to discontinue treatment."
Prevention of Preterm Labor
The truth is that none of the treatments for preterm labor are universally effective and some, such as tocolytics, come with a heavy price tag to the mother. The best recommendation for prevention of preterm labor is to do what you can to reduce stress and reduce the length of time you are on your feet at work. There is also some limited evidence about fish oil supplements as well as monitoring the vaginal pH levels to prevent infection. It is also helpful if mothers avoid substances such as alcohol and exposure to cigarette smoke to decrease harmful effects to their babies. Eating a healthy pregnancy diet and getting good prenatal care that involves being monitored for any complications such as gestational diabetes and high blood pressure are effective ways to avoid preterm labor.
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