Premature Labor

You’ve circled your due date on the calendar and you're mentally counting down the weeks until the big day. Then something totally unexpected happens. Weeks before your due date you wake up in the middle of the night with contractions. You may be having premature labor.

Because no one yet understands the mechanism by which normal labor starts, we are often at a loss to explain why some women begin their labor before their due date. Labor is defined as regular uterine contractions that produce a change in the dilatation of the cervix. Premature labor is defined as labor that begins before 37 weeks of gestation.

Premature labor is often associated with other conditions. The most common, and easily treatable, is a urinary tract infection. Because the bladder is next to the uterus, an infection of the bladder can cause irritation of the uterus, leading to uterine contractions. Maternal dehydration is another, easily treatable cause of premature labor. Finally, the use of drugs, especially cocaine, may trigger premature labor.

What should you do if you think you might be starting labor prematurely? If you are experiencing repeated uterine contractions before 37 weeks of gestation, or if you are having menstrual-like cramping or constant low backache, you should contact your practitioner right away. To determine whether these are true premature contractions or just Braxton-Hicks contractions (the normal, painless contractions that occur in late pregnancy), she or he will ask you various questions-how often the contractions occur, how long they last, and how painful they are. In most cases, you will be asked to come to the office or the hospital for a complete evaluation.

The only way to accurately diagnose premature labor is by examining your cervix for any changes. Before the last month of pregnancy, the cervix is usually closed (although it may be slightly open in women who have previously given birth). The fetal monitor will be used both to check the fetal heart rate and to detect uterine contractions.

If there are any signs of premature labor, your physician will probably take several additional steps. Your urine will be checked for any sign of infection. You will be given fluid intravenously to counteract the effects of possible dehydration. Bed rest is a cornerstone of the treatment of premature labor. It is also easier to monitor the fetus and contractions while the expectant mother is in a bed. Amazingly enough, something as simple as this can be quite helpful. In most cases, no further evaluation or treatment is required. Most episodes of premature contractions (without any change in the cervix) will stop by themselves.

Occasionally, some women do experience true premature labor, which causes the cervix to open and puts the fetus at risk for premature delivery. If this occurs before 36 weeks of gestation, your practitioner will recommend treatment to prevent premature delivery. There are several different medications used for this purpose. The most common are ritodrine and terbutaline. They are initially given by injection, but if they succeed in stopping the contractions, they can be taken orally.

If there appears to be a risk of the baby being delivered within a few days of the initial treatment, most obstetricians will also recommend the steroid betamethasone. The biggest hurdle facing premature newborns is whether their lungs are sufficiently mature to breathe on their own. Betamethasone speeds up the process of lung maturation, giving babies born early every possible advantage; however, it takes approximately 48 hours to act, so if it appears that delivery is imminent, betamethasone will not help.

Most cases of premature labor respond readily to treatment. Even if pregnancy can be prolonged only one additional week, it's often enough to give a premature newborn a big advantage. Special care nurseries can often support even the tiniest newborns (26 weeks gestation and sometimes younger) until they can breathe on their own.