In many areas, preterm labor is on the rise. While the exact reason for regional or seasonal outbreaks of preterm labor is unknown, Perinatal Specialists (defined as doulas, childbirth educators, etc) should be aware of the signs, symptoms and impact of preterm labor.
What Is Preterm Labor?
Preterm labor is defined as regular uterine contractions with progressive cervical changes or regular uterine contractions with a cervix that is 2 cm dilated and 80% effaced at less than 37 weeks gestation. Preterm births account for more than 60% of non-anomalous related (no anomalies) related neonatal mortality and morbidity. Most neonatal mortality occurs in those preterm deliveries that occur between 20 and 30 weeks of gestation or in infants weighing less than 1500 grams. Survival of neonates delivered at tertiary care centers has improved yearly, particularly for those pregnancies ending at 25 - 32 weeks of gestation. Significant increases in survival rates occur at 25-26 weeks (20% at 24 weeks to 50% at 26 weeks). Long term impairment has remained high for those survivors delivered at 25 weeks gestation or earlier. About 10% of women will have a preterm labor. (Note: Preterm labor may be used interchangeably with premature labor.)
Signs & Symptoms of Preterm Labor
The Perinatal Specialist should be aware of the warning signs of preterm labor: regular uterine contractions (with or without pain) that last for more than 1 hour; leaking of watery discharge (amniotic liquid), sudden increase in vaginal discharge or mucous; markedly increased pelvic or vaginal pressure; rhythmic, low-back pain, backache or back pain - the discomfort may be manifest as dull pain, sharp pain, or pressure; intestinal cramping, with or without diarrhea; pain or a heaviness in the low abdomen or thighs; spotting or blood tinged discharge (the mucus plug being lost) or leakage of fluid (premature rupture of membranes); clinical progression signs include thinning of the cervix (effacement greater than 50%), dilation of the cervix beyond 1 cm, presence of contractions as determined by palpation or monitor, and, in some cases, evidence of ruptured membranes.
Education is a key factor in the prevention of preterm labor. Perinatal Specialists will want to share with their preterm - prone clients the following:
- Frequent and communicative interaction with the physician is important to understanding and preventing/delaying preterm labor.
- Drink at least three glasses of water to counteract dehydration that stimulates uterine contractions. The recommended daily intake of fluids (water and juice) is 64 fl oz or one half gallon.
- Empty the bladder often as a full bladder may stimulate uterine contractions.
- Lie down, preferably on the left side, to promote uterine blood flow.
- Notify physician of more than four contractions in one hour.
Medical Management of Preterm Labor
Before deciding to stop preterm labor, care providers assess the condition of the mother and baby to determine if continuing the pregnancy is appropriate: if the baby would have a better chance outside or inside the uterine environment. According the Reeder/Martin/Koniak-Griffith, only 25% of all preterm labor clients are candidates for interventions and treatment due to PROM (premature rupture of membranes), serious maternal or fetal distress (such as abruption, HELLP syndrome or congenital anomalies), or advanced cervical dilatation (>6cm).
Fetal lung maturity occurs from 36 to 38 weeks so babies born during this time with weights >2500 g generally do not need pulmonary support at the time of birth. Indications for tocolytic(or drugs used to inhibit uterine contractions primarily in an effort to suppress preterm labor) therapies hinge on the diagnosis of preterm labor, gestational age greater than 20 weeks but less than 36 weeks, estimated fetal weight less than 2500 g, and immature fetal lung profile indicating inadequate alveolar surfactants (LS or lecithin-sphingomyelin ratio less than 2:1; PG or phosphatidylglycerol absent).
The management of preterm labor involves treatment of the underlying cause (when possible), evaluation of maternal health, evaluation of fetal well being, and discrimination between labor which may be stopped with treatment and labor in which birth is imminent.
One component involved in the management of preterm labor is treatment of an underlying cause. Antibiotics will be used to treat infections and fluids will be given to counteract dehydration. If labor occurs before 20 weeks because of an incompetent cervix, the physician may suture the cervix (the procedure is called cerclage). Unfortunately, many factors which contribute to preterm labor, including things like placenta previa and multiple gestation, have no direct treatment.
The second component of the management of preterm labor is the evaluation of maternal and fetal well being. If preterm labor is associated with problems with the mother's health and continuation of the pregnancy is judged to be too hazardous to the mother (as in the case of severe preeclampsia or hemorrhage), the decision may be made to allow labor to continue. Additionally, a physician may not try to arrest labor if the dilation and effacement of the cervix indicate that birth is imminent (as may occur with an incompetent cervix). If the mother's health or problems with the placenta cause the infant to be in distress the physician may decide that the baby has a better chance in an intensive care unit than a hospital. In these instances, the physician will run the diagnostic tests to evaluate the age, size, and maturity of the fetus and preparations will be made for delivery. Depending on circumstances, delivery may be vaginal or by cesarean. If delivery is inevitable but time allows, a woman will generally be transferred to a facility with a neonatal intensive care, particularly if the gestational age is less than 34 weeks. If the gestational age is greater than 34 weeks, a secondary facility (one with intermediate care facilities for the newborn) may be acceptable. If the fetus is between 27 and 34 weeks gestation and delivery is expected, the physician will probably administer a steroid injection (a glucocorticoid, most commonly Betamethasone). Given to the mother, the injections reduce the incidence of respiratory distress in the premature newborn by speeding the maturation of the lungs. If time allows, two Betamethosone injections are administered 24 hours apart (other steroids have different dosing schedules). If circumstances allow, an obstetrician may try to stabilize the mother and delay the delivery for a brief period to administer the steroids and help the baby's lungs mature before birth.
Most often, mother and baby are both in general good health. The fetus does not exhibit distress (as determined by fetal monitoring). The placenta is still able to nourish the developing baby. The mother may have a treatable infection, be free of infection (as in placenta previa or multiple gestation), or even have a chronic illness which can be controlled. In these instances, treatment is directed toward stopping labor. The initial evaluation and treatment occurs in the hospital setting. The mother is placed on bed rest. The monitor will be used to observe contractions and allow for an evaluation of the effectiveness of drug therapy. Usually, intravenous fluids are administered for a short period to ensure hydration. In 50% of cases where labor is not associated with bleeding or rupture of membranes, labor can be stopped with bed rest and fluids.
If bed rest and fluids are not sufficient to stop labor, drugs may be used. Drug therapy may stop labor in as many as70-80% of cases that are free from bleeding and rupture of membranes. Three drugs may be used to stop contractions: Terbutaline, Ritodrine, and Magnesium sulfate. Terbutaline and Magnesium sulfate are the most commonly used medications. Terbutaline comes as a subcutaneous injection or a tablet. During premature labor, a woman will usually receive an injection every 3 hours until labor stops (or the decision is made to switch to an alternate treatment). Once contractions have stopped, a woman will be switched to Terbutaline tablets. If labor remains controlled, the woman may be released to home. Usually, she will continue to take Terbutaline until 37 weeks gestation. The mother may be placed on bed rest or advised to reduce activities. Currently, many women are sent home with a home monitoring system. The woman attaches the machine to her abdomen several times a day to monitor contractions. The information is transmitted to a center where the strip is evaluated and the pregnant woman is advised what to do based on several protocols (she may be advised to increase her dose of terbutaline or call her physician). This technology allows for better monitoring of preterm labor and medication dosing based on uterine activity.
For some women, Terbutaline may not be the best treatment choice. In women with particular health conditions like hypertension, heart disease, diabetes or hyperthoroidism, Terbutaline should not be used. In other women, Terbutaline may not be effective enough to stop labor. In these cases, a woman will usually be placed on Magnesium sulfate. Magnesium sulfate is an intravenous drug. Woman on this medication will remain in the hospital under close observation. Once contractions are stopped (the cessation of contractions is called "tocolysis"), the woman will be switched to oral Terbutaline. If the woman remains free of contractions, she will often be released to home after a further period of observation. In some cases, a woman's labor can never be adequately controlled with oral terbutaline. If labor can be managed with injectable Terbutaline, though, the woman may be able to be released to home with a special monitor which continuously evaluates contractions and administers subcutaneous doses of terbutaline as necessary (within prescribed parameters). The woman is placed on bed rest at home.
The pattern of preterm labor varies with the cause and particular circumstances. Preterm labor does not always mean that their will be a premature birth. After an initial diagnosis of preterm labor, some women have no further problems. These women usually remain on oral Terbutaline until 37 weeks of pregnancy, when the medication is stopped and the pregnancy is allowed to progress to labor (often, labor does not start until term). Other women have periodic problems with preterm labor. These women may require peiodic hospitalizations to stop labor with aggressive therapies. However, they may be released home on bed rest between episodes. In the preterm labor cannot be well controlled or if the mother is at very high risk for preterm labor, delivery, or potential fetal distress, the mother may remain hospitalized until the baby or babies are born. Generally, if the mother and babies are stable, the physician will try to delay labor as long as possible to allow the babies to be as mature as possible at birth. If the physician believes that the preterm labor is likely to result in preterm delivery, the mother is usually given steroid injections (most commonly Betamethasone) to help the baby's lungs mature more rapidly and reduce the risk of respiratory distress in the newborn.
Occasionally, preterm labor is accompanied by rupture of the membranes. When the membranes rupture, birth will typically occur within 3-7 days. In the past, physician's believed that birth should occur within 24 hours of the rupture of membranes or the mother would be at increased risk of infection. However, recent research findings indicate that there is no increased risk of infection after 24 hours. If the membranes have ruptured, most physicians will attempt to evaluate the maturity of the fetus' lungs. If the lungs are not mature, the physician may try to delay birth for a few days in order to administer steroids.
Many women who experience preterm labor do not deliver until term. However, in many other cases, preterm labor results in preterm birth.
Bed rest is sometimes recommended for women who have experienced preterm labor or other complications of pregnancy ( placenta previa, incompetent cervix, pregnancy induced hypertension, intrauterine growth retardation or chronic health problems). Some physicians recommend reduced activity levels, but others recommend complete bed rest. Currently, there is some debate about the routine use of bed rest in high risk pregnancy. However, bed rest can be beneficial in some circumstances. If your physician directs you to bed, it is best to comply. Many women dislike bed rest, but the potential long term benefit to the baby far outweighs the short term problems for the mother.
The Mayo Clinic cites three benefits of total bed rest:
- The reclining position decreases the pressure of the baby on the cervix. The reduction in pressure may reduce stretching of the cervix. Cervical pressure can cause contractions and miscarriage.
- Bed rest increases blood flow to the placenta, thereby improving oxygenation and nutrition for the fetus who is growing poorly or hindered by problems with the placenta
- Helps the mother's organs function more efficiently. Improved heart and kidney function can help in the management of high blood pressure (hypertension/PIH).
Very few women enjoy bed rest. However, bed rest can be an important treatment in the management of complicated pregnancies. Perinatal Specialists can help Moms manage bed rest by following some of these helpful tips.
- Remember that bed rest is temporary - help her focus on the improved health and well-being of her baby.
- Make sure your client understand the physician's definition of bed rest. Is she allowed to get up to go to the bathroom. Is there a certain position that is best for her situation? Can she sleep in the bedroom at night but transfer to a more public room such as the living room during the day so she does not feel isolated?
- If her physician has told her that the left side-lying position is the best, few people can lie in this position for 24 hours a day. Have her consult her physician as to possible alternatives. Back lying is almost never the position of choice due to the vena cava syndrome (the weight of the baby, placenta, uterus and contents presses on the vena cava) and the reduction of blood flow and oxygen. Investigate as to whether she can switch from side-to-side every hour or two. Side lying increases blood flow to the heart, thereby increasing the blood and oxygen supply to the fetus.
- Encourage your client to avoid getting out of bed alone, especially alone and in a hurry. After a lot of time in bed, your client needs to move slowly to avoid dizziness. Have her sit on the bed and dangling her legs gently up and down for a minute before standing. If she feels dizzy when attempting to stand, have her sit back down for another minute. This is due to a sudden drop in blood pressure.
- Bed rest can cause aches and pains. Your client may be interested in a Massage Therapist who specializes in pregnancy and makes house calls for bed rest mothers. Stationary exercises such and bending and stretching of calves and feet, ankle rotating, rotating of hands and wrists, or neck stretches may help to stretch out the kinks.
- Remember that is important to try to keep stress to a minimum. Help your client to consider how to pass the time: read, develop e-mail buddies, surf the Net or browse some forums or chat rooms, get involved in a hobby, watch television or videos, volunteer time to a charity and help with phones or mailings or newsletters. Encourage visitors if she can enjoy the company. Stimulating activities will improve her outlook and pass the time more pleasurably. Be sure to intersperse activity with rest. Help her to select a room for bed rest and set it up to make your life as comfortable as possible. Be sure to have someone assemble the items she will use, including hobby items and grooming items, tissues, the television remote, and a water pitcher. Be sure that she have a telephone within reach. If your client will spend long periods of the day by herself, have her spouse provide a nutritious lunch and snacks that can be stored at bed side (in a cooler if necessary).
- Help your client consider what household help she will need. Can her husband or partner manage any cooking and cleaning? Is she single? Does she have other children that require supervision? Encourage her to ask friends and relatives for help. Help her to be specific about her needs (meals, cleaning, company, helping with children). Consider hiring help. If she does not have adequate resources, contact a church or synagogue, La Leche, Moms Club or any community resource available.
- Reeder, S., Martin, L., and Koniak-Griffin, D. Maternity Nursing: Family, Newborn and Women's Health Care. Lippincott: Philadelphia & New York. 18th Edition, 1997.
The author wishes to acknowledge the assistance of Leslie Harris RN of Dayton, Ohio
for her significant contributions to this article.