93 Preterm labor
Overview/pathophysiology
Preterm labor (PTL) is the onset of labor before 37 wk gestation. A preterm birth occurs before the completion of 37 wk of pregnancy. A preterm (premature) newborn is an infant born after 20 wk gestation and before 37 completed wk of pregnancy. All pregnant women are considered at risk for PTL, although approximately 8% of all pregnancies end in PTL.
It is difficult to understand exactly what triggers PTL when triggers that initiate onset of term labor are poorly understood. The pathophysiology of PTL is considered a multifactorial process. See table, below, for details. The end results of the triggering factors are increased uterine irritability, decreased placental functioning, increased prostaglandin synthesis, cervical changes, and preterm labor. Prematurity is the second leading cause of infant mortality in the United States after congenital anomalies. Many preterm infants who survive have life-long mental or physical impairments.
| Medical Risks | |
| Three groups of women are at greatest risk of preterm labor and birth: | Certain medical conditions during pregnancy may increase the likelihood that a woman will have PTL. These conditions include:
• Urinary tract infections, vaginal infections, sexually transmitted infections, and possibly other infections
|
| Lifestyle and Environmental Risks | |
| Some studies have found that certain lifestyle factors may put a woman at greater risk of PTL. These factors include: | Short time period between pregnancies (less than 6-9 mo between birth and the beginning of the next pregnancy) |
Health care setting
Some patients may be managed via primary care on an outpatient basis with frequent clinic evaluation or in a high-risk perinatal clinic. Others may receive acute care in an inpatient antepartum setting.
Assessment
Symptoms of PTL may range from subtle to obvious. Many symptoms do not cause pain. PTL does not present in the same way as labor at term. All pregnant women should be taught the symptoms of PTL during early prenatal care and then be reassessed at each prenatal visit. The mother may feel that the baby is “balling up” in her abdomen and describe a “heavy” feeling in the perineum or pelvic pressure.
Contractions/uterine tightening:
As the pregnancy progresses, so does the frequency of uterine activity. Uterine tightening/contractions begin in the first trimester as the uterus enlarges and continue throughout the pregnancy. These contractions are called Braxton-Hicks. They occur at irregular intervals, usually are painless, and do not change the cervix. PTL may feel like light menstrual-like cramping or strong, palpable contractions. PTL is diagnosed when uterine contractions are persistent and accompanied by cervical change, either dilation or effacement.
Backache:
This is a very common complaint in pregnancy. Any woman with a history of preterm labor/delivery who complains of new-onset backache needs to be evaluated for cervical changes, especially if she describes the backache as low and lumbar/sacral in location, deep tissue in nature, or a dull aching sensation that radiates around the hips to the lower abdomen/pelvic area and down the thighs.
Pelvic pressure:
The woman may state that she feels the “baby has dropped.” Pelvis pressure may be described as a constant or intermittent “heaviness” or a sensation of “fullness in the pelvis.”
Abdominal cramping:
Gastrointestinal (GI) symptoms such as increased flatus or diarrhea may be present. The abdomen may be tender to palpate, as is seen with chorioamnionitis (inflammatory reaction in the amniotic membranes caused by bacteria or virus).
Vaginal discharge:
An increase in vaginal discharge is normal during pregnancy. It can be clear, thick, or thin and “milky white” or light yellow. It may become watery in nature as with preterm premature ruptured membranes (PPROM) or bloody as with placental abruption or when the cervix dilates and its surface vessels break. Vaginal itching or burning or a foul odor may indicate an infection. Vaginal bleeding may range from light pink spotting to bright red bleeding.
Fever:
Temperature may range from 98.6° F (37° C) to 101° F (38.3° C) or higher if an infection is present.
General complaints:
Other symptoms may include a feeling of unease and body aches. The woman may state, “I just feel different.”
Physical assessment:
Even with vague symptoms, cervical changes may be taking place. Therefore, it is important not to underestimate reported symptoms. Early evaluation and treatment are critical in attempting to stop PTL and preventing fetal morbidity and mortality.
Diagnostic tests
There are several biochemical markers and assessments that assist in the diagnosis of PTL.
Cervical evaluation:
Sterile speculum cervical exams provide information about cervical effacement, cervical dilation, and whether amniotic fluid is leaking or abnormal secretions are present in the vagina. Cervical or vaginal secretions can be collected for a ferning test (rupture of membranes) or fetal fibronectin (fFn) test to diagnose an infection or confirm mild occult blood loss.
Transvaginal ultrasonography:
May be used to measure cervical length when cervical effacement is less than 80% and to evaluate funneling of the internal os as well as effacement and dilation of the cervix. The shorter the cervix, the greater the risk of PTL. The shortest acceptable length is 3 cm (2.5 cm length or less is associated with PTL).
Fetal fibronectin (FFn):
Fetal fibronectins are glycoproteins present in the cervical and vaginal secretions early in pregnancy. After 22 wk gestation, they are not detectable in vaginal secretions. Their presence returns within 2 wk of delivery, whether it is preterm or term. Therefore negative fFn results between 24-35 wk gestation are strongly associated with not going into labor for the next 1-2 wk. The negative predictive power of fFn is used to avoid further and unnecessary interventions for the woman at risk for PTL. A positive fFn finding is less predictive of labor because false positives occur with recent sexual intercourse, vaginal bleeding, amniotic fluid, or recent cervical examinations. The health care provider gathers the sample for testing before doing a vaginal examination for cervical changes because the lubricant used for manual vaginal exams may interfere with test results.
Uterine contraction evaluation:
Sometimes a contraction frequency of 4 per 20 min with cervical effacement of 80% or more and cervical dilation of 2 cm is used to make the diagnosis. The focus of care is on stopping PTL if intervention can begin before the woman has reached 3 cm cervical dilation. If PTL cannot be stopped, management is focused on maternal safety and reduction of the preterm infant’s risk for respiratory distress syndrome.
PPROM:
Preterm premature rupture of membranes occurs first in 25% of preterm births. See discussion, p. 667.
Urinalysis for microscopy:
Urinary tract infections (UTIs) are associated with PTL. A clean-catch urine specimen should be obtained when attempting to rule out PTL, even when the patient is asymptomatic. When a UTI is present, antibiotic therapy will be initiated.
Nursing diagnosis:
Anxiety
related to perceived or actual threats to self and well-being of fetus and inadequate time to prepare for labor/delivery
Desired Outcomes: Immediately after intervention, patient describes the signs of anxiety she is feeling. Within 1-2 hr of intervention, patient reports that the detrimental anxiety reactions are lessened.
| ASSESSMENT/INTERVENTIONS | RATIONALES |
|---|---|
| Assess maternal level of understanding, language, and ability to communicate her feelings and concerns, cultural-bound anxiety, and the impact of fatigue. | Assessment provides information about the woman’s and family’s emotional needs, communication needs, and cognitive level. When interventions are provided at the appropriate level and understood, behavioral changes take place. Anxiety can be culture-bound and is manifested differently from culture to culture. |
| Assess maternal vital signs (VS) and fetal heart rate (FHR) patterns q4-8h. | Maternal temperature and pulse rise if an infection is present. Physiologic stress reaction also increases pulse and respirations. Muscle tension and vasoconstriction may cause uteroplacental insufficiency and reduce oxygenation to the fetus. |
| Help patient anticipate and problem solve her needs related to procedures, procedural side effects, how they affect her and her unborn baby, her changing labor status, the fetal condition, and hoped for outcomes. | Anxiety is reduced with clarification of needs, medical interventions, procedures, and anticipated medications. |
| Encourage questions and verbalization of concerns. Answer honestly, while maintaining an optimistic attitude. | When concerns are verbalized and clarified, the nurse can give realistic feedback and provide appropriate emotional support. |
| Assess and guide the patient to develop a personal support system and use community resources while in the hospital in anticipation of her return home to self-care and outpatient monitoring. | Refer to interventions and rationales for support under Ineffective Coping, p. 662. |
| Encourage self-nurturing with rest, assistance with relaxation techniques, prayer or meditation as related to the woman’s faith, and by administration of sedatives if prescribed when other measures are insufficient. | When the usual quiescence of the uterus is interrupted by the threat of preterm delivery, mother and family can become severely stressed. Rest, meditation, prayer, and focused relaxation improve physiologic, psychologic, and spiritual well-being. |
Nursing diagnosis:
Activity intolerance
related to need for rest to prevent the effects of activity on advancing PTL
Desired Outcomes: Within 1-2 hr after interventions, the patient describes her at-home situation, mobilizes appropriate support for home care (or family while in the hospital), and verbalizes plans to reduce her activity level as prescribed.
| ASSESSMENT/INTERVENTIONS | RATIONALES |
|---|---|
| Assess readiness of the patient, her partner, and family to learn from within their cultural context. Assess ability of the family unit to assume care responsibilities in preparation for patient’s discharge to home care. | Changes in family functioning and behavior occur when education is given at the appropriate level of understanding.
Barriers to effective functioning may include anemia, physical weakness, impaired mental functioning relative to the prescribed medications, familial conflicts, and uncontrollable outside stressors.  Stay updated, free articles. Join our Telegram channel
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