CHAPTER 27 1 Identify factors in a patient’s prenatal history that put her at risk for preterm labor. 2 Describe important assessment parameters for patients who are at high risk for preterm labor. 3 Summarize treatments for the patient in preterm labor. 4 Discuss side effects of tocolytic therapy. 5 Describe methods commonly used for pregnancy dating. 7 Differentiate between a postterm pregnancy and a postmature infant. 8 Identify early signs and symptoms of chorioamnionitis. 9 List potential complications for the patient with premature rupture of the membranes (PROM). 10 Identify risk factors associated with multiple gestation. 11 Describe delivery room preparation and added precautions for a multiple birth. 12 Discuss physical findings that lead to a diagnosis of a stillbirth. 13 Describe the stages of grief. 14 Differentiate between perinatal grief and other grieving responses. 15 Describe possible intervention strategies for delivery management. 16 Explain the pathophysiology of anaphylactoid syndrome of pregnancy. 17 Describe the signs and symptoms that lead to a diagnosis of anaphylactoid syndrome of pregnancy. 18 Discuss the mortality and morbidity associated with anaphylactoid syndrome of pregnancy. 19 Identify patients at high risk for uterine rupture. 20 Discuss life-threatening complications that may result from uterine rupture. 21 Classify the types of uterine rupture. 22 Rank emergency actions in order of priority for a patient presenting with traumatic uterine rupture. A Preterm labor is defined as regular uterine contractions and cervical dilation before completion of the 36th week of gestation. B Certain factors are associated with a high incidence of preterm labor; recurrent preterm labor is related to a short cervix, bacterial infection, or short interval between pregnancies; bacterial infection accounts for 25% to 40% of all preterm births because endotoxins have a preinflammatory effect and stimulate prostaglandin production. Other factors are stress, uterine anomalies or cervical trauma; uterine stretch caused by multiple gestation or polyhydramnios; smoking, drug, or alcohol use; and maternal age extremes or low socioeconomic and educational status or on uncontrolled medical condition. C Preterm labor has increased in the past few years in spite of all the efforts to identify patients at risk and provide patient education. Therefore, the focus is shifting to prophylactic treatment for at risk patients. a. Signs and symptoms of uterine contractions, low back pain, menstrual-like cramps, or pelvic pressure b. Increased vaginal discharge or bloody show c. Presence of risk factors associated with spontaneous preterm labor, accounting for 75% of cases (Ananth & Vintzileos, 2006; Morken, Kallen, & Jacobsson, 2007) (2) Preterm premature rupture of the membranes (PROM) (3) Bacterial infections including mycoplasma of the genital track, pyelonephritis, asymptomatic bacteriuria, and pneumonia (Goldenberg, Culhane, & Johnson, 2005) (4) Uterine stretch caused by hydramnios and multiple gestation (5) Uterine anomalies (Zlopasa, Skrablin, & Kalafatic, 2007) (7) Drug or alcohol use (Behrman & Stith, 2007) (8) Low socioeconomic and educational status (Smith, Draper, Manktelow, Dorling, & Field, 2007; Thompson, Irgens, Rasmussen, & Daltveit, 2006) (9) African American (Behrman & Stith, 2007) (10) Trauma including domestic violence (11) Maternal age extremes (younger than 16 or older than 40 years) (Smith et al, 2007; Thompson et al, 2006) (12) Cervical injury from an elective abortion (Virk, Zhang, & Olsen, 2007) or prior cervical surgery (Jakobsson, Gissler, Sainio, Paavonen, & Tapper, 2007; Nohr, Tabor, Frederiksen, & Kjaer, 2007; Sjoborg et al, 2007). d. Presence of risk factors associated with indicated preterm labor, accounting for 25% of cases (2) Hypertensive disorders of pregnancy (3) Inadequate control of diabetes (4) Poor nutrition as measured by low body mass index (Hendler et al, 2005) (5) Smoking (Cnattingius, 2004; Nabet, Lelong, Ancel, Saurel-Cubizolles, & Kaminski, 2007; Tikkanen, Nuutila, Hiilesmaa, Paavonen, & Yikorkala, (2006) a. Uterine contractions (painful or painless) palpable or evident on external fetal monitor b. Cervical changes: softening, effacement, dilation, or shortening of cervical length c. Engagement of fetal presenting part d. Fetal heart rate (FHR): tachycardia (may indicate maternal infection) e. Elevated temperature or tachycardia (may indicate dehydration or infection) f. Costovertebral angle (CVA) tenderness g. Evidence of nitrites, leukocytes or white blood cells (WBCs), and/or red blood cells (RBCs) in urine 3. Risk screening for preterm birth a. Presence of fetal fibronectin in cervicovaginal secretions; fibronectin is a glycoprotein that adheres the maternal decidua to the fetal membranes; when uterine contractions are stimulated the adherence is disrupted and fetal fibronectin is released indicating a risk of preterm delivery b. Cervical length is measured, preferably with transvaginal ultrasound (TVU) (Burwick, Lee, Benedict, Ross, & Kjos, 2009; Matijevic, Grgic, & Vasili, 2006; Owen, 2003; Romero, 2007) or U. S. Food and Drug Administration (FDA)–approved CervilLenz cervical length measuring device (Ross et al, 2007) because the risk of preterm delivery increases as the cervical length in the second trimester declines. c. Clinical markers of an inflammatory cascade resulting from an ascending genital tract infection or a systemic infection such as pyelonephritis, asymptomatic bacteriuria, or pneumonia may indicate a risk for preterm labor; bacterial vaginitis is an example of a clinical marker of preterm labor because its presence correlates with an increased risk of preterm birth, but treatment and eradication do not decrease its risk; periodontal disease may be another marker (Klebanoff & Searle, 2006). 4. Diagnostic procedures of related risk factors a. Complete blood count (CBC): elevated WBC count may indicate infection (WBC count is normally elevated in pregnancy and in labor, but a WBC count greater than 18,000 is considered significant for infection) b. Urinalysis: Note presence of WBCs, RBCs, bacteria, nitrites, or leukocytes. c. Urine culture and sensitivity testing f. Wet mount; assess for bacterial vaginosis or trichomonas vaginalis g. Ultrasound examination to assess: B Interventions to prevent preterm labor 1. Interventions indicated by research reviews that decrease the risk of preterm labor are: a. Smoking cessation program (Lumley, Oliver, Chamberlain, & Oakley, 2004) b. Routine screening and treatment for asymptomatic bacteriuria (Smaill & Vasquez, 2007) c. Use of a laminaria for women undergoing second-trimester dilation and evacuation (Kalish, Chasen, Rosenzweig, Rashbaum, & Chervenak, 2002) d. Preconception medical management of medical conditions such as diabetes, seizures, asthma, or hypertension (Haas et al, 2005) 2. Interventions once thought to lower the risk of preterm labor but not proven by research a. Early access to care (Healy, Fergal, Malone, & Sullivan, 2006) b. Nutritional supplements such as protein (Kramer & Kakuma, 2003), calcium (Hofmeyr, Atallah, & Duley, 2006), and vitamins C and E (Rumbold et al, 2006) c. Periodontal care (Michalowicz et al, 2006) d. Routine screening and treatment of bacterial vaginosis (BV) (Centers for Disease Control and Prevention [CDC], 2006) C Intervention for women at risk for preterm labor 1. Progestational supplementation: Current research indicates that progesterone vaginal gel or cream may be beneficial in reducing preterm labor by 40% especially in women with a history of preterm birth and a short cervical length verified by vaginal ultrasound (DeFranco et al, 2007; Dodd, Flenady, Cincotta, & Crowther, 2006; Farine et al, 2008; Fonseca, Celik, Parra, Singh, & Nicolaides, 2007; Romero, 2007; Weiner & Buhimschi, 2009) a. Physiologic benefits of progesterone (Sfakianaki & Norwitz, 2006) (1) Reduces gap junction formation in the uterus (2) Antagonizes oxytocin receptors (3) Maintains cervical integrity b. Contraindications (Weiner & Buhimschi, 2009) D Interventions to treat preterm labor 1. Treat presence of bacterial infections such as pyelonephritis, asymptomatic bacteriuria, and pneumonia. 2. Hydrate patient with oral (PO) or intravenous (IV) fluids (uterine contractions or irritability may result from dehydration). 3. Monitor intake and output (I&O); avoid volume overload. 4. Monitor maternal vital signs. 5. Continuous external fetal monitoring for: 6. Palpate patient’s abdomen to assess strength of uterine contractions. 7. Administer tocolytic therapy as ordered to delay delivery long enough to administer therapy. a. Corticosteroids to treat fetal lung maturity b. Complete maternal transport to a Level III center prior to delivery. a. No medication has been identified to effectively stop preterm labor. b. No one drug is approved in the United States or has been proven superior as a tocolytic agent. Medication selection is individualized based on efficacy, risks, and side effects. c. The following drugs are used as tocolytics per FDA as “off-label” use. (1) Nifedipine: calcium channel blocker that works primarily by blocking the flow of calcium ions through the cell membrane, thereby decreasing the activation of smooth muscle contractile proteins. According to a Cochrane Review (King, Flenady, Papatsonis, Dekker, & Carbonne, 2003) and several meta-analyses (Weiner & Buhimschi, 2009), nifedipine can delay delivery by 2 to 7 days and has a favorable ratio of risk-to-benefit related to decreased adverse side effects. Also, nifedipine is more cost-effective than terbutaline or magnesium sulfate (Weiner & Buhimschi, 2009). [i] Initial loading dose: 10 to 40 mg PO, followed by 30 to 60 mg of a long-acting preparation PO every 8 to 12 hours for maximum of 48 hours (b) Side effects: usually mild, less common with long-acting preparations [i] Insignificant decrease in blood pressure (no change in heart rate) [vi] Fetal effects: minimal randomized, controlled studies at this time; however, clinical evidence indicates beneficial effects of decreased respiratory distress syndrome (RDS), intracranial bleeding, and neonatal jaundice (c) If nifedipine is given with magnesium sulfate or erythromycin, sudden cardiac arrest can occur (Weiner & Buhimschi, 2009). (d) Contraindicated in the presence of an intrauterine infection, maternal hypertension, or cardiac disease (2) Indomethacin: prostaglandin synthetase inhibitor; a Cochrane Review concludes that indomethacin significantly reduces contractions for 48 to 72 hours but has greater adverse fetal effects following 1 week of use as compared to nifedipine (King, Flenady, Cole, & Thornton, 2005). Both nifedipine and indomethacin are more cost-effective then terbutaline or magnesium sulfate (Weiner & Buhimschi, 2009). [i] Maternal: increased bleeding time; potential to exacerbate hypertensive disorders [ii] Fetal: after 1 week or more exposure, oligohydramnios, premature closure of the ductus arteriosus, increased risk of necrotizing enterocolitis (NEC), increased risk of intraventricular hemorrhage (IVH) and renal dysfunction (c) Contraindications (maternal) [i] If labor is imminent within 24 hours, the initial 50-mg dose may prolong maternal bleeding time. [ii] Poorly controlled maternal hypertension [v] Active peptic ulcer disease (3) Terbutaline sulfate: beta-adrenergic agonist; a Cochrane Review concludes that beta-mimetic drugs can delay delivery by 48 hours but have greater maternal side effects than other tocolytic agents. Its long-term use is not supported (Anotayanonth, Subhedar, Neilson, & Harigopal, 2004). [i] Subcutaneous (SC) dosage: 0.25 mg times one to arrest contractions to facilitate maternal transport or initiate tocolysis while another agent with a slower onset of action is started. (d) Relative contraindications (4) Magnesium sulfate (MgSO4): relaxes smooth muscle by competing with calcium at the motor end plate (reducing the release of acetylcholine) or at the cell membrane decreasing calcium influx into the cell. A Cochrane Review concludes that magnesium sulfate has limited effect as a tocolytic agent, with severe risk factors such as pulmonary edema and cardiovascular problems (Crowther, Hiller, & Doyle, 2002). However, research indicates that magnesium sulfate may have a neuroprotective benefit, protecting the brain of the very preterm infant by possibly reducing the risk of cerebral palsy (Marret et al, 2007; Rouse et al, 2008). [i] Loading dose: 4 to 6 g/hr IV piggyback (IVPB) over 20 to 30 minutes [ii] Maintenance dose: 1 to 3 g/hr IVPB [ii] Monitor DTRs (generally graded on a scale of 0 to 4) • 4+: very brisk, hyperactive; associated with clonus (clonus is the series of rhythmic contractions or convulsive movements of the ankle when the foot is sharply dorsiflexed; it is measured in beats [e.g., “two beats of clonus”]) • 2+: average; normal reflex response • 0: absent (Seidel, Ball, Dains, & Benedict, 2006) • The patellar tendon is most commonly used to assess reflexes because it is easiest to elicit, but biceps or triceps reflexes may also be used. [iii] Monitor serum magnesium levels. • Although laboratory values may vary slightly from one institution to another, approximate values are as follows: • Discontinue magnesium sulfate in the presence of elevated serum levels or of signs and symptoms of central nervous system (CNS) or cardiovascular depression. • Be prepared to administer antidote (calcium chloride) if necessary. 9. Interventions related to unknown pregnancy outcome a. Encourage patient to verbalize her feelings and assist her in identifying specific concerns. b. Provide realistic information about preterm labor and delivery. c. Provide information about premature infants; be as detailed as possible, giving information related to her specific gestational age. (See Chapter 17 for complete discussion.) d. Visit neonatal intensive care unit (NICU) with patient to familiarize her with that environment. e. Allow patient and family to participate in plan of care whenever possible. A Teach patient to recognize signs and symptoms of preterm labor. 1. Uterine contractions, cramping, and low back pain 2. Feeling of pelvic pressure or fullness 3. Change in amount or character of vaginal discharge 4. Bloody show; discharge of mucus plug 5. GI upset: nausea, vomiting, and diarrhea B Teach patient how to palpate uterine contractions. 1. Tell patient to sit up from a reclining position and to palpate her abdomen immediately. (This action will usually induce a uterine contraction.) 2. Patient may also palpate the sensation of a muscular contraction by placing her hand over her biceps and flexing her arm. 3. Describe contraction intensity; compare the feeling of firmness to the following: 4. If any preterm labor symptoms occur, teach patient to: C Review timing of contractions with the patient; time contractions from onset to onset. D Patient should call health care provider or go to the hospital if contractions are coming regularly. E Discuss treatment routines with the patient. 1. Try bedrest in the lateral position. (Mild uterine activity may subside with increased uterine blood flow.) 2. Maintain adequate hydration. (Uterine activity or irritability may result from dehydration.) 3. If uterine activity persists, the patient should call her health care provider or go to the hospital for further evaluation; hospitalization for IV tocolytic therapy may be required. 1. Term pregnancy: 37 to 42 completed weeks from the last menses or 35 to 40 weeks from the time of conception 2. Postterm pregnancy (prolonged pregnancy): exceeds 42 completed weeks of menstrual age 3. Postmaturity: a diagnosis that cannot be made in the antepartal period but is made by recognizable clinical findings in the infant that are associated with dysmaturity B Decreased amniotic fluid after 42 weeks’ gestation is the most frequently associated factor, reducing the cushioning effect and increasing the risk for umbilical cord compression. a. Nägele’s rule: Add 7 days to the first day of the last menstrual period (LMP) count back 3 months and adjust year (assumes regular 28-day menstrual cycle). b. Timing of positive pregnancy test result d. When fetal heart rate can be auscultated e. Ultrasound examination provides a more accurate gestational age date; by measuring crown-rump length (CRL), fetal biparietal diameter, femur length, abdominal circumference, or chest circumference; or by using a formula involving the ratio of these values; ultrasound dating is most accurate when done in the first trimester of pregnancy using the CRL (see Chapter 8 for complete discussion of antepartum testing). a. Gestational age by ultrasound examination (1) Measurement from symphysis pubis to top of fundus correlates approximately with the number of weeks of gestation (e.g., 28 cm indicates approximately 28 weeks’ gestation). (2) If fetal presenting part is engaged, the fundal height is less accurate. c. Decreased amniotic fluid volume (AFV) occurs most commonly and can cause fetal distress related to cord compression. d. Macrosomia, another common finding, can lead to shoulder dystocia and birth trauma. e. Dysmaturity syndrome in response to uteroplacental insufficiency occurs in only 1% to 2% of the cases and is characterized by (see Chapter 17 for complete discussion): (2) Fear of unknown: Expectations of delivery by estimated date of confinement (EDC) have not been fulfilled. b. Behavioral response: impatience with normal discomforts of pregnancy 4. Antepartum fetal surveillance testing (see Chapter 8 on antepartum testing) 1. Antepartum intervention is still controversial. 2. According to the Cochrane Review, there is no conclusive evidence that one protocol affords greater benefit or greater risk to low-risk patients (Gulmezoglu, Crowther, & Middleton, 2006). 3. According to the Society of Obstetricians and Gynaecologists of Canada (SOGC) clinical practice guideline, women should be offered induction at 41 to 42 weeks’ gestation (SOGC, 2008). 4. If expectant management is chosen by the patient, antepartum fetal surveillance should be used. BPP or a modification of BPP such as NST and AFI is preferred (Resnik & Resnik, 2009; SOGC, 2008). 5. Fetal membrane sweeping has been shown to reduce the number of pregnancies exceeding 41-plus weeks by increasing production of prostaglandins (Boulvain & Irion, 2004). Risks of the procedure are discomfort at the time of the procedure and bleeding. 6. Prostaglandin gel may be used for cervical ripening. 1. Perform continuous fetal monitoring during labor and delivery. 2. Maintain patient in the lateral position as much as possible to maximize placental blood flow. 3. Keep patient well hydrated to maximize placental perfusion. 4. Administer amnioinfusion to relieve repetitive deep variable decelerations secondary to low fluid volume. However, amnioinfusion is not beneficial for the treatment of meconium-staining as was once thought (Fraser et al, 2005). A Define terms of normal gestation. B Explain function of amniotic fluid. C Explain function of placenta. D Review fetal growth and development. 1. Organ development and maturation are complete by the 36th week. 2. Last 4 weeks of gestation are primarily for weight gain. (See Chapter 17 for a complete discussion of late preterm infant.) 3. Vernix caseosa, the oily substance that protects the fetal skin in utero, begins to disappear after the 36th week, making the infant’s skin appear dry and peeling. E Discuss physiology of labor. 1. Precise mechanism for initiation of labor is unknown. 2. Cervix may require ripening with prostaglandin gel. a. Gel is inserted intracervically to induce softening and effacement. b. Continuous fetal monitoring is recommended after the insertion of prostaglandin gel because it may induce uterine contractions; assess for uterine activity and FHR patterns. 3. Induction or augmentation of labor may be necessary and is commonly done with oxytocin (Pitocin); it should not be done without continuous FHR monitoring. F Discuss effect of postterm pregnancy on the fetus. A Premature rupture of membranes (PROM) refers to the spontaneous rupture of the amniotic membrane before the onset of labor; this may occur at or before term. B Gestational age usually determines the plan and intervention. C The patient at or near term generally benefits from expedited delivery if fetal pulmonary maturity is documented; patients with PROM remote from term are at much greater risk for increased neonatal morbidity related to gestational age. D Induction or augmentation of labor may be necessary. E For the purpose of this section, PROM refers to the rupture of membranes (ROM) before term; often called preterm PROM. F Strong clinical evidence links PROM to intrauterine infection; clinical trials with antibiotic therapy have demonstrated a delay in the onset of infection, as well as a delay in delivery, decreased postpartum maternal endometritis, and decreased infant morbidity related to sepsis, pneumonia, and RDS.
Labor and Delivery at Risk
PRETERM LABOR
CLINICAL PRACTICE
HEALTH EDUCATION
POSTTERM PREGNANCY
CLINICAL PRACTICE
HEALTH EDUCATION
PREMATURE RUPTURE OF MEMBRANES
