Premature Labor & Birth

Premature Labor & Birth

Objectives

  • Identify risk factors for preterm birth and premature rupture of membranes

  • Discuss nursing management in preterm labor

  • Describe role and responsibility of the nurse in emergency childbirth situations

Preterm Labor and Birth

  • Preterm Labor (PTL):

    • Defined as:

    • Regular contractions along with a change in cervical effacement or dilation, or both.

    • Presentation with regular uterine contractions and cervical dilation of at least 2 cm.

  • Preterm Birth:

    • Defined as any birth occurring between 20 0/7 and 36 6/7 weeks of gestation.

    • Decreasing rates of preterm birth in the last decade attributed to:

    • Improved fertility practices reducing the risk for higher-order multiple gestations.

    • Quality improvement programs limiting scheduled late preterm and near-term births to those with valid indications.

    • Increased use of strategies to prevent recurrent preterm birth.

Sub-Categories of Preterm Labor and Birth

  • Very Preterm: < 32 weeks of gestation

  • Moderately Preterm: 32 to 34 weeks of gestation

  • Late Preterm: 34 0/7 to 36 6/7 weeks of gestation

  • Preterm Birth vs. Low Birth Weight:

    • Preterm Birth = length of gestation, regardless of birth weight.

    • More concerning than birth weight alone; less time in the uterus correlates with immaturity of body systems.

    • Low Birth Weight: 00 grams at birth, has multiple potential causes including preterm birth and intrauterine growth restriction (IUGR).

Spontaneous vs. Indicated Preterm Birth

  • Spontaneous Preterm Birth:

    • Comprises about 75% of preterm births.

  • Indicated Preterm Birth:

    • Comprises about 25% of preterm births.

Causes of Spontaneous Preterm Labor and Birth

  • Multifactorial causes arise from several pathologic processes, including:

    • Infection

    • Congenital structural abnormalities of the uterus

    • Placental causes

    • Maternal and fetal stress

    • Uterine overdistention

    • Allergic reactions

    • Decrease in progesterone levels

Predicting Spontaneous Preterm Labor and Birth

  • Utilizing known risk factors and biochemical markers including:

    • Fetal Fibronectin (fFN): A "biologic glue" produced by the chorion.

    • Testing salivary estriol.

    • Note: The cost of determining biochemical markers can be high.

    • Endocervical Length: Measured via ultrasound to predict preterm birth risk.

Preterm Labor: Nursing Assessment

  • Assessment includes:

    • Risk Factors

    • Subtle Signs:

    • Contraction pattern (6-8 contractions in 1 hour).

    • Laboratory and Diagnostic Testing:

    • Complete blood count

    • Urinalysis

    • Amniotic fluid analysis

    • Fetal fibronectin testing

    • Cervical length measurement via transvaginal ultrasound

    • Salivary estriol testing

    • Home uterine activity monitoring.

Risk Factors for Preterm Birth

  • Physical Characteristics:

    • Small stature

    • Multi-fetal pregnancy

  • Medical Conditions:

    • Hydramnios

    • Bleeding and placental problems

    • Infections, UTI

    • Premature Rupture of Membranes (PROM)

    • Fetal anomalies

    • Maternal anemia

    • Domestic violence

    • Medical diseases such as diabetes, hypertension, and anemia.

Amniotic Fluid Considerations

  • Alterations in Amniotic Fluid Volume:

    • Too little amniotic fluid (<500 mL at term) is known as oligohydramnios:

    • Associated with uteroplacental insufficiency, fetal renal abnormalities, higher risks for surgical births, and low-birth-weight infants.

    • Too much amniotic fluid (>2,000 mL at term) is termed hydramnios:

    • Related to maternal diabetes, neural tube defects, chromosomal deviations, and malformations of the central nervous system and gastrointestinal tract that prevent normal swallowing of amniotic fluid by the fetus.

Fetal Fibronectin Testing

  • Fetal Fibronectin: A glycoprotein produced by the chorion.

    • A fetal fibronectin test is useful primarily if the result is negative. During weeks 24 to 34 of gestation, there should be minimal fetal fibronectin detectable in vaginal secretions.

    • Studies indicate less than 10% of women with a negative result deliver before 35 weeks of pregnancy.

    • A positive result may not be as informative; approximately 70% of women who test positive with fetal fibronectin remain pregnant past 35 weeks.

Cervical Length Measurement

  • Cervical Length:

    • Measured via transvaginal ultrasound.

    • Best obtained between 16 and 24 weeks gestation.

    • A length of 3 cm or more indicates an unlikely chance of delivery within 14 days.

Care Management

  • Prevention:

    • Addressing risk factors through preventive strategies.

    • Educating about early symptoms of preterm labor.

    • Providing instructions on actions to take if symptoms occur.

    • Note: Patients may ignore symptoms due to ignorance regarding significance or the belief that symptoms are normal during pregnancy.

Recognizing Symptoms of Preterm Labor

  • Some subtle symptoms include:

    • Change in vaginal discharge (presence of mucous or blood)

    • Pelvic pressure (pushing sensation)

    • Low, dull backache

    • Menstrual-like cramps

    • Symptoms of urinary tract infections (UTIs)

    • Gastrointestinal upset, nausea, vomiting, diarrhea

    • Heaviness or aching in thighs

    • Uterine contractions that are painful or painless; more than 6 contractions in an hour.

Teaching Guidelines for Preventing Preterm Labor

  • Suggested preventative measures include:

    • Avoid long-distance travel by car, train, plane, or bus.

    • Avoid heavy lifting of objects, such as laundry, groceries, or young children.

    • Prevent engaging in physically demanding work, like yard work or moving furniture.

    • Encourage mild to moderate exercise such as daily walking.

    • Aim to achieve an appropriate prepregnancy weight.

    • Maintain adequate iron stores through a balanced diet.

    • Wait at least 18 months between pregnancies.

    • Visit a dentist early in pregnancy to evaluate and treat any periodontal disease.

    • Enroll in smoking cessation programs if needed.

    • Curtail sexual activity until after 37 weeks if experiencing preterm labor symptoms.

    • Consume a well-balanced diet to ensure appropriate weight gain.

    • Avoid substance abuse (e.g., marijuana, cocaine, heroin).

    • Manage stress effectively and seek help for intimate partner violence or any personal stressors.

Actions if Experiencing Signs of Preterm Labor

  • If experiencing signs, it is advised to:

    • Stop current activities and rest for one hour.

    • Urinate to empty the bladder.

    • Lie down on the side.

    • Drink 2-3 glasses of water to stay hydrated.

    • Monitor the abdomen's hardness during contractions and describe the intensity:

    • Mild: Feels like the tip of the nose.

    • Moderate: Feels like the tip of the chin.

    • Strong: Feels like a forehead.

Care Management (Continued)

  • Lifestyle Modifications:

    • Activity restrictions including bed rest, limited work, and restrictions on sexual activity.

    • Environmental modifications and home uterine monitoring as needed.

  • Suppression of Uterine Activity:

    • Tocolytic medications aim to delay birth long enough to implement interventions that can reduce neonatal morbidity and mortality.

    • Commonly Used Tocolytics:

    • Magnesium sulfate

    • Beta-adrenergics

    • Nifedipine

    • Indomethacin

Expected Outcomes with Tocolytic Therapy

  • Clinical research indicates that a gain of 48 hours to several days is the optimal result expected with tocolytic use. The primary goal is to provide sufficient time for administering glucocorticoid steroids that promote fetal lung maturity and minimize respiratory complications in preterm infants.

Drug Guide: Medications Used with Preterm Labor

  • Magnesium Sulfate:

    • Action: Relaxes uterine muscles; has off-label use for stopping contractions.

    • Administration: IV loading dose of 4-6 g over 15-30 minutes, thereafter maintaining an infusion of 1-4 g/hr.

    • Nursing Implications: Monitor vital signs, deep tendon reflexes (DTRs) hourly, and assess for magnesium toxicity.

  • Indomethacin (Indocin):

    • Action: Non-steroidal anti-inflammatory drug (NSAID) that inhibits prostaglandins, which stimulate contractions, thereby inhibiting uterine activity.

    • Nursing Implications: Assess for nausea, vomiting, and other common side effects.

  • Nifedipine (Procardia):

    • Action: Calcium channel blocker that inhibits uterine activity to manage preterm labor.

    • Nursing Implications: Continuous monitoring during administration; caution in patients with cardiovascular disease.

  • Betamethasone (Celestone):

    • Action: Promotes fetal lung maturity, preventing respiratory distress syndrome.

    • Administration: Two doses, 12 mg each, administered 12-24 hours apart. Most effective 2-7 days post-administration.

Contraindications for Tocolytics

  • Mnemonic: CCLAPP:

    • C: Chorioamnionitis

    • C: Congenital anomalies

    • L: Late pregnancy (>34 weeks)

    • A: Advanced labor

    • P: Placenta abruption

    • P: Pre-eclampsia

Management of Inevitable Preterm Birth

  • When labor progresses to a dilation of 4 cm, the likelihood of inevitable preterm birth increases. Skilled nurses are required to manage emergency situations involving unexpected deliveries.