Preterm Labor and Birth

Preterm Labor (PTL) and Preterm Birth (PTB)

• Preterm labor (PTL) is regular contractions with cervical changes before 36 6/7 weeks of gestation
• Preterm birth (PTB) is birth before 36 6/7 weeks of gestation
• Preterm birth is a leading cause of newborn death and disability
• Preterm birth complicates 1 in 8 deliveries
• About 13.4 million babies are born prematurely worldwide yearly, with 1 million dying from preterm complications
• Preterm births account for 85% of all neonatal deaths
• In the U.S. the preterm birth rate was 10.5% in 2021, which is a 4% increase and largely affected by race

Preterm Birth Categories

• Very preterm is defined as less than 32 weeks
• Moderately preterm is defined as between 32 and 34 weeks
• Late preterm is defined as between 34 and 36 6/7 weeks
• The degree of prematurity correlates directly to outcomes
• Around 75% of U.S. preterm births are late preterm

Risk Factors for Preterm Labor and Birth

• Potential risk factors are infection, multifetal pregnancy, smoking, substance abuse, violence or abuse, or limited education
• Potential risk factors are prior preterm labor/birth, lack of prenatal care (PNC), or bleeding in the 1st or 2nd trimesters
• Potential risk factors are uterine abnormalities, being under/over pre-pregnancy weight, or advanced maternal age
• Additional risk factors are race (Black, Asian) & history of assisted reproductive technology
• 20-25% of preterm labor cases have no known cause

Potential Signs of Preterm Labor

• Signs and symptoms include regular uterine contractions every 10 minutes that last over an hour
• Cervical change with contractions must be present to have preterm labor
• Include low back pain, dullness or radiating pain to the front, feeling the baby is pushing down, and vaginal discharge
• Further signs and symptoms include abdominal cramping with/without diarrhea, urinary frequency, and prelabor rupture of membranes (PROM)

Diagnostic Procedures for Preterm Labor and Birth

• Include external fetal monitoring (EFM)
• Include ultrasounds to determine viability and cervical length (shortening to under 30mm means labor)
• Consider non-stress tests (NST) and biophysical profiles (BPP)
• Include lab tests like fetal fibronectin (FFN) which indicates a higher risk of labor within 2 weeks
• False negatives for FFN can occur if semen or lubrication is in the vaginal canal
• Other tests include cervical cultures, complete blood counts (CBC), and urinalysis

Treatment for Preterm Labor

• The goal is to attempt to stop the labor
• Include modified bedrest and pelvic rest
• Patients should lay on their left side several times daily to increase blood flow and perfusion to the uterus
• Hydration is key
• Tocolytic medications may be used to slow labor, such as magnesium sulfate to help with neuroprotection of the fetus

Things That Prevent Preterm Labor from being Stopped

• Preeclampsia with severe features, eclampsia, bleeding with hemodynamic instability, and/ or chorioamnionitis are contraindications for stopping labor
• Specific contradictions to tocolytic drugs like allergies or cardiac issues are contraindications for stopping labor
• Fetal conditions such as demise, lethal anomaly, or a non-reassuring NST/BPP are contraindications for stopping labor

Tocolytic Therapy

• It is used to stop or reduce labor to allow more time for steroids to become effective for fetal lung development
• Nifedipine, indomethacin, terbutaline, magnesium sulfate, betamethasone, and progesterone are all different tocolytic therapies

Prelabor Rupture of Membranes (PROM) & Preterm Prelabor Rupture of Membranes (PPROM)

• PROM is the spontaneous rupture of amniotic membranes before the onset of true labor
• PPROM is the spontaneous rupture of amniotic membranes after week 20 and before week 37 of gestation

PROM & PPROM Risk Factors

• Risk factors include infection, history of preterm birth, short cervix, and 2nd or 3rd trimester bleeding
• Pulmonary or connective tissue disorders, low BMI, deficiencies in copper or ascorbic acid, tobacco or substance abuse, and overdistention of the uterus can also be risk factors

PROM & PPROM Expected Findings

• Amniotic fluid should be present in the vaginal canal
• The Nitrazine paper test will be positive (blue) and/ or ferning test will be positive
• Assess for prolapsed cord and observe the fetal heart rate (FHR) as abrupt variable decelerations or prolonged decelerations can occur with either a visible or palpable cord

Nursing Considerations for PROM & PPROM

• These usually depend on gestational age and the fetal/maternal condition
• The goal is to keep the patient pregnant and healthy until the steroids take effect
• Keep the patient in the hospital until delivery and apply a fetal heart rate monitor to assess contractions and the FHR
• Tocolytics may be considered
• Prepare for delivery and obtain a group B streptococcus (GBS) swab, lab work, and frequent vital signs
• Administer antibiotics (ampicillin for GBS, ampicillin, and gentamycin for chorio) and betamethasone if labor is delayed
• Limit vaginal exams, monitor for daily kick counts via NST, and ensure the patient is on bedrest with bathroom privileges if labor is delayed

Cervical Insufficiency

• Also known as a shortened cervix or premature cervical dilatation

Cervical Insufficiency Risk Factors

• Include a history of cervical trauma/surgery, congenital abnormalities of the uterus or cervix, and in-utero exposure to diethylstilbestrol (DES daughters)
• Pink-tinged vaginal discharge, PROM, uterine contractions with the delivery of the fetus, and increased pelvic pressure/urge to push can be expected findings

Cervical Insufficiency Nursing Care

• Include modified bed rest, pelvic rest, and assessing the support system
• Assessing vaginal discharge, monitoring for contractions, daily kick counts with NST, and checking vital signs are also part of nursing care

Cervical Insufficiency Diagnostic Procedures

• Ultrasound is a diagnostic procedure for cervical insufficiency and is the least invasive method
• It measures the cervix length/effacement/funneling; a cervix less than 25mm is considered a "short cervix"

Cervical Insufficiency Treatment

• A transvaginal cerclage is a surgical procedure to create a suture placement around the cervix (McDonald procedure)
• Preventative placement is done with a history of preterm birth/labor, or a short cervix between 12-14 weeks
• Therapeutically placement is determined by ultrasound findings between 14-23 weeks
• Rescue placement is done with a dilated cervix (over 1cm) between 16-23 weeks
• Cerclages are removed around 36 weeks gestation or with rupture of membranes (ROM)
• A transabdominal cerclage consists of a permanent suture placed around the internal os of the cervix and is placed by laparotomy
• Can be considered preventatively after a failed vaginal cerclage and placed before conception or by 11-12 weeks gestation
• Cesarean section (C/S) delivery is required after and it is never removed

Nursing Care with Cerclage

• Patients are discharged with restricted activity and/or bed rest
• Ensure hydration, pelvic rest, and monitor for PROM
• Teach patients how to monitor for signs and symptoms of infection, contractions
• Cervical cerclages will typically be removed around 36-38 weeks gestation
• Teach patients how to administer progesterone vaginally