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Preterm Labor

Labor is the the presence of uterine contractions which are strong and frequent enough to expel the products of conception from the uterus.

Preterm labor is labor which occurs between 20 and 37 weeks. This is the leading cause of neonatal mortality in the United States.

Risk factors

• Multiple gestation (approximately 10% of preterm births)
• Low socioeconomic status
• Mother younger than 18
• Mother older than 40
• Mother with a low pre-pregnancy weight
• Previous premature birth
• Maternal health issues including DM, HTN
• Placental abruption

Clinical presentation

Patient presents in labor before 37 weeks

Clinical presentation of early labor

• Regular contractions 5–8 minutes apart with any one of the following
• Cervical changes
• Cervical dilation of great than 2 cm
• Cervical effacement greater than 80%

Clinical presentation of labor

• Pressure
• Watery or bloody vaginal discharge
• Low back pain

Diagnostic Tests

• U/S – Examine the cervix – Monitor fetal health

Treatment

• Bed rest
• Tocolytics (anti labor/contraction med). Magnesium
• Steroids for fetal lung development
• Surgically a cervical cerclage may be of benefit for an incompetent cervix

Premature Rupture of Membranes (PROM)

PROM – a patient more than 37 weeks gestation presents with ruptured membranes prior to the onset of labor. Most will quickly go on to labor.

Preterm Premature Rupture of Membranes (PPROM) -a patient presents before 37 weeks gestation with ruptured membranes prior to the onset of labor.

PROM happens in about 10% of all pregnancies. PPROM occurs in about 3% of all pregnancies and will lead to 30–40% of preterm deliveries.

Clinical Presentation

• Leakage of fluid from the vagina
• Pelvic Pressure
• Vaginal Bleeding
• No contractions

Physical Exam findings

• Pooling of fluid in the vagina
• Visualization of fluid leaking from the cervix

Labs/Testing

• U/S
  • Assess fluid volume in the uterus
  • Monitor fetal health

Treatment

• Deliver the baby, but consider gestational age
• Fetus greater than 32 weeks prognosis is good
• Infection rate is 10% within 24 hours.
• Infection is an indication for immediate delivery
• No digital exams
• Steroids for lung maturity between 24 and 34 weeks

Labor and Delivery

Labor – “uterine contractions that bring about demonstrable effacement and dilation of the cervix” – Williams Obstetrics

Clinical Presentation

• Braxton Hicks’ contractions – begin in the first trimester but a typically are not felt until the third trimester.
  • Irregular
  • Do not get closer together -Do not get more forceful -Typically dissipate with walking or even change in position
• “My water broke” – amniotic fluid from the vagina.
• Bloody show – passage of mucus plug which was covering the cervix.
• “True” contractions -Regular intervals -Last about 60 seconds -Progress in strength -Get closer together -Felt more in the lower back

Labs and Studies

• Urinalysis
• CBC
• BMP

Physical Exam Findings

• Cervical dilation
• Station of fetus
  • Presenting part in relation to ischial spines, –3cm, –2cm, –1cm, 0, +1cm, +2, cm, +3 cm -Vitals – BP, pulse, temperature
• Internal or external monitors are used to track uterine contractions and the babies heart rate.
• Normal fetal heart rate is 120–160bpm

Stages of Labor

First stage

The longest phase of labor and begins with true contractions and ends with full dilation of the cervix

• Early phase
  •  0–3 cm dilation
  • 8 –12 hours
• Active phase
  • 3–7 cm dilation
  • 3–5 hours (typically when people come into the hospital)
• Transition phase
  • 7–10 cm dilation
  • 30 min–2 hours

Second stage

• Full dilation to delivery
• 20min – 2 hours

Third stage

• Delivery of infant to delivery of placenta
• 5–30 minutes
• Uterus contracts and the cord seems to lengthen as it detaches from the uterus.
• There is an increase in blood from the vagina and the placenta follows soon after.
• The placenta should be intact, remnants can cause postpartum bleeding
• The cord should have two arteries and one vein

Fourth stage

• Technically not a stage of labor
• Assessment and treatment of lacerations, tears or hemorrhage
• Often Oxytocin is given to help the uterus contract which decreases the volume of blood loss

Postpartum Complications

Hemorrhage

• The uterus and placenta receive between 500–800 mls of blood per minute.

Early postpartum hemorrhage

Account for 99% of cases and occur less than 24 hours after delivery

Causes

• Uterine atony
  • As the uterus contracts the blood vessels, which run in a corkscrew pattern, will naturally tamponade.
• Retained portions of placenta
• Cervical or vaginal laceration

Late Postpartum Hemorrhage

• Greater than 24 hours after delivery

Causes

• Uterine atony
• Endometritis
• Retained products of conception

Clinical Presentation

• Increased bleeding from the vagina
• Pain
• Fever may be present
• Uterus feels boggy or soft and remains enlarged

Tests and Labs

• H&H
• CBC, elevated WBC’s may indicate toxic shock or endometritis
• PT, aPTT, INR
• BMP
• Type and Cross
• U/S may show signs of retained placenta or products of conception

Treatment

• Uterine massage and compression!!
• Uterotonic medications including oxytocine,methylgonovine (Methergine), prostaglandines
• Fluids/blood transfusion
• Consider surgical intervention if bleeding is uncontrollable

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