Preterm Labour Flashcards
What is the definition of preterm birth (PTB)?
Birth before 37 completed weeks of gestation
PTB is a major obstetric problem, with an incidence of 8.6% of annual births.
What is the incidence of preterm birth (PTB) globally?
8.6% of the annual births
The incidence of PTB is increasing throughout the world.
What are the categories of preterm birth based on gestation?
- Extreme prematurity: <28 weeks
- Severe prematurity: 28-31+6 weeks
- Premature: 32-33+6 weeks
- Near term: 34-36+6 weeks
Near term accounts for 60% of premature deliveries.
List some maternal risk factors associated with preterm birth.
- Lower socioeconomic status
- Smoking
- Low pre-pregnancy weight <55kg
- Maternal age <18 years and >40
- Poor nutrition
These factors increase the risk of preterm labor.
What obstetric history risk factors are associated with preterm birth?
- Shortened cervix
- Cervical surgery (e.g., cone biopsy)
- Previous history of repeat TOP
- Previous second trimester miscarriage
These factors contribute to the likelihood of PTB.
What pregnancy complications are risk factors for preterm birth?
- Multiple pregnancy
- Infections
- Bleeding <24 weeks
- Previous preterm delivery (risk: 17 to 37%)
These complications can trigger premature labor.
What are some risks of prematurity for the baby?
- Neonatal death
- Respiratory distress syndrome (RDS)
- Necrotising enterocolitis (NEC)
- Intraventricular haemorrhage (IVH)
- Infection
- Jaundice
- Hypothermia
- Hypoglycaemia
- Long-term: developmental delay, cerebral palsy, blindness, deafness, poor educational attainment, broncho-pulmonary dysplasia
These complications can have severe long-term effects on a child’s health.
What is the aetiology of preterm labor?
- Cervical weakness
- Infection
- Decidual haemorrhage and placental abruption
- Uterine distension from multiple pregnancy
- Maternal illness
- Fetal stress
These factors contribute to initiating preterm labor.
What is the significance of cervical length in assessing preterm birth risk?
A cervical length less than 15 mm is a sensitive predictor of severe prematurity, associated with a 50% risk of delivery prior to 32 weeks’ gestation
Cervical length is measured via transvaginal ultrasound.
What does funnelling of the cervix indicate?
Opening of the internal os with a closed cervix below; an independent risk factor for PTL
Cerclage is not recommended for funnelling in the absence of cervical shortening.
What is fetal fibronectin?
An extracellular matrix glycoprotein found in cervico-vaginal secretions prior to labor
Detection after 24 weeks indicates an increased risk of delivery within 7 days.
What are some preventative strategies for preterm labor?
- Educational programs
- Home uterine activity monitoring
- Cervical suture insertion
- Screening and treating bacterial vaginosis (BV)
Treating BV has shown a documented reduction in preterm birth rates.
What is the role of progesterone in preventing preterm labor?
Acts as an anti-inflammatory agent, reducing the risk of PTL in women with a singleton pregnancy and a previous history of preterm delivery
Evidence on improving neonatal outcomes is limited.
What are the main tocolytics used for managing preterm labor?
- Calcium channel blockers (e.g., nifedipine)
- Oxytocin antagonists (e.g., atosiban)
Ritodrine is no longer recommended due to adverse maternal side effects.
What are the contraindications for tocolysis?
- Severe hemorrhage
- Abruption
- Severe preeclampsia
- Eclampsia
- Intrauterine fetal death
- Severe intrauterine growth restriction
- Fetal maturity
- Chorioamnionitis
These conditions indicate that tocolysis should not be attempted.
What is the optimum time for corticosteroid administration in preterm labor?
24 hours to 7 days before delivery
Corticosteroids increase fetal surfactant and accelerate lung maturity.
What is the significance of GBS in preterm labor?
Intrapartum antibiotics lower the rate of early onset neonatal sepsis
Management can be based on screening cultures or risk factors.
What are prenatal risk factors for Group B Streptococcus (GBS)?
- Previous GBS infected baby
- GBS bacteriuria during current pregnancy
These factors increase the risk of GBS transmission during labor.
What should be done for women with a history of GBS infection?
Offer intravenous antibiotics when labor begins
This applies to those with previous GBS infants or GBS bacteriuria.
What is a key question to evaluate in a patient suspected of preterm labor?
Is the patient in labor?
Other evaluation questions include membrane status and gestational age.
What is the recommended management for GBS screening cultures?
Anogenital culture on all patients at 35-37 weeks
Cultures should be collected without speculum.
What should be offered when a positive GBS culture is obtained?
IV antibiotics when labour begins
This is particularly important for those with prior GBS infants or GBS bacteriuria.
What is the protocol for managing GBS risk factors during labour?
Intrapartum antibiotics given to all women who develop risk factors in labour
There are no routine antenatal cultures recommended.
What treatment is recommended for women with a previous GBS infant or GBS bacteriuria during this pregnancy?
They should be treated with intrapartum antibiotics
This is part of the management based on GBS risk factors.
What is the dosage of Benzylpenicillin for GBS prophylaxis?
3g IV stat dose followed by 1.5g IV every 4 hours until baby born
This is the standard prophylactic treatment for GBS.
What should be administered if there is an allergy to penicillin?
Clindamycin 900 mg IV every 8 hours until delivery
This serves as an alternative for those allergic to penicillin.
What is the management for a newborn showing symptoms of sepsis or born at < 35 weeks?
Full septic evaluation and antibiotics
This is critical for ensuring the health of the newborn.
What is the management for a baby that is asymptomatic and > 35 weeks with intrapartum antibiotics < 4 hours?
Limited sepsis evaluation and close observation for 48 hours
This is to monitor the baby closely for any signs of infection.
What should be done for a baby with intrapartum antibiotics > 4 hours?
Observation for at least 48 hours
This is necessary to monitor for potential complications.
