Preterm Labour Flashcards

1
Q

What is the definition of preterm birth (PTB)?

A

Birth before 37 completed weeks of gestation

PTB is a major obstetric problem, with an incidence of 8.6% of annual births.

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2
Q

What is the incidence of preterm birth (PTB) globally?

A

8.6% of the annual births

The incidence of PTB is increasing throughout the world.

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3
Q

What are the categories of preterm birth based on gestation?

A
  • 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.

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4
Q

List some maternal risk factors associated with preterm birth.

A
  • 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.

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5
Q

What obstetric history risk factors are associated with preterm birth?

A
  • 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.

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6
Q

What pregnancy complications are risk factors for preterm birth?

A
  • Multiple pregnancy
  • Infections
  • Bleeding <24 weeks
  • Previous preterm delivery (risk: 17 to 37%)

These complications can trigger premature labor.

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7
Q

What are some risks of prematurity for the baby?

A
  • 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.

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8
Q

What is the aetiology of preterm labor?

A
  • Cervical weakness
  • Infection
  • Decidual haemorrhage and placental abruption
  • Uterine distension from multiple pregnancy
  • Maternal illness
  • Fetal stress

These factors contribute to initiating preterm labor.

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9
Q

What is the significance of cervical length in assessing preterm birth risk?

A

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.

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10
Q

What does funnelling of the cervix indicate?

A

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.

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11
Q

What is fetal fibronectin?

A

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.

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12
Q

What are some preventative strategies for preterm labor?

A
  • 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.

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13
Q

What is the role of progesterone in preventing preterm labor?

A

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.

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14
Q

What are the main tocolytics used for managing preterm labor?

A
  • Calcium channel blockers (e.g., nifedipine)
  • Oxytocin antagonists (e.g., atosiban)

Ritodrine is no longer recommended due to adverse maternal side effects.

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15
Q

What are the contraindications for tocolysis?

A
  • 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.

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16
Q

What is the optimum time for corticosteroid administration in preterm labor?

A

24 hours to 7 days before delivery

Corticosteroids increase fetal surfactant and accelerate lung maturity.

17
Q

What is the significance of GBS in preterm labor?

A

Intrapartum antibiotics lower the rate of early onset neonatal sepsis

Management can be based on screening cultures or risk factors.

18
Q

What are prenatal risk factors for Group B Streptococcus (GBS)?

A
  • Previous GBS infected baby
  • GBS bacteriuria during current pregnancy

These factors increase the risk of GBS transmission during labor.

19
Q

What should be done for women with a history of GBS infection?

A

Offer intravenous antibiotics when labor begins

This applies to those with previous GBS infants or GBS bacteriuria.

20
Q

What is a key question to evaluate in a patient suspected of preterm labor?

A

Is the patient in labor?

Other evaluation questions include membrane status and gestational age.

21
Q

What is the recommended management for GBS screening cultures?

A

Anogenital culture on all patients at 35-37 weeks

Cultures should be collected without speculum.

22
Q

What should be offered when a positive GBS culture is obtained?

A

IV antibiotics when labour begins

This is particularly important for those with prior GBS infants or GBS bacteriuria.

23
Q

What is the protocol for managing GBS risk factors during labour?

A

Intrapartum antibiotics given to all women who develop risk factors in labour

There are no routine antenatal cultures recommended.

24
Q

What treatment is recommended for women with a previous GBS infant or GBS bacteriuria during this pregnancy?

A

They should be treated with intrapartum antibiotics

This is part of the management based on GBS risk factors.

25
Q

What is the dosage of Benzylpenicillin for GBS prophylaxis?

A

3g IV stat dose followed by 1.5g IV every 4 hours until baby born

This is the standard prophylactic treatment for GBS.

26
Q

What should be administered if there is an allergy to penicillin?

A

Clindamycin 900 mg IV every 8 hours until delivery

This serves as an alternative for those allergic to penicillin.

27
Q

What is the management for a newborn showing symptoms of sepsis or born at < 35 weeks?

A

Full septic evaluation and antibiotics

This is critical for ensuring the health of the newborn.

28
Q

What is the management for a baby that is asymptomatic and > 35 weeks with intrapartum antibiotics < 4 hours?

A

Limited sepsis evaluation and close observation for 48 hours

This is to monitor the baby closely for any signs of infection.

29
Q

What should be done for a baby with intrapartum antibiotics > 4 hours?

A

Observation for at least 48 hours

This is necessary to monitor for potential complications.