Fall_25_Pre-term_labor

Question 1

How is preterm delivery defined?

Answer 1

Delivery before 37 weeks’ gestation.

Question 2

What percentage of pregnancies result in preterm delivery?

Answer 2

5–9%.

Question 3

What percentage of neonatal deaths are due to preterm birth?

Answer 3

75–80%.

Question 4

What gestational age defines extremely preterm?

Answer 4

Less than 28 weeks.

Question 5

Define very preterm and late preterm.

Answer 5

Very preterm: 28–31 6/7 weeks; Late preterm: 34–36 6/7 weeks.

Question 6

Define peri-viable birth.

Answer 6

Between 20 0/7 and 25 6/7 weeks’ gestation.

Question 7

What are the classifications of low birth weight?

Answer 7

LBW: <2500 g; VLBW: <1500 g; ELBW: <1000 g.

Question 8

What is the survival rate at 28 weeks’ gestation?

Answer 8

Approximately 94%.

Question 9

Which sex has higher neonatal mortality?

Answer 9

Males.

Question 10

What percentage of preterm births occur between 32–36 weeks?

Answer 10

84%.

Question 11

What are common complications of preterm infants?

Answer 11

RDS, IVH, NEC, PDA, sepsis, ROP, metabolic disturbances.

Question 12

What are the three main causes of preterm delivery?

Answer 12

1. Preterm PROM (~25%) 2. Spontaneous preterm labor (~45%) 3. Indicated early delivery (~30%).

Question 13

What percentage of preterm births occur in multiple gestation?

Answer 13

21.6%.

Question 14

What is the leading infectious cause of preterm labor?

Answer 14

Ureaplasma urealyticum.

Question 15

How does short cervical length affect risk?

Answer 15

Increases risk for preterm birth.

Question 16

What interventions have been studied to prevent preterm labor?

Answer 16

Tocolytics, cerclage, antibiotics, progesterone, nutrition, stress reduction.

Question 17

When is prophylactic cerclage performed?

Answer 17

Early second trimester in women with prior mid-trimester losses.

Question 18

Does prophylactic antibiotic therapy prevent preterm labor?

Answer 18

No, not supported by evidence.

Question 19

What therapy may reduce preterm birth risk in women with short cervix?

Answer 19

Vaginal progesterone (<20 mm cervix at ≤24 weeks).

Question 20

Criteria for diagnosing preterm labor?

Answer 20

Gestation 20 0/7–36 6/7 weeks with regular contractions and cervical change or dilation ≥2 cm.

Question 21

What is first step in evaluating suspected preterm labor?

Answer 21

Physical exam, FHR, and contraction monitoring.

Question 22

When is tocolysis indicated?

Answer 22

Between 24 and 34 weeks if fetal/maternal status reassuring and no infection.

Question 23

Name contraindications to tocolysis.

Answer 23

Fetal death, lethal anomalies, chorioamnionitis, severe hemorrhage, nonreassuring status.

Question 24

What benefits do antenatal corticosteroids provide?

Answer 24

Reduce neonatal RDS, IVH, and mortality.

Question 25

When should steroids be given for late preterm birth?

Answer 25

34–37 weeks if delivery expected within 7 days.

Question 26

Are prophylactic antibiotics indicated in intact membranes?

Answer 26

No — only for GBS or preterm PROM.

Question 27

How does magnesium sulfate help the fetus?

Answer 27

Reduces risk of cerebral palsy when given before anticipated early preterm birth.

Question 28

What is rescue cerclage?

Answer 28

Placement when cervix is dilated or membranes prolapsed to prolong gestation.

Question 29

When should cerclage be removed for vaginal delivery?

Answer 29

36–37 weeks.

Question 30

What are contraindications to cerclage?

Answer 30

Chorioamnionitis, preterm PROM, fetal demise, heavy bleeding, or active labor.

Question 31

What are the four main classes of tocolytic agents?

Answer 31

1. Beta-adrenergic agonists 2. Calcium-channel blockers 3. NSAIDs 4. Magnesium sulfate.

Question 32

What is the goal of tocolytic therapy?

Answer 32

Delay delivery 24–48 hours to allow corticosteroid administration.

Question 33

Which tocolytic is first-line?

Answer 33

Nifedipine (calcium-channel blocker).

Question 34

Nifedipine MOA and side effects?

Answer 34

Blocks L-type calcium channels; SE: headache, flushing, dizziness, hypotension; may potentiate volatile anesthetic hypotension.

Question 35

Indomethacin MOA and risks?

Answer 35

COX inhibition → ↓ prostaglandins; SE: GI upset, fetal oligohydramnios; safe for neuraxial anesthesia.

Question 36

Terbutaline MOA and major side effects?

Answer 36

Beta2 agonist → ↑ cAMP → ↓ intracellular Ca; SE: tachycardia, arrhythmias, pulmonary edema, hypokalemia, hyperglycemia; avoid ephedrine.

Question 37

Atosiban mechanism and status in U.S.?

Answer 37

Oxytocin receptor antagonist; not FDA approved (higher perinatal death rate).

Question 38

Magnesium sulfate mechanism and anesthetic relevance?

Answer 38

Ca antagonist; SE: hypotension, sedation, pulmonary edema; potentiates NMBAs—stop before neuraxial anesthesia.

Question 39

Why are preterm infants more prone to acidosis?

Answer 39

Decreased hemoglobin and oxygen-carrying capacity.

Question 40

Long-term complications of prematurity?

Answer 40

BPD, cerebral palsy, developmental delay, hypertension, glucose dysregulation.

Question 41

Why are preterm fetuses more sensitive to anesthetic drugs?

Answer 41

Low protein binding, immature metabolism, incomplete BBB, higher acidosis incidence.

Question 42

Why is bupivacaine preferred for neuraxial anesthesia in preterm parturients?

Answer 42

High protein binding (96%) → low fetal transfer.

Question 43

What local anesthetic is ideal for short cerclage procedures?

Answer 43

2-Chloroprocaine — short-acting and rapidly metabolized.

Question 44

How does neuraxial labor analgesia benefit uteroplacental perfusion?

Answer 44

Reduces catecholamines and improves perfusion if hypotension is avoided.

Question 45

Which anesthesia technique is preferred for preterm cesarean?

Answer 45

Regional (epidural/spinal) — avoids neonatal respiratory depression from GA agents.

Question 46

What increases VTE risk in preterm labor hospitalization?

Answer 46

Prolonged immobility and obesity.

Question 47

What prophylaxis does the National Partnership for Maternal Safety recommend?

Answer 47

LMWH daily or UFH twice daily for patients hospitalized >72 hours.