What is the classification and management of term vs preterm pregnancy in a female patient of childbearing age with a history of pregnancy or current pregnancy?

Classification of Term and Preterm Pregnancy

Pregnancy should be classified using the refined gestational age categories established by ACOG: preterm (<37 weeks), early term (37 0/7-38 6/7 weeks), full term (39 0/7-40 6/7 weeks), late term (41 0/7-41 6/7 weeks), and postterm (≥42 weeks), as these distinctions carry significant implications for neonatal outcomes and delivery timing. 1

Preterm Birth Classification

Preterm birth is stratified into three severity categories based on gestational age, with progressively worsening neonatal outcomes 2:

• Mild preterm: 32-36 weeks gestation 2
• Very preterm: 28-31 weeks gestation 2
• Extremely preterm: <28 weeks gestation 2

Etiology-Based Classification

Preterm births arise from three distinct pathways 2:

• Medically indicated (iatrogenic): 25% of cases, primarily due to maternal-fetal conditions requiring early delivery 2
• Preterm premature rupture of membranes (PPROM): 25% of cases, predominantly infection-related 2
• Spontaneous (idiopathic): 50% of cases, associated with lifestyle factors and stress 2

Multiple pregnancies account for 10% of all preterm births, with 50% delivered for medical indications. 2

Term Pregnancy Refined Classification

The traditional 37-42 week "term" designation has been abandoned because neonatal outcomes vary significantly within this range 3, 1. The current evidence-based classification system recognizes four distinct categories 1:

Early Term (37 0/7 - 38 6/7 weeks)

• Associated with increased neonatal mortality and morbidity compared to later term births 3
• Respiratory complications are notably higher in this window 1
• Elective delivery should be avoided during this period unless medically indicated 3

Full Term (39 0/7 - 40 6/7 weeks)

• Represents the optimal delivery window for uncomplicated pregnancies 1
• Recent evidence supports considering elective induction in low-risk nulliparous patients starting at 39 0/7 weeks, which decreases cesarean deliveries and hypertensive disorders 4

Late Term (41 0/7 - 41 6/7 weeks)

• Requires initiation of antepartum monitoring to mitigate risks of perinatal morbidity and mortality 4
• Induction at 41 weeks reduces perinatal mortality and stillbirth compared to expectant management 4

Postterm (≥42 0/7 weeks)

• Fetal mortality, NICU admission rates, and stillbirth risk increase exponentially at 42 weeks 4
• All patients should undergo induction by 42 weeks gestation 4

Clinical Management Algorithm

For Preterm Presentations (<37 weeks)

At <24 weeks (previable PPROM): Offer abortion care as an option; if expectant management chosen, consider antibiotics at 20 0/7-23 6/7 weeks 5

At 24-34 weeks (periviable PPROM): Administer broad-spectrum antibiotics (IV ampicillin and erythromycin for 48 hours, then oral amoxicillin and erythromycin for 5 days) to prolong latency 5

Monitoring during expectant management: Weekly outpatient visits for vital signs, fetal heart rate, physical examination, and laboratory evaluation; daily home temperature monitoring and assessment for vaginal bleeding, discharge changes, and abdominal pain 5

For Term Presentations (≥37 weeks)

At 37-38 6/7 weeks: Avoid elective delivery; manage complications expectantly when safe 1

At 39-40 6/7 weeks: Optimal delivery window; consider elective induction in low-risk nulliparous patients 4

At 41-41 6/7 weeks: Begin antepartum monitoring; strongly consider induction 4

At ≥42 weeks: Mandatory induction of labor 4

Critical Pitfalls to Avoid

• Do not use the outdated term "term pregnancy" without gestational age specification, as this obscures clinically significant outcome differences 1
• Do not delay delivery planning in postterm pregnancies beyond 42 weeks, as risks escalate exponentially 4
• Do not assume all preterm births share the same etiology; the three distinct pathways (iatrogenic, PPROM, spontaneous) require different preventive and management strategies 2
• Avoid amoxicillin-clavulanic acid in PPROM management due to increased necrotizing enterocolitis risk 5