Care in the Third Trimester of Pregnancy

Key Points

• Third-trimester care prioritizes early detection of maternal-fetal deterioration and labor readiness.
• Interval symptom screening, fetal movement patterns, and focused physical exam guide triage decisions.
• Late-pregnancy labs (including GBS) support intrapartum infection prevention and delivery planning.
• Patient education expands to labor signs, birth plan completion, and newborn-care preparation.

Pathophysiology

Late pregnancy (about 28 weeks through 40 weeks and 6 days) increases physiologic stress on placental, cardiovascular, and metabolic systems. Risk of hypertensive disorders, preterm complications, and fetal compromise is higher, so surveillance frequency and triage sensitivity increase.

Fetal positioning and descent become clinically relevant for intrapartum planning. Third-trimester changes in maternal symptoms can indicate either normal progression or urgent pathology; interpretation requires integrated maternal-fetal assessment.

Classification

• Maternal surveillance domain: BP, edema, symptom triage, and trend review.
• Fetal surveillance domain: Movement counts, heart rate assessment, growth and position monitoring (including Leopold assessment from about 32 weeks when indicated).
• Laboratory domain: CBC/H&H, STI retesting, and GBS screening window (commonly 35 to 37 6/7 weeks; results typically usable for about 5 weeks).
• Preparation domain: Labor education, feeding planning, pediatric-provider selection, and transfer readiness.
• Visit-cadence domain: In uncomplicated pregnancy, visits are commonly every 2 weeks until about 36 weeks, then weekly until birth.

Nursing Assessment

NCLEX Focus

Any change in fetal movement pattern or severe maternal symptom cluster warrants immediate escalation.

• Obtain interval history for bleeding, fluid leakage, contractions, pain, visual change, headache, and decreased fetal movement.
• Include specific late-pregnancy triage cues in interval history: persistent vomiting, dysuria/back pain, dizziness/syncope, Braxton Hicks pattern change, and edema distribution in legs/hands/face.
• In late third trimester, assess whether patient reports regular fetal movement and any sudden deviation from baseline pattern.
• When fetal movement drops, assess reversible contributors such as maternal low glucose status while escalating for potential placental-perfusion compromise.
• Trend BP and edema; treat BP at or above 140/90 mmHg as a preeclampsia warning threshold requiring prompt reassessment.
• Perform fundal-height and fetal heart assessments; evaluate presentation/position when indicated.
• If fundal-height trend differs from expected by more than about 2 cm, coordinate ultrasound growth assessment.
• At or after 36 weeks, interpret fundal-height trends with caution because fetal descent into pelvis can reduce week-to-centimeter approximation.
• During Leopold assessment in late pregnancy, use an ordered four-step sweep (abdomen sides for lie, fetal back location, fundal contents, then suprapubic presenting part) to reduce documentation drift between examiners.
• Use Leopold findings to choose fetal heart auscultation site; fetal heart sounds are usually loudest over the fetal back near the shoulder region.
• Count fetal heart rate for a full 1 minute and document rhythm regularity during office Doppler checks.
• Integrate Leopold findings with fundal-height trend to support bedside fetal-weight estimation before labor.
• When symptoms are positive, coordinate targeted follow-up testing (for example, liver panel with persistent epigastric pain).
• Review third-trimester lab results and required intrapartum prophylaxis plans.
• Review 35 to 37 6/7-week testing set and intrapartum implications: CBC/H&H, syphilis screen, gonorrhea/chlamydia cultures, and vaginal-rectal GBS culture.
• Assess psychosocial adaptation in multiparous patients, including family-role strain, partner-support concerns, and need for prenatal anxiety/depression screening.
• Confirm understanding of labor versus preterm-warning signs.

Nursing Interventions

• Teach daily fetal movement counting and escalation thresholds (goal: at least 10 movements within 2 hours).
• Teach response if movement is absent after 1 hour: change activity (walk briefly), eat/drink, then repeat count for another hour and escalate if threshold is not reached.
• Reinforce when to present to triage for labor, ROM, bleeding, or severe symptoms.
• Explain that daily fetal movement counting begins near the end of the second trimester and continues through the third trimester.
• Coordinate GBS-positive intrapartum antibiotic planning and explain why treatment is timed during labor (recolonization risk if treated too early antepartum); include that maternal GBS carriage is common (about 1 in 4).
• Explain that cervical exam and cervical-ripening assessment commonly begin when indicated at or after 36 weeks, with ripening often earlier in multiparous than primiparous patients.
• Teach travel safety: in uncomplicated pregnancy, commercial air travel is generally acceptable, and long car trips should include hourly stops for voiding and at least 5 minutes of walking.
• Support childbirth preparation, feeding decisions, and postpartum/newborn transition planning.
• Arrange higher-acuity monitoring when growth or maternal signs deviate.

Fetal-Movement Delay

Delayed response to reduced fetal movement can postpone treatment for fetal compromise.

Pharmacology

Drug Class	Examples	Key Nursing Considerations
antibiotics (intrapartum-antibiotic-prophylaxis)	Penicillin and alternatives for GBS contexts	Given during labor, not antepartum eradication, to reduce early-onset neonatal infection.
preeclampsia (antihypertensives-in-pregnancy)	Labetalol and nifedipine contexts	Used for gestational hypertensive disorders with close maternal-fetal monitoring.

Clinical Judgment Application

Clinical Scenario

At 35 weeks, a patient reports markedly reduced fetal movement and new persistent RUQ pain with elevated BP.

• Recognize Cues: Maternal and fetal warning signs are both present.
• Analyze Cues: Pattern suggests potential hypertensive-placental compromise.
• Prioritize Hypotheses: Priority is urgent maternal-fetal assessment and stabilization.
• Generate Solutions: Initiate triage protocol, continuous monitoring, and targeted labs.
• Take Action: Escalate immediately to obstetric team.
• Evaluate Outcomes: Maternal-fetal risks are identified and managed without delay.

Related Concepts

• care-in-the-second-trimester-of-pregnancy - Midpregnancy findings influence third-trimester risk planning.
• choosing-a-birthing-place - Risk evolution may alter recommended delivery setting.
• common-discomforts-of-pregnancy - Distinguish expected discomforts from urgent pathology.
• conditions-limited-to-pregnancy - Third-trimester disorders often require rapid intervention.
• person-and-family-centered-care - Late-pregnancy counseling should include family preparedness.

Self-Check

1. Which third-trimester findings most strongly predict urgent maternal-fetal risk?
2. Why is GBS treatment timed intrapartum rather than earlier in pregnancy?
3. How can nurses improve patient recognition of true labor and emergency signs?