Preterm labor nursing: tocolysis agents, antenatal corticosteroids, and PPROM management

Preterm labor – the onset of regular contractions with cervical change before 37+0 weeks gestation – precedes about half of all preterm births, and preterm birth affects roughly 1 in 10 US births (10.41% in 2024). ACOG calls preterm birth the leading cause of neonatal mortality: it accounts for approximately 70% of neonatal deaths and 36% of infant deaths in the United States. For nurses working in labor and delivery, antepartum, or maternal-fetal medicine settings, recognizing preterm labor early and executing the correct interventions in the right sequence can meaningfully change neonatal outcomes. The priorities are clear: confirm the diagnosis, administer antenatal corticosteroids to mature fetal lungs, suppress contractions long enough for steroids to work, and prepare both the family and the NICU team. This reference covers the complete clinical picture – from diagnosis criteria and risk stratification through tocolytic management, magnesium monitoring, PPROM protocols, and the NCLEX concepts tested most frequently.

Quick reference: preterm labor at a glance

Definition and classification

Preterm birth is defined by the World Health Organization and ACOG as delivery before 37 completed weeks of gestation (37+0 weeks). The sub-classification by gestational age matters clinically because it shapes resuscitation decisions, NICU resource allocation, and parental counseling:

• Extremely preterm (less than 28+0 weeks): the highest-acuity group. Survival rates have improved substantially with modern NICU care, but survivors face significant risks of chronic lung disease, neurodevelopmental disability, retinopathy of prematurity, and necrotizing enterocolitis. A neonatal resuscitation team should be present at delivery.
• Very preterm (28+0 to 31+6 weeks): substantial risk; antenatal corticosteroids, magnesium sulfate for neuroprotection, and NICU-level care are all indicated.
• Moderate preterm (32+0 to 33+6 weeks): corticosteroids remain indicated and tocolysis may be used to complete the course; magnesium for neuroprotection is reserved for births before 32 weeks.
• Late preterm (34+0 to 36+6 weeks): the largest sub-category, accounting for roughly three-quarters of preterm births (7.69% of all US births in 2024, against an overall preterm rate of 10.41%). Though often perceived as “almost term,” late preterm infants have meaningfully higher rates of respiratory distress, hypoglycemia, feeding difficulties, and NICU admission than term infants. A single course of betamethasone is recommended for this group if no prior course has been given (ACOG Committee Opinion 713, 2017).

ACOG defines preterm labor as regular uterine contractions accompanied by a change in cervical dilation, effacement, or both – or regular contractions with cervical dilation of at least 2 cm at initial presentation. Contractions alone without cervical change do not confirm preterm labor, and ACOG advises that patients with preterm contractions but no cervical change, especially with dilation under 2 cm, generally should not receive tocolytics. Many of these patients do not deliver preterm.

Ruling out false labor: fFN and cervical length

Two tools help stratify risk before committing to inpatient treatment:

Fetal fibronectin (fFN) is a glycoprotein found at the interface between the chorion and the decidua. Normally present before 22 weeks and near term, a positive fFN between 22+0 and 34+6 weeks suggests disruption of the fetal-maternal interface. A negative result is the clinically useful finding – its high negative predictive value means delivery within the next 7–14 days is unlikely, which can help avoid unnecessary tocolysis and admission. A positive result is far less informative: ACOG notes that the positive predictive value of a positive fFN or a short cervix alone is poor, and neither should be used by itself to direct management of acute symptoms. A 2019 Cochrane review of six trials in symptomatic patients found that management based on a known fFN result may make little or no difference to preterm birth before 34 weeks or maternal hospitalization, on low-quality evidence (Berghella and Saccone). Collect the specimen before any digital cervical exam, transvaginal ultrasound, or lubricant use; recent intercourse (within 24 hours), vaginal bleeding, or ruptured membranes can produce a false positive.

Cervical length by transvaginal ultrasound provides independent risk stratification. In the NICHD cervical length study, risk of spontaneous preterm birth rose steadily as cervical length at 24 weeks fell (Iams 1996). In symptomatic patients, a cervical length above 30 mm makes preterm birth unlikely, and fFN is most useful when length is intermediate. In asymptomatic patients with a singleton pregnancy and no prior spontaneous preterm birth, a cervical length of 20 mm or less before 24 weeks is an indication for daily vaginal progesterone, which should also be considered at 21–25 mm through shared decision-making (SMFM Consult Series #70, 2024; ACOG Practice Bulletin 234). Patients with a prior spontaneous preterm birth before 34 weeks and a cervix shorter than 25 mm before 24 weeks may be offered cerclage. Intramuscular 17-hydroxyprogesterone caproate (17-OHPC, Makena) is no longer an option: the FDA withdrew its approval on April 6, 2023, after the confirmatory trial failed to show benefit. Progesterone is a prevention strategy and is not a treatment for active preterm labor.

Risk factors

Prior spontaneous preterm birth is the strongest historical risk factor for preterm birth; ACOG notes it is commonly reported to confer a 1.5- to 2-fold increased risk in the next pregnancy, and the risk climbs with the number of prior preterm births and the earlier they occurred. Other major risk factors include:

• Multiple gestation (twins, triplets): uterine overdistension and cervical incompetence increase risk substantially
• Cervical insufficiency / short cervix: previous LEEP or cone biopsy, prior painless second-trimester cervical dilation; selected patients are managed with cerclage (Suhag and Berghella 2014)
• Intrauterine infection / chorioamnionitis: ascending bacteria from the lower genital tract trigger prostaglandin release and cervical ripening
• Preterm premature rupture of membranes (PPROM): membrane rupture before 37 weeks without labor onset; responsible for approximately one-third of preterm births
• Uterine anomalies: septate uterus, bicornuate uterus, large fibroids distorting the cavity
• Substance use: cocaine, methamphetamine, and tobacco use are all independently associated with preterm birth and fetal growth restriction
• Socioeconomic and demographic factors: Black women in the United States experience preterm birth at roughly 1.6× the rate of White women (14.86% vs 9.49% in 2024; NCHS final birth data), a disparity linked to chronic stress, structural racism, and unequal access to prenatal care, with race acting as a marker of exposure to these factors
• Gestational diabetes and preeclampsia: both conditions increase preterm birth risk; refer to the gestational diabetes nursing reference and the preeclampsia nursing reference for management of these comorbidities

Nursing assessment

When a patient presents with possible preterm labor, the nursing assessment should proceed systematically:

1. Uterine activity monitoring: Place the patient on continuous external electronic fetal monitoring (EFM). Assess contraction frequency (minutes between starts), duration (seconds), and intensity (palpation). Establish a baseline fetal heart rate and assess for category II or III FHR patterns that might indicate fetal compromise.

2. Cervical assessment: Perform a sterile vaginal exam if membranes are intact (or use sterile speculum exam if rupture is suspected) to document dilation (0–10 cm), effacement (0–100%), station (−5 to +5), consistency, and position. Document serially to identify change. Note: if PPROM is suspected, avoid digital exam – use sterile speculum only.

3. Rule out PPROM: Assess for pooling of fluid in the posterior vaginal vault on speculum exam. Confirm with:

• Nitrazine (pH) test: amniotic fluid is alkaline (pH 7.1–7.3); a positive Nitrazine result turns paper blue. False positives occur with blood, semen, or vaginosis.
• Ferning: amniotic fluid on a dry slide forms a fern-like crystallization pattern under microscopy.
• AmniSure (PAMG-1) or ROM Plus tests: immunoassay-based; higher sensitivity and specificity than Nitrazine or ferning.

4. Vital signs and infection assessment: Obtain maternal temperature, heart rate, blood pressure, and respiratory rate. Fever above 38°C in a patient with preterm labor or PPROM raises concern for chorioamnionitis and requires further evaluation (fundal tenderness, maternal and fetal tachycardia, foul-smelling discharge, elevated WBC).

5. Hydration assessment: Assess for clinical dehydration (urine specific gravity, mucous membranes, intake history) and correct it if present. ACOG lists hydration and bed rest among practices with little evidence of effectiveness for preventing or treating preterm labor, so a fluid bolus should not be relied on to stop contractions in a well-hydrated patient, and excess IV fluid adds risk if magnesium or a beta-agonist follows.

6. Laboratory workup (per provider order): CBC with differential, vaginal-rectal GBS culture (if status unknown), urinalysis and urine culture (urinary infection is a common preterm labor trigger), and fFN collection before any cervical exam.

Medical management and nursing interventions

Antenatal corticosteroids – the priority intervention

Antenatal corticosteroids (ACS) are the single most important intervention in preterm labor. They accelerate fetal lung maturation by stimulating surfactant production. In the 2020 Cochrane review (McGoldrick et al.), ACS reduced respiratory distress syndrome (RDS) by about 29% (RR 0.71, 95% CI 0.65–0.78), neonatal death by about 22% (RR 0.78, 95% CI 0.70–0.87), and perinatal death (RR 0.85), all on high-certainty evidence, and probably reduced intraventricular hemorrhage (IVH) by about 42% (RR 0.58, 95% CI 0.45–0.75). The 2020 update removed trials that failed new trustworthiness screening and supersedes the 2017 version (Roberts et al.), which had reported larger effects.

Regimens:

• Betamethasone: 12 mg IM × 2 doses, given 24 hours apart (the standard regimen in the United States)
• Dexamethasone: 6 mg IM × 4 doses, given 12 hours apart (used when betamethasone is unavailable; equivalent efficacy for most outcomes)

Gestational age windows (ACOG Committee Opinion 713 and 2021 practice advisory):

• Recommended from 24+0 to 33+6 weeks for patients at risk of delivery within 7 days, including those with ruptured membranes or multiple gestation
• May be considered from 23+0 weeks, and from 22+0 weeks when neonatal resuscitation is planned after family counseling
• 34+0 to 36+6 weeks (late preterm): a single betamethasone course for patients at risk of delivery within 7 days who have not received a prior course. In the ALPS trial, betamethasone lowered the neonatal respiratory composite from 14.4% to 11.6% but raised neonatal hypoglycemia from 15.0% to 24.0%, so these newborns need glucose monitoring. ALPS excluded multiple gestations, pregestational diabetes, and chorioamnionitis, and tocolysis is not used to delay delivery for late preterm steroids.

Timing of benefit: Benefit is greatest when delivery occurs 2–7 days after the first dose, and ACOG advises giving ACS even when delivery is expected before the second dose. A single course is the standard. A single repeat course should be considered at less than 34 weeks if the patient is at risk of delivery within 7 days and the prior course was given more than 14 days earlier; a rescue course can be given as early as 7 days after the prior dose when the clinical picture warrants. Regularly scheduled or serial courses (more than two) are not recommended.

Nursing responsibilities: Administer IM (gluteal muscle – rotate sites for second dose), document time of each injection precisely, and educate the patient: “We’re giving you two steroid injections to help mature your baby’s lungs in case delivery happens soon. The full benefit takes about 24 hours, so every hour we can buy matters.”

Tocolytics – suppressing contractions

Tocolytics have not been shown to prevent preterm birth or to directly improve neonatal outcomes. Their value is short-term: ACOG supports first-line tocolysis with a beta-adrenergic agonist, a calcium channel blocker, or an NSAID to prolong pregnancy for up to 48 hours, which buys time to complete corticosteroids, give magnesium for neuroprotection, and transfer the patient to a center with an appropriate NICU. Maintenance tocolysis after that window is not effective and is not recommended, and tocolysis is generally not offered before viability or from 34 weeks (ACOG Practice Bulletin 171, 2016).

Tocolysis is contraindicated when continuing the pregnancy is riskier than delivery: intrauterine fetal demise, a lethal fetal anomaly, nonreassuring fetal status, severe preeclampsia or eclampsia, maternal hemorrhage with hemodynamic instability, intraamniotic infection, or a maternal contraindication to the specific drug.

Magnesium sulfate is still used as a tocolytic in some units, often because the patient is already receiving it for neuroprotection. The evidence does not support that role: a 2014 Cochrane review found magnesium sulfate ineffective at delaying or preventing preterm birth compared with placebo or other tocolytics (Crowther et al.). In 2013 the FDA advised against continuous magnesium sulfate for more than 5–7 days because of fetal hypocalcemia and bone abnormalities. ACOG and SMFM responded in 2016 by supporting short courses, usually under 48 hours, for appropriate indications (Committee Opinion 652, since withdrawn by ACOG); the neuroprotection guidance in Committee Opinion 455 remains current.

Magnesium sulfate nursing monitoring in depth: Because MgSO4 is given in preterm labor for fetal neuroprotection (see below), sometimes doubling as a tocolytic, and because toxicity can be life-threatening, nurses must know the progression of toxicity findings by serum level (Lu and Nightingale 2000):

• Therapeutic range: commonly cited as 4–7 mEq/L (4.8–8.4 mg/dL, or 2–3.5 mmol/L); many labs report magnesium in mg/dL, so check the units before comparing a result with these thresholds
• Loss of patellar deep tendon reflexes (DTRs): about 7–10 mEq/L (3.5–5 mmol/L) – the earliest reliable clinical sign of toxicity; check DTRs every 1–2 hours during infusion
• Respiratory depression and paralysis: about 10–13 mEq/L (5–6.5 mmol/L) – treat RR <12/min as a hard stop
• Cardiac conduction changes (prolonged PR and QRS, heart block): about 15–25 mEq/L
• Cardiac arrest: above 25 mEq/L (12.5 mmol/L)

Urine output must be maintained at ≥30 mL/hr because magnesium is renally cleared – oliguria rapidly raises serum levels into the toxic range. If urine output falls below 30 mL/hr, notify the provider promptly; the order may be to reduce or stop the infusion and check a serum level. If DTRs are absent or respirations fall below 12/min, stop the infusion and call for help. The antidote – calcium gluconate 1 g (10 mL of 10% solution) IV push over 3 minutes – must be drawn up and at the bedside for every patient on a MgSO4 infusion. See the electrolyte imbalances nursing reference for additional magnesium physiology.

Magnesium sulfate for fetal neuroprotection

Magnesium sulfate given before anticipated delivery at less than 32 weeks reduces cerebral palsy in surviving infants. In the NICHD MFMU BEAM trial (Rouse et al., NEJM 2008; 24–31 weeks), moderate or severe cerebral palsy fell from 3.5% to 1.9% (RR 0.55, 95% CI 0.32–0.95), although the primary composite of stillbirth, infant death, or cerebral palsy did not differ. Meta-analyses confirm the effect: the 2009 Cochrane review found a cerebral palsy RR of 0.68 (95% CI 0.54–0.87), with 63 women treated to prevent one case (Doyle et al.), and the 2017 individual participant data meta-analysis found the same RR 0.68 with no increase in mortality (Crowther et al.).

This is a separate indication from tocolysis. ACOG and SMFM support magnesium for neuroprotection before anticipated early preterm birth (less than 32 weeks) and ask each unit to set its own criteria for drug choice and timing (ACOG Committee Opinion 455). In BEAM, delivery was considered imminent with cervical dilation of 4–8 cm and intact membranes, or with preterm PROM; magnesium is also given before indicated preterm births under 32 weeks. The infusion and nursing monitoring are the same as above. If delivery no longer appears imminent, the infusion is discontinued.

GBS prophylaxis

Group B Streptococcus colonization at the time of preterm delivery carries significant neonatal sepsis risk. Per ACOG Committee Opinion 797 (2020), a patient in preterm labor with unknown GBS status should have a vaginal-rectal GBS culture collected and intrapartum prophylaxis started; if she is found not to be in true labor, prophylaxis is stopped, and a negative culture within 5 weeks means it is not needed at a later admission. Prophylaxis is also given when the patient is GBS-positive. Regimens:

• Penicillin G 5 million units IV × 1 loading dose, then 2.5–3 million units IV every 4 hours until delivery (first-line)
• Ampicillin 2 g IV × 1, then 1 g IV every 4 hours (acceptable alternative)
• Penicillin allergy (low anaphylaxis risk): cefazolin 2 g IV × 1, then 1 g IV every 8 hours
• Penicillin allergy (high anaphylaxis risk): clindamycin 900 mg IV every 8 hours if the isolate is susceptible; otherwise vancomycin 20 mg/kg IV every 8 hours (maximum 2 g per dose)

Antibiotics given only to prolong pregnancy in preterm labor with intact membranes are not recommended (ACOG Practice Bulletin 171); GBS prophylaxis is a different indication.

PPROM-specific management

When preterm labor is complicated by premature rupture of membranes, the clinical priorities shift. The patient is now at risk for ascending infection (chorioamnionitis), umbilical cord prolapse, and fetal malpresentation. Key nursing actions:

1. Confirm rupture: Sterile speculum exam only – no digital exam (digital exam dramatically increases infection risk by introducing vaginal flora into the cervical os). Check for pooling, perform Nitrazine and ferning tests, or use AmniSure.

2. Latency antibiotics (expectant management before 34 weeks): Ampicillin 2 g IV every 6 hours plus erythromycin 250 mg IV every 6 hours for 48 hours, followed by amoxicillin 250 mg orally every 8 hours plus erythromycin base 333 mg orally every 8 hours for 5 days – the 7-day regimen from the NICHD MFMU trial (Mercer et al., JAMA 1997) endorsed in ACOG Practice Bulletin 217. This regimen prolongs latency and reduces maternal and neonatal infection. When erythromycin is unavailable, ACOG notes that a single oral dose of azithromycin 1 g is a reasonable substitute. Amoxicillin-clavulanate is avoided because it has been linked to higher rates of necrotizing enterocolitis.

3. Other PPROM treatment: Corticosteroids are given at 24+0 to 33+6 weeks (considered from 23+0), magnesium for neuroprotection before 32 weeks when delivery is anticipated, and GBS prophylaxis as indicated. ACOG notes that tocolysis can be considered for steroid benefit or maternal transport but is not recommended between 34+0 and 36+6 weeks. At 34+0 to 36+6 weeks, either immediate delivery or expectant management is a reasonable option after shared decision-making; expectant management should not continue beyond 37+0 weeks.

4. Surveillance for intraamniotic infection (chorioamnionitis): Monitor maternal temperature every 2–4 hours or per protocol, fetal heart rate baseline (fetal tachycardia above 160 bpm can be an early sign), maternal heart rate, and fundal tenderness. Purulent or foul-smelling amniotic fluid is a later finding, and maternal leukocytosis (WBC above 15,000/mm³) supports the diagnosis. ACOG Committee Opinion 712 defines suspected intraamniotic infection as maternal fever of 39.0°C or higher, or 38.0–38.9°C with at least one other clinical risk factor. Once intraamniotic infection is diagnosed, broad-spectrum antibiotics are started and delivery is indicated regardless of gestational age; the infection is not managed expectantly.

5. Activity and monitoring: Modified activity rather than strict bed rest (ACOG lists bed rest among practices with little evidence of benefit, and prolonged immobility raises thromboembolism risk), regular vital signs, fetal movement counts, periodic non-stress tests or biophysical profiles per protocol, and serial ultrasound for growth and amniotic fluid.

Clinical applications

In labor and delivery

When a patient arrives at triage with uterine contractions at 29 weeks, the nursing priority sequence is: establish IV access, place EFM, collect fFN before any vaginal exam, perform sterile speculum exam first if rupture is suspected, and notify the provider. Once the diagnosis of preterm labor is confirmed, corticosteroids should be ordered and administered before the patient is transferred to antepartum – the steroid clock starts the moment the first injection is given.

For patients already admitted on MgSO4, the most important nursing task is scheduled reflex and respiratory checks (every 1–2 hours, or more often per protocol). A nurse who misses early DTR loss before the provider is notified is the critical failure point in MgSO4 toxicity events. Never leave these assessments to “as needed” status – build them into the care rhythm as a timed intervention.

Patient education priorities

Patients sent home after an episode of preterm contractions that resolved need to know the warning signs requiring immediate return: regular contractions every 10 minutes or more frequently (even if painless), pelvic pressure or a feeling that the baby is pushing down, low dull back pain (especially rhythmic), watery or bloody vaginal discharge, or the sensation that something has “popped.” Pelvic rest is sometimes prescribed; if it is, explain specifically what it means (no intercourse, no tampons, nothing in the vagina). Strict bed rest is not recommended, because ACOG finds little evidence that it prevents preterm birth and it carries risks such as blood clots and deconditioning. Encourage normal fluid intake; extra hydration has not been shown to prevent preterm labor. Patients with a prior spontaneous preterm birth or a short cervix should know about prevention options (vaginal progesterone, cerclage) for future pregnancies. Smoking cessation counseling should occur at every encounter given the established association between tobacco and preterm birth.

Coordination with the NICU team

When delivery before 34 weeks appears imminent, involve the NICU team early. A team with full neonatal resuscitation skills, including intubation, should be present at any preterm birth, and units commonly define which gestational ages trigger NICU attendance. Parents benefit from a pre-delivery consultation with the neonatology team – hearing survival statistics, likely length of NICU stay, and what the first hours look like reduces parental anxiety and supports informed consent for resuscitation decisions at the margin of viability. See the obstetric nursing reference for the broader context of high-risk obstetric nursing care.

Common confusions

Preterm labor vs. preterm PROM: Preterm labor has intact membranes with contractions and cervical change. PPROM has ruptured membranes before the onset of labor – labor may follow within hours or days, or may be delayed for weeks. Management differs: the initial exam differs (speculum only in PPROM), latency antibiotics are recommended in PPROM before 34 weeks but are not given to prolong pregnancy when membranes are intact, and infection surveillance is more intensive. On NCLEX, if you see “gush of fluid” or “pooling” – think PPROM first and avoid the digital exam.

Tocolysis vs. cervical ripening: Tocolytics suppress contractions to delay delivery. Cervical ripening agents (misoprostol, dinoprostone, mechanical dilation) promote delivery. These are never used together. The prostaglandin link runs in opposite directions: indomethacin blocks prostaglandin synthesis to quiet the uterus, while misoprostol (a prostaglandin E1 analog) and dinoprostone (prostaglandin E2) supply prostaglandin to ripen the cervix and stimulate contractions.

Nifedipine vs. magnesium: They work by different mechanisms (calcium channel blockade vs. CNS depression/calcium antagonism), and only nifedipine is an effective first-line tocolytic. Case reports described neuromuscular blockade and profound hypotension when the two were combined, so many protocols advise caution. A 2005 cohort study found no increase in serious magnesium-related effects when nifedipine was added (Magee et al.), and the combination is used routinely in preeclampsia. On NCLEX, the expected nursing response is closer blood pressure, reflex, and respiratory monitoring and provider awareness of both drugs; an absolute ban is not the expected answer.

Betamethasone for fetal lungs vs. corticosteroids for maternal illness: Students sometimes confuse antenatal corticosteroids (given to the mother to benefit the fetus) with systemic steroids prescribed for maternal conditions like asthma. These are different indications. Betamethasone administered IM for fetal lung maturation is a time-sensitive obstetric intervention – it should never be delayed waiting for a second opinion.

NCLEX high-yield points

1. Betamethasone is always the priority. Before tocolytics, before antibiotics (except GBS prophylaxis if delivery is imminent), before most other interventions – administer antenatal corticosteroids. They are recommended from 24+0 to 33+6 weeks when delivery is likely within 7 days, may be considered from 22–23 weeks, and a single late preterm course may be given at 34+0 to 36+6 weeks if no prior course was received.

2. MgSO4 antidote = calcium gluconate 1 g IV. It must be at the bedside. If asked what to do first when you see signs of magnesium toxicity, the answer is: stop the infusion AND have calcium gluconate ready.

3. Loss of patellar DTRs is the first clinical warning sign of MgSO4 toxicity (about 7–10 mEq/L). Check them every 1–2 hours. If the reflex is absent, stop the infusion and notify the provider immediately.

4. Minimum urine output = 30 mL/hr on MgSO4. Magnesium is renally cleared. Below 30 mL/hr, the drug accumulates and serum levels rise toward toxic range.

5. Avoid indomethacin at 32 weeks or later. From 32 weeks, the fetal ductus arteriosus is sensitive to prostaglandin inhibition and can constrict prematurely, causing pulmonary hypertension. Limit use to <32 weeks for no more than 48 hours.

6. Nifedipine plus magnesium sulfate calls for closer monitoring. Case reports linked the combination to neuromuscular blockade and hypotension, but a 2005 cohort found no excess of serious magnesium-related effects. The expected nursing answer is to monitor blood pressure, reflexes, and respirations closely and make sure the provider knows both drugs are running.

7. Terbutaline: monitor maternal HR and blood glucose. Beta-2 stimulation causes tachycardia and promotes glycogenolysis (hyperglycemia). Also watch for hypokalemia and chest pain. Terbutaline carries an FDA boxed warning: injectable terbutaline must not be used for prolonged tocolysis (beyond 48–72 hours), and oral terbutaline must not be used for preterm labor at all.

8. Negative fFN = high reassurance. A negative fetal fibronectin result has a high negative predictive value, making delivery within 7–14 days unlikely. It helps rule out true preterm labor and avoid unnecessary hospitalization or tocolytic treatment; a positive result alone should not drive management.

9. GBS prophylaxis is indicated when GBS status is unknown or positive and preterm delivery is anticipated. Penicillin G is first-line. Begin infusion as early as possible – the goal is ≥4 hours of antibiotics before delivery.

10. Chorioamnionitis signs: fever, uterine tenderness, fetal tachycardia, maternal tachycardia, foul amniotic fluid odor. When chorioamnionitis is diagnosed, delivery is the treatment – regardless of gestational age. Tocolytics are contraindicated in the setting of active intra-amniotic infection.

Related references

For a complete picture of high-risk obstetric nursing, this article works alongside several companion references on this site. The obstetric nursing reference covers the full scope of antepartum and intrapartum care. The postpartum hemorrhage nursing reference addresses the immediate postpartum period, which can follow preterm delivery after tocolysis fails. The preeclampsia nursing reference covers an overlapping patient population – preeclampsia is a common reason for indicated preterm delivery. The gestational diabetes nursing reference covers another condition linked to increased preterm risk. For interpreting the laboratory values relevant to magnesium monitoring, infection workup, and coagulation status in these patients, see the nursing lab values cheat sheet.

References

1. American College of Obstetricians and Gynecologists. Practice Bulletin No. 171: Management of preterm labor. Obstet Gynecol. 2016;128(4):e155–e164. doi:10.1097/AOG.0000000000001711. Reaffirmed 2022.
2. American College of Obstetricians and Gynecologists. Committee Opinion No. 713: Antenatal corticosteroid therapy for fetal maturation. Obstet Gynecol. 2017;130(2):e102–e109. doi:10.1097/AOG.0000000000002237. Reaffirmed 2024.
3. American College of Obstetricians and Gynecologists; Society for Maternal-Fetal Medicine. Practice Advisory: Use of antenatal corticosteroids at 22 weeks of gestation. September 2021.
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