CurrentAetnaPolicy 0088

Antepartum Fetal Surveillance

Defines medical necessity, coverage, and coding guidance for antepartum fetal surveillance tests (NST, CST, BPP, modified BPP, and Doppler velocimetry) for pregnant members at risk of adverse perinatal outcomes; applies to Aetna-covered providers and members.

Policy Summary

PayerAetna

PolicyAntepartum Fetal Surveillance

Policy CodePolicy 0088

Change TypeNo material changes

Effective DateJan 12, 1996

Next Review DateJan 25, 2024

Key ActionDocument medical necessity and ensure selection criteria/indications are met before billing covered antepartum fetal surveillance tests.

SourceLink

POLICY UPDATE CHANGES

No material clinical or coverage changes in this revision.

5primary modalities

32–34wusual GA to begin

26wearlier GA threshold

9items listed experimental

>=3RCTs for UA Doppler

10/24/2023

Trek Health ingests and normalizes Transparency in Coverage data and payer policy updates to give provider organizations a clear view of how commercial reimbursement behaves across markets, payers, and services. Our platform transforms raw payer disclosures into structured intelligence that supports contract evaluation, payer negotiations, and service line strategy. By combining market benchmarks with ongoing policy visibility, Trek helps teams identify variability, risk, and opportunity in commercial reimbursement. The result is faster insight, stronger negotiating positions, and more informed financial decisions.

Coverage Criteria for Antepartum Fetal Surveillance

Medical necessity for NST/CST/BPP/modified BPP

Covered when ALL of the following are met:

Primary criteria: 1) Test is one of: non-stress test (NST), contraction stress test (CST), biophysical profile (BPP), or modified BPP; 2) Member has risk factors for stillbirth due to utero-placental insufficiency or other listed high-risk maternal/pregnancy conditions (examples include bleeding, chronic or pregnancy-induced hypertension, antiphospholipid syndrome, fetal growth restriction, gestational diabetes, impaired renal function, maternal heart disease NYHA class III/IV, oligohydramnios, significant isoimmunization, steroid-dependent or poorly controlled asthma); 3) Testing begins when interventions can be undertaken (generally 32–34 weeks gestation for most at-risk pregnancies; as early as 26 weeks for multiple or particularly worrisome high-risk conditions).gestational age thresholds noted

Policy follows ACOG guidance that testing should begin when interventions can be undertaken and lists examples of high-risk conditions.

Repeat testing

Covered when ANY of the following are present:

Repeat testing: Repeat antepartum fetal surveillance testing (weekly or twice-weekly depending on the specific test used and the presence of certain high-risk conditions) is medically necessary while the prompting clinical condition persists; repeat testing is also medically necessary for any significant deterioration in maternal status or any acute diminution in fetal activity regardless of time since the last test.frequency dependent on test and condition

Follow-up frequency determined by test modality and clinical risk as described in policy.

CST/BPP after abnormal NST

Covered when ALL of the following are met:

CST or full BPP after abnormal NST: A contraction stress test (CST) or a full biophysical profile (BPP) is medically necessary following an abnormal NST or modified BPP; subsequent management should be based on the CST or BPP results, gestational age, degree of oligohydramnios (if assessed), and the maternal condition.

This is a reflex step-up evaluation after abnormal initial antepartum testing per policy.

Doppler velocimetry (umbilical artery, MCA)

Covered when ALL of the following are met:

Umbilical artery Doppler velocimetry is medically necessary only in pregnancies complicated by intrauterine growth restriction (fetus estimated <10th percentile for gestational age), oligohydramnios, twin–twin transfusion syndrome, and/or discordant growth in multiple gestation; decisions about timing of delivery should integrate Doppler findings with other fetal testing and maternal status.fetus <10th percentile for estimated fetal weight

Discordant growth in multiples commonly defined as a 15–25% reduction in estimated fetal weight of the smaller fetus.

Middle cerebral artery (MCA) Doppler: Middle cerebral artery Doppler velocimetry is medically necessary for pregnancies complicated by twin–twin transfusion syndrome or when fetal anemia is suspected (for example isoimmunization or parvovirus B-19 infection).

MCA PSV used as a noninvasive screen for fetal anemia and can reduce need for invasive fetal sampling.

Doppler utilization — covered and not covered contexts

Use of Doppler velocimetry — distinct contexts and logic

Umbilical artery Doppler in suspected IUGR: Covered when intrauterine growth restriction (IUGR) is suspected or diagnosed and used to guide antepartum surveillance; Doppler results should be integrated with other assessments (amniotic fluid volume, NST/CST, BPP) and maternal status to inform management and timing of delivery.viable fetus; suspected IUGR

Randomized trials in high-risk IUGR populations demonstrated reduced interventions and lower perinatal death in some studies.

Routine Doppler in low-risk populations: Not supported for routine screening in low-risk or unselected populations; evidence, including Cochrane review data, shows no clear benefit in perinatal mortality or other key outcomes and routine use is not recommended.low-risk or unselected population

Policy and guideline reviews conclude Doppler is applicable primarily to already defined high-risk populations.

Remote nonstress testing

Remote NST/telemonitoring

Remote NST/telemonitoring coverage: Remote/home NST or telemonitoring may be considered for high-risk pregnancies when validated, FDA‑cleared or established systems are used and clinical utility is documented; published studies report high acceptability and clinical interpretability with comparable accuracy to in-clinic cardiotocography.use of validated device and clinical indication for NST

Evidence includes prospective and randomized trials and systematic reviews but further research is recommended for broad adoption.

Biophysical profile

BPP and modified BPP

BPP use: Biophysical profile (BPP) is a composite fetal assessment (score 0–10) used to evaluate fetal well‑being; randomized trial evidence is insufficient to definitively support its use as a test of fetal wellbeing in high‑risk pregnancies, though it remains a commonly used surveillance tool.clinical indication for fetal assessment

Modified BPP (NST + AFI) is a shorter alternative combining short- and long-term indicators.

Contraction Stress Test

Contraction stress test

CST use: Contraction stress test (CST) assesses fetal heart rate response to uterine contractions and is rarely used in current practice; consider CST only when other, less invasive tests are insufficient and the clinical indication justifies inducing or observing contractions (oxytocin may be used if spontaneous contractions are absent).specific clinical indication

Policy notes limited contemporary use and recommends considering less invasive alternatives first.

Use of Doppler velocimetry (uterine/umbilical) — coverage stance

Covered when used for surveillance and management of pregnancies with clinical indications such as fetal growth restriction or preeclampsia; routine screening in low-risk/unselected populations not supported.

Indications for Doppler surveillance: Use Doppler velocimetry (umbilical or uterine as clinically indicated) for pregnancies with suspected fetal growth restriction, preeclampsia, or other clear clinical indications, and as an adjunct to standard antepartum testing (NST, BPP); routine use in low‑risk/unselected populations is not supported by evidence.

When used in IUGR, Doppler added to standard testing has been associated with reduced perinatal death in some trials; decisions should integrate Doppler with other fetal surveillance and maternal status.

Interpretation and limitations

Evidence and test performance considerations to guide clinical use:

Test performance notes: Abnormal second‑trimester uterine artery Doppler (UAD) indices are associated with a 3–4× increased risk of stillbirth, but pooled sensitivity and specificity vary (example pooled sensitivity ~65% and specificity ~82%) and study heterogeneity limits firm conclusions; third‑trimester abnormal UAD moderately predicts perinatal mortality in suspected late SGA but should not be used alone to make decisions.

High heterogeneity and limited external validation of predictive models; use Doppler in combination with other assessments.

Ophthalmic artery Doppler — investigational/adjunct

Evidence on ophthalmic artery Doppler for prediction of preeclampsia is preliminary and primarily investigational.

Current stance on ophthalmic artery Doppler: Ophthalmic artery Doppler indices (for example PMDV or PSV ratio) may improve discrimination for preeclampsia when added to clinical models and uterine artery indices, but evidence is limited to small or at‑risk cohorts and pooled analyses; further validation is required before routine clinical adoption.

Meta-analyses report modest AUCs (e.g., PD1 AUC ~0.68–0.73) and study limitations include small sample sizes and need for external validation.

YKL-40 biomarker — not established for clinical use

Evidence summary and coverage stance:

YKL-40 testing: Available studies show inconsistent associations between maternal serum YKL‑40 and preeclampsia or small‑for‑gestational‑age; major reviews and UpToDate do not recommend YKL‑40 for clinical prediction of preeclampsia or fetal growth restriction, and it is not established for routine clinical use.

Policy considers YKL-40 not supported as a clinical biomarker based on the current evidence.

Test performance findings (evidence summaries)

Studies reported when specific tests or combinations improved prediction of PE

Ophthalmic artery Doppler (first trimester): First diastolic peak (PD1) of ophthalmic artery Doppler at specified cut-offs showed modest sensitivity (~61%) and specificity (~73%) for early‑onset preeclampsia in pooled analyses (AUC ~0.68).PD1 cut-off ~23.3 cm/s

Kalafat et al. meta-analysis.

Ophthalmic artery PSV ratio (mid and late pregnancy): Second‑to‑first PSV ratio improved prediction of preterm and imminent PE in some cohorts (example: detection rate for preterm PE increased from ~56% to ~80% at 10% FPR in one study).improvement examples at 10% FPR

Sapantzoglou and Sarno reported modeled and empirical improvements.

Ischemia-modified albumin (IMA): Meta-analysis of IMA studies reported pooled sensitivity ~0.80, specificity ~0.76 and AUC ~0.86 for detecting preeclampsia, indicating promising diagnostic accuracy though further validation is needed.

Evidence and limitations for angiogenic marker use

Summary of clinical evidence and limitations for use of PlGF and sFlt-1/PlGF ratio:

Evidence summary: Studies demonstrate altered sFlt‑1 (elevated) and PlGF (reduced) in preeclampsia and that adding the sFlt‑1/PlGF ratio to baseline clinical models can improve short‑term prediction of PE‑related delivery (particularly <35 weeks); however, marker performance varies with population and confounders (smoking, BMI, age, ethnicity), and models largely lack external validation, limiting routine clinical adoption.

UpToDate does not recommend PlGF screening as a management tool in some settings; the added predictive utility diminishes after 35 weeks gestation.

The policy lists uterine artery Doppler studies among items considered experimental or investigational for routine risk assessment or screening during pregnancy. Source evidence summarized in the background indicates uterine artery Doppler has been associated with adverse outcomes (preeclampsia, fetal growth restriction) but that peer-reviewed evidence and guideline panels do not support its routine clinical use as a screening test in average- or low-risk populations. Heterogeneity in sampling technique, definitions of abnormal flow, and timing across studies limit generalizability and clinical utility for universal screening.

Because Doppler of vessels other than the umbilical artery and middle cerebral artery (for example, ductus venosus or uterine artery in many contexts) lacks robust randomized trial evidence demonstrating improved outcomes in unselected populations, these applications are listed as investigational in this Clinical Policy Bulletin and are not supported as standard screening tools.

Routine umbilical or uterine artery Doppler screening in low-risk or unselected populations is not supported by the evidence summarized in randomized trials and systematic reviews. A Cochrane review of routine fetal and umbilical Doppler in unselected pregnancies (5 trials, >14,000 women) found no clear benefit for substantive short-term clinical outcomes, including perinatal mortality, and did not support routine use.

The rationale for exclusion is that Doppler testing provides greatest benefit when applied to already-identified high-risk pregnancies (for example, suspected intrauterine growth restriction), whereas routine application in low-risk populations has not demonstrated improved outcomes and may increase false positives, unnecessary interventions, and costs.

Routine fetal and umbilical artery Doppler ultrasound for screening in low-risk pregnancies lacks conclusive evidence of clinical benefit. Systematic reviews and randomized trials indicate that while Doppler findings correlate with IUGR and hypoxemic morbidity in high‑risk cohorts, routine application in average-risk populations did not demonstrate reductions in perinatal mortality or meaningful improvement in obstetric or neonatal outcomes.

Consequently, the policy does not endorse routine screening Doppler in unselected pregnancies; instead, Doppler velocimetry is recommended for surveillance when clinical indications (e.g., suspected fetal growth restriction, oligohydramnios, twin‑twin transfusion) are present and results will be integrated with other antepartum testing to guide management.

The document excerpts do not provide explicit, blanket exclusions for the use of ophthalmic artery Doppler or specific serum biomarkers (for example, PlGF or other angiogenic markers) in all settings. Instead, ophthalmic artery Doppler and various biomarkers are described as promising but preliminary techniques whose clinical roles remain investigational pending further validation.

Available reviews and individual studies report modest discriminatory performance for some ophthalmic Doppler indices and variable associations for biomarkers; the policy therefore treats these modalities as investigational or adjuncts, rather than established coverage items, until external validation and demonstration of clinical utility are available.

UpToDate guidance cited in the policy does not recommend routine screening with placental growth factor (PlGF) as a management tool. Although PlGF and related angiogenic markers have shown promise in some studies—particularly for ruling out imminent preeclampsia and improving short‑term prognostic models—UpToDate states that their clinical utility remains unclear and that these tests are generally considered investigational in many settings.

The policy notes that PlGF‑based testing is commercially available in some countries and has varying recommendations internationally (for example, NICE guidance in the UK in specific contexts), but UpToDate does not endorse universal PlGF screening for management decisions in routine practice.

Clinical Policy Bulletins are developed to assist in administering plan benefits and do not constitute offers of coverage or medical advice. They contain only a partial, general description of plan or program benefits and do not form a contract. Participating providers remain independent contractors and are responsible for medical care and documentation; coverage determinations are subject to the member’s specific plan provisions.

The policy acknowledges emerging evidence on remote or home nonstress testing (remote NST/telemonitoring). Several recent studies and device evaluations report good acceptability and comparable interpretability to clinic cardiotocography when validated, FDA‑cleared systems are used; however, these technologies are still characterized as novel and, in parts of the bulletin, remote NST is listed among items considered experimental or investigational.

Accordingly, remote NST may be considered in select high‑risk pregnancies if validated devices and documented clinical utility are available, but the policy treats many remote monitoring approaches as investigational and not routinely covered pending stronger, generalizable evidence and explicit coverage criteria.

Evidence does not support routine uterine artery Doppler screening in any particular group; meta-analyses and guideline reviews conclude that uterine artery Doppler has limited predictive value in low‑risk populations and is associated with substantial heterogeneity across studies.

High false-positive rates and lack of consistent improvement in maternal or fetal outcomes with routine screening underpin the policy’s stance that uterine artery Doppler is not appropriate as a universal screening tool and should be reserved for research or selected investigational uses.

Using uterine artery Doppler as a universal screening test in unselected or low‑risk pregnancies is not supported. Systematic reviews and guidance note that while abnormal uterine artery findings are statistically associated with increased risk of stillbirth, preeclampsia, and SGA, the test lacks standardization and sufficient predictive performance to justify routine population screening.

Therefore, the policy recommends individualized use of umbilical and uterine artery Doppler within a management plan for identified high‑risk pregnancies rather than as a standalone universal screening modality.

UpToDate reviews cited in the bulletin do not include ophthalmic artery Doppler among established management options for prediction of preeclampsia. While ophthalmic artery indices have demonstrated modest predictive accuracy in some pooled analyses, UpToDate and other reviews consider the evidence preliminary and do not recommend routine clinical implementation.

Similarly, angiogenic markers such as PlGF and sFlt‑1/PlGF show variable performance across studies and are not included by UpToDate as standard management tools outside specific, evidence‑supported contexts.

No single biomarker has adequate test performance to support routine standalone clinical screening for preeclampsia. Large reviews report that individual markers (including PlGF) may have moderate sensitivity and specificity but are insufficient alone for universal use, and that combined clinical‑biomarker models, although promising, generally lack external validation.

As a result, the policy emphasizes that combined marker models remain investigational until reproducible external validation and evidence that their use improves clinically important maternal or neonatal outcomes are available.

Coding for Antepartum Fetal Surveillance

Antepartum fetal surveillance (NST, CST, BPP) CPT codesCPTCovered

59020	Fetal contraction stress test
59025	Fetal non-stress test
76805	Ultrasound, pregnant uterus, real time with image documentation, fetal and maternal evaluation, after first trimester; transabdominal; single or first gestation
76810	Ultrasound, each additional gestation
76818	Fetal biophysical profile; with non-stress testing
76819	Fetal biophysical profile; without non-stress testing

Umbilical artery Doppler CPTCPTCovered

76820

Doppler velocimetry, fetal; umbilical artery

Middle cerebral artery Doppler CPTCPTCovered

76821

Doppler velocimetry, fetal; middle cerebral artery

Codes mentioned as not covered / experimental mappingsmixedNot Covered

0243U	Obstetrics (preeclampsia), biochemical assay of placental-growth factor, time-resolved fluorescence immunoassay (PIGF)
83520	Immunoassay for analyte other than infectious agent antibody or infectious agent antigen; quantitative, not otherwise specified
93975	Duplex scan of arterial inflow and venous outflow of abdominal, pelvic, scrotal contents and/or retroperitoneal organs; complete study
93976	Duplex scan limited study
93886	Transcranial Doppler study of the intracranial arteries; complete study
93888	Transcranial Doppler study of the intracranial arteries; limited study

Example ICD-10 codes covered when selection criteria metICD-10Covered

D68.61	Antiphospholipid syndrome
E10.10-E10.9	Type 1 diabetes mellitus
E11.00-E11.9	Type 2 diabetes mellitus
I50.1-I51.9	Heart failure
J45.20-J45.998	Asthma (steroid dependent or poorly controlled)
M32.10	Systemic lupus erythematosus
O36.511+ - O36.599+	Maternal care for known or suspected placental insufficiency / poor fetal growth
O41.00x+ - O41.03x+	Oligohydramnios
O36.011+ - O36.099+	Maternal care for rhesus isoimmunization

Remote monitoring and home NST (described studies)mixed

No codes listed

Antepartum fetal surveillance modalities (CST, BPP, Doppler velocimetry, MCA PSV)mixed

No codes listed

Gestational age to initiate testing — usual timing and earlier threshold for high-risk conditions

Usual initiation timingTesting is considered appropriate beginning at 32–34 weeks gestation for most pregnancies at increased risk of stillbirth due to utero-placental insufficiency.

Earlier initiation for high-riskTesting may begin as early as 26 weeks gestation for pregnancies with multiple or particularly worrisome high-risk conditions (e.g., significant bleeding, severe hypertensive disease, antiphospholipid syndrome, severe isoimmunization, maternal NYHA class III/IV heart disease).

Trigger for testingAntepartum fetal surveillance is indicated when the member has risk factors for stillbirth due to utero-placental insufficiency or other listed high‑risk maternal/pregnancy conditions.

Repeat testing frequencyIf the prompting clinical condition persists, repeat testing (weekly or twice‑weekly depending on the test and risk) is medically necessary until delivery.

Provider Actions, Documentation, and Prior Authorization

Documentation Required

Coverage tied to selection criteria — Document medical necessity

Coverage for antepartum fetal surveillance procedures is tied to documented selection criteria and medical necessity. CPT codes for NST, CST, BPP, modified BPP, and Doppler velocimetry are covered only when the patient's clinical indication and gestational age meet the policy's selection criteria (for example, testing typically begins at 32–34 weeks for most increased-risk pregnancies, or as early as 26 weeks for multiple/high-risk conditions). Providers must document the indication, gestational age, and relevant risk factors when submitting claims.

Document gestational age and specific risk factors (e.g., fetal growth restriction, preeclampsia, oligohydramnios, isoimmunization, preterm premature rupture of membranes, maternal cardiac disease).
Submit covered CPT codes only when selection criteria from the policy are met.

Prior Authorization

Prior authorization for remote fetal monitoring

Remote/home nonstress testing (remote NST, telemonitoring, or FDA-cleared remote monitoring systems) may be used as an alternative to in-clinic testing in appropriately selected intermediate- and high-risk pregnancies per emerging evidence; prior authorization expectations should be confirmed with the payer. When remote fetal monitoring is planned, providers should obtain any required prior authorization and document the clinical rationale and plan for escalation to in-person testing if remote monitoring is inconclusive or abnormal.

Background and Rationale

Antepartum fetal surveillance is intended to assess risk of adverse perinatal outcomes related to utero‑placental insufficiency and to guide management when the pregnancy is at increased risk for hypoxia or stillbirth. Common surveillance modalities named as medically necessary in appropriate clinical contexts include NST, CST, BPP (including modified BPP), and Doppler velocimetry of the umbilical and middle cerebral arteries.

Testing is typically initiated when interventions can be undertaken (generally 32–34 weeks for most at‑risk pregnancies; as early as 26 weeks for multiple gestations or particularly concerning high‑risk conditions). Surveillance decisions should integrate clinical risk factors, documented indications, and results from multiple modalities rather than rely on a single test.

Definitions and Test Descriptions

NST — definition and purpose

DefinitionNon-stress test (NST): assessment of fetal heart rate accelerations associated with fetal movement or after acoustic stimulation to evaluate fetal autonomic function and reactivity.

PurposeUsed to assess fetal well‑being and detect loss of reactivity that may indicate fetal acidosis or neurologic depression; informs need for further testing or intervention.

Procedure notesMother indicates fetal movement while external fetal heart rate monitoring records accelerations; acoustic stimulation may be applied up to 3 times to elicit accelerations.

Fetal movement assessment — maternal 'kick counts' surveillance

DefinitionFetal movement assessment: maternal counting of fetal movements ('kick counts') as a method of antepartum surveillance.

Evidence

Policy Summary

PayerAetna

PolicyAntepartum Fetal Surveillance

Policy CodePolicy 0088

Change TypeNo material changes

Effective DateJan 12, 1996

Next Review DateJan 25, 2024

Key ActionDocument medical necessity and ensure selection criteria/indications are met before billing covered antepartum fetal surveillance tests.

SourceLink

On This Page

MCA PSV for alloimmunization:

MCA peak systolic velocity (PSV) Doppler is covered when used to screen for fetal anemia in pregnancies with red-cell alloimmunization (as an alternative to invasive fetal sampling) due to its high sensitivity for severe anemia.

alloimmunization pregnancies

May reduce the need for cordocentesis or amniocentesis.

no universal cut-off provided

Seshadri et al. systematic review.

Combined angiogenic and clinical models: Combinations of maternal factors, uterine artery Doppler and biochemical markers (PlGF, sFlt‑1, PAPP‑A and others) achieved higher detection rates for PE in some studies (examples: combined PlGF+sFlt‑1+NGAL DR 77% at 10% FPR; PAPP‑A + 2nd trimester sFlt‑1/PlGF DR 87.5% at 5% FPR), but results vary by study and lack broad external validation.various by study and gestational age

Youssef, von See and others report variable DR/AUC across cohorts.

Condition-based escalationSignificant deterioration in maternal status or acute diminution in fetal activity warrants repeat or immediate testing regardless of prior timing.

Obtain prior authorization when required by the plan before initiating remote/home NST or telemonitoring.
Document device used (make/model or FDA-cleared system), number/frequency of expected remote NSTs, and criteria for in-person follow-up.

Prior Authorization

Prior authorization expectation for Doppler testing — Denial risk for routine Doppler in low-risk pregnancies

When Doppler testing (umbilical artery, middle cerebral artery, or uterine artery) is used for surveillance—particularly for suspected intrauterine growth restriction (IUGR) or preeclampsia—providers should expect prior authorization in some cases; confirm payer-specific requirements. Routine Doppler screening in low-risk or unselected pregnancies is not supported by evidence and may be denied.

Prior authorization may be required for Doppler studies when used outside clearly established indications—check plan rules.
Avoid routine Doppler in low-risk/unselected pregnancies to reduce denial risk.

Prior Authorization

Prior authorization status — None stated in this document excerpt

No explicit prior authorization rules are specified in portions of this bulletin; providers should verify current payer-specific authorization policies. This document is intended to assist benefit administration but does not replace plan contract terms.

If no prior authorization requirement is stated in the CPB excerpt, confirm via the payer's provider portal or medical management contact.
Clinical Policy Bulletins do not substitute for plan-specific authorization rules.

Denial Risk

Denial triggers from not-covered codes

Denials can result from submission of CPT or ICD-10 codes that are listed as not covered for the indications in this bulletin. Providers should ensure coding matches documented indications and selection criteria to avoid claim denials.

Review the policy's code lists before submission; do not bill covered CPTs for non-covered indications.
Codes explicitly listed as not covered (e.g., certain Doppler or investigational biomarker codes) may trigger denials if used outside allowed indications.

Note

Use of PlGF-based testing is considered limited/investigational — Clinical use of angiogenic markers

PlGF-based testing and angiogenic marker assays (sFlt-1, PlGF, and ratios) have emerging evidence for short-term prediction of preeclampsia but remain of uncertain clinical utility in many settings; availability and coverage vary by jurisdiction. In some countries these tests are used to rule out preeclampsia up to 35 weeks, but in the United States they are generally considered investigational or of limited recommendation—confirm payer coverage policy before ordering.

Document the clinical question (e.g., suspected preeclampsia) and how results would change management when ordering angiogenic marker testing.
Expect that PlGF-based testing may be considered investigational or limited by the plan; prior authorization may be required.

Documentation Required

Documentation for Doppler when used in IUGR — Documentation when using UA Doppler

When Doppler testing is performed for suspected IUGR, document the clinical suspicion/diagnosis, relevant fetal measurements (estimated fetal weight percentile), and the intended management plan. Use of umbilical artery Doppler should be integrated with NST/BPP and other surveillance modalities rather than as a standalone test.

Record estimated fetal weight, percentile, amniotic fluid assessment (deepest vertical pocket or AFI), and how Doppler findings will influence timing of delivery or surveillance frequency.
Document concurrent use of NST or BPP when UA Doppler is used for decision-making.

Note

Required study data elements (informational) — When reporting or using sFlt-1 and PlGF

Required study data elements and reporting considerations for angiogenic marker testing (informational): include gestational age, maternal demographics and medical history, measured biomarker values, and modifiers that affect interpretation (smoking status, BMI, age, ethnicity). When reporting sFlt-1 and PlGF, note factors that may alter levels and document how results will be used clinically.

Include gestational age, maternal BMI, smoking status, and relevant comorbidities in the report.
Report assay method and units for sFlt-1 and PlGF and any established cutoffs or risk algorithms used.

Documentation Required

Provider responsibility and documentation context — Document medical necessity and indication

Providers are responsible for documenting medical necessity, indications, and management plans in the member's medical record. Participating providers are independent; treating providers retain responsibility for clinical decisions and for obtaining any required authorizations.

Maintain clear documentation of why testing was ordered, expected frequency of surveillance, and criteria for escalation.
Confirm and follow payer-specific prior authorization and billing requirements; treating providers remain responsible for patient care.

Step Therapy

Step-up to CST — Stepwise surveillance approach

A CST is rarely used; when considering escalation after an abnormal NST or modified BPP, prefer less invasive stepwise surveillance (repeat NST or BPP) before CST in most cases. CST may be considered when indicated and when its results would alter management.

CST or full BPP is medically necessary following an abnormal NST or modified BPP when indicated—document rationale.
Use a stepwise surveillance approach integrating NST, BPP, and Doppler findings rather than relying on a single modality.

Note

No step therapy pathways are described

No formal step-therapy pathways are described in this bulletin for biomarker testing or Doppler use; studies evaluate single and combination strategies without mandated sequencing. Clinical judgement should guide test ordering within policy-covered indications.

There is no required sequence for angiogenic marker testing or Doppler studies specified by this CPB.
When multiple tests are considered, document how each result will inform management.

Fetal movement counting is the only antepartum testing method shown to reduce mortality in a randomized controlled trial and is widely adhered to by pregnant women.

LimitationNo reliable quantitative 'alarm limit' has been established; most proposed numeric thresholds for decreased movements should be discouraged.

BPP — components and scoring

ComponentsBPP comprises five components: amniotic fluid index (AFI), fetal breathing movements, fetal movement, fetal tone, and a non‑stress test.

ScoringEach component is scored 0 or 2 points for a total score of 0–10; scores 8–10 are normal, 6 borderline, and <6 concerning.

Modified BPPA modified BPP typically combines the NST and an assessment of amniotic fluid volume (AFI or deepest vertical pocket) as a shorter surveillance approach.

CST — contraction stress test definition and procedure

DefinitionContraction stress test (CST): assessment of fetal heart rate response to uterine contractions to evaluate fetal ability to tolerate the stress of labor.

ProcedureFetal heart rate and uterine contractions are simultaneously recorded until the mother has had 3 moderate contractions within a 10‑minute period; oxytocin may be used to induce contractions if absent.

Clinical useCST is rarely used in current practice and is considered when other tests are insufficient to answer clinical questions about fetal tolerance of contractions.

MCA PSV — middle cerebral artery peak systolic velocity for fetal anemia screening

DefinitionMiddle cerebral artery peak systolic velocity (MCA PSV): Doppler measurement of peak systolic flow in the fetal middle cerebral artery used to noninvasively screen for fetal anemia.

Test performanceReported overall sensitivity of ~93% to detect severe fetal anemia and ~88% for moderate anemia; specificity about 75% (false‑positive rates increase after 33 weeks).

IndicationsMedically necessary for suspected fetal anemia (e.g., red‑cell alloimmunization) and in twin‑twin transfusion syndrome contexts as an alternative to invasive fetal sampling.

Abnormal uterine artery Doppler (UAD) — study-defined thresholds

DefinitionAbnormal uterine artery Doppler (UAD) in studies defined as UtA pulsatility index (PI) >95th percentile, or ≥2 standard deviations above the mean, or bilateral uterine artery notching.

ContextThird‑trimester abnormal UAD has been evaluated for prediction of adverse perinatal outcomes in suspected SGA fetuses; predictive accuracy varies by outcome.

Interpretation caveatUAD findings should be integrated with other fetal surveillance (AFV, NST, BPP) and maternal status rather than used alone for delivery decisions.

Ophthalmic artery PMDV — definition and reported cut-off

DefinitionOphthalmic artery PMDV (peak meso‑diastolic velocity): a Doppler parameter measured in the maternal ophthalmic artery evaluated as a predictor of preeclampsia.

Reported cut‑offOne study reported an optimal PMDV cut‑off of greater than 22.11 cm/s associated with PE (AUC ~0.73; sensitivity ~70%, specificity ~75%).

RoleMay increase discriminatory ability for predicting PE when added to clinical models and uterine artery indices but requires further validation before routine use.

PlGF / sFlt-1 — angiogenic markers definitions and context

DefinitionsPlacental growth factor (PlGF) is an angiogenic factor; soluble fms‑like tyrosine kinase‑1 (sFlt‑1) is an anti‑angiogenic factor. Altered levels (low PlGF, high sFlt‑1) are associated with preeclampsia.

Clinical contextThe sFlt‑1/PlGF ratio rises in PE and adding these markers to clinical models can improve short‑term prediction of PE‑related delivery, particularly <35 weeks; performance varies by population and confounders.

LimitationsMarker levels are influenced by factors (e.g., BMI, smoking, maternal age, ethnicity) and models lack broad external validation; clinical utility for routine screening remains uncertain.

Ischemia-modified albumin (IMA) — biomarker definition and potential utility

DefinitionIschemia‑modified albumin (IMA): a serum biomarker reflecting ischemia and oxidative stress proposed as a marker for preeclampsia.

EvidenceA meta‑analysis of 6 studies reported pooled sensitivity 0.80, specificity 0.76, diagnostic odds ratio 14.32, and AUC 0.860 for detection of PE, suggesting potential utility.

StatusFindings are promising but require further research and clinical validation before routine adoption.

Ophthalmic artery Doppler indices (PD1, PSV ratio, PI) — definitions of indices

Indices definedOphthalmic artery Doppler measures include the first diastolic peak (PD1), peak systolic velocities (PSV 1 and PSV 2), PSV ratio (second/first PSV), and pulsatility index (PI).

InterpretationPD1, PSV ratio and PI have been studied for prediction of PE; PD1 and PSV ratio showed modest predictive performance in pooled analyses, while PI had limited clinical utility in some reviews.

Use in modelsThese indices have been evaluated as adjuncts to maternal factors and UtA Doppler to improve prediction of preeclampsia, with variable incremental gains requiring validation.

sFlt-1/PlGF ratio — continuous biomarker ratio definition and interpretation

DefinitionsFlt‑1/PlGF ratio: the continuous ratio of soluble fms‑like tyrosine kinase‑1 to placental growth factor; it rises steeply in preeclampsia.

InterpretationAn increased sFlt‑1/PlGF ratio is associated with PE and can improve prediction of PE‑related delivery within 1–2 weeks when added to clinical models, particularly before 35 weeks gestation.

LimitationsPerformance varies by population and is affected by confounders; routine standalone screening with this ratio is not established and external validation is limited.

Fetal growth restriction (FGR) — definition (EFW <10th percentile)

DefinitionFetal growth restriction (FGR): a fetus whose estimated weight is below the 10th percentile for its gestational age.

SynonymFormerly called intra‑uterine growth restriction (IUGR).

Clinical relevanceFGR is an indication for umbilical artery Doppler surveillance and integration with other fetal testing to guide management and delivery timing.

Oligohydramnios — AFI / deepest pocket thresholds

Oligohydramnios definitionAmniotic fluid volume defined as no ultrasonographically measurable vertical pocket >2 cm or an amniotic fluid index (AFI) ≤5 cm.

Isolated oligohydramniosIsolated oligohydramnios is defined as a single deepest vertical pocket less than 2 cm.

Clinical implicationOligohydramnios is a listed indication for antepartum fetal surveillance and may prompt integration of AFV assessment with NST/BPP and Doppler as appropriate.

Polyhydramnios (moderate or severe) — thresholds for AFI/DP

Moderate/severe polyhydramnios thresholdsModerate or severe polyhydramnios defined as deepest vertical pocket ≥12 cm or amniotic fluid index (AFI) ≥30 cm.

GradingPolyhydramnios is often categorized as mild, moderate, or severe based on deepest vertical pocket and AFI ranges (e.g., mild 8–11 cm DVP or AFI 24.0–29.9 cm).

Clinical relevanceModerate/severe polyhydramnios may prompt increased antepartum surveillance depending on clinical context.

Twin growth discordance — definition

DefinitionTwin growth discordance: a significant size or weight difference between twins in a multiple gestation.

Typical thresholdDiscordant growth commonly defined in the policy context as approximately 15–25% reduction in estimated fetal weight of the smaller fetus when considering Doppler surveillance.

ImplicationSignificant twin growth discordance is an indication to consider Doppler velocimetry (including umbilical artery) and intensified antepartum surveillance.

Antepartum fetal surveillance — general definition of surveillance methods

DefinitionAntepartum fetal surveillance: clinical methods to assess fetal well‑being during pregnancy including fetal movement assessment, non‑stress testing (NST), contraction stress testing (CST), biophysical profile (BPP, modified BPP), and Doppler ultrasound velocimetry.

PurposeAimed at assessing risk of adverse perinatal outcomes related to utero‑placental insufficiency (hypoxia, stillbirth) and to guide timing of intervention/delivery.

Integration principleSurveillance modalities should be used in combination and integrated with maternal clinical status to inform management rather than as standalone determinants of delivery.