1. Aetna considers ultrasounds not medically necessary if done solely to determine the fetal sex, or to provide parents with a view and photograph of the fetus.

2. Aetna considers a fetal ultrasound with detailed anatomic examination medically necessary to evaluate the fetus for amniotic band syndrome (also known as amniotic constriction band syndrome), or if there are known or suspected fetal anatomic abnormalities, including anatomic abnormalities due to genetic conditions (see attached ICD-9 coding), pregnancies resulting from advanced reproductive technology (ART), severe obesity (BMI of 35 or more) complicating pregnancy, or pregnancies with a fetal nuchal translucency measurement of 3.5 mm or greater in the first trimester. More than one detailed ultrasound fetal anatomic examination per pregnancy per practice is considered experimental and investigational, as there is inadequate evidence of the clinical utility of multiple serial detailed fetal anatomic ultrasound examinations during pregnancy.

3. Aetna considers detailed ultrasound fetal anatomic examination experimental and investigational for all other indications including routine evaluation of pregnant women who are on bupropion (Wellbutrin), and pregnant women who smoke or abuse cannabis.  There is inadequate evidence of the clinical utility of detailed ultrasound fetal anatomic examination for indications other than evaluation of suspected fetal anatomic abnormalities.  Detailed ultrasound fetal anatomic examination is not considered medically necessary for routine screening of normal pregnancy.

4. Aetna considers three-dimensional (3D) and four-dimensional (4D) fetal ultrasounds experimental and investigational because of a lack of evidence that 3D and 4D ultrasounds alter management over standard two-dimensional (2D) ultrasounds such that clinical outcomes are improved.

For Aetna’s policy on first trimester ultrasonographic assessment of fetal nuchal skinfold thickness, see CPB 282 - Noninvasive First Trimester Down Syndrome Screening.

See also: CPB 106 - Fetal Echocardiograms.

This policy is based in part on The American College of Obstetricians and Gynecologists (ACOG) Practice Bulletin on Ultrasonography in Pregnancy  and guidelines from the Society for Maternal-Fetal Medicine (SMFM).

Ultrasonography in pregnancy should be performed only when there is a valid medical indication.  ACOG (2009) stated, "The use of either two-dimensional or three-dimensional ultrasonography only to view the fetus, obtain a picture of the fetus, or determine the fetal sex without a medical indication is inappropriate and contrary to responsible medical practice." 

Indications for a first-trimester ultrasound (performed before 13 weeks and 6 days of gestation) include:

• As adjunct to chorionic villus sampling, embryo transfer, or localization and removal of an intrauterine device
• To assess for certain fetal anomalies, such as anencephaly, in patients at high risk
• To confirm cardiac activity
• To confirm the presence of an intrauterine pregnancy
• To diagnosis or evaluate multiple gestations
• To estimate gestational age
• To evaluate a suspected ectopic pregnancy
• To evaluate maternal pelvic or adnexal masses or uterine abnormalities
• To evaluate pelvic pain
• To evaluate suspected hydatidiform mole
• To evaluate vaginal bleeding

• To screen for fetal aneuploidy.

ACOG recommended that in the absence of specific indications, the optimal time for an obstetric ultrasound examination is between 18 - 20 weeks of gestation because anatomically complex organs, such as the fetal heart and brain, can be imaged with sufficient clarity to allow detection of many major malformations.  This recommendation is based primarily on consensus and expert opinion (Level C).  ACOG stated that it may be possible to document normal structures before 18 weeks of gestation but some structures can be difficult to visualize at that time because of fetal size, position, and movement; maternal abdominal scars; and increased maternal abdominal wall thickness.  A second or third trimester ultrasound examination, however, may pose technical limitations for an anatomic evaluation due to suboptimal imaging, and when this occurs, ACOG recommended documentation of the technical limitation and that a follow-up examination may be helpful. 

ACOG uses the terms "standard" (also called basic), "limited," and "specialized" (also called detailed) to describe various types of ultrasound examinations performed during the second or third trimesters.  

Standard Examination

A standard ultrasound includes an evaluation of fetal presentation, amniotic fluid volume, cardiac activity, placental position, fetal biometry, and fetal number, plus an anatomic survey.  A standard examination of fetal anatomy includes the following essential elements:

• Abdomen (stomach, kidneys, bladder, umbilical cord insertion site into the fetal abdomen, umbilical cord vessel number)
• Chest (heart)
• Extremities (presence or absence of legs and arms)
• Head, face and neck (cerebellum, choroid plexus, cisterna magna, lateral cerebral ventricles, midline falx, cavum septi pellucidi, upper lip)
• Sex (medically indicated in low-risk pregnancies only for the evaluation of multiple gestations).

• Spine (cervical, thoracic, lumbar, and sacral spine).

Limited Examination

A limited examination does not replace a standard examination and is performed when a specific question requires investigation (e.g., to confirm fetal heart activity in a patient experiencing vaginal bleeding or to establish fetal presentation during labor).  A limited examination may be performed during the first trimester to evaluate interval growth, estimate amniotic fluid volume, evaluate the cervix, and assess the presence of cardiac activity. 

Specialized Examination

A detailed or targeted anatomic examination is performed when an anomaly is suspected on the basis of history, laboratory abnormalities, or the results of either the limited or standard examination.  Other specialized examinations might include fetal Doppler ultrasonography, biophysical profile, amniotic fluid assessment, fetal echocardiography, or additional biometric measurements.  Specialized examinations are performed by an operator with experience and expertise in such ultrasonography who determines that components of the examination on a case-by-case basis.

Indications for a second and third trimester ultrasound include the following:

• Adjunct to amniocentesis or other procedure
• Adjunct to cervical cerclage placement
• Adjunct to external cephalic version
• Determination of fetal presentation
• Estimation of gestational age
• Evaluation for abnormal biochemical markers
• Evaluation for fetal well-being
• Evaluation for premature rupture of membranes of premature labor
• Evaluation in those with a history of previous congenital anomaly
• Evaluation of abdominal and pelvic pain
• Evaluation of cervical insufficiency
• Evaluation of fetal condition in late registrants for prenatal care
• Evaluation of fetal growth
• Evaluation of pelvic mass
• Evaluation of suspected amniotic fluid abnormalities
• Evaluation of suspected ectopic pregnancy
• Evaluation of suspected fetal death
• Evaluation of suspected multiple gestation
• Evaluation of suspected placental abruption
• Evaluation of suspected uterine abnormality
• Evaluation of vaginal bleeding
• Examination of suspected hydatidiform mole
• Follow-up evaluation of a fetal anomaly
• Follow-up evaluation of placental location for suspected placenta previa
• Significant discrepancy between uterine size and clinical dates
• To assess for findings that may increase the risk of aneuploidy

• To screen for fetal anomalies.

The Society for Maternal-Fetal Medicine (SMFM) has stated that a fetal ultrasound with detailed anatomic examination (CPT 76811) is not necessary as a routine scan for all pregnancies (SMFM, 2004).  Rather, this scan is necessary for a known or suspected fetal anatomic or genetic abnormality (i.e., previous anomalous fetus, abnormal scan during pregnancy, etc.).  Thus, the SMFM has stated that the performance of this scan is expected to be rare outside of referral practices with special expertise in the identification of, and counseling about, fetal abnormalities (SMFM, 2004).

SMFM has also determined that no more than one fetal ultrasound with detailed anatomic examination is necessary per pregnancy, per practice, when medically necessary (SMFM, 2004).  Once this detailed fetal anatomical exam is done, a second one should not be performed unless there are extenuating circumstances with a new diagnosis.  The SMFM has stated that it is appropriate to repeat the detailed fetal anatomical ultrasound examination when a patient is seen by another maternal-fetal medicine specialist practice, for example, for a second opinion on a fetal anomaly, or if the patient is referred to a tertiary center in anticipation of delivering an anomalous fetus at a hospital with specialized neonatal capabilities.

A focused ultrasound assessment is sufficient for follow-up to provide a reexamination of a specific organ or system known or suspected to be abnormal, or when doing a focused assessment of fetal size by measuring the bi-parietal diameter, abdominal circumference, femur length, or other appropriate measurements (SMFM, 2004).

An ultrasound without detailed anatomic examination is appropriate for a fetal maternal evaluation of the number of fetuses, amniotic/chorionic sacs, survey of intracranial, spinal and abdominal anatomy, evaluation of a 4-chamber heart view, assessment of the umbilical cord insertion site, assessment of amniotic fluid volume, and evaluation of maternal adenexa when visible and appropriate (SMFM, 2004).

Amniotic band sequence refers to a highly variable spectrum of congenital anomalies that occur in association with amniotic bands. Amniotic banding affects approximately 1 in 1200 live births. It is also believed to be the cause of 178 in 10,000 miscarriages. Up to 50% of cases have other congenital anomalies including cleft lip, cleft palate, and clubfoot deformity. Hand and finger anomalies occur in up to 80%. The diagnosis is based upon the presence of characteristic structural findings on prenatal ultrasound or postnatal physical examination. The diagnosis should be suspected when limb amputations or atypical body wall or craniofacial defects are present, or when bands of amnion are seen crossing the gestational sac and adherent to the fetus.

In a practice bulletin on screening for fetal chromosomal anomalies, the American College of Obstetricians and Gynecologists (ACOG, 2007) has stated that patients who have a fetal nuchal translucency measurement of 3.5 mm or greater in the first trimester, despite a negative result on an aneuploidy screen, normal fetal chromosomes, or both, should be offered a targeted ultrasound examination, fetal echocardiogram, or both, because such fetuses are at a significant risk for nonchromosomal anomalies, including congenital heart defects, abdominal wall defects, diaphragmatic hernias, and genetic syndromes.

The ACOG practice bulletin on the use of psychiatric medications during pregnancy and lactation (2008) stated that atypical antidepressants are non-tricyclic antidepressants and non-selective serotonin reuptake inhibitors antidepressants that work by distinct pharmacodynamic mechanisms. The atypical antidepressants include bupropion, duloxetine, mirtazapine, nefazodone, and venlafaxine. The limited data of fetal exposure to these antidepressants do not suggest an increased risk of fetal anomalies or adverse pregnancy events. In the one published study of bupropion exposure in 136 patients, a significantly increased risk of spontaneous abortion, but not an increased risk of major malformations, was identified. In contrast, the bupropion registry maintained at GlaxoSmithKline has not identified any increased risk of spontaneous abortion, although these data have not undergone peer review.

In a Cochrane review, Stampalija and colleagues (2010) evaluated the effects on pregnancy outcome, and obstetric practice, of routine utero-placental Doppler ultrasound in first and second trimester of pregnancy in pregnant women at high and low risk of hypertensive complications. These investigators searched the Cochrane Pregnancy and Childbirth Group's Trials Register (June 2010) and the reference lists of identified studies. Randomized and quasi-randomized controlled trials of Doppler ultrasound for the investigation of utero-placental vessel waveforms in first and second trimester compared with no Doppler ultrasound were included in this review. These researchers excluded studies where uterine vessels have been assessed together with fetal and umbilical vessels. Two authors independently assessed the studies for inclusion, assessed risk of bias and carried out data extraction. They found 2 studies involving 4,993 participants. The methodological quality of the trials was good. Both studies included women at low risk for hypertensive disorders, with Doppler ultrasound of the uterine arteries performed in the second trimester of pregnancy. In both studies, pathological finding of uterine arteries was followed by low-dose aspirin administration. They identified no difference in short-term maternal and fetal clinical outcomes; identified no randomized studies assessing the utero-placental vessels in the first trimester or in women at high risk for hypertensive disorders. The authors concluded that present evidence failed to show any benefit to either the baby or the mother when utero-placental Doppler ultrasound was used in the second trimester of pregnancy in women at low risk for hypertensive disorders. However, this evidence can not be considered conclusive with only 2 studies included. There were no randomized studies in the first trimester, or in women at high risk. They stated that more research is needed to examine if the use of utero-placental Doppler ultrasound may improve pregnancy outcome.

Three-Dimensional and Four-Dimensional Ultrasound in Obstetrics

Three-dimensional (3D) ultrasound can furnish a 3-dimensional image of the fetus. To create a 3-dimensional image, a transducer takes a series of thin slices of the subject, and a computer translates these images and presents them in three dimensions.

Proponents of 3D ultrasound scanning have argued that volumetric measurements from 3D ultrasound scan are more accurate and that both clinicians and parents can better appreciate a certain abnormality with a 3D scan than a standard 2-dimensional (2D) scan. In addition, there is the possibility of increasing psychological bonding between the parents and the baby (Ji, et al., 2005).

In the diagnosis of congenital anomalies, there is evidence to suggest that smaller defects such as spina bifida, cleft lip and palate, and polydactyly may be more lucidly demonstrated with 3D ultrasound (Gonçalves, et al., 2005; Kurjak, et al., 2007). Other more subtle features such as low-set ears, facial dysmorphia or clubbling of feet may be better assessed, which has the potential to lead to more effective diagnoses of chromosomal abnormalities.

In addition, the use of 3D technology can reduce scanning time while maintaining adequate visualization of the fetus in obstetrical ultrasound (Benacerraf, et al., 2005; Benacerraf, et al., 2006).

Jones and colleagues (2010) examined the intra- and inter-observer reproducibility of 3D power Doppler (3-DPD) data acquisition from women at 12 weeks gestation, which were then subsequently measured by a single observer. Women with an uncomplicated, viable singleton pregnancy were scanned between 12 + 0 and 13 + 6 weeks gestations with a Voluson 730 Expert. 3-DPD data were acquired of the whole placenta by 2 observers: the first observer captured 2 datasets and the second a single dataset. Each dataset was analysed using VOCAL in the A plane with 9 degree rotation steps. A total of 18 low risk women were recruited with a total of 54 datasets analysed. The intra-class correlation coefficient (ICC) was highest for the vascular indices vascularisation index (VI) and vascularisation-flow index (VFI), greater than 0.75. Intra-class correlation coefficient for flow index (FI) showed moderate correlation at 0.47 to 0.65. Bland Altman plots showed the most precise vascular index to be the FI (-15 % to 10 % for inter-observer agreement). There was no bias between datasets. Prospective studies are now required to identify if this analysis tool and method is sensitive enough to recognise patients with early-onset placental dysfunction.

More recently, 4-dimensional (4D) or dynamic 3D scanners have come on the market, with the attraction of being able to look at fetal movements. These have also been referred to as "reassurance scans" or "entertainment scans." Proponents argue that 4D scans may have an important catalytic effect for mothers to bond to their babies before birth. However, the impact of 4D scans on diagnosis and management of fetal abnormalities is unknown.

Three-dimensional ultrasound appears to have been useful in research on fetal embryology. However, there is no evidence that the results of 3D ultrasound alters clinical management over standard 2D ultrasound such that clinical outcomes are improved. Whether 3D ultrasound will provide unique, clinically relevant information remains to be seen.

Current guidelines on ultrasonography in pregnancy from the American College of Obstetricians and Gynecologists (2009) state: "The technical advantages of 3-dimensional ultrasonography include its ability to acquire and manipulate an infinite number of planes and to display ultrasound planes traditionally inaccessible by 2-dimensional ultrasonography.  Despite these technical advantages, proof of a clinical advantage of 3-dimensional ultrasonography in prenatal diagnosis in general is still lacking.  Potential areas of promise include fetal facial anomalies, neural tube defects, and skeletal malformations where 3-dimensional ultrasonography may be helpful in diagnosis as an adjunct to, but not a replacement for, 2-dimensional ultrasonography.  Until clinical evidence shows a clear advantage to conventional 2-dimensional ultrasonography, 3-dimensional ultrasonography is not considered a required modality at this time."

Yagel et al (2009) described the state of the science of 3D/4D ultrasound (3D/4D US) applications in fetal medicine. They noted that 3D/4D US applications are many and varied. Their use in fetal medicine varies with the nature of the tissue to be imaged and the challenges each organ system presents, versus the advantages of each ultrasound application. The investigators stated that 3D/4D US has been extensively applied to the study of the fetus. Fetal applications include all types of anatomical assessment, morphometry and volumetry, as well as functional assessment. The authors concluded that 3D/4D US provides many advantages in fetal imaging; however, its contribution to improving the accuracy of fetal scanning over rates achieved with 2D US, remains to be established.

In a prospective study, Chen et al (2009) examined the feasibility and reproducibility of measurements of nasal bone length using a 3D US in the first trimester. A total of 118 consecutive pregnant women attending for Down syndrome screening at 11- to 13(+6)-week were recruited. They had successful fetal nasal bone measurement by 2D US by 4 operators. Three-dimensional volumes were recorded in the mid-sagittal plane of fetal profile by the 5th operator and examined using multi-planar techniques. Another independent investigator randomly compared his measurements with one of the 4 operators. In the subsequent 3D examination, the nasal bone length could be examined in 94 cases (79.7 %). The mean difference between the 2D and 3D measurements was 0.19 mm [95 % confidence interval (CI) 0.08 to 0.31] (p < 0.05). Limits of agreement were -0.73 to 1.11. The mean differences between these two observers were 0.66 mm (95 % CI -0.47 to 0.86) (p < 0.05). The authors concluded that there was significant inter-method difference between the results obtained by 2D and 3D, as well as substantial inter-observer variation in 3D measurement of fetal nasal bone length in the first trimester. They stated that independent 3D measurement of nasal bone offers no additional advantages over 2D US.

Kurjak and colleagues (2010) stated that an evolving challenge for obstetricians is to better define normal and abnormal fetal neurological function in utero in order to better predict ante-natally which fetuses are at risk for adverse neurological outcome. In a multi-center study, these investigators examined the use of 4D US in the assessment of fetal neurobehavior in high-risk pregnancies. Pre-natal neurological assessment was carried out in high-risk fetuses using 4D US applying the recently developed Kurjak ante-natal neurodevelopmental test (KANET). Post-natal neurological assessment was performed using Amiel Tison's neurological assessment at term (ATNAT) for all live-borns and general movement (GM) assessment for those with borderline and abnormal ATNAT. Inclusion criteria were met by 288 pregnant women in 4 centers of whom 266 gave birth to a live-born baby. It was revealed that 234 fetuses were neurologically normal, 7 abnormal and 25 borderline. Out of 7 abnormal fetuses ATNAT was borderline in 5 and abnormal in 2, whereas GM assessment was abnormal in 5 and definitely abnormal in 2. Out of 25 KANET borderline fetuses, ATNAT was normal in 7, borderline in 17 and abnormal in 1, whereas the GM assessment was as follows: normal optimal in 4, normal suboptimal in 20, and abnormal in 1. In summary, out of 32 borderline and abnormal fetuses, ATNAT was normal in 7, borderline in 22 and abnormal in 3; GM assessment was normal optimal in 4, normal suboptimal in 20, abnormal in 6 and definitely abnormal in 2. The authors concluded that 4D US requires further studies before being recommended for wider clinical practice.