BlueCross and BlueShield of Montana Medical Policy/Codes
Home Uterine Activity Monitoring (HUAM)
Chapter: Maternity/Gyn/Reproduction
Current Effective Date: June 01, 2013
Original Effective Date: October 01, 1990
Publish Date: June 01, 2013
Revised Dates: November 7, 2008, February 15, 2012; April 3, 2013

The home uterine activity monitor (HUAM) is a device intended to provide early detection of preterm labor (PTL) in women at high risk of developing PTL and preterm birth. A monitoring device worn by the patient collects data on uterine activity. After using the device, the patient transmits data recordings to a provider who assesses risk of PTL onset based on frequency of uterine contractions and responses to interview questions.

The HUAM device consists of a guard-ring tocodynamometer (worn as a belt around the abdomen), a data recorder, and a data transmitter. Usually, the patient is instructed to use the device daily for two 1-hour periods. After monitoring, the patient transmits the recordings by telephone modem link to a remote base station. Base station nurses not only facilitate transmission and analysis of the monitor tracings, they also maintain daily telephone contact with the patient to assess signs and symptoms and to provide advice and counseling.

Nurses employed in HUAM services look for evidence of the onset of PTL, either on the basis of uterine activity exceeding a threshold level or from the findings of a telephone interview with the patient. Signs and symptoms of PTL include back pain, increased vaginal discharge, menstrual-like cramps, and pelvic pressure or heaviness. The threshold number of uterine contractions signaling the possible onset of PTL is usually 4 to 6 per hour. If signs and symptoms are present or the uterine activity exceeds a certain threshold, patients are instructed to perform the following: empty the bladder, hydrate orally, and assume the left lateral recumbent position. The patient is also instructed to remonitor for one additional hour. If uterine activity still exceeds threshold or signs and symptoms persist, the patient is instructed to see her physician immediately for a cervical examination. The cervical examination would then play a pivotal role in diagnosing whether PTL is occurring and whether to initiate tocolytic therapy.

Regulatory Status

In March 2001, the U.S. Food and Drug Administration (FDA) reclassified HUAMs from class III (Premarket Approval) to class II (Special Controls) devices. The HUAM is a post-amendment device and thus, was automatically reclassified into class III. Devices with 510(k) marketing clearance from the FDA include the Fetal Assist (Huntleigh Diagnostics, Eatontown, NJ) and the Carefone Home Uterine Activity Monitoring System (Carelink Corp, Santa Ana, CA). The HUAM is described as an electronic system for at home antepartum measurement of uterine contractions, data transmission by telephone to a clinical setting, and for receipt and display of the uterine contraction data at the clinic. The HUAM system comprises a tocotransducer, an at-home recorder, a modem, and a computer and monitor that receive, process, and display data. The FDA indicates that the device is intended for use in women at least 24 weeks’ gestation with a previous preterm delivery to aid in the detection of preterm labor.



Blue Cross and Blue Shield of Montana (BCBSMT) considers home uterine activity monitoring (HUAM) through a monitoring device and/or daily nursing contact experimental, investigational and unproven.

Federal Mandate 

Federal mandate prohibits denial of any drug, device or biological product fully approved by the FDA as investigational for the Federal Employee Program (FEP). In these instances coverage of these FDA-approved technologies are reviewed on the basis of medical necessity alone.

Rationale for Benefit Administration

This medical policy was developed through consideration of peer reviewed medical literature, FDA approval status, accepted standards of medical practice in Montana, Technology Evaluation Center evaluations, and the concept of medical necessity. BCBSMT reserves the right to make exceptions to policy that benefit the member when advances in technology or new medical information become available.

The purpose of medical policy is to guide coverage decisions and is not intended to influence treatment decisions. Providers are expected to make treatment decisions based on their medical judgment. Blue Cross and Blue Shield of Montana recognizes the rapidly changing nature of technological development and welcomes provider feedback on all medical policies.

When using this policy to determine whether a service, supply or device will be covered please note that member contract language will take precedence over medical policy when there is a conflict.


The policy was based in part on a 1996 Blue Cross Blue Shield Association (BCBSA) Technology Evaluation Center (TEC) Assessment (1) and was regularly updated with peer reviewed literature using MedLine. The most recent search was completed through February 2013. The following is a summary of the key literature.

At the time the 1996 TEC Assessment was published, there had been numerous randomized controlled trials (RCTs) of home uterine activity monitor (HUAM), many of these contained methodologic weaknesses. (1) In addition, several meta-analyses had been published. The 3 meta-analyses that specifically addressed whether HUAM or nursing contact, alone or combined, achieved better health outcomes than standard care found that the data were insufficient to support the clinical use of HUAM. None of the meta-analyses identified significant effects of monitoring on referral to neonatal intensive care unit, (NICU) the intermediate outcome most related to neonatal morbidity.

Most recently, in 2012, a Cochrane review was published on HUAM for detecting preterm labor. (2) The review identified 15 RCTs that compared use of HUAM to standard care, or to an alternative type of surveillance, for women at increased risk of preterm labor. Although the literature was searched through November 2011, all of the trials identified were published in 1999 or earlier. The trials included a total of 6,008 participants; sample sizes ranged from fewer than 100 participants to more than 1,000 participants. Only 2 studies (those with a sham-control) were double-blind. Two of the 15 trials did not contribute data to the meta-analysis; one did not report relevant outcomes, and the other did not report data in a form that could be included in the analyses. Two trials (total sample size: 2,589) reported the perinatal mortality rate as a study outcome. A pooled analysis of data from these studies did not find a statistically significant difference in perinatal mortality in groups that did and did not receive HUAM (risk ratio [RR]: 1.22, 95% confidence interval [CI]: 0.86 to 1.72). In addition, in a pooled analysis of data from 8 trials (total sample size: 4,834), there was not a significant difference between groups in the rate of preterm birth at less than 37 weeks’ gestation (RR: 0.85, 95% CI: 0.72 to 1.01). There was a significantly lower rate of preterm birth before 34 weeks’ gestation in women managed with HUAM compared to an alternative intervention (RR: 0.78, 95% CI: 0.62 to 0.99). That analysis included 3 studies with a total sample size of 1,596. However, a sensitivity analysis that excluded data from the 2 lower-quality and substantially smaller trials and included one trial with n=1,292 found a non-significant difference between groups in the rate of preterm birth before 34 weeks (RR: 0.75, 95% CI: 0.57 to 1.00). Similarly, a pooled analysis of 5 studies (n=2,367) found a significantly lower rate of admission to NICUs in the group that used HUAM (RR: 0.77, 95% CI: 0.62 to 0.96). The difference in NICU admission rates was not statistically significant when lower-quality studies were excluded and only the single higher-quality large study (n=1,292) remained in the analysis (RR: 0.86, 95% CI: 0.74 to 1.01).

In 2009, the Health Technology Assessment program in the United Kingdom published a systematic review of literature on various screening techniques for preventing spontaneous preterm birth; one of these techniques was HUAM. (3) The review of HUAM included three trials with a total sample size of 618. Only one of the trials was considered to be of good quality; the others were considered to be poor quality. Study findings were not pooled due to clinical heterogeneity. According to the assessment, the trials found no statistically significant difference in the incidence of spontaneous preterm birth (PTB) before 34 or 37 weeks’ gestation in women who received HUAM compared to controls. Similarly, there were no statistically significant differences in the rate of admission to NICUs.

Two of the studies with larger sample sizes and designed to determine whether adding HUAM to nursing contact would improve clinical outcomes are described below. In 1995, the Collaborative Home Uterine Monitoring Study Group published a randomized double-blind multicenter trial that randomly assigned 1,292 women to active or sham HUAM compared to twice-daily nursing contact. (4) The investigators found similar outcomes in the 2 groups e.g. rates of preterm labor, preterm birth, and need for neonatal intensive care. Another large sturdy was published in 1998 by Dyson et al. (5) The investigators randomly assigned 2,422 pregnant women at high risk for preterm labor (PTL) to receive either weekly contact with a nurse, daily contact with a nurse, or daily contact with a nurse plus HUAM. Therefore, this study was designed to determine whether adding HUAM to nursing contact would improve clinical outcomes. However, there were no significant differences among the groups for the primary endpoint of birth at less than 35 weeks’ gestation. The authors concluded that women who have daily contact with a nurse, with or without home monitoring of uterine activity, have no better pregnancy outcomes than women who have weekly contact with a nurse.

Also in 2009, Rittenberg et al. published a retrospective study comparing outcomes in high-risk pregnant women who received weekly nursing visits with injections of 17 alpha-hydroxyprogesterone caproate (17P) versus daily perinatal nursing surveillance, including HUAM, twice a day. (6) Eligibility criteria included a singleton pregnancy, less than 27 weeks’ gestation, previous spontaneous preterm delivery (SPTD), and no current signs or symptoms of PTL. Patients receiving 17P and HUAM patients were matched on a one-to-one basis; 342 matched pairs were included in the analysis. Primary and secondary study outcomes are summarized in the table:

Primary outcomes

Weekly contact with 17P No (%)

Daily contact with HUAM No. (%)

p Value

SPTD before 37 wks

117 (34.2)*

102 (29.8)


SPTD before 35 wks

41 (12.0)

37 (10.8)


SPTD before 32 wks

13 (3.8)

17 (5.0)


Secondary outcomes




Hospitalized for suspected preterm labor

43 (12.6)

147 (43.0)


Diagnosis of preterm labor

134 (39.2)

208 (60.8)



44 (12.9)

170 (49.7)


Preterm premature rupture of membranes

25 (7.3)

29 (8.5)


* Correction provided by study author, Dr. Rittenberg, October 2009: Table III in the published article contained an error in the reporting of data on SPTD before 37 weeks in the 17P group.

The rate of spontaneous recurrent preterm delivery, the primary outcome, did not differ significantly between the two groups when calculated as before 37, 35, or 32 weeks’ gestation. The authors concluded that there is no difference in recurrent SPTD between women treated with 17P and daily surveillance with HUAM. However, it is not valid to draw this conclusion for several reasons. First of all, there were statistically significant differences between groups on three of four reported secondary outcomes. Women in the 17P group experienced significantly less tocolysis, were diagnosed less often with PTL, and had fewer hospitalizations for suspected PTL. Moreover, the study was not randomized, and we cannot be certain that they were equivalent at baseline; there may have been demographic or clinical differences between the groups, which affected study outcomes. Furthermore, as noted elsewhere in this summary, it is also difficult to separate the impact of HUAM from that of nurse visits. In addition to HUAM, patients in this group received daily rather than weekly nursing contact. Also, because the study was retrospective, we cannot be certain that a consistent protocol was followed. Finally, a company that provides in-home prenatal care including 17P and HUAM supplied the study data, and two authors were employees of the company.

There is less evidence on the use of HUAM for the tertiary prevention of preterm delivery. Most trials on HUAM included only patients who were considered “at risk” for PTL, and many specifically excluded those patients who had a history of PTL in the current pregnancy. Four trials were identified that evaluated the use of HUAM for tertiary prevention; none of these found that HUAM improved health outcomes. The trials are briefly summarized below:

  • Iams and colleagues conducted a trial looking at HUAM in 76 women who had been successfully treated for preterm labor. (7) Women were randomly assigned to receive either HUAM or a program of education and uterine self-palpation. Both groups also received nursing contact five days per week. Rates of recurrent PTL and preterm delivery did not differ between the groups.
  • Blondel and colleagues randomly assigned 74 women with successfully treated PTL to either undergo HUAM and nursing contact or weekly or biweekly home nursing visits. (8) There was no significant difference in the rate of preterm deliveries between the two groups.
  • Nagey and colleagues reported on a study that randomly assigned 56 women with a history of successfully treated PTL to receive either HUAM or standard treatment. (9) There was no difference in the incidence in preterm birth between the two groups.
  • Brown and colleagues reported on the results of a trial that randomly assigned 162 women who had experienced an episode of PTL in the current pregnancy to undergo HUAM plus standard care or standard care alone. (10) There were no differences in outcomes between the two groups, including percentage of women delivered at less than 35 weeks’ gestation, the term delivery rate, neonatal intensive care admissions, and percentage of women receiving corticosteroid treatment for prevention of neonatal complications.

Technology Assessments, Guidelines, and Position Statements

  • The U.S. Preventive Services Task Force (USPSTF) current topic page on HUAM states, “Home uterine monitoring is no longer considered a part of standard obstetric care and is not relevant to clinical practice. The USPSTF will not update its 1996 recommendation.” (11)
  • In 2002, the National Institute of Child Health and Human Development (NICHD) issued a news release declaring that home uterine monitors are not useful for predicting premature birth. (12) The news release describes a study sponsored by the NICHD which found that ambulatory monitoring of uterine contractions did not identify women most likely to have preterm delivery.
  • In 2003, an American College of Obstetricians and Gynecologists (ACOG) Practice Bulletin included the following statement: “No evidence exists to support the use of tocolytic therapy, HUAM, elective cerclage, or narcotics to prevent preterm delivery in women with contractions but no cervical change. “ (13) The position statement was affirmed in 2008.


There is a substantial literature on home uterine activity monitoring for reducing preterm birth in high-risk pregnant women. Numerous RCTs have been performed prior to the year 2000. The trials that were the largest in size and highest in quality have not reported a benefit for HUAM, and systematic reviews of the available trials have not concluded that health outcomes are improved. The available evidence suggests that HUAM does not improve health outcomes, and HUAM is not recommended by national organizations such as the ACOG and the USPSTF. Thus, HUAM is considered experimental, investigational and unproven.

ICD-9 Codes
75.34, 644
ICD-10 Codes
O47.00-O47.9, O60.00-O60.03
Procedural Codes: S9001, 99500
  1. Blue Cross and Blue Shield Association Technology Evaluation Center (TEC). Home uterine activity monitoring for secondary prevention of preterm birth. TEC Assessments 1996; Volume 11, Tab 15.
  2. Urquhart C, Currell R, Harlow F et al. Home uterine monitoring for detecting preterm labour. Cochrane Database Syst Rev 2012; 5:CD006172.
  3. Honest, H., Forbes, C.A., et al. Screening to prevent spontaneous preterm birth: systematic reviews of accuracy and effectiveness literature with economic modeling. Health Technol Assess (2009) 13 (43):1-627.
  4. A multicenter randomized controlled trial of home uterine monitoring: active versus sham device. The Collaborative Home Uterine Monitoring Study (CHUMS) Group. Am J Obstet Gynecol 1995; 173(4):1120-7.
  5. Dyson, D.C., Danbe, K.H., et al. Monitoring women at risk for preterm labor. N Engl J Med (1998) 338(1):15-9.
  6. Rittenberg, C., Newman, R.B., et al. Preterm birth prevention by 17 alpha-hydroxyprogesterone caproate vs. daily nursing surveillance. J Reprod Med (2009) 54(2): 47-52.
  7. Iams, J.D., Johnson, F.F., et al. Ambulatory uterine activity monitoring in the post-hospital care of patients with preterm labor. Am J Perinatol (1990) 7(2):170-3.
  8. Blondel, B., Breart, G., et al. Home uterine activity monitoring in France: a randomized, controlled trial. Am J Obstet Gynecol (1992) 167(2):424-9.
  9. Nagey, D.A., Bailey-Jones, C., et al. Randomized comparison of home uterine activity monitoring and routine care in patients discharged after treatment for preterm labor. Obstet Gynecol (1993) 82(3):319-23.
  10. Brown, H.L., Britton, K.A., et al. A randomized comparison of home uterine activity monitoring in the outpatient management of women treated for preterm labor. Am J Obstet Gynecol (1999) 180(4):798-805.
  11. U.S. Preventive Services Task Force. Screening Home Uterine Activity Monitoring, 1996. Available online at: accessed (2010 October) (reaffirmed 22 March 2013).
  12. National Guideline Clearinghouse. American College of Obstetricians and Gynecologists. Management of Preterm Labor. Available online at: (accessed 2010 October) (reaffirmed 22 March 2013).
  13. American College of Obstetricians and Gynecologists (ACOG). Management of Preterm Labor. Available online at:  (accessed 22 March 2013).
  14. Home Uterine Activity Monitoring. Chicago, Illinois: Blue Cross Blue Shield Association Medical Policy Reference Manual (2012 November) OB/GYN Reproduction 4.01.09.
February 2012 Policy updated with literature review. Policy statement unchanged 
April 2013 Title changed from "Home Uterine Monitoring, Ambulatory" to "Home Uterine Activity Monitoring (HUAM)".  Policy formatting and language revised.  Policy statement changed from Not Medically Necessary to Investigational.
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Home Uterine Activity Monitoring (HUAM)