Calculate chance of succesful vaginal birth after cesarean section using iPhone app

Purpose of App Review

  • to review the utility of the VBAC calculator for assessing likelihood of success
  • to evaluate the medical evidence this app uses

Introduction

Vaginal birth after cesarean sections (VBACs) are not for everyone – some women will not succeed in a successful vaginal delivery even if they decide to undertake a trial of labor.

Part of the counseling that goes into discussing the desire for a VBAC includes discussing the likelihood of success. The VBAC calculator app seeks to provide an “on phone” option for easy access to the VBAC calculator available online through the Maternal Fetal Medicine Unit (MFMU).

User Interface

Opening the app brings you to the app’s Home and only screen.

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The default setting for the app allows you to immediately start entering your new patient’s information. The top four questions require you to put in the age, weight, and height. The calculator will calculate BMI for you.

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The bottom five questions allow you to choose yes/no to ethnicity/race, previous vaginal deliveries, and history of labor dystocia.

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Once all of the patient’s information is entered, you can select Calculate. The app will then provide a pop-up window with the estimated probability of a successful VBAC, complete with a confidence interval.

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You can set the app back to the default home screen by selecting Clear. For example, my patient is 32, 250lbs, and 5’9”. She is African-American, has not had a previous vaginal delivery before or after a cesarean section, and does not have a history of dystocia. The VBAC calculator puts her probability of a successful VBAC at 40.7%.

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If she is Hispanic or Caucasian, rather than African-American, her probability changes to 40.5% and 57.3% respectively.

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When I compared the app’s results to the online VBAC calculator, the results were very similar, but not exact (within 1-2 tenths of a decimal). This difference likely does not matter.

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If you think in the metric system rather than the royal measurement system, you can change these parameters in the Help section (help icon). The Help section also cites the article used to create the calculator.

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Evidence to support use

  • Cites the calculator’s source, the same article available cited by the online VBAC calculator.
  • The calculator is useful for helping to cancel  out a patient, but is not an absolute. Given how close this app is to online calculations, I feel comfortable using it with my patients.

Price

  • $1.99

Likes

  • near exact replica of the online calculator
  • easy to use
  • cites article used

Dislikes

  • no link provided to the online calculator
  • no ability to save a patient’s information for future review
  • does not include link to or additional feature for the extended VBAC calculator

Healthcare providers that would benefit from the app

  • Healthcare providers counseling patients about a trial of labor after cesarean section and likelihood of success of a vaginal birth after cesarean section.

Conclusion

  • The VBAC Calculator medical app provides a straightforward, trusted VBAC calculator in app form. The calculations are not exactly the same as the online calculator, but are very close and not likely to affect patient counseling.

Availability on Android

  • As of publish, not currently available

iMedicalApps recommended?

  • Yes

iTunes Link

Rating: 3.5/5
1. User Interface – 4. Easy to use, but does not explain that it will calculate the BMI for you.
2. Multimedia usage – 2. Does not use photos or videos, but does use smooth transitions and easy selection buttons.
3. Price – 4. $1.99 is on the cheaper end of the spectrum.
4. Real world applicability – 4.  Could be used on a weekly basis, if not more frequently, depending on your patient population and prevalence of patients with history of one-two cesarean sections.

App version: 1.1
Compatibility: iPhone 3GS, iPhone 4, iPhone 4S, iPhone 5, iPod touch (3rd generation), iPod touch (4th generation), iPod touch (5th generation) and iPad. Optimized for iPhone 5.
Requires: Requires iOS 5.1 or later.
Tested on: iPhone 4S

References
Grobman WA, Lai Y, Landon MB, Spong CY, Leveno KJ, Rouse DJ, Varner MW, Moawad AH, Caritis SN, Harper M, Wapner RJ, Sorokin Y, Miodovnik M, Carpenter M, O’Sullivan MJ, Sibai BM, Langer O, Thorp JM, Ramin SM, Mercer BM; National Institute of Child Health and Human Development (NICHD) Maternal-Fetal Medicine Units Network (MFMU), “Development of a nomogram for prediction of vaginal birth after cesarean delivery,” Obstetrics and Gynecology, volume 109, pages 806-12, 2007.

Grobman WA, Lai Y, Landon MB, Spong CY, Leveno KJ, Rouse DJ, Varner MW, Moawad AH, Simhan HN, Harper M, Wapner RJ, Sorokin Y, Miodovnik M, Carpenter M, O’Sullivan MJ, Sibai BM, Langer O, Thorp JM, Ramin SM, Mercer BM; the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Maternal-Fetal Medicine Units Network (MFMU), “Does information available at the time of admission for delivery improve prediction of successful birth after cesarean?” American Journal of Perinatology, 2009.

Disclaimer:
This post does not establish, nor is it intended to establish, a patient physician relationship with anyone. It does not substitute for professional advice, and does not substitute for an in-person evaluation with your healthcare provider. It does not provide the definitive statement on the subject addressed. Before using these apps please consult with your own physician or healthcare provider as to the apps validity and accuracy as this post is not intended to affirm the validity or accuracy of the apps in question. The app(s) mentioned in this post should not be used without discussing the app first with your healthcare provider.

Author:

Kelli Barbour MD

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