Report updated May 20, 2026
Perfect OB Wheel
For healthcare providers and obstetricians requiring precise, multi-method gestational dating tools, as well as patients seeking clinical-grade pregnancy tracking.
Perfect OB Wheel is a well-regarded medical app that is free with in-app purchases. With a 4.9/5 rating from 3.5K reviews, it maintains solid user satisfaction. Users particularly appreciate clinical utility of the calculation modules provides reliable support for busy prenatal care providers, though inconsistent trimester dating logic contradicts standard medical guidelines used by major professional organizations remains a common concern.
What is Perfect OB Wheel?
Perfect OB Wheel is a clinical-grade gestational age and due date calculator for healthcare providers and patients on iOS and Android.
Users hire the app to replace inaccurate paper wheels with a rapid, multi-method digital tool that functions offline, saving time during high-pressure clinical shifts.
Current Momentum
v2.1 · 9mo ago
Zombie- Shipped enhanced iCloud synchronization.
- Corrected international date line calculations.
- Redesigned user interface modules.
Active Nemesis
Pregnancy + | Tracker App
By Philips Digital UK
Other Rivals
7-Day Rank Pulse 🇺🇸
MedicalRating Pulse 🇺🇸
Recent User Mood
What makes this app unique?
What Does It Look Like?
What Are The Key Features?
Computes gestational age and due date using LMP, USG, CRL, IVF, HC, and SFH inputs
Quantifies variance between LMP-based and ultrasound-based gestational age estimates
Stores pregnancy data, notes, and images for multiple patients with passcode protection
How much does it cost?
- Free version with banner ads
- Paid iOS version at $1.99
- In-app purchase for Perfect OB Tracker upgrade
Hybrid model combining a low-cost upfront purchase on iOS with an ad-supported free tier on Android and optional IAP for professional tracking features.
Who Built It?
Evan Schoenberg
Providing healthcare professionals with high-precision digital utilities to replace traditional paper-based reference tools and calculators.
Portfolio
10
Apps
What other apps does Evan Schoenberg make?
Explore the full Evan Schoenberg report
Portfolio breakdown, audience, momentum, and every app published by Evan Schoenberg.
What do users think recently?
High confidence · 61 reviews analyzed · Based on 61 reviews. Signal may be noisy.
How did the latest release land?
What is the recent mood?
Recent user voice shows a excited sentiment. Users appreciate clinical utility of the calculation modules provides reliable support for busy prenatal care providers, but report inconsistent trimester dating logic contradicts standard medical guidelines used by major professional organizations.
What Users Love
What Frustrates Users
What Users Want
How have ratings & review volume moved?
Rating, review sentiment, and total reviews over time, with release markers showing the post-launch impact.
Vertical markers = app releases. Hover any release for the post-release impact delta.
View the full user-sentiment analysis
Mood gauge, ratings & review-volume history, every praise / complaint / request, and sentiment over time.
What is the competitive landscape for Perfect OB Wheel?
Where is it available?
Localized markets (2)
How's The Medical Market?
How does it evolve in the Medical market?
Perfect OB Wheel holds the #40 Paid position in the US Medical category, maintaining a 4.9-star rating across 3,538 reviews. The $1.99 price point targets professional users who value utility over the ad-supported content feeds of larger competitors.
Rank progression
89 active rankings tracked — 30-day window
Which niche is Perfect OB Wheel in?
to calculate gestational age and due dates
Explore the full Pregnancy Calculators niche
Every app in this space — 7 tracked, the niche's live rankings, and Marlvel's editorial take on the job-to-be-done.
The rivals identified
Nemeses(1)
Dextograma directly mirrors the core utility of Perfect OB Wheel by providing a digital replacement for traditional clinical obstetrical wheels, targeting the same medical professional user base.
Contenders(3)
While specialized, this app competes for the same clinical screen time by providing essential labor-readiness calculations for obstetricians.
A legacy competitor that provides clinical reference tools and wheel calculations, directly overlapping with the target's core medical utility.
This app competes by offering a similar clinical calculation suite but shifts the focus slightly toward patient-facing pregnancy tracking.
Same space(4)
This app competes by offering a comprehensive wellness ecosystem that encompasses the pregnancy period, potentially reducing the need for standalone calculators.
Storky competes for the user's attention during the final stages of pregnancy by providing specialized labor monitoring tools.
BabyTime occupies the broader pregnancy and postpartum tracking space, competing for the user's attention during the same life stage.
This app targets the same demographic of expectant mothers but focuses on wellness and mental preparation rather than clinical calculations.
Compare Perfect OB Wheel against every rival
All rivals in one side-by-side table — identity, store metrics, ratings & sentiment, and strategic intel — plus a head-to-head page for each.
The outtake for Perfect OB Wheel
Strengths to defend, gaps to attack
Core Strengths
- Clinical-grade multi-method calculation engine replaces physical paper wheels
- Minimalist UI design minimizes cognitive load during high-pressure clinical shifts
Critical Frictions
- Trimester dating logic contradicts established medical guidelines
- Performance instability on specific Android builds causes application crashes
Growth Levers
- Customizable cycle length settings would accommodate non-standard menstrual patterns
- B2B partnerships with medical clinics could scale professional adoption
Market Threats
- Free institutional alternatives with standardized medical logic threaten professional retention
- Hidden monetization tiers drive negative sentiment among clinical users
What are the next best moves?
Audit trimester dating logic because it contradicts medical guidelines → restore professional credibility
Specialists report dating discrepancies, which is the #1 threat to the app's professional-grade reputation.
Trade-off: Pause the UI redesign sprint — medical accuracy is a higher retention risk than visual polish.
Ship customizable cycle length settings because users request it for non-standard patterns → increase calculation accuracy
Users currently manipulate data manually, indicating a clear gap in the core utility workflow.
Trade-off: Deprioritize the Android performance patch — cycle length is a high-value feature for the core clinical base.
A counter-intuitive read
The app's reliance on a paid utility model is its primary defense against the content-bloat of free competitors, as it filters for professional users who prioritize speed over daily articles.
Feature Gaps vs Competitors
- Integrated community forum (available in BabyCenter but absent here)
- Personalized daily content feed (available in Pregnancy+ but absent here)
Key Takeaways
Perfect OB Wheel maintains strong clinical retention through its specialized calculation engine, but the dating logic errors threaten its professional reputation, so the PM must prioritize medical accuracy over new feature development to prevent churn to institutional alternatives.
Where Is It Heading?
Mixed Signals
The market for pregnancy utilities is consolidating around content-heavy platforms, leaving specialized tools like Perfect OB Wheel exposed if they fail to maintain clinical precision. The app must reconcile its dating logic with professional standards to retain its authority, as the current discrepancy creates a clear opening for institutional competitors to capture the professional segment.
Inconsistent trimester dating logic contradicts medical guidelines, which erodes trust among board-certified specialists and risks professional churn.
The minimalist interface design sustains high daily usage among clinicians, providing a stable retention base despite technical instability.