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Cleavage rate (day 2 - any cleavage)

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Written by Andrew Manderson

What this card shows

The Cleavage rate (day 2 - any cleavage) card shows what share of normally fertilized eggs had started dividing by Day 2, month by month.

Cleavage is the first cell division. A normally fertilized egg (2PN, two pronuclei at the Day 1 check) should be at two cells or more by Day 2. An embryo still at one cell has not started to develop.

There are three lines:

  • Cleavage rate: your monthly rate.

  • Competency: the Vienna Consensus competency level, 95% or above.

  • Benchmark: the Vienna Consensus benchmark, 99% or above.

This is the least demanding of the development cards. Almost every normally fertilized embryo should clear it, which is why the thresholds sit so high.

Reading the card

  • The denominator is normally fertilized eggs that were actually graded on Day 2. Embryos with no Day 2 grading on file are left out, as are Day 2 entries recorded as degenerated or as non-assessments.

  • This is a deliberate departure from the strict Vienna formula, which uses all normally fertilized eggs as the denominator. Most labs now grade at Day 5 rather than Day 2, so the strict denominator would be dominated by embryos nobody looked at rather than by embryos that failed to divide. Scoring only what was assessed keeps the number about biology.

  • The practical consequence: if your lab grades only a subset of embryos at Day 2, this card describes that subset. It is not a whole-cohort figure.

  • The Competency and Benchmark lines are flat reference lines from the Vienna Consensus, not measurements from your lab.

  • Hover any point to see the exact figure.

Read this with Embryo development rate (day 2 - 4 or more cells) on the same tab. This card asks whether the embryo divided at all; that one asks whether it divided on schedule.

The card lives on the Laboratory performance (Vienna consensus KPIs) dashboard, on the Embryo Development tab, and responds to the filters at the top:

  • Date: change the time window. It scopes by the date of fertilization, and defaults to the past 6 months plus the current month.

  • Clinic: focus on one or more locations, if your organization has several.

  • Treatment type, Age at cycle start and BMI: narrow to a subset of cycles.

Where this data comes from

Both halves of this card come from the Culture tab of the patient's Cycle page: the Day 1 observation carries the pronuclei grading that puts an embryo into the cohort, and the Day 2 observation carries the cell count.

Because the denominator here is "embryos graded on Day 2", a missing Day 2 entry removes the embryo from the card rather than counting against you. What matters for accuracy is that Day 2 entries you do record carry a cell count, and that embryos which failed to cleave are recorded rather than skipped.

Opening this card

In wawa, open Insights from the sidebar, then go to Standard Reports → Laboratory Performance → Laboratory performance (Vienna consensus KPIs). Select the Embryo Development tab. The Cleavage rate (day 2 - any cleavage) card is on it.

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