May 20, 2021

Exhibit 10.20

May 20, 2021

Xxxxxx X. Xxxxxxxx

0000 Xxxxxxxxx Xxxx

Xxxxx Xxxx Xxxx, XX 00000

Re: 1st Amendment to Employment Agreement for Xxxxxx X. Xxxxxxxx dated March 30, 2021

Dear Rob:

This letter is an amendment (the “Amendment No.1”) to the Employment Agreement between you and Sera Prognostics, Inc. dated March 30, 2021 (the “Employment Agreement”) for the purpose of amending your bonus percentage. The following sentence in Section 2(b) (“Stock Option Grant(s) and Bonuses”):

You will be eligible to participate in the Company’s Annual Incentive Plan, which currently provides for a bonus target of 30% of your base salary, prorated for time of service, and with respect to the calendar year ending December 31, 2021, payment will be contingent based on achievements mutually agreed by you and your supervisor.

shall be deleted and replaced with the following sentence:

You will be eligible to participate in the Company’s Annual Incentive Plan, which currently provides for a bonus target of 35% of your base salary, prorated for time of service, and with respect to the calendar year ending December 31, 2021, payment will be contingent based on achievements mutually agreed by you and your supervisor.

All other terms, conditions, and provisions of the Employment Agreement, including but not limited to all other provisions of Section 2(b), shall remain unchanged by this amendment and are in full force and effect. This Amendment No.1 shall be effective upon execution by both parties below.

0000 Xxxx Xxxxxxx Xxx - Xxxxx 000 | Xxxx Xxxx Xxxx, Xxxx 00000 | Phone 000.000.0000 | Fax 000.000.0000

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Sincerely, Sera Prognostics, Inc.

By: /s/ Xxxxxxx Xxxxxxxxxxx        

Xxxxxxx Xxxxxxxxxxx

Its: Chairman, President, and CEO

This Amendment is accepted and agreed to as of the date hereof:

/s/ Xxxxxx X. Xxxxxxxx            

Xxxxxx X. Xxxxxxxx

Dated: May 20, 2021            

0000 Xxxx Xxxxxxx Xxx - Xxxxx 000 | Xxxx Xxxx Xxxx, Xxxx 00000 | Phone 000.000.0000 | Fax 000.000.0000

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