-------------------------- OMB APPROVAL -------------------------- OMB Number: 3235-0145 Expires: December 31, 2005 Estimated average burden hours per response......11 -------------------------- UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 ------------ SCHEDULE 13G/A INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULES 13d-1 (b), (c) AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO 13d-2 (b) (Amendment No. 1)* Natus Medical Incorporated -------------------------------------------------------------------------------- (Name of Issuer) Common Stock -------------------------------------------------------------------------------- (Title of Class of Securities) 639050 10 3 -------------------------------------------------------------------------------- (CUSIP Number) December 31, 2002 -------------------------------------------------------------------------------- (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: |_| Rule 13d-1(b) | | Rule 13d-1(c) |X| Rule 13d-1(d) *The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page. The information required in the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes). Page 1 of 18 pages CUSIP No. 639050 10 3 Page 2 of 18 Pages -------------------------------------------------------------------------------- 1 NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) Delphi Ventures, L.P. ("DV") Tax ID Number: -------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) |_| (b) |X| -------------------------------------------------------------------------------- 3 SEC USE ONLY -------------------------------------------------------------------------------- 4 CITIZENSHIP OR PLACE OF ORGANIZATION Delaware -------------------------------------------------------------------------------- 5 SOLE VOTING POWER 0 shares. -------------------------------------------------------- NUMBER OF 6 SHARED VOTING POWER SHARES BENEFICIALLY 0 shares. OWNED BY -------------------------------------------------------- EACH 7 SOLE DISPOSITIVE POWER REPORTING PERSON 0 shares. WITH -------------------------------------------------------- 8 SHARED DISPOSITIVE POWER 0 shares. -------------------------------------------------------------------------------- 9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0 shares. -------------------------------------------------------------------------------- 10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* |_| -------------------------------------------------------------------------------- 11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 0% -------------------------------------------------------------------------------- 12 TYPE OF REPORTING PERSON* PN -------------------------------------------------------------------------------- *SEE INSTRUCTION BEFORE FILLING OUT! CUSIP No. 639050 10 3 Page 3 of 18 Pages -------------------------------------------------------------------------------- 1 NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) Delphi BioInvestments, L.P. ("DBI") Tax ID Number: -------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) |_| (b) |X| -------------------------------------------------------------------------------- 3 SEC USE ONLY -------------------------------------------------------------------------------- 4 CITIZENSHIP OR PLACE OF ORGANIZATION Delaware -------------------------------------------------------------------------------- 5 SOLE VOTING POWER 0 shares. -------------------------------------------------------- NUMBER OF 6 SHARED VOTING POWER SHARES BENEFICIALLY 0 shares. OWNED BY -------------------------------------------------------- EACH 7 SOLE DISPOSITIVE POWER REPORTING PERSON 0 shares. WITH -------------------------------------------------------- 8 SHARED DISPOSITIVE POWER 0 shares. -------------------------------------------------------------------------------- 9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0 shares. -------------------------------------------------------------------------------- 10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* |_| -------------------------------------------------------------------------------- 11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 0.0% -------------------------------------------------------------------------------- 12 TYPE OF REPORTING PERSON* PN -------------------------------------------------------------------------------- *SEE INSTRUCTION BEFORE FILLING OUT! CUSIP No. 639050 10 3 Page 4 of 18 Pages -------------------------------------------------------------------------------- 1 NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) Delphi Ventures II, L.P. ("DV II") Tax ID Number: -------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) |_| (b) |X| -------------------------------------------------------------------------------- 3 SEC USE ONLY -------------------------------------------------------------------------------- 4 CITIZENSHIP OR PLACE OF ORGANIZATION Delaware -------------------------------------------------------------------------------- 5 SOLE VOTING POWER 0 shares. -------------------------------------------------------- NUMBER OF 6 SHARED VOTING POWER SHARES BENEFICIALLY 0 shares. OWNED BY -------------------------------------------------------- EACH 7 SOLE DISPOSITIVE POWER REPORTING PERSON 0 shares. WITH -------------------------------------------------------- 8 SHARED DISPOSITIVE POWER 0 shares. -------------------------------------------------------------------------------- 9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0 shares. -------------------------------------------------------------------------------- 10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* |_| -------------------------------------------------------------------------------- 11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 0% -------------------------------------------------------------------------------- 12 TYPE OF REPORTING PERSON* PN -------------------------------------------------------------------------------- *SEE INSTRUCTION BEFORE FILLING OUT! CUSIP No. 639050 10 3 Page 5 of 18 Pages -------------------------------------------------------------------------------- 1 NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) Delphi BioInvestments II, L.P. ("DBI II") Tax ID Number: -------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) |_| (b) |X| -------------------------------------------------------------------------------- 3 SEC USE ONLY -------------------------------------------------------------------------------- 4 CITIZENSHIP OR PLACE OF ORGANIZATION Delaware -------------------------------------------------------------------------------- 5 SOLE VOTING POWER 0 shares. -------------------------------------------------------- NUMBER OF 6 SHARED VOTING POWER SHARES BENEFICIALLY 0 shares. OWNED BY -------------------------------------------------------- EACH 7 SOLE DISPOSITIVE POWER REPORTING PERSON 0 shares. WITH -------------------------------------------------------- 8 SHARED DISPOSITIVE POWER 0 shares. -------------------------------------------------------------------------------- 9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0 shares. -------------------------------------------------------------------------------- 10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* |_| -------------------------------------------------------------------------------- 11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 0.0% -------------------------------------------------------------------------------- 12 TYPE OF REPORTING PERSON* PN -------------------------------------------------------------------------------- *SEE INSTRUCTION BEFORE FILLING OUT! CUSIP No. 639050 10 3 Page 6 of 18 Pages -------------------------------------------------------------------------------- 1 NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) Delphi Management Partners, L.P. ("DMP") Tax ID Number: -------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) |_| (b) |X| -------------------------------------------------------------------------------- 3 SEC USE ONLY -------------------------------------------------------------------------------- 4 CITIZENSHIP OR PLACE OF ORGANIZATION Delaware -------------------------------------------------------------------------------- 5 SOLE VOTING POWER 0 shares. -------------------------------------------------------- NUMBER OF 6 SHARED VOTING POWER SHARES BENEFICIALLY 0 shares. OWNED BY -------------------------------------------------------- EACH 7 SOLE DISPOSITIVE POWER REPORTING PERSON 0 shares. WITH -------------------------------------------------------- 8 SHARED DISPOSITIVE POWER 0 shares. -------------------------------------------------------------------------------- 9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0 shares. -------------------------------------------------------------------------------- 10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* |_| -------------------------------------------------------------------------------- 11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 0% -------------------------------------------------------------------------------- 12 TYPE OF REPORTING PERSON* PN -------------------------------------------------------------------------------- *SEE INSTRUCTION BEFORE FILLING OUT! CUSIP No. 639050 10 3 Page 7 of 18 Pages -------------------------------------------------------------------------------- 1 NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) Delphi Management Partners II, L.P. ("DMP II") Tax ID Number: -------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) |_| (b) |X| -------------------------------------------------------------------------------- 3 SEC USE ONLY -------------------------------------------------------------------------------- 4 CITIZENSHIP OR PLACE OF ORGANIZATION Delaware -------------------------------------------------------------------------------- 5 SOLE VOTING POWER 0 shares. -------------------------------------------------------- NUMBER OF 6 SHARED VOTING POWER SHARES BENEFICIALLY 0 shares. OWNED BY -------------------------------------------------------- EACH 7 SOLE DISPOSITIVE POWER REPORTING PERSON 0 shares. WITH -------------------------------------------------------- 8 SHARED DISPOSITIVE POWER 0 shares. -------------------------------------------------------------------------------- 9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0 shares. -------------------------------------------------------------------------------- 10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* |_| -------------------------------------------------------------------------------- 11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 0% -------------------------------------------------------------------------------- 12 TYPE OF REPORTING PERSON* PN -------------------------------------------------------------------------------- *SEE INSTRUCTION BEFORE FILLING OUT! CUSIP No. 639050 10 3 Page 8 of 18 Pages -------------------------------------------------------------------------------- 1 NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) James J. Bochnowski ("Bochnowski") Tax ID Number: -------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) |_| (b) |X| -------------------------------------------------------------------------------- 3 SEC USE ONLY -------------------------------------------------------------------------------- 4 CITIZENSHIP OR PLACE OF ORGANIZATION U.S. Citizen -------------------------------------------------------------------------------- 5 SOLE VOTING POWER 93,361 shares (includes 18,055 shares issuable upon exercise of options) -------------------------------------------------------- NUMBER OF 6 SHARED VOTING POWER SHARES BENEFICIALLY 0 shares. OWNED BY -------------------------------------------------------- EACH 7 SOLE DISPOSITIVE POWER REPORTING PERSON 93,361 shares (includes 18,055 shares issuable upon WITH exercise of options) -------------------------------------------------------- 8 SHARED DISPOSITIVE POWER 0 shares. -------------------------------------------------------------------------------- 9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 93,361 shares (includes 18,055 shares issuable upon exercise of options) -------------------------------------------------------------------------------- 10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* |_| -------------------------------------------------------------------------------- 11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 0.58% -------------------------------------------------------------------------------- 12 TYPE OF REPORTING PERSON* IN -------------------------------------------------------------------------------- *SEE INSTRUCTION BEFORE FILLING OUT! CUSIP No. 639050 10 3 Page 9 of 18 Pages -------------------------------------------------------------------------------- 1 NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) David L. Douglass ("Douglass") Tax ID Number: -------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) |_| (b) |X| -------------------------------------------------------------------------------- 3 SEC USE ONLY -------------------------------------------------------------------------------- 4 CITIZENSHIP OR PLACE OF ORGANIZATION U.S. Citizen -------------------------------------------------------------------------------- 5 SOLE VOTING POWER 0 shares. -------------------------------------------------------- NUMBER OF 6 SHARED VOTING POWER SHARES BENEFICIALLY 0 shares. OWNED BY -------------------------------------------------------- EACH 7 SOLE DISPOSITIVE POWER REPORTING PERSON 0 shares. WITH -------------------------------------------------------- 8 SHARED DISPOSITIVE POWER 0 shares. -------------------------------------------------------------------------------- 9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 0 shares. -------------------------------------------------------------------------------- 10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* |_| -------------------------------------------------------------------------------- 11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 0% -------------------------------------------------------------------------------- 12 TYPE OF REPORTING PERSON* IN -------------------------------------------------------------------------------- *SEE INSTRUCTION BEFORE FILLING OUT! CUSIP No. 639050 10 3 Page 10 of 18 Pages -------------------------------------------------------------------------------- 1 NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) Donald J. Lothrop ("Lothrop") Tax ID Number: -------------------------------------------------------------------------------- 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) |_| (b) |X| -------------------------------------------------------------------------------- 3 SEC USE ONLY -------------------------------------------------------------------------------- 4 CITIZENSHIP OR PLACE OF ORGANIZATION U.S. Citizen -------------------------------------------------------------------------------- 5 SOLE VOTING POWER 8,765 shares -------------------------------------------------------- NUMBER OF 6 SHARED VOTING POWER SHARES BENEFICIALLY 0 shares. OWNED BY -------------------------------------------------------- EACH 7 SOLE DISPOSITIVE POWER REPORTING PERSON 8,765 shares WITH -------------------------------------------------------- 8 SHARED DISPOSITIVE POWER 0 shares. -------------------------------------------------------------------------------- 9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 8,765 shares -------------------------------------------------------------------------------- 10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* |_| -------------------------------------------------------------------------------- 11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 0.05% -------------------------------------------------------------------------------- 12 TYPE OF REPORTING PERSON* IN -------------------------------------------------------------------------------- *SEE INSTRUCTION BEFORE FILLING OUT! Page 11 of 18 Pages This Amendment No. 1 amends the Statement on 13(G) (the "Original Statement") filed by Delphi Ventures III, L.P., a Delaware limited partnership ("DV III"), Delphi BioInvestments III, L.P., a Delaware limited partnership ("DBI III"), and Delphi Management Partners III, L.L.C., a Delaware limited liability company ("DMP III") and the general partner of DV III and DBI III, James J. Bochnowski ("Bochnowski"), David L. Douglass ("Douglass") and Donald J. Lothrop ("Lothrop"), the members of DMP III. The foregoing entities and individuals are collectively referred to as the "Reporting Persons." Only those items as to which there has been a change to the Original Statement are included in this Amendment No. 1. Item 5. Ownership of Five Percent or Less of a Class If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following: [X] Yes Page 12 of 18 Pages SIGNATURES After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. Dated: January 31, 2003 DELPHI VENTURES, L.P., a Delaware Limited Partnership By: Delphi Management Partners, L.P., a Delaware Limited Partnership Its General Partner By: /s/ James J. Bochnowski ------------------------------------- James J. Bochnowski General Partner DELPHI BIOINVESTMENTS, L.P., a Delaware Limited Partnership By: Delphi Management Partners, L.P., a Delaware Limited Partnership Its General Partner By: /s/ James J. Bochnowski ------------------------------------- James J. Bochnowski General Partner DELPHI MANAGEMENT PARTNERS, L.P., a Delaware Limited Partnership By: /s/ James J. Bochnowski ------------------------------------- James J. Bochnowski General Partner DELPHI VENTURES II, L.P., a Delaware Limited Partnership By: Delphi Management Partners II, L.P., a Delaware Limited Partnership Its General Partner By: /s/ James J. Bochnowski ------------------------------------- James J. Bochnowski General Partner DELPHI BIOINVESTMENTS II, L.P., a Delaware Limited Partnership By: Delphi Management Partners II, L.P., a Delaware Limited Partnership Its General Partner By: /s/ James J. Bochnowski ------------------------------------- James J. Bochnowski General Partner Page 13 of 18 Pages DELPHI MANAGEMENT PARTNERS II, L.P., a Delaware Limited Partnership By: /s/ James J. Bochnowski ------------------------------------- James J. Bochnowski General Partner Page 14 of 18 Pages JAMES J. BOCHNOWSKI By: /s/ James J. Bochnowski ------------------------------------- James J. Bochnowski DAVID L. DOUGLASS By: /s/ David L. Douglass ------------------------------------- David L. Douglass DONALD J. LOTHROP By: /s/ Donald J. Lothrop ------------------------------------- Donald J. Lothrop Page 15 of 18 Pages EXHIBIT INDEX Found on Sequentially Exhibit Numbered Page ------- ------------- Exhibit A: Agreement of Joint Filing 16 Page 16 of 18 Pages EXHIBIT A Agreement of Joint Filing The undersigned hereby agree that a single Schedule 13G (or any amendment thereto) relating to the Common Stock of Natus Medical Incorporated shall be filed on behalf of each of the undersigned and that this Agreement shall be filed as an exhibit to such Schedule 13G. Date: January 31, 2003 January 31, 2003 DELPHI MANAGEMENT PARTNERS, L.P., a Delaware Limited Partnership By: /s/ James J. Bochnowski ------------------------------------- James J. Bochnowski, General Partner January 31, 2003 DELPHI VENTURES, L.P., a Delaware Limited Partnership By: Delphi Management Partners, L.P., a Delaware Limited Partnership Its General Partner By: /s/ James J. Bochnowski ------------------------------------- James J. Bochnowski, General Partner January 31, 2003 DELPHI BIOINVESTMENTS, L.P., a Delaware Limited Partnership By: Delphi Management Partners, L.P., a Delaware Limited Partnership Its General Partner By: /s/ James J. Bochnowski ------------------------------------- James J. Bochnowski, General Partner Page 17 of 18 Pages January 31, 2003 DELPHI MANAGEMENT PARTNERS II, L.P., a Delaware Limited Partnership By: /s/ James J. Bochnowski ------------------------------------- James J. Bochnowski, General Partner January 31, 2003 DELPHI VENTURES II, L.P., a Delaware Limited Partnership By: Delphi Management Partners II, L.P., a Delaware Limited Partnership Its General Partner By: /s/ James J. Bochnowski ------------------------------------- James J. Bochnowski, General Partner January 31, 2003 DELPHI BIOINVESTMENTS II, L.P., a Delaware Limited Partnership By: Delphi Management Partners II, L.P., a Delaware Limited Partnership Its General Partner By: /s/ James J. Bochnowski ------------------------------------- James J. Bochnowski, General Partner Page 18 of 18 Pages January 31, 2003 By: /s/ James J. Bochnowski ------------------------------------- James J. Bochnowski January 31, 2003 By: /s/ David L. Douglass ------------------------------------- David L. Douglass January 31, 2003 By: /s/ Donald J. Lothrop ------------------------------------- Donald J. Lothrop