UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                  SCHEDULE 13D
                    Under the Securities Exchange Act of 1934
                               (Amendment No. 11)

                       NATUS MEDICAL INCORPORATION (BABY)
                                (Name of Issuer)

                                  Common Stock
                         (Title of Class of Securities)

                                    639050103
                                 (CUSIP Number)

                                David Nierenberg
                               The D3 Family Funds
                               19605 NE 8th Street
                                 Camas, WA 98607
                                 (360) 604-8600

                                 With a copy to:

                               Henry Lesser, Esq.
                                DLA Piper US LLP
                             2000 University Avenue
                            East Palo Alto, CA 94303
                                 (650) 833-2000

                  (Name, Address and Telephone Number of Person
                Authorized to Receive Notices and Communications)

                                  April 4, 2008
             (Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report
the acquisition that is the subject of this Schedule 13D and is filing this
schedule because of Sections 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check
the following box |_|.



--------------------------------------------------------------------------------
1    NAME OF REPORTING PERSON
     S.S. OR I.R.S. IDENTIFICATION NOS. OF ABOVE PERSON

     The D3 Family Fund, L.P.
--------------------------------------------------------------------------------
2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                 (a)  |X|
                                                                 (b)  |_|
--------------------------------------------------------------------------------
3    SEC USE ONLY


--------------------------------------------------------------------------------
4    SOURCE OF FUNDS*

     WC
--------------------------------------------------------------------------------
5    CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
     PURSUANT TO ITEMS 2(d) OR 2(e)                                   |_|


--------------------------------------------------------------------------------
6    CITIZENSHIP OR PLACE OF ORGANIZATION

     Washington
--------------------------------------------------------------------------------
               7    SOLE VOTING POWER

                    702,291 Common shares (3.1%)
               -----------------------------------------------------------------
  NUMBER OF    8    SHARED VOTING POWER
   SHARES
BENEFICIALLY        0
  OWNED BY     -----------------------------------------------------------------
    EACH       9    SOLE DISPOSITIVE POWER
  REPORTING
   PERSON           702,291
    WITH       -----------------------------------------------------------------
               10   SHARED DISPOSITIVE POWER

                    0
--------------------------------------------------------------------------------
11   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     For the reporting person listed on this page, 702,291; for all
     reporting persons as a group, 4,359,845 shares (19.1%)
--------------------------------------------------------------------------------
12   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*  |_|


--------------------------------------------------------------------------------
13   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

     19.1%
--------------------------------------------------------------------------------
14   TYPE OF REPORTING PERSON*

     PN
--------------------------------------------------------------------------------
                     *SEE INSTRUCTIONS BEFORE FILLING OUT!


                                       2


--------------------------------------------------------------------------------
1    NAME OF REPORTING PERSON
     S.S. OR I.R.S. IDENTIFICATION NOS. OF ABOVE PERSON

     The D3 Family Bulldog Fund, L.P.
--------------------------------------------------------------------------------
2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                 (a)  |X|
                                                                 (b)  |_|
--------------------------------------------------------------------------------
3    SEC USE ONLY


--------------------------------------------------------------------------------
4    SOURCE OF FUNDS*

     WC
--------------------------------------------------------------------------------
5    CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
     PURSUANT TO ITEMS 2(d) OR 2(e)                                   |_|


--------------------------------------------------------------------------------
6    CITIZENSHIP OR PLACE OF ORGANIZATION

     Washington
--------------------------------------------------------------------------------
               7    SOLE VOTING POWER

                    2,569,995 common shares (11.3%)
               -----------------------------------------------------------------
  NUMBER OF    8    SHARED VOTING POWER
   SHARES
BENEFICIALLY        0
  OWNED BY     -----------------------------------------------------------------
    EACH       9    SOLE DISPOSITIVE POWER
  REPORTING
   PERSON           2,569,995
    WITH       -----------------------------------------------------------------
               10   SHARED DISPOSITIVE POWER

                    0
--------------------------------------------------------------------------------
11   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     For the reporting person listed on this page, 2,569,995; for all
     reporting persons as a group, 4,359,845 shares (19.1%)
--------------------------------------------------------------------------------
12   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*  |_|


--------------------------------------------------------------------------------
13   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

     19.1%
--------------------------------------------------------------------------------
14   TYPE OF REPORTING PERSON*

     PN
--------------------------------------------------------------------------------
                     *SEE INSTRUCTIONS BEFORE FILLING OUT!


                                       3


--------------------------------------------------------------------------------
1    NAME OF REPORTING PERSON
     S.S. OR I.R.S. IDENTIFICATION NOS. OF ABOVE PERSON

     The D3 Family Canadian Fund, L.P.
--------------------------------------------------------------------------------
2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                 (a)  |X|
                                                                 (b)  |_|
--------------------------------------------------------------------------------
3    SEC USE ONLY


--------------------------------------------------------------------------------
4    SOURCE OF FUNDS*

     WC
--------------------------------------------------------------------------------
5    CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
     PURSUANT TO ITEMS 2(d) OR 2(e)                                   |_|


--------------------------------------------------------------------------------
6    CITIZENSHIP OR PLACE OF ORGANIZATION

     Washington
--------------------------------------------------------------------------------
               7    SOLE VOTING POWER

                    129,931 common shares (0.6%)
               -----------------------------------------------------------------
  NUMBER OF    8    SHARED VOTING POWER
   SHARES
BENEFICIALLY        0
  OWNED BY     -----------------------------------------------------------------
    EACH       9    SOLE DISPOSITIVE POWER
  REPORTING
   PERSON           129,931
    WITH       -----------------------------------------------------------------
               10   SHARED DISPOSITIVE POWER

                    0
--------------------------------------------------------------------------------
11   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     For the reporting person listed on this page, 129,931; for all
     reporting persons as a group, 4,359,845 shares (19.1%)
--------------------------------------------------------------------------------
12   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*  |_|


--------------------------------------------------------------------------------
13   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

     19.1%
--------------------------------------------------------------------------------
14   TYPE OF REPORTING PERSON*

     PN
--------------------------------------------------------------------------------
                     *SEE INSTRUCTIONS BEFORE FILLING OUT!


                                       4


--------------------------------------------------------------------------------
1    NAME OF REPORTING PERSON
     S.S. OR I.R.S. IDENTIFICATION NOS. OF ABOVE PERSON

     The DIII Offshore Fund, L.P.
--------------------------------------------------------------------------------
2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                 (a)  |X|
                                                                 (b)  |_|
--------------------------------------------------------------------------------
3    SEC USE ONLY


--------------------------------------------------------------------------------
4    SOURCE OF FUNDS*

     WC
--------------------------------------------------------------------------------
5    CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
     PURSUANT TO ITEMS 2(d) OR 2(e)                                   |_|


--------------------------------------------------------------------------------
6    CITIZENSHIP OR PLACE OF ORGANIZATION

     Washington
--------------------------------------------------------------------------------
               7    SOLE VOTING POWER

                    957,628 common shares (4.2%)
               -----------------------------------------------------------------
  NUMBER OF    8    SHARED VOTING POWER
   SHARES
BENEFICIALLY        0
  OWNED BY     -----------------------------------------------------------------
    EACH       9    SOLE DISPOSITIVE POWER
  REPORTING
   PERSON           957,628
    WITH       -----------------------------------------------------------------
               10   SHARED DISPOSITIVE POWER

                    0
--------------------------------------------------------------------------------
11   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     For the reporting person listed on this page, 957,628; for all
     reporting persons as a group, 4,359,845 shares (19.1%)
--------------------------------------------------------------------------------
12   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*  |_|


--------------------------------------------------------------------------------
13   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

     19.1%
--------------------------------------------------------------------------------
14   TYPE OF REPORTING PERSON*

     PN
--------------------------------------------------------------------------------
                     *SEE INSTRUCTIONS BEFORE FILLING OUT!


                                       5


--------------------------------------------------------------------------------
1    NAME OF REPORTING PERSON
     S.S. OR I.R.S. IDENTIFICATION NOS. OF ABOVE PERSON

     Nierenberg Investment Management Company, Inc.
--------------------------------------------------------------------------------
2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                 (a)  |X|
                                                                 (b)  |_|
--------------------------------------------------------------------------------
3    SEC USE ONLY


--------------------------------------------------------------------------------
4    SOURCE OF FUNDS*

     AF
--------------------------------------------------------------------------------
5    CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
     PURSUANT TO ITEMS 2(d) OR 2(e)                                   |_|


--------------------------------------------------------------------------------
6    CITIZENSHIP OR PLACE OF ORGANIZATION

     Washington
--------------------------------------------------------------------------------
               7    SOLE VOTING POWER

                    0
               -----------------------------------------------------------------
  NUMBER OF    8    SHARED VOTING POWER
   SHARES
BENEFICIALLY        4,359,845 shares (19.1%)
  OWNED BY     -----------------------------------------------------------------
    EACH       9    SOLE DISPOSITIVE POWER
  REPORTING
   PERSON           0
    WITH       -----------------------------------------------------------------
               10   SHARED DISPOSITIVE POWER

                    4,359,845 shares
--------------------------------------------------------------------------------
11   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     For the reporting person listed on this page, 4,359,845; for all
     reporting persons as a group, 4,359,845 shares (19.1%)
--------------------------------------------------------------------------------
12   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*  |_|


--------------------------------------------------------------------------------
13   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

     19.1%
--------------------------------------------------------------------------------
14   TYPE OF REPORTING PERSON*

     CO
--------------------------------------------------------------------------------
                     *SEE INSTRUCTIONS BEFORE FILLING OUT!


                                       6


--------------------------------------------------------------------------------
1    NAME OF REPORTING PERSON
     S.S. OR I.R.S. IDENTIFICATION NOS. OF ABOVE PERSON

     Nierenberg Investment Management Offshore, Inc.
--------------------------------------------------------------------------------
2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                 (a)  |X|
                                                                 (b)  |_|
--------------------------------------------------------------------------------
3    SEC USE ONLY


--------------------------------------------------------------------------------
4    SOURCE OF FUNDS*

     AF
--------------------------------------------------------------------------------
5    CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
     PURSUANT TO ITEMS 2(d) OR 2(e)                                   |_|


--------------------------------------------------------------------------------
6    CITIZENSHIP OR PLACE OF ORGANIZATION

     Bahamas
--------------------------------------------------------------------------------
               7    SOLE VOTING POWER

                    0
               -----------------------------------------------------------------
  NUMBER OF    8    SHARED VOTING POWER
   SHARES
BENEFICIALLY        957,628 common shares (4.2%)
  OWNED BY     -----------------------------------------------------------------
    EACH       9    SOLE DISPOSITIVE POWER
  REPORTING
   PERSON           0
    WITH       -----------------------------------------------------------------
               10   SHARED DISPOSITIVE POWER

                    957,628 common shares
--------------------------------------------------------------------------------
11   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     For the reporting person listed on this page, 957,628; for all
     reporting persons as a group, 4,359,845 shares (19.1%)
--------------------------------------------------------------------------------
12   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*  |_|


--------------------------------------------------------------------------------
13   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

     19.1%
--------------------------------------------------------------------------------
14   TYPE OF REPORTING PERSON*

     CO
--------------------------------------------------------------------------------
                     *SEE INSTRUCTIONS BEFORE FILLING OUT!


                                       7


--------------------------------------------------------------------------------
1    NAME OF REPORTING PERSON
     S.S. OR I.R.S. IDENTIFICATION NOS. OF ABOVE PERSON

     David Nierenberg
--------------------------------------------------------------------------------
2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                 (a)  |X|
                                                                 (b)  |_|
--------------------------------------------------------------------------------
3    SEC USE ONLY


--------------------------------------------------------------------------------
4    SOURCE OF FUNDS*

     AF
--------------------------------------------------------------------------------
5    CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
     PURSUANT TO ITEMS 2(d) OR 2(e)                                   |_|


--------------------------------------------------------------------------------
6    CITIZENSHIP OR PLACE OF ORGANIZATION

     Washington
--------------------------------------------------------------------------------
               7    SOLE VOTING POWER

                    0
               -----------------------------------------------------------------
  NUMBER OF    8    SHARED VOTING POWER
   SHARES
BENEFICIALLY        4,359,845 common shares (19.1%)
  OWNED BY     -----------------------------------------------------------------
    EACH       9    SOLE DISPOSITIVE POWER
  REPORTING
   PERSON           0
    WITH       -----------------------------------------------------------------
               10   SHARED DISPOSITIVE POWER

                    4,359,845
--------------------------------------------------------------------------------
11   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     For the reporting person listed on this page, 4,359,845; for all
     reporting persons as a group, 4,359,845 shares (19.1%)
--------------------------------------------------------------------------------
12   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*  |_|


--------------------------------------------------------------------------------
13   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

     19.1%
--------------------------------------------------------------------------------
14   TYPE OF REPORTING PERSON*

     IN
--------------------------------------------------------------------------------
                     *SEE INSTRUCTIONS BEFORE FILLING OUT!


                                       8


      This Amendment No. 11 to Schedule 13D (this "Amendment") amends the
below-indicated items from the Schedule 13D (the "Schedule 13D") previously
filed by or on behalf of the undersigned parties (the "Reporting Persons") by
supplementing such Items with the information below:

Item 2. Identity and Background.

      The Reporting Persons now include The D3 Family Canadian Fund, L.P., a
Washington State limited partnership ("The D3 Family Canadian Fund"), of which
Nierenberg Investment Management Company, Inc, a Reporting Person, is the
general partner.

      The Reporting Persons now also include David Nierenberg. His business
address is 19605 NE 8th Street, Camas WA 98607; his principal occupation is
President of Nierenberg Investment Management Company, Inc. and Nierenberg
Investment Management Offshore, Inc, two of the other Reporting Persons; and he
is a citizen of the United States of America.

      During the past five years neither The D3 Family Canadian Fund, L.P. nor
David Nierenberg have been convicted in a criminal proceeding required to be
reported in response to Item 2(d), or a party to a civil proceeding required to
be reported in response to Item 2(e), of Schedule 13D.

Item 3. Source and Amount of Funds or Other Consideration.

      The total amount of funds used by the Reporting Persons to make all
purchases of Shares beneficially owned by the Reporting Persons, as reported in
Item 5(a, b), was $36,714,462. The total amount of funds used by the Reporting
Persons to make all of the purchases of Shares reported in Item 5(c) was
$3,197,250. The source of funds for all purchases of Shares by each of the
Reporting Persons (including The D3 Family Canadian Fund) is the working capital
of the applicable D3 Family Fund (each, a "Fund").

Item 4. Purpose of Transaction

      On April 4, 2008, two of the Funds (identified in Item 5(c)) agreed to
purchase from the Company's underwriter, and the underwriter agreed to sell to
each Fund, the number of Shares set forth in Item 5 at a purchase price of
$18.27 per Share. These Shares will be issued pursuant to the Company's
Registration Statement on Form S-3 (File No. 333-233480), as amended, in
connection with an underwritten offering of its common stock by the Company (the
"Offering"). Concurrently with the settlement of these purchases and the
issuance of the Shares to the purchasing Funds (anticipated to occur on April
9,2008), the Company and each of the purchasing Funds will enter into a
Registration Rights Agreement anticipated to be dated as of April 9, 2008 (the
"Registration Rights Agreement") pursuant to which, subject to the terms and
conditions thereof, the Company will grant to the Funds certain rights to
require the Company to register for resale all Shares held by the Reporting
Persons as of the date of the Registration Rights Agreement. The form of
Registration Rights Agreement is filed as Exhibit 1 to this Amendment and the
terms thereof are incorporated into this Item by reference.


                                       9


      The Reporting Persons hold their shares of the Company's common stock for
investment. The Reporting Persons reserve the right to increase or decrease
their investment in the Company depending on market conditions, circumstances
affecting the Company and/or extrinsic factors such as developments in the
Company's industry and the economic environment, and to discuss the Company and
their investment in the shares of the Company with the directors and executive
officers of the Company and third parties, without amending the Schedule 13D
except as required by applicable rules.

Item 5. Interest in Securities of the Issuer.

      (a, b) The Reporting Persons, in the aggregate, beneficially own 4,359,845
Shares, constituting approximately 19.1% of the outstanding Shares. All
percentages in this Amendment have been calculated based on the information to
be provided by the Company in the Registration Rights Agreement as to the number
of Shares that will be outstanding following the completion of the Offering.

      (c) On April 4, 2008, the Reporting Persons named below agreed to purchase
the following number of Shares through the transactions reported in respect to
Item 4.

         Fund                       Transaction Date  Shares Acquired    Price
         ----                       ----------------  ---------------    -----
         D3 Family Bulldog Fund, LP     4/4/2008          146,000        18.27
         D3 Family Canadian Fund, LP    4/4/2008           29,000        18.27

Item 6. Contracts, Arrangements, Understandings or Relationships with Respect to
Securities of the Issuer.

      Reference is made to the Registration Rights Agreement (see Item 4), which
is filed as an exhibit to this Amendment (see Item 7) and the terms of which are
incorporated by reference in response to this Item.

Item 7. Material to be filed as Exhibits

         Exhibit 1         Form of Registration Rights Agreement anticipated to
                           be dated as of April 9, 2008, by and among the
                           Company and each of the four Funds.

         Exhibit 2         Joint Filing Agreement among the Reporting Persons
                           dated March 5, 2008 pursuant to which all of the
                           Reporting Persons have authorized the filing of
                           Schedule 13D's and amendments thereto as a group.


                                       10


                                    SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, each of the
undersigned certifies that the information set forth in the Statement is true,
complete and correct.

                               D3 Family Fund, L.P., D3 Bulldog Fund, L.P., and
                               D3 Family Canadian Fund, L.P.

                               By: Nierenberg Investment Management
                                    Company, Inc.

                               Its: General Partner

April 8, 2008                  By: /s/ David Nierenberg
-------------------------      -------------------------------------------
                                       David Nierenberg, President

                               DIII Offshore Fund, L.P.

                               By: Nierenberg Investment Management
                                    Offshore, Inc.

                               Its: General Partner

April 8, 2008                  By: /s/ David Nierenberg
-------------------------      -------------------------------------------
                                       David Nierenberg, President

                               Nierenberg Investment Management
                                    Company, Inc.

April 8, 2008                  By: /s/ David Nierenberg
-------------------------      -------------------------------------------
                                       David Nierenberg, President

                               Nierenberg Investment Management
                                    Offshore, Inc.

April 8, 2008                  By: /s/ David Nierenberg
-------------------------      -------------------------------------------
                                       David Nierenberg, President


April 8, 2008                  /s/ David Nierenberg
-------------------------      -------------------------------------------
                                   David Nierenberg


                                       11