Record of Decease - any advice would be welcome

[Escaliba1234]

I am searching for records of decease for my grandmother: Marie Thomsen (nee Andersen).
She was born 30 March 1896 (in Ishøj I think).
She died on the 21 March 1928, at Glostrup, 1 week before her thirty-second birthday.
I would very much like to know what she died from, if that is at all possible.
The attached photograph shows my grandmother's grave with her youngest daughter, who was three weeks short of her fourth birthday when her mother died.
Would it be at all possible to identify the graveyard?
As always, many thanks for all input.

[Vibeke Jespersen]

Marie Thomsens grave - Glostrup Søndre Kirkegård/cemetery.
Stephan Marius Thomsen in the same grave.

Grave no. 1.17 01018.

Mvh
Vibeke

[Inger Toudal]

Burial record, Glostrup:
https://www.sa.dk/ao-soegesider/da/billedviser?epid=17115380#150417,24934648

Death record, Diakonissestiftelsen, Frederiksberg:
https://www.sa.dk/ao-soegesider/da/billedviser?epid=17118682#156613,26251983 - No 27

- cause of death: Peritonitis

https://en.wikipedia.org/wiki/Diakonissestiftelsen

The hospital at Diakonissestiftelsen closed in 1984: https://da.wikipedia.org/wiki/Diakonissestiftelsen

Venlig hilsen
Inger Toudal