Look up how Puerto Rico's Department of Health and follow the instructions below. However, I do highly suggest going to Puerto Rico yourself and doing research through their libraries and records department.
Department of Health, Demographic Registrar:
Here is a list of offices located in the various municipalities holding birth, marriage and other vital records. There are no governmental records listing such events prior to 1885 when the task of official vital record keeping was made a governmental function. Before that date, the Catholic parish churches of the respective municipalities of Puerto Rico were the official originators and repositories of these records.
The procedure for requesting abstracts of any of these official government records is as follows:
If the event happened before July 22, 1931, your request for a vital record should be made to the Demographic Registrar office in the municipality where the person resided at the time. (See list below)
If event occurred after July 22 your request should go to:
Departamento de Salud, Registro Demografico
PO Box 11854, San Juan, PR 00910
Your request for a document must include:
1. A money order of $5.00 for each record made to the order of Secretary of the Treasury of Puerto Rico.
2. The full and complete name and surnames of the person whose record you want.
3 Your relationship to that person and why you want the document.
4. Copy of your ID, preferably a drivers license, a passport or other document that has a photo and lists your place of birth.
5. A stamped, self-addressed envelope.
Click on to the website below for list of Demographic Registrars of Puerto Rico