Women’s Tennis Association, 2013 Official Rule Book (PDF)
5. Medical Procedures
a. Medical Conditions
A medical condition is a medical illness or a musculoskeletal injury that warrants medical evaluation and/or medical treatment by the PHCP in conjunction with the Tournament Physician, if appropriate, during the warm-up or the match.
i. Treatable Medical Conditions
(a) Acute Medical Condition
The sudden development of a medical illness or musculoskeletal injury during the warm- up or the match that requires immediate medical attention.
(b) Non-Acute Medical Condition
A medical illness or musculoskeletal injury that develops or is aggravated during the warm-up or the match and requires medical attention at the change of ends or set break.
ii. Non-Treatable Medical Conditions
Players may not receive treatment at any time during the match (or warm-up) for the following conditions:
(a) Any medical condition that cannot be treated appropriately.
(b) Any medical condition (inclusive of symptoms) that will not be improved by available medical treatment within the time allowed, specifically chronic conditions such as overuse injuries and recurring injuries.
(c) General player fatigue.
(d) Any medical condition requiring injections, intravenous infusions or oxygen, except for diabetes for which prior medical certification has been obtained and for which subcutaneous injections of insulin may be administered.
b. Medical Evaluation
The purpose of the medical evaluation is to determine if a player has sustained or aggravated a treatable medical condition and, if so, to determine when medical treatment is warranted and whether a Medical Time-Out (as further described in sub-Section c below, “MTO”) is necessary. The development of the condition need not be witnessed by the Chair Umpire.
ii. Player Request and Process
If at any time during the warm-up or the match, the player believes that medical evaluation and treatment are required, she may request, through the Chair Umpire only, to see a PHCP. The Chair Umpire may ask the player if she is able to continue playing; however, the Chair Umpire is under no obligation to do so.
The player has the option to:
(a) Stop play and wait until the PHCP arrives, only in the case that a player believes she has developed an acute, treatable medical condition necessitating an immediate stop in play; or
(b) Wait until the next change of ends or set break to see the PHCP, if the injury is a non- acute, treatable medical condition. The player is expected to be forthright about whether she believes she suffers with an acute medical condition that warrants a stop in play; otherwise, she is subject to a penalty in accordance with the Unsportsmanlike Conduct section of the Code of Conduct.