OPINION
BURGESS, Judge.Hope Cumpian appeals from a judgment terminating her parent-child relationship with M.A.C. The Texas Department of Protective and Regulatory Services initiated the suit while M.A.C. was a newborn, because M.A.C. tested positive for cocaine at birth. As the appointed temporary sole managing conservator of M.A.C., the Department maintained custody of the child throughout this litigation. We shall address Cumpian’s three points of error in reverse order.
Point of error three contends, “The trial court committed reversible error when it failed to allow a no-cost physical examination of the child by a medical expert of the appellant’s choosing.” Cumpi-an filed a motion to permit Dr. Marie Ferris, a board certified pediatrician, to examine M.A.C., for the purpose of assessing the existence and severity of the infant’s alleged fetal alcohol syndrome or fetal cocaine syndrome. Cumpian asked that Dr. Ferris be treated as her consulting expert. See Tex.R. Civ. P. 192.3(e).
The Department argues the motion was not presented to the trial court in a timely manner because it was filed within thirty days of the date set for trial. See Tex.R. Civ. P. 190.3(b)(1)(A). The motion was filed the first time in December, some two months before the case actually went to trial. The trial court denied the motion but advised Cumpian that he would reconsider his ruling if the need for an expert became apparent during trial. Cumpian re-urged her motion after the trial was reset at the Department’s request. A trial resetting has the effect of nullifying the discovery deadline. J.G. v. Murray, 915 S.W.2d 548, 550 (Tex.App.—Corpus Christi 1995, orig. proceeding). Thus, the motion was not untimely under Rule 190.3(b)(1)(A).
Good cause for a physical examination is established where the petitioner intends to use expert medical testimony to prove a fact in controversy. See Laub v. Millard, 925 S.W.2d 363, 364 (Tex.App.—Houston [1st Dist.] 1996, orig. proceeding). During the hearing on the motion, the Department notified the trial court that it would present expert witnesses at trial. Cumpian’s attorney apprised the court that she needed the assistance of an expert because she did not understand the medical records. Cumpian’s attorney also informed the trial court that Dr. Ferris would not provide her expert opinion of M.A.C.’s condition based only upon a review of the medical records because actual examination of the child was required before she could make a diagnosis. By forbidding the examination, the court placed such a severe restriction on the Cumpian’s ability to discover facts to contradict the opinions of the Department’s expert witnesses that she was deprived of a champion in the “battle of experts.” See Sherwood Lane Associates v. O’Neill, 782 *925S.W.2d 942, 945 (Tex.App. — Houston [1st Dist.] 1990, orig. proceeding).
The importance of a medical expert was borne out at trial. The Department based its “best interest” allegation almost exclusively upon M.A.C.’s current physical condition and prognosis. According to the Department’s representative, Kathy Huie, the main factor in the Department’s decision to seek termination of Cumpian’s parental rights was the existence of M.A.C.’s physical ailments, esophageal reflux and developmental delay. Huie admitted Cumpian had made substantial progress in her life by getting off drugs and maintaining a job, but in Huie’s opinion Cumpian could not meet MAC.’s special needs.
In order to meet its burden of proof at trial, the Department offered M.A.C.’s voluminous medical records, which Cumpi-an’s counsel had admitted she could not adequately understand without expert assistance. The Department presented expert testimony from MAC.’s treating pediatrician, a neonatologist, an occupational therapist, and a speech pathologist. The pediatrician, Dr. Richard Calvin, diagnosed MAC.’s syndromes by patient history and testified that M.A.C. had both delayed communication skills and a significant feeding disorder. According to Dr. Calvin, MAC.’s special needs require a custodian who understands his diagnosis and treatment.
The Department argues that its witnesses were independent medical providers. We disagree. Although he was also the child’s treating physician, Dr. Calvin clearly testified as an expert on behalf of the Department. The trial court abused its discretion by denying Cumpian’s motion to permit her own expert to examine M.A.C. As M.A.C.’s physical condition formed the basis of the Department’s allegation that termination would be in the child’s best interest, the error probably resulted in the rendition of an improper judgment. Tex.R.App. P. 44.1(a)(1). Point of error three is sustained. We decline to rule upon points of error one and two, as they would not result in greater relief to the appellant. The judgment is reversed. We remand the cause to the trial court for a new trial.
REVERSED AND REMANDED.