This language is even less probative than the inconclusive studies upon which Plaintiffs' witnesses relied. Furthermore, the inclusion of a boilerplate warning on a drug package insert may reflect no more than an overly cautious response to possible liability, not scientific proof of causation.
In sum, Plaintiffs' witnesses did not rely on a single, controlled study that showed a statistically significant correlation between antibiotic use and decreased effectiveness of oral contraceptives. Consequently, the Court finds that Plaintiffs' evidence does not satisfy the first prong of the Daubert standard.
Scientific evidence must also meet the "fit" requirement by having a valid scientific connection to the inquiry at issue in the case. Daubert, 509 U.S. at 591; Daubert, 43 F.3d at 1320. The "fit" requirement pertains primarily to the relevance of the evidence under Fed. R. Evid. 402, but also recognizes the special dangers inherent in scientific expert testimony. Daubert, 509 U.S. at 591; Daubert, 43 F.3d at 1321 n.17. Such testimony "'can be both powerful and quite misleading because of the difficulty in evaluating it.'" Daubert, 509 U.S. at 595 (quoting Weinstein, Rule 702 of the Federal Rules of Evidence is Sound: It Should Not Be Amended, 138 F.R.D. 631, 632 (1991)). Therefore, a federal judge should exclude scientific expert testimony under the second prong of the Daubert standard unless he is "convinced that it speaks clearly and directly to an issue in dispute in the case." Daubert, 43 F.3d at 1321 n.17.
Here, as mentioned previously, Plaintiffs' scientific evidence was proffered to show causation. Under California law, the plaintiff has the burden of proving causation to a reasonable medical probability based on competent medical testimony.
The plaintiff must show both: (1) general causation - that the defendant's conduct increased the likelihood of injury; and (2) specific causation - that the defendant's conduct was the probable, not merely a possible, cause of the injury. Jones v. Ortho Pharmaceutical Corp., 163 Cal. App. 3d 396, 402-03, 209 Cal. Rptr. 456, 460 (1985); Daubert, 43 F.3d at 1320.
1. General Causation: Interaction between Penicillin-VK and Triphasil-28
To show general causation, Plaintiffs were required to demonstrate that there is a scientifically validated interaction between Penicillin-VK and Triphasil-28 birth control pills that made it more likely that Karyn would become pregnant while taking both drugs than if she were merely taking birth control pills alone. Here, even if Plaintiffs evidence had survived the first prong of the Daubert standard, it still does not meet the fit requirement.
To the contrary, Plaintiffs' entire theory of causation is flawed. Plaintiffs' witnesses testified that antibiotics kill bacteria in the digestive system, thereby interfering with the mechanism by which oral contraceptives release estrogen into the woman's body. This lowering of estrogen levels supposedly reduces the contraceptive effect of the birth control pills and allows the woman to ovulate and become pregnant. Tr., vol. 2, at 243-48, vol. 4, at 643.
However, Triphasil-28 birth control pills have two components, estrogen and progestin. Each component has independent contraceptive effect.
The progestin component is metabolized in a different way than the estrogen component, and Plaintiffs' experts presented no scientific evidence whatsoever demonstrating that antibiotics interfere with metabolization of progestin.
Therefore, even assuming that Scientific evidence showed that antibiotics interfered with the estrogen component, the progestin component would still prevent pregnancy.
2. Specific Causation: Probable Cause of Karyn's Pregnancy
To show specific causation, Plaintiffs had to demonstrate that the interaction between Penicillin-VK and Triphasil-28 birth control pills was the probable, not merely a possible, cause of Karyn's pregnancy. Under Daubert, Plaintiffs could carry this burden if they could show that such an interaction occurs at more than double the rate of the known failure rate for oral contraceptives alone. 43 F.3d at 1320 ("plaintiffs must establish not just that their mothers' ingestion of Benedictin increased somewhat the likelihood of birth defects, but that it more than doubled it").
Here, Plaintiffs have utterly failed to present any competent testimony on this issue. As mentioned previously, none of the articles cited by Dr. Hinderstein or Dr. Harralson contain a controlled, broad-based study of the existence of an interaction between antibiotics and oral contraceptives, let alone the rate at which such an interaction occurs. Given that over 14 million women in the United States are currently using oral contraceptives, and an unknown number of them are prescribed antibiotics from time to time, Plaintiffs' reliance on studies involving only a handful of women is clearly not Statistically defensible.
II. Plaintiffs' Case
Liability for negligence under California law requires proof of the following elements: (1) a legal duty of care; (2) a breach of that duty; and (3) causation. Ann M. Pacific Shopping Ctr., 6 Cal. 4th 666, 673, 25 Cal. Rptr. 2d 137, 141, 863 P.2d 207 (1993). In this case, even if the Court had found that Plaintiffs' scientific evidence was sufficient under Daubert to proceed to the trier of fact, Plaintiffs have still failed to meet their burden of persuasion on: (1) duty of care - whether the Army doctors were required to warn Karyn that antibiotics might interfere with the effectiveness of her birth control pills; and (2) causation - whether Karyn became pregnant while she was taking the antibiotics.
A. Legal Duty: Informed Consent
Under California law, a physician has a duty "of reasonable disclosure of the available choices with respect to Proposed therapy and of the dangers Inherently and potentially involved." Arato v. Avedon, 5 Cal. 4th 1172, 1183, 23 Cal. Rptr. 2d 131, 138, 858 P.2d 598 (1993) (en banc) (quoting Cobbs v. Grant, 8 Cal. 3d 229, 242, 104 Cal. Rptr. 505, 514, 502 P.2d 1 (1972)); Hanna v. United States, 845 F. Supp. 1390, 1392 (E.D. Cal. 1993). This duty does not require the physician to conduct a "mini course in medical science" or to discuss "the relatively minor risks inherent in common procedures, when it is common knowledge that such risks inherent in the procedure are of very low incidence." Cobbs, 8 Cal. 3d at 244-45, 104 Cal. Rptr. at 515; See also, Arato, 5 Cal. 4th at 1186, 23 Cal. Rptr. 2d at 139-140. However, when recommending treatment, the physician must disclose any known risks of death or serious bodily injury and must explain in lay terms the complications that might possibly occur. The physician must also disclose "such additional information as a skilled practitioner of good standing would provide under similar circumstances." Arato, 5 Cal. 4th at 1190, 23 Cal. Rptr. 2d at 143.
Most often, determining whether a potential risk is material enough to require disclosure is a question of fact that does not necessitate the admission of expert testimony However, in certain situations, expert testimony concerning the standard of care in the medical profession may help the trier of fact to determine whether a physician had a duty to disclose a potential risk. Arato, 5 Cal. 4th at 1191, 23 Cal. Rptr. at 143-44.
In this case, reference to expert testimony is appropriate to assist the Court, as the trier of fact, in determining whether a warning of the possible interaction between Penicillin-VK and Triphasil-28 was required. Such testimony is helpful to the Court in interpreting the complex and conflicting scientific evidence as to whether, and how often, such an interaction actually occurs.
At trial, both sides presented witnesses to testify whether the Army doctors were or were not required to warn Karyn that the penicillin they prescribed for her could interfere with the effectiveness of her birth control pills.
After considering this testimony, as well as the other evidence presented at trial, the Court finds that Plaintiffs have failed to carry their burden of establishing that a warning was required. As discussed in Section I.A, supra, the existence of a such a drug interaction is unproven and the danger of it occurring appears to be extremely remote. Consequently, the standard of care in Monterey County in early 1992 did not require a warning for this small risk inherent in the extremely common practice of prescribing antibiotics.
B. Causation: Date of Conception
Plaintiffs also failed to prove by a preponderance of the evidence that Karyn became pregnant during the time that she was taking Penicillin-VK. To the contrary, for several reasons, the Court finds that it is more likely than not that Karyn conceived before she began taking antibiotics.
First, at the time that Karyn's first pregnancy test was positive on February 19 at 9:57 a.m., it was too early for the test to sense conception that supposedly occurred on February 8 or 9. The timeline is as follows. After conception, the fertilized egg spends approximately 3 to 4 days in the fallopian tube. Then it moves into the endometrial cavity and spends an additional 3 to 4 days there. Then the egg implants in the uterus. Approximately one or two days following implantation, there is detectable human chorionic gonadotrophin ("HCG") in the woman's urine. For the next thirty-five days, the level of HCG doubles every 1.4 to 1.6 days. In other words, if the HCG level is one milli international unit of HCG eight days after conception, there would be 2 milli after approximately 9.5 days, 4 milli after 11 days and so on. Tr., vol. 8, at 30-35, 36-40.
According to its labelling, the Icon II pregnancy test administered to Karyn was sensitive to 50 milli of HCG. However, defense witness Dr. Roy admitted that in controlled laboratory trials the Icon II was able to detect levels of HCG as low as 20 milli. Tr., vol. 8, at 119. Either way, if Karyn conceived on the evening of February 8, the Icon II test could not have detected her pregnancy only 10.5 days later on the morning of February 19. As footnote 14 demonstrates, it takes at least 13 to 14 days after conception to arrive at 20 milli of HCG. If a pregnancy test administered on February 19 was positive, Karyn must have conceived, at the latest, on February 6 or 7. Conception on February 8 or 9 would not be detectable until February 21 or 22.
Second, it is highly improbable that Karyn would have been able to ovulate on February 8 or 9 if she had already taken six birth control pills on February 2 through 7. According to Dr. Archer's unrebutted testimony, the estrogen component of the Triphasil-28 pills would have inhibited Karyn's production of follicle stimulating hormone ("FSH") and luteinizing hormone ("LH") to such an extent during the first six days of her cycle that it would have prevented her follicles from enlarging sufficiently thereafter to produce an ovum on February 8 or 9. Tr., vol. 5, at 899-900. In other words, even assuming that the antibiotics interfered with the effectiveness of Karyn's birth control pills, there was not enough time after Karyn started taking the antibiotics to result in pregnancy within two days.
Based on the foregoing, the Court finds for Defendant and against Plaintiff. Judgment will be entered accordingly.
IT IS SO ORDERED.
United States District Judge