title: Relaxin as a hormonal aid to evaluate pregnancy and pregnancy loss in bottlenose dolphins (Tursiops truncatus).
abstract: This study was conducted to critically evaluate weekly and monthly circulating concentrations of immunoreactive relaxin throughout pregnancies that resulted in live births, stillbirths, and abortions in aquarium-based bottlenose dolphins. A relaxin RIA was used to analyze serum collected during 74 pregnancies involving 41 dolphins and 8 estrous cycles as well as 8 non-pregnant dolphins. Pregnancies resulted in live births (n=60), stillbirths (n=7), or abortions (n=7). Relative to parturition (Month 0), monthly changes (P<0.0001) in relaxin was indicated by relatively low concentrations during early pregnancy (Months -12 to -9) which subsequently increased (P<0.05) during mid- (Months -8 to -5) to late (Months -4 to -1) pregnancy; relaxin was highest (P<0.05) at the time of parturition. Post-parturition (Month 1), concentrations decreased (P<0.05). During the first 4weeks post-ovulation, relaxin concentrations were not different between pregnant and non-pregnant dolphins (status-by-week interaction, P=0.59). Status-by-month interaction (P<0.0002) involving different pregnancy outcomes was due, impart, to an increase in relaxin during early pregnancy (P<0.05) that was comparable among dolphins with live births, stillbirths, and abortions except concentrations were lower (P<0.05; 52%) at mid-pregnancy in association with pregnancy loss. Thereafter, concentrations increased (P<0.05) during late pregnancy in dolphins with stillbirths but not in dolphins with abortions. In conclusion, this study provided new information on the pregnancy-specific nature of relaxin, critical evaluation of the fundamental characteristics of relaxin during pregnancy and pregnancy loss, and clarification on the strengths and limitations of relaxin as a diagnostic aid to determine pregnancy status and assess maternal-fetal health in bottlenose dolphins.
authors.affiliation: Department of Biomedical Sciences, Ross University School of Veterinary Medicine, Basseterre KN 00265, Saint Kitts and Nevis, West Indies. Electronic address: dbergfelt@rossvet.edu.kn.
authors.forename: Don R
authors.initials: DR
authors.lastname: Bergfelt
authors.affiliation: Department of Environmental Medicine, New York University School of Medicine, Tuxedo, NY 10987, United States. Electronic address: Jason.Blum@nyumc.org.
authors.forename: Jason L
authors.initials: JL
authors.lastname: Blum
authors.affiliation: Department of Environmental Medicine, New York University School of Medicine, Tuxedo, NY 10987, United States. Electronic address: berniesteinetz@gmail.com.
authors.forename: Bernard G
authors.initials: BG
authors.lastname: Steinetz
authors.affiliation: SeaWorld and Busch Gardens Reproductive Research Center, San Diego, CA 92109, United States. Electronic address: Karen.Steinman@SeaWorld.com.
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Steinman
authors.affiliation: SeaWorld and Busch Gardens Reproductive Research Center, San Diego, CA 92109, United States. Electronic address: Justine.OBrien@SeaWorld.com.
authors.forename: Justin K
authors.initials: JK
authors.lastname: O'Brien
authors.affiliation: SeaWorld and Busch Gardens Reproductive Research Center, San Diego, CA 92109, United States. Electronic address: Todd.Robeck@SeaWorld.com.
authors.forename: Todd R
authors.initials: TR
authors.lastname: Robeck
mesh_terms: D000034:Abortion, Veterinary / Q000097:blood*; D000818:Animals; D050681:Bottle-Nosed Dolphin / Q000097:blood / Q000502:physiology*; D005260:Female; D036801:Parturition / Q000502:physiology; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000662:veterinary; D011270:Pregnancy, Animal / Q000097:blood / Q000502:physiology; D012065:Relaxin / Q000097:blood*; D050497:Stillbirth / Q000662:veterinary*
chemical_list: D012065:Relaxin
keywords: Abortion; Bottlenose dolphins; Pregnancy; Relaxin; Stillbirth