ALTRENOGEST AND PROGESTERONE THERAPY DURING PREGNANCY IN BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS) WITH PROGESTERONE INSUFFICIENCY

Abstract

Progesterone production is essential for growth and development of the conceptus during pregnancy. Abnormal development of the corpus luteum (CL) after conception can result in early embryonic loss or fetal abortion. Routine monitoring of bottlenose dolphin (Tursiops truncatus) pregnancy after artificial insemination or natural conception with ultrasonography and serum progesterone determination has allowed for the establishment of expected fetal growth rates and hormone concentrations. Using these monitoring techniques, we revealed four pregnant dolphins (12-24 yr old) with abnormally low progesterone production indicative of luteal insufficiency. Once diagnosed, animals were placed on altrenogest (0.044-0.088 mg/kg once daily) alone or with oral progesterone (50-200 mg twice daily). Doses of hormone were increased or decreased in each animal based on how fetal skull biparietal and thoracic growth rates compared with published normal values. Hormones were withdrawn starting from day 358 of gestation in animals 1 and 2, with labor occurring 6 and 7 days after withdrawal and at 376 and 373 days of gestation, respectively. Both deliveries were dystocic, with each calf requiring manual extraction and fetotomy for calf 1. The fetuses in animals 3 and 4 died at 348 and 390 days of gestation, respectively. Induction of labor was attempted in both animals, after fetal death, by using a combination of rapid progesterone withdrawal and steroid and prostaglandin F2alpha administration. The calf of animal 4 had to be removed with manual cervical dilation and fetotomy All adult females survived the procedures. These data provide the first in vivo evidence that the CL is the primary source of progesterone throughout pregnancy in the bottlenose dolphin. Until further characterization of hormones required during pregnancy and at parturition has been accomplished, the exogenous progestagen supplementation protocol described here cannot be recommended for treatment of progesterone insufficiency in bottlenose dolphins.

Comparisons of Serum Progesterone and Progestagen Concentrations in Normal and Abnormal Bottlenose Dolphin (Tursiops truncatus) Pregnancies

“…In cattle and horses, dystocia has a complex multifactorial etiology with primary influences being parity or age at first calf and genetics (i.e., calf size), as demonstrated by a dystocia rate that is twice as common in primiparous females compared to multiparous females (McDermott et al, 1992;Meyer et al, 2000;Johanson and Berger, 2003). Although human intervention during prolonged or dystocic labor is common for dairy cattle and horses, this type of intervention is still rare with bottlenose dolphins and calf size may be an important variable that influences stillbirth rates in bottlenose dolphins (Robeck et al, 2012). Furthermore, historically inaccurate identification of conception dates or data collection at birth impedes evaluation using obvious factors, such as gestation length, length of labor and calf birth weight, as potential risk-increasing identifiers of perinatal mortality in bottlenose dolphins.…”

Long-Term Moderate Oxidative Stress Decreased Ovarian Reproductive Function by Reducing Follicle Quality and Progesterone Production

“…Progesterone is also secreted by ovarian corpus luteum cells, which are luteinized granulosa cells [ 50 , 51 ]. Oxidative stress plays a vital role in granulosa lutein insufficiency [ 52 ], which explains low progesterone levels in mice experiencing oxidative stress [ 53 , 54 ]. An age-related decrease in egg quality is commonly considered the principal driving force for poor pregnancy success rates in aging females.…”

Ultrasonographic findings associated with normal pregnancy and fetal well‐being in the bottlenose dolphin (Tursiops truncatus)

“…Ultrasound is also a critical component of bottlenose dolphin ( Tursiops truncatus ) medicine and has been used to evaluate pulmonary, cardiac, reproductive, hepatic, urinary, gastrointestinal, and lymphatic systems . Improved understanding of Tursiops reproduction through routine imaging in managed care has led to advancements in hormone analysis, gonadal evaluation, early fetal monitoring, parturition prediction, and artificial insemination . This knowledge has successfully been applied to longitudinal investigations of wild dolphin health …”

“…in hormone analysis, gonadal evaluation, early fetal monitoring, parturition prediction, and artificial insemination. [10][11][12][13] This knowledge has successfully been applied to longitudinal investigations of wild dolphin health. 14…”