Current Advances in Gestation and Parturition in Cats and Dogs

Preliminary Ultrasonographic Study of Healthy California Sea Lion (Zalophus californianus) Pregnancy and Fetal Development

Reproductive success is an important aspect of marine mammals' population health, as it is an indicator of the trajectory for the population into the future. The aim of this study is to provide additional relevant data on fetus-maternal ultrasonographic monitoring in sea lion species, in order to evaluate possible fetal distress or abnormalities. From 2018 to 2023, serial ultrasonographic scans of two healthy California sea lion females (16 ± 4 years old), kept under human care, were performed over the course of two pregnancies for each female. Animals were monitored from the ovulation to the delivery. Ultrasonography was performed weekly, and, during the last month, daily images were recorded using Logiq Versana Active, General Electric, with a 2-5 MHz curvilinear transducer, and Logiq V2, General Electric, with a 2-5 MHz curvilinear transducer. Right and left lateral recumbencies have been used during the examination. To the author's knowledge, this is the first study describing in detail the sea lion organogenesis and their correlation with the stage of pregnancy.

High-definition ultrasonography for evaluation of embryonic and fetal development in bitch

ABSTRACT In women, high-definition ultrasonography provides high-quality images of normal and diseased tissues throughout pregnancy, however there are no veterinary studies describing the use of this technology in pregnant dogs. The objective was to evaluate pregnant female dogs daily, using high-definition ultrasonography (HD) in brachycephalic, documenting daily findings of maternal-fetal structures. Twelve healthy brachycephalic females were evaluated daily by HD ultrasound until delivery. It was possible to identify and categorize all maternal, embryonic, and fetal structures and their development, including some fetal tissues not yet described in the literature. The HD exam is an excellent method to monitor the pregnancy of female dogs and identify structures early, providing safe and complete information regarding fetal development.

Dead or Alive? A Review of Perinatal Factors That Determine Canine Neonatal Viability

Simple Summary

The article summarizes the current knowledge on factors related to pregnancy, parturition, and newborns that affect the health status of a puppy and determine its chances for survival and development. The detailed information is provided in terms of breed predispositions, objectives of pregnancy monitoring, potential sources of complications, and veterinary advances in care and treatment of perinatal conditions. Successful pregnancy outcomes still pose challenges in veterinary neonatology; thus, publications presenting the current state of knowledge in this field are in demand.

Abstract

The perinatal period has a critical impact on viability of the newborns. The variety of factors that can potentially affect the health of a litter during pregnancy, birth, and the first weeks of life requires proper attention from both the breeder and the veterinarian. The health status of puppies can be influenced by various maternal factors, including breed characteristics, anatomy, quality of nutrition, delivery assistance, neonatal care, and environmental or infectious agents encountered during pregnancy. Regular examinations and pregnancy monitoring are key tools for early detection of signals that can indicate disorders even before clinical signs occur. Early detection significantly increases the chances of puppies’ survival and proper development. The purpose of the review was to summarize and discuss the complex interactions between all elements that, throughout pregnancy and the first days of life, have a tangible impact on the subsequent fate of the offspring. Many of these components continue to pose challenges in veterinary neonatology; thus, publications presenting the current state of knowledge in this field are in demand.

Pregnancy and Fetal Development: Cephalic Presentation and Other Descriptive Ultrasonographic Findings from Clinically Healthy Bottlenose Dolphins (Tursiops truncatus) under Human Care

Simple Summary

Ultrasound data are vital for monitoring and detecting problems in pregnancies, and although there is a significant amount of data for domestic species, data for marine mammals are scarce. In domestic species, the use of ultrasonography to monitor a pregnancy usually has the following aims: fetal movements, fetal heart rates, measurements of the skull and the thorax for the prediction of the birth date interval, the morphological aspects of the fetal organs, the appearance of the umbilical cord, and the placentation. The purpose of this study is to provide to the clinician additional relevant data on fetal development and well-being during a dolphin pregnancy that may also be useful for wild population monitoring. This study is the result of a retrospective analysis of 192 ultrasound scans over 10 years that, for the first time, describes the sonographic findings of the bottlenose dolphin organogenesis and their correlation with the stage of pregnancy, as well as the calf presentation at birth, according to its position within the uterus, and moreover a complete literature review.

Abstract

Ultrasonography is widely used in veterinary medicine for the diagnosis of pregnancy, and can also be used to monitor abnormal pregnancies, embryonic resorption, or fetal abortion. Ultrasonography plays an important role in modern-day cetacean preventative medicine because it is a non-invasive technique, it is safe for both patient and operator, and it can be performed routinely using trained responses that enable medical procedures. Reproductive success is an important aspect of dolphin population health, as it is an indicator of the future trajectory of the population. The aim of this study is to provide additional relevant data on feto-maternal ultrasonographic monitoring in bottlenose dolphin (Tursiops truncatus) species, for both the clinicians and for in situ population studies. From 2009 to 2019, serial ultrasonographic exams of 11 healthy bottlenose dolphin females kept under human care were evaluated over the course of 16 pregnancies. A total of 192 ultrasound exams were included in the study. For the first time, the sonographic findings of the bottlenose dolphin organogenesis and their correlation with the stage of pregnancy are described. Furthermore, this is the first report that forecasts the cephalic presentation of the calf at birth, according to its position within the uterus.

The View of the French Dog Breeders in Relation to Female Reproduction, Maternal Care and Stress during the Peripartum Period

In France, as in many other western countries, dogs are an important part of the society as pets or working animals. The exact demand for puppies in France is unknown, as is the proportion of dogs coming from different breeding sources. Nevertheless, the origin of puppies is important since young dogs from puppy mills and pet stores appear to be more likely to develop behavioral disorders. Puppies coming from responsible breeders, on the other hand, tend to be better adapted. In well-managed kennels, an explanation for these behavioral differences may be associated with greater contact of litters with the dam and humans. Another factor that might influence a dog's temperament and character is maternal behavior. Although recent studies have shown that the quality of maternal care in dogs is important, direct effects on the development of behavioral problems such as fearfulness or noise sensitivity are still controversial. To better understand the view of breeders, due to an increased interest in maternal care of dogs, an online questionnaire was developed to assess the dog breeders' profiles and to explore their perception of normal maternal and stress-related behaviors during the peripartum period. In addition, the management of the female during this critical time was queried. Three-hundred and forty-five French dog breeders, representing 91 breeds, completed the online survey. Considering the demographics of the responders, breeding activity in France is mostly family-based with 76% raising two breeds of dogs that produce, on average, five litters/year. Around 60% of the breeders use progesterone levels to determine breeding date. The whelping date is estimated using multiple criteria and most labors and deliveries happen under human supervision. The majority of behaviors associated to good maternal care are defined by the vast majority as being related to more attention of the bitch towards the puppies with the frequency of nursing and licking being important clues. Globally, the peripartum is perceived as a stressful period and to minimize stress and reassure the bitch the favored method used is increasing human presence. Problems related to maternal behavior were described, notably with primiparous bitches.

Sonographic appearance of the late gestation equine fetal intestine

Variable gestation length in the mare poses a challenge for determination of fetal readiness for birth. The objectives of this study were to describe sonographic characteristics of the fetal GI tract in the late gestation mare and identify changes that occur with progressing fetal maturity. Based on these characteristics, a grading scale modeled after the existing human and canine scoring system was developed. Weekly sonographic examination of the fetus by one observer beginning 2-3 weeks prior to a calculated due date of 330 days was performed. Fetal assessment included; presence of stomach rugae, bowel segment definition (uniform echogenic, some defined, clearly defined), bowel segment dilation (none, segmental dilation), intestinal contents (none, mixed echogenicity) and peristalsis (none, occasional, every 3 s, continuous). Based on these characteristics a phase was assigned to the GI tract (1-5). Phase 1 was defined as a uniform echogenic grey area caudal to the diaphragm. The differentiation of Phase 2-5 was based primarily on the frequency of peristalsis, with Phase 2 exhibiting no peristalsis, Phase 3 exhibiting occasional peristalsis, Phase 4 exhibiting peristalsis every 3 s and Phase 5 exhibiting continuous peristalsis. Only data from mares with a normal parturition and healthy foals were included in the statistics (N = 10). Associations amongst sonographic fetal GI characteristics and days prepartum were validated using a simulation-based bootstrap approach with 1000 replicates using Stata 14. Stomach rugae, peristalsis, intestinal contents, tail head relaxation and udder development were all highly correlated with days prepartum. Using a multiple linear regression model, tail head relaxation and peristalsis predicted days prepartum with a 95% CI ± 6 days. The same model predicted days prepartum with a 95% CI ± 4 days when day of gestation, tail head relaxation and peristalsis were included as variables. Based on these findings, characterization of the fetal GI tract could provide valuable information concerning the maturity of the equine fetus. Further studies are needed comparing high risk mares to normal mares before this information could be used with confidence in the clinical setting.

Assessment of umbilical artery flow and fetal heart rate to predict delivery time in bitches

The aim of this study was to quantitatively investigate the oscillation of the fetal heart rate (HR) in advance of normal delivery and whether this index could be used to indicate impending delivery. In addition, fetal HR oscillation and umbilical artery resistive index (RI) were correlated to determine if the combination of these parameters provided a more accurate prediction of the time of delivery. Sonographic evaluation was performed in 11 pregnant bitches to evaluate the fetal HR and umbilical artery RI at the following antepartum times: 120 to 96 hours, 72 to 48 hours, 24 to 12 hours, and 12 to 1 hours. Statistical analysis indicated a correlation between the oscillation of fetal HR and the umbilical artery RI. As delivery approached a considerable reduction in the umbilical artery RI was documented and greater oscillations between maximum and minimum HRs occurred. We conclude that the quantitative analysis of fetal HR oscillations may be used to predict the time of delivery in bitches. The combination of fetal HR and umbilical artery RI together may provide more accurate predictions of time of delivery.

Intra- and inter-observer variability in ultrasonographical measurements of the uterus and ovaries in healthy, non-pregnant queens

OBJECTIVES

We aimed to (1) evaluate how frequently the uterus and ovaries of healthy, non-pregnant queens are visible; (2) describe their appearance; (3) take their measurements; and (4) determine intra- and inter-observer variabilities in their measurements. We hypothesised that, using a high-frequency linear probe, the uterus and ovaries could be ultrasonographically visualised during any period of the sexual cycle and with any level of operator expertise.

METHODS

Eight queens were enrolled in the study and the ultrasonographical appearance of their uterus and ovaries assessed with a high-frequency linear probe of 15-19 MHz. The diameter of the uterine horns, body and cervix in transverse and longitudinal sections, and the length of the ovaries were recorded. Three observers of different expertise level participated in the study, and the differences between the separate measurements made per queen were evaluated.

RESULTS

The ovaries and the entire uterus were visualised in every queen. The ovaries were ovoid structures with submillimetric follicles during anoestrus and additional larger follicles depending on the stage of the cycle. An ovarian pattern suggesting cortex and medulla was observed in half the cases. In the uterus, the serosa was a thin hyperechoic outer rim, and layering was observed in half the cases. The cervix was difficult to identify. The intra- and inter-observer variabilities in the uterine horns and the ovaries were minimal (coefficient of variation [CV] 1.4-4.1%) compared with the differences within the queens (CV 10.9-43.4%). The longitudinal and transverse measurements of the horns and the uterine body were the same.

CONCLUSIONS AND RELEVANCE

The ovaries and uterine horns in queens are accessible ultrasonographically at any stage of their cycle, and can be measured with low intra- and inter-observer variabilities.

In utero development of the fetal intestine: Sonographic evaluation and correlation with gestational age and fetal maturity in dogs

Modern high-resolution ultrasound images enable earlier assessment of measures of fetal development, including identification of the bowel. The aim of this study was to describe the ultrasonographic development of fetal bowel and correlate this with gestational age; define whether ultrasonographic visualization of fetal intestinal peristalsis in utero is associated with fetal maturation and determine whether there is a difference in fetal intestinal peristalsis detection time between fetuses delivered by normal delivery and cesarean. A cohort study was conducted in pregnant bitches presented to a veterinary hospital, to assess fetal bowel development. Statistical analysis was used to establish the correlation of the stage of fetal bowel development, as recorded by ultrasound, with outcomes of normal delivery and cesarean section. The study was broken down into three stages: the first stage was a descriptive analysis of fetal bowel development by ultrasound; the second stage compared time (in days) of bowel development between groups (normal delivery vs. cesarean); and the third stage was correlated survival probability for fetuses born on any day after detection of intestinal peristalsis with fetal maturity. All statistical analyses were significant. It is possible to monitor pregnancy progression using ultrasonographic evaluation of bowel development and this can reliably identify the end of fetal organogenesis. However, ultrasonographic detection of bowel segments with visualization of wall layers and associated peristalsis should not be used as the sole indicator for cesarean section planning because it is not possible to determine ultrasonographically whether the bowel is functional (mature).