Post-Partum Involution of the Canine Uterus - Gross Anatomical and Histological Features

Uterine horn intussusception in immediate post-partum in a Pomeranian Spitz dog

A 2-year-old Pomeranian-Spitz dog (5.8 kg) was admitted with symptoms of uterine prolapse and lethargy 1 day after whelping three puppies. The prolapsed uterus was corrected, but the next day, prolapse reoccurred. To fix the cervix to the abdominal wall, the dog underwent a surgery operation where intussusception in the left horn of the uterus was found. Ovariohysterectomy was performed as the treatment of choice. The diagnosis of intussusception is challenging, and exploratory laparotomy is the reliable diagnostic approach. Although uterine intussusception is rare, it should be one of the important considerations in dogs within the post-partum period.

Time to Resumption of Menses, Spatial Distribution, and Predictors Among Post-partum Period Women in Ethiopia, Evidence From Ethiopian Demographic and Health Survey 2016 Data: Gompertz Inverse Gaussian Shared Frailty Model

Background

The timing of the resumption of post-partum menses is important for a woman who intends to avoid subsequent unintended pregnancy, and it has key implications on maternal, neonatal, and child health outcomes. Despite this, information is scant about the time to resumption of post-partum menses and predictors in Ethiopia. Therefore, this study aimed to determine the time it takes to start menses and spatial distribution among post-partum period women in Ethiopia and identify its predictors.

Methods

A secondary data analysis was conducted based on 2016 Ethiopian Demographic and Health Survey (EDHS). A total weighted sample of 6,489 post-partum women was included in the analysis. STATA 14 was used to weigh, clean, and analyze the data. The shared frailty model was applied since the EDHS data have a hierarchical nature. For checking the proportional hazard assumption, the Schenefold residual test, Log-Log plot, Kaplan–Meier, and predicted survival plot were applied. Akakie Information Criteria (AIC), Cox–Snell residual test, and deviance were used for checking model adequacy and for model comparison. Based on these, the Gompertz inverse Gaussian shared frailty model was the best-fitted model for this data. Variables with a p < 0.2 were considered for the multivariable Gompertz inverse Gaussian shared frailty model. Finally, the adjusted hazard ratio (AHR) with a 95% confidence interval (CI), and a p < 0.05 was reported to identify the significant predictors of time to the resumption of post-partum menses.

Results

The median survival time to post-partum menses resumption was 14.6 months. In this study, 51.90% [95% CI: 50.03, 53.76] of post-partum period women had resumed, and the risk of menses resumption was 1.17 times [AHR: 1.17; 95% CI: 1.03–1.33] higher among urban resident, 1.14 times [AHR: 1.14; 95% CI: 1.0–1.24] in women who had attended formal education, and 1.63 times [AHR: 1.63; 95% CI: 1.4–1.7] higher among women who used hormonal contraceptives. However, the risk of post-partum menses resumption was lower among 7–24 months breastfeeding women by 36% [AHR: 0.64; 95% CI: 0.5–0.76], women with child alive by 26% [AHR: 0.74; 95% CI: 0.6–0.85], and multiparous women by 27% [AHR: 0.73; 95% CI: 0.6–0.80].

Conclusion

Almost half of the participants had resumed post-partum menses, with the median survival timing of menses resumption at 14.5 months. Women residing in urban areas, who attended formal education, and using hormonal contraceptives have a shorter time to resume post-partum menses, whereas a woman with an alive child, breastfeeding practice, and multiple parity has a longer time to resume post-partum menses. Therefore, the healthcare providers and program managers should act on the resumption of post-partum menses through health education and promotion to cultivate the 14 months lag period identified by considering the significant factors.

Placentation in the African Elephant (Loxodonta africana)

The female elephant shows a 3-week "follicular phase" to commence her 16-week estrous cycle at the end of which a second surge in pituitary luteinizing hormone (LH) release matures and ovulates an ovarian follicle in association with estrous behavior and mating, whereas the first LH surge at the start of the follicular phase causes luteinization of 3-5 partially developed follicles. The prolonged pregnancy of 22 months is supported by a zonary endotheliochorial placenta which secretes placental lactogen (ePL) from around 40 days of gestation in association with replacement of the lumenal epithelium of the endometrium by trophoblast and the development of large corpora lutea (CLs) in the maternal ovaries from the previously formed luteinized follicles in response to the first LH peak early in the follicular phase. The zonary placenta develops above, rather than within, the endometrium. The elephant placenta secretes neither estrogens nor progestagens throughout gestation, as pregnancy maintenance relies on 5α-dihyroprogesterone and other 5α reduced progestagens secreted by secondary CLs stimulated by ePL and the stromal tissue of the fetal gonads, which become extremely enlarged during the second half of the 22-month pregnancy. In female fetuses, this ovarian enlargement includes the development and subsequent regression of multiple primary and secondary follicles with a consequent substantial decline in primary follicle numbers at birth. During the next 8-9 years of pre-pubertal life, however, oocyte and primary follicle numbers recover to levels near those found in late gestation, which may be evidence of postnatal oogenesis occurring in the elephant.

A descriptive angiographic study of the uterine arteries during pregnancy, the postpartum period and CEH/pyometra in bitches

The aim of this descriptive study was to monitor the changes in uterine arteries during pregnancy, postpartum period and pyometra in bitches using angiography. Fifteen uteri of mixed breed bitches on days 24, 30, 33, 40, 43, 47, 50 and 56 of pregnancy and weeks 1, 2, 3, 4 and 7-8 of postpartum and two CEH/pyometra bitches were examined after ovariohysterectomy. The results showed that with the onset of normal pregnancy and in about 30 ± 1 days of gestation, anastomoses begin to form between the left and right middle uterine arteries, developing during the next days and continuing until 4 weeks postpartum. On 4th week after parturition, when physiologic changes occur and the uterus returns to non-pregnant conditions, these anastomoses begin to degenerate, and they completely disappear approximately on the 7th-8th week after parturition. Similarly, in CEH/pyometra bitches, anastomoses were formed between left and right median uterine arteries. These findings can be considered as a part of the physiological changes of the uterus and its vessels during pregnancy and postpartum periods and could affect the results and interpretation of relevant findings.

Abundance of insulin-like growth factors 1 and 2, and type 1 insulin-like growth factor receptor in placentas of dogs

Insulin-like growth factors (IGFs) are among the primary compounds regulating placental development. In bitches, relative abundance of IGF1, IGF2 and IGFR1 mRNA transcripts have been studied in the pre-implantation uterus and early endotheliochorial placentas. The IGF2 and IGFR1 distribution has also been previously described in the uterus before embryo implantation. The aim of this study was to detect, characterize, and localize the presence of IGF1, IGF2, and IGFR1 in early-developing and mature placentas of dogs. Placentas of 15 bitches were analyzed using immunohistochemistry. The IGFs were located in endometrial epithelium and glands, with the staining pattern and intensity being less in mature placentas. Cytotrophoblast cells (CTB) and syncytiotrophoblast (STB) cells contained both IGFs; the labeling was greater in CTB of the early-developing than mature placentas. The maternal endothelium was positively stained for both IGFs, while the vascular endothelium of the chorioallantoic membrane were only stained for IGF2. The IGFR1 was detected in all cell populations evaluated. Results regarding trophoblastic IGF are quite consistent with those reported in human placentas. Spatiotemporal IGFs/IGFR1 pattern might reflect the occurrence of autocrine and paracrine signaling during placentation in bitches, and the involvement in early placental developmental processes. Furthermore, it is hypothesized that, besides hemotrophic actions of plasma IGFs, endometrial secreted IGFs may promote early placental development through histotrophic signaling.

The bitch around parturition

Around parturition, a bitch has to cope with various challenges such as hormonal changes, whelping, nursing, milk production, and uterine involution. Monitoring the health of bitches in this period is essential to detect potential illnesses and dystocia early. In that regard, it is elementary to know the normal progress and parameters during pregnancy, parturition and in the puerperium. Some research has been published in the past 50 years giving insights into hormonal and functional changes and findings including definitions of normal parturition and dystocia or puerperal conditions. However, taking a closer look into the literature reveals that for some issues heterogeneous data and varying conclusion were presented, indicating that further research is required. This paper gives an overview on endocrinology and methods to predict the time of parturition in the dog. Furthermore, the stages and mechanisms of parturition and signs of dystocia and puerperal health monitoring are discussed. Fields in which contradictory data have been published include for example the decline of hematocrit in the second half of pregnancy, the body temperature immediately before and after parturition, the interpretation of ultrasound findings, and the length of the canine puerperium. Even if thresholds are not clear for each parameter, examinations such as regular temperature measurement or ultrasound are important to monitor the bitches' health status. Nevertheless, for the practitioner it is important to know that research findings for some parameters used in daily practice are controversial.

Quantitative ultrasound elastography and biometry of the bitch uterus in the early puerperium after vaginal delivery and caesarean section

Elastography is an actual imaging method used to qualitatively and quantitatively evaluate the elastic properties of tissues. The aim of this study was to evaluate and compare uterine tissue biometry and stiffness during post-partum period in brachycephalic bitches (n = 12) after c-section (GCS; n = 8) or normal delivery (GNB; n = 4). These animals were evaluated daily by abdominal ultrasound from the day of delivery until the 10th day post-partum; measuring uterine diameter, myometrial and endometrial thickness (mm) and shear wave velocity (SWV; m/s), by B-mode and ARFI (acoustic radiation force impulse) elastography, respectively. Uterine diameter was higher (p = .012) in animals submitted to c-section (15.26 ± 4.73 mm) than in normal birth (12.53 ± 2.64 mm) during the first 7 days post-partum. Uterine thickness gradually involuted in both groups (p < .0001), the myometrium during the first 9 days (p = .005) and the endometrium during the first 6 days (p = .003). The myometrial and endometrial SWVs were similar between types of delivery (p = .7846 and .8273) and presented a gradual increase (p = .411; .0043, respectively), during the first 10 days post-partum. It was concluded that bitches with normal delivery had smaller uterine thickness and faster puerperal involution than submitted to c-section, while uterine tissue stiffness was similar between delivery types and increased gradually during post-partum.

Bacteriological findings in the canine uterus during Caesarean section performed due to dystocia and their correlation to puppy mortality at the time of parturition

Canine intrauterine bacteriological flora during dystocia is unknown. Thus, frequency (bacterial growth (not) detected), quality (species and number of different bacterial isolates) and quantity (colony-forming units) of intrauterine bacteria in relation to in utero foetal death in 50 bitches undergoing emergency Caesarean section were investigated. Bacterial growth was quantified from single colonies, (+) (0.5), to strong growth, +++ (3) and was observed in 34 bitches (68%), with Staph. epidermidis (n = 12), Staph. intermedius-group (n = 7), β-haemolytic streptococci (n = 6), Staph. aureus, α- and γ-haemolytic streptococci (n = 4 each) being most common and one to four bacteria per sample. Regarding the quantity, most often (n = 46) low growth was identified. In bitches with living pups only (group I), mean number of isolates was 0.78 ± 0.83 compared to 1.60 ± 1.10 (living + stillborn pups, group II) and 1.0 ± 1.15 (stillborn pups only, group III) and mean bacterial growth in groups I/II/III was + (1.0, quantity), + (1.4) and ++ (1.6). Taking just positive samples into consideration, mean number of bacterial isolates was significantly higher in group II compared to I (p = .0088). We concluded that the canine uterus cannot be considered free of bacteria during dystocia. Mean numbers of different bacterial isolates and quantity of bacterial growth are higher in bitches with in utero foetal death.

Apoptosis in Living Animals Is Assisted by Scavenger Cells and Thus May Not Mainly Go through the Cytochrome C-Caspase Pathway

Because billions of cells die every day in their bodies, animals have evolutionarily developed apoptosis to preserve the tissue environment from adverse effects of dead cells, a process achieved via phagocytosis of the cell corpses by professional or amateur phagocytes that are collectively referred to as scavengers. Hence, apoptosis is a merger of two procedures separately occurring inside the dying and the scavenger cells, respectively. The task of apoptosis research is to study how these death procedures occur without hurting the host tissues, and recruitment of in vitro system into the study must be justified for this purpose. Cells in culture have no motivation to preserve the environment, and their death does not involve corpse clearance by scavengers. Therefore, programmed cell death in culture should be redefined, for example as stress-induced cell death, to avoid many sources of confusions, since the word “apoptosis” had already been defined, prior to the era of cell culture, as a silent and beneficial cell suicide with corpse clearance as a distinctive hallmark. We should start over again on apoptosis research by determining whether different physiological apoptotic procedures in animals involve the cytochrome c-caspase pathway, since it has been established from cultured cells as a central mechanism of “apoptosis” but whether it overarches any physiological apoptotic procedure in animals is still unclear. Probably, cells in living animals are programmed to use scavengers to assist their apoptosis but cells in culture have no scavengers to help and thus need to go mainly through the cytochrome c-caspase pathway.

Histological features in the mammary glands of female dogs throughout lactation

The objective of this study was to describe the histology of the mammary glands of female dogs throughout lactation. Twelve lactating female dogs were operated 4, 7, 10, 14, 21, 28, 35, 42, 56, 70 and 84 days post-partum; four mammary glands of each animal were excised for histological, ultrastructural and morphometric examination. During early lactation and mid-lactation, all lobes and lobules within the same gland had similar features; alveoli were well developed and distended and had a spherical to slightly ovoid structure, with muscular fibres grasping them around; inflammatory cells were seen in the inter- and intra-alveolar space; mammary lobules were separated with a scant amount of connective tissue. In late lactation, connective tissue was abundant and dense, with large numbers of inflammatory cells; alveoli appeared to be irregularly shaped and collapsing, shrunken or fully collapsed. Number of alveoli per lobule and number of epithelial cells per alveolus, as well as diameter of alveoli and height of epithelial cells decreased as lactation progressed. The third mammary glands (from caudal to cranial) had a significantly smaller number of alveoli, but not of epithelial cells per alveolus, than each of the two mammary glands caudally to that. The results suggest that progressive involution of the normal mammary gland starts around the end of the 2nd month of lactation and continues until the end of the 3rd month.