Ultrasonographic analysis of fetal gastrointestinal motility during the peripartum period in the dog.

The aim of this study was to investigate fetal gastrointestinal motility (FGM) of dogs using ultrasonic imaging and its association with vaginal and rectal temperature, serum progesterone concentrations and fetal heart rate. Pregnant bitches were examined after day 54 of gestation and there were determinations of vaginal and rectal temperature and serum progesterone concentrations. The fetal abdomen was evaluated for 30 s using longitudinal and transversal assessments, and FGM was scored as 0 (no peristalsis) or 1 (evident peristalsis). Number of fetuses with a 1 or 0 score were determined for each bitch (number and the percentage of fetuses with FGM). A total of 135 FGM measurements were recorded. There was FGM in 0/3, 0/6, 1/6 (16.7 %), 3/20 (15 %), 5/18 (27.3 %), 18/28 (64.3 %), 12/17 (70.6 %), 14/22 (63.6 %), 6/9 (66.7 %), 4/6 (66.7 %) fetuses from day -9 until 0 preceding parturition, respectively. In the last 5 days before parturition, 63.3 % of fetuses had FGM. Vaginal and rectal temperature were strongly and positively correlated (P < 0.001). Vaginal temperature was positively correlated with progesterone concentrations and fetal heart rate (P < 0.01), and there was a small negative correlation with FGM (r = -0.331, P < 0.05). Due to ease of data collection, the assessment of FGM is a valuable procedure for evaluation of fetal maturity in dogs. Vaginal and rectal temperatures are reliable variables to be assessed during the last week of pregnancy for estimating the time of parturition.

Pulsoximetric monitoring of fetal arterial oxygen saturation and fetal pulse at stage II of labor to predict acidosis in newborn Holstein Friesian calves.

During stage II of parturition, the bovine fetus is at risk of oxygen deficiency caused by insufficient gas exchange between the dam and the fetus. The early detection of this critical condition, followed by assistance at calving, can help to improve the vitality of the newborn calf, or even prevent it from being born dead. By using pulse oximetry, the arterial oxygen saturation, as well as the pulse rate, can be continuously and non-invasively measured. The aim of our study was to identify critical thresholds for the parameters 'arterial oxygen saturation (FSpO2)' and 'pulse rate (PR)' that indicate a severe postnatal risk for calves to suffer from acidosis. FSpO2 and PR from 40 bovine fetuses were recorded during the last 25 min of calving with a commercially available pulse oximeter (Radius-7, Masimo Corporation, Irvine, USA). The calves were tested immediately after birth for acidosis by analyzing their blood with a portable blood gas analyzer (VetScan iStat1, Abaxis Inc., Union City, USA). Retrospectively, the pulsoximetric data were scanned for predefined patterns. The validity of these patterns to predict acidosis in newborn calves was analyzed by using receiver operating characteristics (ROC) curve analyses. In general, PR was a stronger predictive parameter for acidosis than FSpO2, with the greatest area under the curve (AUC) for the PR criteria 'Pulse rate > 120 beats per minute (bpm) for at least 2 min', with an AUC of 0.764, in contrast to an AUC of 0.613 for the best FSpO2 criteria 'FSpO2 < 40% for at least 50% of the measurement'. Further studies should investigate whether vitality after calving can be improved and fetal death rate can be reduced when obstetric assistance is performed as soon as one of these criteria apply to the bovine fetus. For more practical implementation in the field, improvement of the device's hardware would be necessary.

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 ±â€¯6 days. The same model predicted days prepartum with a 95% CI ±â€¯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.

Maternal and fetal arterial blood gas data in normotensive, singleton, isoflurane anesthetized sheep at 124-126 days of gestation.

The aim of this case series was to describe the differences between maternal and fetal blood-gas results during anesthesia. Sixteen singleton adult merino ewes weighing 60.1 ± 5.1 kg at 125.7 d (124 to 126 d) gestation were anesthetized. Maternal (radial) and fetal (umbilical) arterial blood gas samples were collected 79 ± 6 min after the start of anesthesia if maternal mean arterial pressure (MAP) was stable and > 65 mmHg. Fetal pH, partial arterial pressure of oxygen (PaO2), glucose, arterial hemoglobin oxygen saturation (SaO2), sodium, and chloride were significantly lower and fetal partial arterial pressure of carbon dioxide (PaCO2), lactate, hematocrit, total hemoglobin, potassium, and calcium were significantly higher than maternal blood-gas values. Fetal pH, PaO2, and BE were lower and fetal lactate was higher than fetal umbilical arterial samples previously reported, which may indicate a non-reassuring fetal status. Further refinement of the ovine experimental model is warranted with fetal monitoring during maternal anesthesia.

L'objectif de l'étude était de décrire les différences dans les résultats d'analyse des gaz sanguins maternel et foetal durant l'anesthésie. Seize brebis mérinos primipares pesant 60,1 ± 5,1 kg à 125,7 j (124 à 126 j) de gestation ont été anesthésiées. Des échantillons de sang artériel maternel (radiale) et foetal (ombilicale) ont été prélevés 79 ± 6 min après le début de l'anesthésie si la pression artérielle moyenne (PAM) maternelle était stable et > 65 mmHg. Pour le sang foetal, les valeurs de pH, de la pression artérielle partielle en oxygène (PaO2), du glucose, de la saturation en oxygène de l'hémoglobine artérielle (SaO2), du sodium, et du chlorure étaient significativement inférieures, et les valeurs de la pression artérielle partielle en dioxyde de carbone (PaCO2), du lactate, de l'hématocrite, de l'hémoglobine totale, du potassium, et du calcium étaient significativement supérieures que celles du sang maternel. Les valeurs foetales du pH, de la PaO2, et de BE étaient plus basses et le lactate foetal étaient plus élevées que les valeurs d'échantillons provenant du sang artériel ombilical foetal rapportées précédemment, ce qui pourrait indiquer un statut foetal non-rassurant. Des améliorations de ce modèle expérimental ovin sont souhaitées avec un suivi foetal durant une anesthésie maternelle.(Traduit par Docteur Serge Messier).

Effectiveness of determining the parturition date in bitches using the ultrasonographic fetometry as compared to hormonal and cytological methods.

In clinical practice, the parturition date in bitches is calculated on the basis of the established ovulation date, using determination of the level of LH and P4. Additionally cytological examination of vaginal smears makes it possible to establish the onset of diestrus, from which the delivery occurs after about 57 days. The latest method used in bitches for this purpose is foetal biometry. Measurements of the inner chorionic cavity diameter (ICC) and biparietal diameter (BP) with formulas published by Luvoni and Grioni have been popularized and the most practically useful. In a group of six bitches the effectiveness obtained with the use of ICC was 66.67% with an accuracy of 1 day and 100% with an accuracy of 2 days. BP measurements gave better results, as the accuracy was respectively 83.33% and 100%. The effectiveness of predicting the delivery date on the base of method consisting in determining the LH surge was 66.67% with an accuracy of 1 day and 100% with an accuracy of 2 days. The best effectiveness was obtained while using the method based on P4 level determination (100% both with an accuracy of 1 day, as well as of 2 days). The lowest accuracy was obtained while using the cytological method. Generally, a comparison of the methods used for predicting the date of delivery in bitches confirms practical usefulness of fetometry. Its effectiveness was not lower than traditional methods used so far, while its advantage lies in the ease of performance and the long term of application during gestation. However, full confirmation of the practical usefulness of this method requires further research on a larger number of animals.

Current advances in gestation and parturition in cats and dogs.

This article provides an overview of pregnancy in the bitch and queen. Emphasis will be placed on pregnancy diagnosis, monitoring pregnancy, and prevention of fetal loss and maternal morbidity.

Telemetric monitoring of fetal blood pressure and heart rate in the freely moving pregnant sheep: a feasibility study.

Remote telemetric monitoring of fetal haemodynamics in pregnant sheep would allow unrestricted animal movement, minimize suffering and distress, and improve animal welfare, while enhancing the quality of data collected. This may also be useful in clinical practice following fetal surgery. Using an open fetal surgical technique at approximately two-thirds of gestation, we implanted the catheter of a D70-PCTP haemodynamic telemetric device (Data Sciences International, Tilburg, The Netherlands) into the carotid artery of the fetal sheep (n = 4). The attached transmitter was secured to the posterior aspect of the maternal anterior abdominal wall. Two receivers, with a range of 1 m each, were sited in an 11 m² sheep enclosure to maximize animal freedom while allowing continuous monitoring of the ewe. The receivers were connected by cable to a nearby computer. In the first two procedures, both fetuses died eight and 12 days after surgery, and the catheter tip was observed to be lying in the bicarotid trunk. In the next two procedures the catheter tip was threaded further upstream from the insertion point, in an attempt to reach the fetal aorta, and both fetuses survived until the scheduled postmortem examination at the end of pregnancy. After catheter implantation, fetal blood pressure (BP) and heart rate (HR) were successfully recorded continuously for seven days and then hourly per day for a further three weeks. The fetal BP and HR values were in the normal range for healthy sheep fetuses.

Uterine activity and fetal electronic monitoring in parturient sows treated with vetrabutin chlorhydrate.

The aims of the study were to characterize the uterine activity in sows treated with vetrabutin chlorhydrate (VC), an uterotonic and muscle-tropic drug during farrowing, and to measure the effects of the drug on piglet neonatal viability. The experiment involved 1478 piglets from 130 Yorkshire-Landrace sows, randomly allotted into two groups. Farrowing monitoring began 12 h after PGF2alpha synchronization. Group 1 was given physiological solution (G1, n = 65); Group 2 was treated with VC (1 mL/60 kg LW) at the initiation of fetal expulsion (G2, n = 65). In spite of the total duration of expulsion being significantly longer (P < 0.0001), approximately 35 min in the VC treatment, VC application at the time the first piglet was expulsed favored the alive birth of at least one more piglet. Even though the pressure in the uterus was similar in both groups, the number and duration of uterus contractions recorded were significantly less (P < 0.0001) in G2, favoring fewer births with acute fetal suffering, compared with that in G1. VC treated group compared with the control group also had fewer (5.01% vs. 24%) alterations in umbilical cords, as well as a lesser incidence of secondary apnea (2.08% vs. 7.46%) and bradycardia (1.94% vs. 7.61%), which favored a significantly higher vitality score (P < 0.002). With the intent to evaluate uterine activity in sows during the farrowing process, we propose using the equation used in human medical practices to calculate Montevideo Units applied to swine obstetrics for the first time.

Monitoring the bovine fetus during stage II of parturition using pulse oximetry.

Measurement of oxygen saturation using pulse oximetry is an established method of continuous monitoring of the well-being of the human fetus during parturition. In veterinary medicine, pulse oximetry has been used almost exclusively in intensive care and anesthesiology. The goal of the present study was to investigate the physiological changes in oxygen saturation of the bovine fetus during stage II of parturition and to determine whether the findings can be used to predict postnatal acidosis. The correlation between the oxygen saturation (SpO(2)) measured via pulse oximetry and the oxygen saturation (SaO(2)) of arterial blood measured via blood gas analysis was determined in 23 newborn calves. In addition, the oxygen saturation was monitored continuously via pulse oximetry (FSpO(2)) in 33 bovine fetuses during stage II of parturition. Correlations between the FSpO(2) values during the last 30 and 5min of stage II of parturition and the postpartum values for pH, partial pressures of oxygen and carbon dioxide, bicarbonate concentration, BE, SaO(2) and lactate concentration in arterial blood were determined. There was a high correlation between SpO(2) and SaO(2) postpartum (r=0.923). The FSpO(2) values correlated moderately with the pH and BE and weakly with the lactate concentration postpartum; calves with a pH<7.2, a BE<-3mM/L or a lactate concentration of >5.4mM/L had significantly lower FSpO(2) values than non-acidotic calves. FSpO(2) values <30% for a period of at least 2min had the highest predictive value for a calf born with a pH<7.2. Pulse oximetry is a novel method of monitoring the bovine fetus during parturition; however, technical modifications are required to improve its usefulness.

Blood gas analysis of bovine fetal capillary blood during stage II labor.

The aim of this study was to determine whether blood gas variables in fetal capillary blood during the last 30 min of stage II labor can be used to diagnose fetal asphyxia. Twenty-five newborn calves were used to investigate the correlation between capillary blood gas values obtained from the dorsolateral aspect of the distal pastern and those in arterial and venous blood. The pH, partial pressure of oxygen, partial pressure of carbon dioxide, concentration of bicarbonate, base excess and oxygen saturation were determined. The bicarbonate concentration (arterial, r=0.759; venous, r=0.766; both P<0.0001) and base excess (arterial, r=0.730; venous, r=0.807; both P<0.0001) had the highest correlations. Fetal capillary blood was collected during the last 30 min of stage II labor and the results of blood gas analysis were compared with those of arterial and venous blood collected immediately after birth in 38 calves. The pH (arterial, r=0.806; venous, r=0.885; both P<0.0001) and base excess (arterial, r=0.822; venous, r=0.871; both P<0.0001) had the highest correlations. The pH and base excess were significantly lower after birth than during the last 30 min of stage II labor. The severity of fetal acidosis during stage II labor can be easily and reliably determined using the pH or base excess of fetal capillary blood.

Fetal well-being assessment in bovine near-term gestations: current knowledge and future perspectives arising from comparative medicine.

Cloning technology is associated with multiple losses throughout pregnancy and in the neonatal period. Any maternal or fetal disease can compromise pregnancy. A paucity of data are available on bovine fetal well-being in late pregnancy; development of well-being assessment methods might augment early diagnosis of abnormal pregnancy or fetal distress, allowing early intervention. This review presents the current knowledge on fetal well-being based on bovine, ovine, equine, and human studies, as well as interesting research parameters that have been studied in other species and not yet investigated in cattle. Transabdominal ultrasonography allows for diagnosis of large placentomes and hydrallantois that frequently accompany clone pregnancies. Fetal inactivity or large hyperechoic particles imaged within the fetal annexes are associated with fetal distress or death, and should be reassessed to confirm compromised pregnancy. Measurements of different fetal parameters (thoracic aorta, metacarpal or metatarsal thickness) could be reliable tools for early detection of the large offspring syndrome commonly found in cloned calves.

Comparative routes of oxytocin administration in crated farrowing sows and its effects on fetal and postnatal asphyxia.

Oxytocin is used to induce and control parturition; nevertheless, an increase in uterine contractions decreases blood flow and gaseous exchange through the uterus predisposing to intra-partum mortality in pigs. The objective of the present study was to evaluate the effect of different oxytocin administration routes on myometrial activity, fetal intrauterine hypoxia and postnatal asphyxia in crated farrowing sows. Yorkshire x Landrace hybrid sows (n = 300), that were approaching the time of parturition, were randomly assigned into six groups. Each group included 50 sows, 10 for each of the parities from one to five. A 40-IU oxytocin dosage was administered by intramuscular (IM), or intravulvar (IVU) routes, or 20 IU was administered via intravenous (IV) route. Groups 1 (G1), 3 (G3) and 5 (G5) were administered 0.9% saline solution (NaCl) IM, IVU and IV, respectively, whereas groups 2 (G2), 4 (G4) and 6 (G6) were treated with oxytocin IM, IVU and IV, respectively. There was a significantly (P < 0.05) greater number of intra-partum stillbirths (IPS) for the oxytocin treatments, as compared with the control groups, especially with the IVU and IV routes; a lesser number of IPS and lesser IPS with broken umbilical cords was observed with the IM administration route. Oxytocin and control IV administration resulted in longer farrowing durations. Administration of IV-oxytocin resulted in a greater number (P < 0.05) of intrauterine distressed neonates compared with its corresponding control and interpreted through dips II, a fetal cardiac frequency deceleration which determines acute fetal suffering. Independent of the route of oxytocin administration, the treatments resulted in twice as many dips II compared with the respective control groups. The use of the cardiotocograph proved to be an excellent tool for establishing the oxytocin response dose in farrowing sows. A greater number of piglets born alive, which had undergone bradycardia, also showed severe acidosis and greater meconium staining in oxytocin-treated sows, indicating that the administration time (at birth of the first piglet) as well as the dosage used were not adequate treatment regimens in the present study. Further studies will be conducted to evaluate different dosages and oxytocin administration timing to determine the most desirable treatment regimen to increase myometrial contractibility without compromising fetal welfare and neonatal survival.

Uterine and fetal asphyxia monitoring in parturient sows treated with oxytocin.

Oxytocin is used to induce and control parturition, nevertheless, the increase of uterine contractions decreases blood flow and gaseous exchange through the womb predisposing to intra-partum mortality. The objective of the present study was to evaluate the effect of oxytocin on myometrial activity, fetal intrauterine hypoxia and postnatal asphyxia in sows during farrowing. Hybrid (n = 120) sows approaching the time of farrowing were randomly assigned in two groups of 60 animals each. Group I (G(1): control) was treated IM with saline solution and Group II (G(2)) was injected IM with oxytocin (1IU/6kg LW) as a single dose at birth of the first piglet. Both average number of myometrial contractions and intensity in G(2) were greater (P < 0.01) as compared with G(1). The mean of intra-partum stillbirths (IPS's) and those where fetal cardiac frequency (FCF) or heart beats, could not be detected after birth, were greater (P < 0.01) in G(2) as compared with G(1). The average decelerations of FCF known as dips II, which indicate severe hypoxia, was greater in G(2) (P < 0.01) as compared with that of G(1). There was a greater (P < 0.01) number of intra-partum stillbirths, stained with severe meconium in G(2) when compared with G(1). Oxytocin treatment increased (P < 0.01) the number of pigs born alive with ruptured umbilical cords and those with different grades of meconium staining on their skin. It was concluded that administration of oxytocin at the onset of parturition increased the myometrial activity, decreased fetal cardiac frequency, predisposed the rupture of umbilical cords and the degree of meconium staining, and increased intra-partum mortality.

Hormonal measurements in late pregnancy and parturition in dairy cows--possible tools to monitor foetal well being.

Three dairy heifers (A, B and C) were induced to parturition with two prostaglandin (PG) F(2alpha) injections on day 268 and 269 of pregnancy. Signs of approaching parturition were carefully observed. The following parameters were registered: degrees of calving difficulty, date and time of parturition, calf's birth weight and calf's sex. Body temperature was measured and blood samples were taken every 3 h 3 days before the first PGF(2alpha) injection until 3 days after parturition. The plasma concentrations of the PGF(2alpha) metabolite, progesterone, cortisol, oestrone sulphate and pregnancy associated glycoproteins (PAGs) were analysed. Heifers A, B and C delivered 48, 51 and 57 h after the first PGF(2alpha) injection, respectively. Heifer A delivered without any signs of calving difficulty, whereas, the parturition was considered to be slight and moderate difficulty occurred in the delivery of heifers B and C, respectively. The calf of heifer C, without any abnormal gross-evidences, was stillborn. All animals had retained foetal membranes. A slight increase of the PGF(2alpha) metabolite at the time of parturition was found only in heifer C, whereas the levels dramatically increased in all animals 15-24 h after parturition. At the same time, progesterone levels decreased within 3 h after the first PGF(2alpha) injection (P < 0.05) and reached 0.8, 2.7 and 12.4 nmol/l at the time of parturition in heifers A, B and C, respectively. High release of cortisol at the time of parturition was seen in heifer C. Rising levels of oestrone sulphate around the time of parturition were recorded in all heifers, whereas, increasing levels of PAGs were recorded only in heifer A. In conclusion, the patterns of the PGF(2alpha) metabolite, cortisol, progesterone and PAGs were changed in the cases of calving difficulty and stillbirth after PGF(2alpha)-induction of parturition. However, the relationship between oestrone sulphate and PAGs and the status of foetal well being prior to parturition require further elucidation.

Uterine and fetal monitoring in the bitch.

The use of uterine and fetal monitoring improves the outcome of canine obstetrics. Much of the guesswork of managing whelping can be eliminated. At normal term, absolute indications for cesarean section are detected with monitoring, before multiple fetal deaths or any serious maternal compromise occurs. Bitches with previous history of cesarean section may be able to whelp vaginally successfully, having medical intervention based on monitoring. The anxiety level of owners during whelping is diminished, and the level of participation of the veterinarian improves.

Noninvasive monitoring of fetal growth and development in the Siberian polecat (Mustela eversmanni).

The Siberian polecat (Mustela eversmanni) is the preferred species to assess procedures and establish normative values for application in the related and endangered black-footed ferret (Mustela nigripes). This study was undertaken to physically, ultrasonographically, and radiographically evaluate fetal development in a spontaneously breeding captive Siberian polecat population. Ultrasonographically, fetal sac enlargement allowed presumptive pregnancy detection as early as 12 days of gestation, the fetal pole was the first definitive sign of pregnancy at about 18 days of gestation, when the fetal heart beat also appeared, and definitive pregnancy detection by ultrasound was essentially 100% accurate after 18 days. The estimation of fetal number by ultrasound was less reliable than by radiography, as it is in other litter-bearing species. Crown-rump growth, organ differentiation, and calcification patterns resembled those of domestic carnivores except that comparable developmental stages in polecats occurred at disproportionately later times, suggesting that young Siberian polecats are delivered in a less developed state. Careful palpation permitted detection of pregnancy after day 17 but with less certainty than with ultrasound. Radiographic evaluation was insensitive and of limited value for pregnancy detection until near term. Litter number and fetal detail were difficult to assess until ossification could be observed, 3-6 days before parturition.

Noninvasive monitoring of fetal heart rate during the last ten days of gestation in sows.

OBJECTIVE: To develop and evaluate a noninvasive technique for monitoring and analyzing porcine fetal heart rate (FHR) during late gestation. ANIMALS: 8 fetuses of 8 pluriparous sows in late gestation. PROCEDURE: With the sow positioned in lateral recumbency, the most caudal fetus was identified, using real time ultrasonography, and its heart rate was recorded for 60 minutes by use of Doppler cardiography. The same fetus was identified and monitored repeatedly during the last 10 days of gestation, excluding the 24 hours before delivery. Visual inspection and computerized analysis of the recordings were performed. RESULTS: 66 one-hour recordings were obtained from 8 fetuses, 1 in each of 8 sows. Mean signal loss was 37.5%. Episodes of low FHR and low FHR variation (FHR pattern A) alternated with episodes of high FHR and high FHR variation (FHR pattern B). This cyclic alternation between 2 distinct. FHR patterns was observed in 46 of 66 (69.7%) recordings, and suggests the presence of different behavioral states in fetal pigs. Basal FHR decreased toward parturition in 7 fetuses, but increased in 1 fetus with abdominal ascites. Basal FHR and long-term FHR variation were negatively correlated (r[S] = -0.73; P < 0.001). CONCLUSION: Noninvasive monitoring of FHR is possible and feasible during late gestation in pigs. This method permits longitudinal studies under pathophysiologic conditions and the evaluation of the effects of endogenous and exogenous influences on porcine FHR.

Relationships of light and heavy fetuses to uterine position, placental weight, gestational age, and fetal cholesterol concentrations.

With emphasis on increasing litter size to improve productivity and profitability, lightweight pigs born will increase in number as litter size increases and may be problematic due to reduced neonatal survival of lightweight pigs. To study developmental aspects of lightweight fetuses, fetal and placental weights were evaluated at three stages of pregnancy (30, 70, and 104 d) from white composite gilts (n = 88, 123, and 135, respectively) in relation to uterine position of light and heavy fetuses. Fetal cholesterol concentrations were analyzed at the beginning (d 70) and end (d 104) of the in utero growth phase (last third of gestation). At 30 d of gestation, no differences were noted between fetal weight and position within the uterine horn, but at 70 d and 104 d of pregnancy, heavy fetuses were found at the tubal ends and light fetuses at the cervical ends of the uterus. Using the criteria of +/- 1 SD or +/- 2 SD of the mean and lower and upper 10 or 20% of fetal weights for each gestational age, light and heavy fetuses in conjunction with their placentas were different from population means at all stages of gestation. Cholesterol concentrations were lower in light fetuses (d 104) and increased in heavy fetuses. In 28 litters (d 104) selected for extremes in within-litter fetal weights, concentrations of IGF-I increased with fetal weight (P < .01), which suggests that growth and development of lightweight pigs may be limited by critical endocrine components.

Transesophageal echocardiography in fetal sheep. A monitoring tool for open and fetoscopic cardiac procedures.

BACKGROUND: Cardiac procedures in exteriorized fetuses or assisted by fetoscopy require monitoring capabilities not attended by conventional maternal transabdominal echocardiography. METHODS: We, therefore, assessed the potential of fetal transesophageal echocardiography (TEE) utilizing an intravascular ultrasound catheter (IVUC) for fetal cardiac monitoring. We inserted a 10-F-10-MHz IVUC into the esophagus in 12 exteriorized fetal sheep and by a fetoscopic approach in 4 fetal sheep. Cardiac events were observed. Heart rate, cardiac rhythm, patency of the foramen ovale and ductus arteriosus, and the width of the branch pulmonary arteries could be assessed in all fetuses. Ventricular contractility could be assessed only in fetuses weighing less than 2.5 kg. Larger fetuses did not allow adequate imaging of the apical portion of the ventricles because of limited tissue penetration of the IVUC. Fetal TEE permitted placing small guide wires in the cardiac atria and left ventricle. Short-lived premature beats following intracardiac manipulations of these wires could be observed by fetal TEE in all cases. RESULTS: At autopsy, no complications from IVUC insertion were observed in the exteriorized fetuses. Fetoscopic placement of the IVUC resulted in minor perioral skin erosion in two nonexteriorized fetuses. CONCLUSIONS: In conclusion, fetal TEE can be achieved with minor fetal injury and may provide useful information during open and fetoscopic cardiac procedures. Further improvements in IVUC design will permit the application of this technique to monitor human fetal cardiac procedures.

Intrauterine endoscopic creation of urinary tract obstruction in the fetal lamb: a model for fetal surgery.

OBJECTIVE: Our purpose was to evaluate the feasibility of intrauterine endoscopic fetal surgery in a fetal lamb model by creating a urinary tract obstruction. STUDY DESIGN: Lower urinary tract obstruction was created by ligation of the urethra and urachus in 21 fetal lambs, eight at 95 to 105 days' gestation (term 145 days) and 13 at 70 to 75 days. The endoscopic approach consisted of a 0-degree 5 mm telescope, three 5 mm cannulas, uterine distention by amnioinfusion, and adapted instrumentation. Intrauterine fetal monitoring included temperature and pulse oximetry registration. RESULTS: In 20 cases the urachus could be identified and ligated inside the umbilical cord. The urethra was ligated in the anterior abdominal wall (n = 7) or obstructed at the level of the penis (n = 13). Mean fetal heart rate was 147 +/- 35 beats/min, and fetal temperature at the end of intervention was 38.14 degrees +/- 2.1 degrees C. The overall postoperative survival rate was 76%. CONCLUSION: Urinary tract obstruction can be created endoscopically in the fetal lamb. This operation can serve as a model for endoscopic fetal surgery.