Effects of twinning on postpartum reproductive performance in cattle selected for twin births.
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The effects of twinning, dystocia, retained placenta, and body weight on postpartum reproduction were evaluated for 3,370 single and 1,014 twin births. Females were bred by AI for 40 d followed by 20 or 30 d of natural service with equal numbers bred and calved in spring and fall. Percentage of dams cyclic by the end of the AI period was lower (P<.05) for dams birthing and nursing a single calf (92.4%) than for dams birthing twins and nursing zero (98.7%) or two (94.7%) calves. Whereas the interval from parturition to first estrus was shorter (P<.01) for dams birthing and nursing a single (56.9 d) than for dams birthing twins and nursing one (68.5 d) or two (69.6 d) calves, length of the interval was further reduced by dystocia in nonlactating dams of either twins or singles (type of birth x dystocia, P<.05). Ensuing pregnancy rates were also affected by type of birth and dystocia. Without dystocia, dams birthing and nursing a single calf had a higher pregnancy rate (79.2%) than dams birthing twins and nursing one (61.7%) or two (66.3%) calves, whereas the lower ensuing pregnancy rates associated with dystocia in dams of singles (71.9%) resulted in similar rates among dams of singles and twins with dystocia (type of birth x dystocia; P<.01). Having a retained placenta resulted in a lower incidence of (93.5 vs. 96.4%, with vs. without; P<.05) and a longer interval to (64.7 vs. 59.2 d; P<.01) estrus while reducing subsequent pregnancy rates (X = 9.6%) in 3 of the 7 yr evaluated (retained placenta x year, P<.01). Because all parous females were bred during the same calendrical period, the shorter gestation length for twin calves (275.6 vs. 281.3 d) resulted in a longer interval from parturition to conception for twin births, whereas means for conception date differed by only 2 d between dams of twins and singles. Furthermore, a reduction (P<.01) in the interval to conception occurred with dystocia in dams of singles (89.3 vs. 85.0 d, without vs. with dystocia) and of twins nursed by zero (116.9 vs. 83.5 d), one (100.2 vs. 92.8 d), or two (96.1 vs. 97.2 d) calves. Another detriment to fertility was the higher incidence of fetal mortality or abortions associated with twin vs. single pregnancies (12.4 vs. 3.5%; P<.01). However, despite the lower conception rates for dams of twins, the increased prolificacy provides an opportunity to increase total beef production with a twinning technology. (+info)
Interpretation of the electronic fetal heart rate during labor.
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Electronic fetal heart rate monitoring is commonly used to assess fetal well-being during labor. Although detection of fetal compromise is one benefit of fetal monitoring, there are also risks, including false-positive tests that may result in unnecessary surgical intervention. Since variable and inconsistent interpretation of fetal heart rate tracings may affect management, a systematic approach to interpreting the patterns is important. The fetal heart rate undergoes constant and minute adjustments in response to the fetal environment and stimuli. Fetal heart rate patterns are classified as reassuring, nonreassuring or ominous. Nonreassuring patterns such as fetal tachycardia, bradycardia and late decelerations with good short-term variability require intervention to rule out fetal acidosis. Ominous patterns require emergency intrauterine fetal resuscitation and immediate delivery. Differentiating between a reassuring and nonreassuring fetal heart rate pattern is the essence of accurate interpretation, which is essential to guide appropriate triage decisions. (+info)
Doppler velocimetry of normal human fetal venous intrapulmonary branches.
(3/202)
OBJECTIVES: To describe the nature of flow velocity waveforms from fetal middle and distal venous pulmonary branches in the second half of normal pregnancy in relation to gestation, and to test repeatability and interrelationships of flow velocity waveform recordings from proximal, middle and distal venous pulmonary branches. DESIGN: Cross-sectional study. SUBJECTS/METHODS: A total of 111 normal singleton pregnancies between 20 and 40 weeks' gestation were studied using a color-coded Doppler ultrasound system. Pulmonary waveforms were obtained at the level of the fetal cardiac four-chamber view. Repeatability was tested from two recordings at 15-min time intervals in 25 separate normal pregnancies. RESULTS: The nature of middle and distal venous pulmonary flow velocity waveforms was comparable with that of proximal waveforms. Acceptable repeatability of pulmonary venous flow velocity waveforms with coefficients of variation below 15% was established for nearly all velocity parameters and their ratios. A gestational age-dependent change was found for all flow velocity waveform parameters including pulsatility index for veins at both middle and distal venous levels. Significant inter-pulmonary changes were observed for nearly all pulmonary venous waveform parameters. CONCLUSIONS: It is speculated that increase in volume flow and venous pulmonary pressure gradient plays a role in gestational age-dependent changes, whereas changes in vessel diameter and distance between the heart and more distal venous pulmonary vessels are responsible for inter-pulmonary changes. (+info)
Fetal heart rate and umbilical artery velocity variability in pregnancies complicated by insulin-dependent diabetes mellitus.
(4/202)
OBJECTIVES: To examine the variability in fetal heart rate and absolute flow velocity, which are possible hemodynamic markers of cardiovascular homeostasis in pregnancies complicated by diabetes mellitus. METHODS: Doppler studies of umbilical artery velocity waveforms were performed at 12-21 weeks of gestation in 16 women with well-controlled type I (insulin-dependent) diabetes mellitus. From umbilical artery velocity waveforms of at least 13 s in duration, we determined absolute values and beat-to-beat variability for fetal heart rate and umbilical artery flow velocities and compared these findings with normal controls matched for gestational age. RESULTS: Fetuses of diabetic women displayed increased fetal heart rate variability and umbilical artery peak systolic velocity. Fetal heart rate, umbilical artery time-averaged velocity and variability in umbilical artery flow velocity were not essentially different between the two groups. CONCLUSION: Fetal heart rate variability and umbilical artery peak systolic velocity may be markers for fetal cardiovascular homeostasis in pregnancies complicated by insulin-dependent diabetes mellitus. (+info)
Sonographic evaluation of antepartum development of fetal gastric motility.
(5/202)
OBJECTIVE: Little is known about the development of fetal gastric motility and emptying. The aim of this study was to evaluate the development of gastric motility sonographically in the human fetus. METHODS: The motility and peristalsis of the fetal stomach were sonographically studied in 76 normal fetuses at 12-39 weeks of gestation. Fetal gastric motility was assessed by videotaping real-time ultrasonic images of the stomach for periods of 60 or more minutes. RESULTS: Gastric peristalsis appeared as early as 14 weeks of gestation, and was detected in all fetuses by 23 weeks. The frequency of peristaltic waves was constant, and was 2.2-3 times per minute at 14-39 weeks of gestation. The onset of fetal gastric peristalsis was sporadic and the period with no peristaltic waves was dominant before 24 weeks of gestation. Fetal gastric peristalsis increased and consolidated into long-term clusters from 24 weeks of gestation. The mean duration of peristalsis increased from 4.1 +/- 1.2 min (n = 6) at 20-23 weeks to 14.1 +/- 3.2 min (n = 14) at 32-35 weeks of gestation, and remained constant thereafter. CONCLUSIONS: Fetal gastric motility was quantified and its development during pregnancy was assessed in this study. There was a critical point of development at around 24-25 weeks of gestation when grouped peristalsis was observed in all fetuses. (+info)
Gastroschisis associated with bladder evisceration complicated by hydronephrosis presenting antenatally.
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We report here a case of gastroschisis associated with bladder evisceration and complicated by rapidly developing hydronephrosis diagnosed antenatally. The timing of delivery was determined by the hydronephrosis, associated bowel dilatation and polyhydramnios. The case highlights the need for continuing ultrasonographic surveillance of fetuses with gastroschisis to identify further associated complications which were hitherto absent but whose presence may influence the timing of delivery and neonatal care. (+info)
Comparison of the non-stress test with the evaluation of centralization of blood flow for the prediction of neonatal compromise.
(7/202)
OBJECTIVE: To determine whether the middle cerebral to umbilical artery systolic/diastolic velocity waveform ratio (MC/UA) was a more sensitive indicator of fetal compromise than the non-stress test (NST). STUDY DESIGN: An outcome study of high-risk patients undergoing NST testing and MC/UA studies within 10 days of delivery. Patients were divided into four groups based on their test results, and neonatal outcome parameters were compared. RESULTS: There were significant differences between all four test result groups with respect to length of stay in the neonatal intensive care unit (NICU). Patients in whom both the NST and MC/UA ratio were normal had significantly lower utilization of Cesarean section for delivery, admission and length of stay in the NICU and occurrence of significant neonatal complications. Logistic regression analysis indicated that the combination of the NST and MC/UA ratio was an excellent predictor of perinatal outcome. CONCLUSIONS: The MC/UA ratio improves the sensitivity for the prediction of poor perinatal outcome when it is combined with the NST. (+info)
Prenatal diagnosis of acute massive fetomaternal hemorrhage.
(8/202)
We present here 2 cases of acute and 2 cases of chronic massive fetomaternal hemorrhage. A sinusoidal fetal heart rate pattern may indicate chronic fetomaternal hemorrhage, but, when increased variability is observed in fetal monitoring, maternal hemoglobin F should be measured to exclude acute fetomaternal hemorrhage. (+info)