Effects of sildenafil on the fetal growth of guinea pigs and their ability to survive induced intrapartum asphyxia.

OBJECTIVE: Our goal was to determine whether sildenafil increased fetal weight and favored fetal tolerance to induced asphyxia at birth in guinea pigs. STUDY DESIGN: Twenty guinea pigs were randomly allocated to placebo (n = 10) or sildenafil 50 microg/kg (n = 5) or 500 microg/kg (n = 5), starting from day 35 of gestation to delivery. Fetuses were delivered by cesarean section. Fetal asphyxia was induced by clamping the umbilical cord at birth for 5 minutes. RESULTS: Sildenafil protected the pups against induced asphyxia at birth in a dose-dependent manner (eg, partial pressure (tension) of carbon dioxide levels were 75.9 +/- 19.3, 66.9 +/- 18.8, and 54.8 +/- 13.0 in the control and low- and high-dose sildenafil groups, respectively). The high-dose sildenafil group of piglets gained 1.5 times more body weight. CONCLUSION: In guinea pigs, low doses of sildenafil administered from day 35 to the end of gestation favored fetal tolerability to induced intrapartum asphyxia. High doses of sildenafil increased fetal weight.

Use of oxytocin in penned sows and its effect on fetal intra-partum asphyxia.

The objective of the present study was to evaluate in penned sows the effect of two commercial oxytocin products on umbilical cord pathology, degree of asphyxia and intra-partum mortality. This study included 120 sows divided in three groups of 40 animals with eight animals for parities one to five per subgroup, respectively. Group 1 (G(1)) or control received saline solution while oxytocin groups (G(2)) and (G(3)) were injected at the onset of fetal expulsion with two oxytocin products. The doses of oxytocin were as follow: Primiparous sows weighing less than 130 kg received 20 IU; multiparous sows weighing 130-180 g received 30 IU, and those above 250 kg, 40 IU. Piglets born alive and/or dead were classified at birth using a subjective scale based on the degree of meconium staining on skin. Umbilical cords of intra-partum stillbirths (IPS) were classified as adhered or ruptured and subdivided into four categories: without pathological changes, edematous, congested and hemorrhagic. Result analyses revealed significant differences (P < 0.01) between groups 1 and 2, and 1 and 3 regarding the following traits: expulsion interval (min) (X: G(1) 27.7; G(2) 22.6; G(3) 22.2), IPS with a severe stain degree (X: G(1) 0.10; G(2) 0.45; G(3) 0.50), IPS with ruptured umbilical cords (X: G(1) 0.07; G(2) 0.42; G(3) 0.47), and detectable heartbeats in IPS (X: G(1) 0.27; G(2) 0.25; G(3) 0.22). Treatment with oxytocin reduced the duration of the expulsion of the fetus, increased the number of IPS with ruptured umbilical cords and with severe meconium-stain degree and reduced the number of fetuses with inspiration attempts. Furthermore, the use of this hormone increased the need for obstetric assistance due to increased frequency of dystocia.