Background:Gardnerella vaginalis (GV) is most frequently associated with bacterial vaginosis and is the second most common etiology causing intrauterine infection after Ureaplasma urealyticum. Intrauterine GV infection adversely affects pregnancy outcomes, resulting in preterm birth, fetal growth restriction, and neonatal pneumonia. The knowledge of how GV exerts its effects is limited. We developed an in vivo animal model to study its effects on fetal development. Materials and Methods: A survival mini-laparotomy was conducted on New Zealand rabbits on gestational day 21 (28 weeks of human pregnancy). In each dam, fetuses in the right uterine horn received intra-amniotic 0.5 × 102 colony-forming units of GV injections each, while their littermate controls in the left horn received sterile saline injections. A second laparotomy was performed seven days later. Assessment of the fetal pups, histopathology of the placenta and histomorphometric examination of the fetal lung tissues was done. Results: Three dams with a combined total of 12 fetuses were exposed to intra-amniotic GV, and 9 fetuses were unexposed. The weights of fetuses, placenta, and fetal lung were significantly lower in the GV group than the saline-inoculated control group [mean gross weight, GV (19.8 ± 3.8 g) vs. control (27.9 ± 1.7 g), p < 0.001; mean placenta weight, GV (5.5 ± 1.0 g) vs. control (6.5 ± 0.7 g), p = 0.027; mean fetal lung weight, GV (0.59 ± 0.11 g) vs. control (0.91 ± 0.08 g), p = 0.002. There was a two-fold increase in the multinucleated syncytiotrophoblasts in the placenta of the GV group than their littermate controls (82.9 ± 14.9 vs. 41.6 ± 13.4, p < 0.001). The mean alveolar septae of GV fetuses was significantly thicker than the control (14.8 ± 2.8 μm vs. 12.4 ± 3.8 μm, p = 0.007). Correspondingly, the proliferative index in the interalveolar septum was 1.8-fold higher in the GV group than controls (24.9 ± 6.6% vs. 14.2 ± 2.9%, p = 0.011). The number of alveoli and alveolar surface area did not vary between groups. Discussion: Low-dose intra-amniotic GV injection induces fetal growth restriction, increased placental multinucleated syncytiotrophoblasts and fetal lung re-modeling characterized by alveolar septal hypertrophy with cellular proliferative changes. Conclusion: This intra-amniotic model could be utilized in future studies to elucidate the acute and chronic effects of GV intrauterine infections.
To assess the relationship of ultrasound assessment for amniotic fluid, fetal weight, cervical length, cervical funneling and clinical factors on the risk of Caesarean delivery after labour induction at term.
This was a prospective observational study to determine the predictive factors for a successful vaginal birth after caesarean section (VBAC) and to develop a relevant antenatal scoring system. Patients with one previous caesarean section were included in this study. All data including maternal demographics, obstetric history, pregnancy progress and outcomes were collected and analysed. A total of 142 out of the 186 women (76.3%) had successful VBAC. History of previous vaginal delivery and non-recurrent indications for previous caesarean section were the significant predictive factors for a successful VBAC. Five variables for our scoring tool were selected. By using a proposed mean score of 4 out of 7, the scoring system had a sensitivity of 81.0%, specificity of 52.3% and a positive predictive value of 84.6%. VBAC antenatal scoring system was potentially a useful predictive tool in antenatal counselling. Impact statement What is already known on this subject: Planned vaginal birth after caesarean section (VBAC) is an important strategy to limit the overall caesarean section rate, which is related to maternal morbidities. However, trial of vaginal delivery does involve potential complications including scar dehiscence, postpartum haemorrhage and emergency hysterectomy. What the results of this study add: Clinical predictors of a successful VBAC include non-recurrent indications for the previous caesarean section, previous vaginal delivery, spontaneous onset of labour and birthweight less than 4kg. There were multiple screening tools developed to predict the likelihood of successful VBAC. These scoring systems involved various variables such as age, ethnicity, Bishop's score and previous caesarean indication. We had prospectively developed an antenatal scoring system based on five variables. Our result showed that patient with a score of four and above will have around 85% chance of successful VBAC. What the implications are of these findings for clinical practice and/or further research: We have also found that, estimated foetal weight based on ultrasound scan is a potential predictor for successful VBAC. This simple scoring method will be useful in-patient counselling regarding mode of delivery after one previous caesarean section. A multicentre study involving large cohort of patients is ideal to validate our scoring system.