Head-to-body delivery by “two-step” approach: effect on cord blood hematocrit

Neonatal outcomes of two-step delivery in low-risk pregnancy: A prospective observational study

AIM

Extraction of the fetal body is typically performed immediately after delivery of the head in Western obstetric care. Reports justifying immediate extraction are few. Two-step delivery entails waiting for the next uterine contraction after delivery of the head. The present study evaluates neonatal asphyxia and respiratory impairment in two-step delivery using the head-to-body delivery interval.

METHODS

This prospective observational study performed at a single birth clinic used the data of 262 low-risk pregnant women with two-step delivery. We measured the time interval of head-to-body delivery and correlation analysis and simple linear regression analysis between the head-to-body delivery interval and umbilical artery pH. The women were divided into two groups according to the head-to-body delivery interval: ≤60 or >60 s. The prevalence of neonatal asphyxia and neonatal respiratory impairment was compared between the groups.

RESULTS

The mean head-to-body delivery interval was 88.9 ± 71.3 s. The umbilical artery pH tended to decrease with increasing head-to-body delivery interval; however, there was almost no correlation and the decline of pH was only 0.010 for every additional minute. Low Apgar score incidence at 5 min did not differ significantly between the groups. No cases of shoulder dystocia were reported, and tachypnea at 4 h after birth occurred in 3% of the births.

CONCLUSIONS

A longer head-to-body delivery interval is not associated with negative outcomes in two-step delivery. We believe that two-step delivery could have some superior outcomes compared with one-step delivery outcomes, particularly as to improving fetal circulation and preventing shoulder dystocia.

A Physiologically-Based Pharmacokinetic Model to Predict Human Fetal Exposure for a Drug Metabolized by Several CYP450 Pathways

BACKGROUND

Pregnant women and their fetuses are exposed to numerous drugs; however, they are orphan populations with respect to the safety and efficacy of drugs. Therefore, the prediction of maternal and fetal drug exposure prior to administration would be highly useful.

METHODS

A physiologically-based pharmacokinetic (PBPK) model for nevirapine, which is metabolized by the cytochrome P450 (CYP) 3A4, 2B6 and 2D6 pathways, was developed to predict maternal and fetal pharmacokinetics (PK). The model was developed in both non-pregnant and pregnant women, and all physiological and enzymatic changes that could impact nevirapine PK were taken into account. Transplacental parameters estimated from ex vivo human placenta perfusion experiments were included in this PBPK model. To validate the model, observed maternal and cord blood concentrations were compared with predicted concentrations, and the impact of fetal clearance on fetal PK was investigated.

RESULTS

By implementing physiological changes, including CYP3A4, 2D6 and 2B6 inductions, we predicted a clearance increase of 21 % in late pregnancy. The PBPK model successfully predicted the disposition for both non-pregnant and pregnant populations. Parameters obtained from the ex vivo experiments allowed the prediction of nevirapine concentrations that matched observed cord blood concentrations. The fetal-to-maternal area under the curve ratio (0-24 h interval) was 0.77, and fetal metabolism had no significant effect on fetal PK.

CONCLUSIONS

The PBPK approach is a useful tool for quantifying a priori the drug exposure of metabolized drugs during pregnancy, and can be applied to evaluate alternative dosing regimens to optimize drug therapy. This approach, including ex vivo human placental perfusion parameters, is a promising approach for predicting human fetal exposure.

Prediction of human fetal pharmacokinetics using ex vivo human placenta perfusion studies and physiologically based models

AIMS

Pregnant women can be exposed to numerous drugs during the gestational period. For obvious ethical reasons, in vivo studies of fetal exposure to drugs are limited. Information about the transplacental transfer of drugs prior to their administration to pregnant women would be highly useful. In the present study, a novel approach was developed quantitatively predict or to predict the fetal exposure to drugs administered to the mother quantitatively.

METHODS

Transplacental parameters estimated from ex vivo human placenta perfusion experiments were implemented in pregnancy-physiologically based pharmacokinetic (p-PBPK) models in order to predict fetal PK. Thereafter, fetal PK profiles for two antiretroviral drugs, tenofovir (TFV) and emtricitabine (FTC) were simulated. These predictions were then compared to observed cord blood concentrations, to validate these models.

RESULTS

Parameters obtained from the ex vivo experiments enabled a good prediction of observed cord blood concentrations without additional a scaling factor. Moreover, a sensitivity analysis showed that fetal predictions were sensitive to changes in transplacental parameters values obtained ex vivo.

CONCLUSION

The integration of ex vivo human placental perfusion parameters in a p-PBPK model should be a promising new approach for predicting human fetal exposure to xenobiotics.

Implementing Family-Centered Cesarean Birth

Cesarean birth is recognized as a physical and psychological stressor for many women. Maternity practices during cesarean birth should meet women's needs, while maintaining safety, to optimize the experience. Family-centered cesarean birth is a package of interventions that encourages a woman to participate in choosing interventions that would be helpful when undergoing a planned or unplanned cesarean birth. Included in family-centered cesarean birth is implementation of skin-to-skin care in the operating room for neonates who appear term and healthy. The process of attempting to implement family-centered cesarean birth at one academic center is presented, including steps for implementation, benefits, challenges, and areas for continued improvement and research. This article is part of a special series of articles that address midwifery innovations in clinical practice, education, interprofessional collaboration, health policy, and global health.

Perfluoroalkyl acid (PFAA) levels and profiles in breast milk, maternal and cord serum of French women and their newborns

One major concern regarding perfluoroalkyl acids (PFAAs) is their potential role in onset of health troubles consecutive to early exposure during the perinatal period. In the present work, the internal exposure levels of 18 targeted PFAAs were determined in ca. 100 mother-newborn pairs recruited in France between 2010 and 2013. In serum, the cumulated concentrations of the 7 most frequently detected compounds were 5.70ng/mL and 2.83ng/mL (median values) in maternal and cord serum, respectively. Perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexylesulfonic acid (PFHxS) and perfluorononanoic acid (PFNA) contributed to around 90% of the total PFAAs contamination, with concentration levels and contamination profiles in accordance with other published work in Europe. Levels measured in breast milk were far lower (20 to 150 fold) than those determined in serum. Associations between the different monitored substances as well as between levels determined in the different investigated biological matrices mostly do not appear statistically significant. The estimated materno-foetal transfer would be thus substance-dependant, mainly driven by the physico-chemical properties of the different PFAAs (nature of polar group and length of alkylated side chain). We conclude that trans-placental passage and breastfeeding are both significant routes of human exposure to PFAAs.

Tranfusion risk: is "two-step" vaginal delivery a risk for postpartum hemorrhage?

OBJECTIVE

In the active management strategy of third stage of labor, the optimal timing for clamping the umbilical cord after birth has been a subject of controversy. We want to evaluate if "two-step" delivery is a risk factor for postpartum hemorrhage (PPH), defined as need of transfusion, comparing to operative delivery, elective caesarean delivery and emergency caesarean delivery.

METHODS

This is a retrospective cohort study conducted in division of Perinatal Medicine, Policlinico Abano Terme. We evaluated the need of transfusion in all cases of PPH verified in all single deliveries between January 2011 and December 2012. The main outcome measure was blood loss and red blood cell transfusion.

RESULTS

We found 17 cases of PPH (0.88%). The distribution of PPH in relation to mode of delivery was 0.71%, 2.46% and 1.98% respectively for two-step vaginal delivery (RR = 0.81 (0.56-1.22)), emergency cesarean section (RR = 2.88 (1.27-7.77)) and operative vaginal delivery (RR = 2.88 (0.59-5.66)). In labor induction there is a stronger relative risk association between PPH and as emergency cesarean delivery (p < 0.05) as operative vaginal delivery (p < 0.05).

CONCLUSION

"Two-step" delivery approach did not increase the risk of PPH with respect to operative delivery, elective caesarean section and emergency caesarean section.

Impact of cesarean section on placental transfusion and iron-related hematological indices in term neonates: a systematic review and meta-analysis

Evidence suggests that cesarean section is likely associated with a reduced placental transfusion and poor hematological status in neonates. However, clinical studies have reported somewhat inconsistent results. We conducted a systematic review and meta-analysis to examine whether cesarean section affects placental transfusion and iron-related hematological indices. Pubmed, Web of Science, ScienceDirect, and Ovid Databases were searched for relevant studies published before April 9, 2013. Mean differences between cesarean section and vaginal delivery in outcomes of interests (placental residual blood volume; hematocrit level, hemoglobin concentration, and erythrocyte count in cord/peripheral blood) were extracted and pooled using a random effects model. We identified 15 studies (n = 8477) eligible for the meta-analysis. Compared with neonates born vaginally, those born by cesarean section had a higher placental residual blood volume [weighted mean difference (WMD), 8.87 ml; 95% confidence interval (CI), 2.32 ml-15.43 ml]; a lower level of hematocrit (WMD, -2.91%; 95% CI, -4.16% to -1.65%), hemoglobin (WMD, -0.51 g/dL; 95% CI, -0.74 g/dL to -0.27 g/dL) and erythrocyte (WMD, -0.16 × 10(12)/L; 95% CI, -0.30 × 10(12)/L to -0.01 × 10(12)/L). Subgroup analysis showed that the WMD for hematocrit in neonate's peripheral blood (-6.94%; 95% CI, -9.15% to -4.73%) was substantially lower than that in cord blood (-1.75%; 95% CI, -2.82%, -0.68%) (P value for testing subgroup differences <0.001). In conclusion, cesarean section compared with vaginal delivery is associated with a reduced placental transfusion and poor iron-related hematologic indices in both cord and peripheral blood, indicating that neonates delivered by cesarean section might be more likely affected by iron-deficiency anemia in infancy.

'Two-step' head-to-body delivery activates foetal gluconeogenesis

AIM

The 'two-step' head-to-body delivery method, which involves waiting for the next contraction to deliver the shoulders, causes a decrease in umbilical artery pH. The aim of this study was to assess whether foetal acidemia activates gluconeogenesis.

METHODS

We tested umbilical artery cord blood glucose concentration and pH after 341 spontaneous and 25 vacuum extractor 'two-step' vaginal deliveries (VD) and after 85 elective and 49 emergency caesarean sections (CS).

RESULTS

Cord blood glucose concentration was significantly higher (95.5 ± 21.4 mg/dL vs 75.6 ± 16.4, p < 0.001), and pH values significantly lower (7.31 ± 0.09 vs 7.33 ± 0.06, p = 0.003) in 'two-step' VD neonates than in CS delivered neonates. In addition, cord blood glucose concentration was significantly higher (101.4 ± 30.6 mg/dL, p = 0.004), and pH values were significantly lower (7.26 ± 0.10, p < 0.001) in VD by vacuum extractor than in all other groups. The cord blood glucose concentration is significantly and negatively correlated with pH in the study population (r = -0.094, p = 0.036) and strongly significantly and negatively correlated in VD by vacuum extractor (r = -0.594, p = 0.007).

CONCLUSION

Cord blood glucose concentrations are significantly higher and pH values significantly lower in 'two-step' VD neonates, indicating activated foetal gluconeogenesis.