Continuous intrapartum pH, pO2, pCO2, and SpO2 monitoring

The goal of intrapartum surveillance and its further development is better patient care for both the fetus and the gravida. A normal FHR pattern is usually associated with the delivery of a normal well-oxygenated infant; however, a nonreassuring FHR is not always associated with the delivery of a compromised infant. This situation has led to an increase in unnecessary obstetric interventions in the form of a rising cesarean section rate. Fetal scalp sampling was developed in an attempt to improve the predictive value of electronic FHR monitoring, but because this technique is not widely used, management decisions are frequently made using FHR patterns alone. Much research has been performed in the search for a continuous biochemical measurement of fetal status, including continuous pH, pO2, or pCO2 and various combinations of these methodologies. None of these measurements are used in current clinical practice, mainly owing to technical problems and difficulties associated with the continuous direct measurement of these parameters in fetal blood throughout labor. The promising new field of fetal pulse oximetry has the potential to provide reliable, meaningful, and reproducible data as shown in early cross-sectional studies and more recent longitudinal studies. By identifying developing hypoxia, this technology may reduce the uncertainty associated with electronic FHR monitoring. Fetal pulse oximetry may also provide critical information relating to the detection and management of the hypoxic fetus. Any new method of intrapartum fetal monitoring requires careful evaluation to assess its potential value before its introduction into clinical practice. The use of fetal SpO2 monitoring in the presence of a nonreassuring FHR pattern is being examined in a multicenter randomized controlled trial. This study will address the question of whether supplementary monitoring of fetal SpO2 levels can lead to a reduction in the cesarean section rate for fetal distress. The available data on fetal noninvasive pulse oximetry have been obtained from a combination of well-designed cohort studies (level II-2 evidence) or from earlier multiple time series (level II-3 evidence). The results from the US Multicenter Trial (level I evidence) should provide a significant addition to current evidence. A continuous fetal noninvasive monitor measuring fetal oxygenation directly could lead to an improvement in the sensitivity and specificity of fetal surveillance. This improvement could ultimately result in a reduction in unnecessary interventions by differentiating hypoxic fetuses from nonhypoxic fetuses and, more importantly, may lead to earlier intervention for fetuses in danger of serious compromise.     

Macrophage-activating lipopeptide-2 induces cyclooxygenase-2 and prostaglandin E(2) via toll-like receptor 2 in human placental trophoblast cells

We have examined whether toll-like receptor (TLR)2-mediated stimulation by macrophage-activating lipopeptide-2 (MALP-2), originally purified from Mycoplasma fermentans, induces cyclooxygenase (COX)-2 and prostaglandin (PG)E(2) in human placental trophoblast cells. The signaling mechanism by which MALP-2 exerts its effect has also been examined. Human placental trophoblast cells isolated from term placenta were used. TLR expression in trophoblast cells was confirmed by multiplex PCR and immunocytochemistry, and examined whether MALP-2 induces COX-2 and PGE(2) by Northern blotting, RT-PCR, Western blotting and ELISA, respectively. The activation of NF-kappaB and MAP kinases (ERK1/2 and p38) was examined by Western blotting. The effects of inhibitors of NF-kappaB, MEK1/2 and p38 on MALP-2-induced PGE(2) production were also evaluated. TLR2, TLR6 and TLR4 were expressed in human placental trophoblast cells. MALP-2 significantly induced COX-2 expression and enhanced PGE(2) production in a dose-dependent manner. MALP-2 induced the activation of NF-kappaB, ERK1/2 and p38 MAPK. Inhibitors of NF-kappaB, MEK1/2 and p38 blocked MALP-2-inducible PGE(2) production. TLR2-mediated stimulation by MALP-2 induces COX-2 and PGE(2) in human placental trophoblast cells via NF-kappaB and MAP kinases pathways.     

Combined intracervical PGE2 and intra-amniotic PGF2 alpha for induction of 2nd trimester abortion

Fourteen consecutive patients (mean gestational age 18.1 weeks, range 15-23 weeks) referred for therapeutic termination of pregnancy were induced into abortion by intra-amniotic PGF2 alpha 40 mg followed by oxytocin stimulation. 14 other patients (mean gestational age 17.9 weeks, range 15-23 weeks) were pretreated with intracervical PGE2 1.0 mg in gel for 4 h prior to induction of abortion with intra-amniotic PGF2 alpha 40 mg without further stimulation. The induction-abortion interval for patients treated with intra-amniotic PGF2 alpha and oxytocin, was 19.1 +/- 2.94 h (+/- SE, n = 14) with a success rate of 80% after 24 h. After pretreatment with intracervical PGE2 1.0 mg in viscous gel, intra-amniotic PGF2 alpha 40 mg induced abortion after 11.2 +/- 1.12 h (+/- SE, n = 14) with a 100% success rate after 24 h. No systemic side effects of the PGE2 pretreatment were noted. No cervical laceration was observed. The results need further confirmation, but still suggest cervical priming with intracervical PGE2 1.0 mg in gel and subsequent induction of abortion by intra-amniotic PGF2 alpha 40 mg as an attractive principle for 2nd trimester abortion.     

Arterial PO2, PCO2, and pH versus transcutaneous PO2 and PCO2 and tissue pH in the fetal dog

In the fetal dog, simultaneous recording by transcutaneous PO2 and PCO2 and tissue pH electrodes were compared to corresponding arterial values during hypoxic episodes produced by occlusion of the maternal abdominal aorta. Before occlusion, the differences between the paired values were minimal. Under anoxic conditions, expected changes in the peripheral circulation were observed. However, the transcutaneous PO2 was lower, the transcutaneous PCO2 much higher, and the tissue pH much lower than in blood. Continuous electrodes demonstrate changes resulting from gas and hydrogen ion coming from cells more readily than blood because they are closer to the former. Additionally, carbon dioxide and hydrogen ion are buffered to a greater degree in blood than in cells. Consequently, under conditions of stress and active metabolism, PCO2 is higher while PO2 and pH are lower in cells than in blood. When compared with monitoring of gases and acid-base balance through blood sampling, continuous transcutaneous and intracutaneous monitoring would seem to be more representative of the environment at the cellular level.     

Multiple pregnancies--Part 2

Increasing rates of multiple pregnancies with ensuing clinical problems such as prematurity, fetal growth disorders and specific disorders of multiple pregnancies are a challenge for providers of prenatal care and delivery. In general clinical and scientific data regarding prenatal care (e.g. use of tocolytics) and birth surveillance (e.g. mode of delivery) are less abundant and valid for multiple pregnancies than for singleton pregnancies. This is why in particular prematurity and supervision of birth are discussed in the following articles. Obviously there is need for multidisciplinary prospective multicenter studies on various problems of multiple pregnancies.