Gayle Olson

Predicting Term and Preterm Delivery With Transabdominal Uterine Electromyography

OBJECTIVE To determine whether delivery can be predicted using transabdominal uterine electromyography. METHODS A total of 99 patients were grouped as either term (37 weeks or more) or preterm (less than 37 weeks). Uterine electrical activity was recorded for 30 minutes in clinic. Electromyographic “bursts” were evaluated to determine the power density spectrum. Measurement-to-delivery time was compared with the average power density spectrums peak frequency. Receiver operating characteristic curve analysis was performed for 48, 24, 12, and 8 hours from term delivery, and 6, 4, 2, and 1 day(s) from preterm delivery. RESULTS The power density spectrum peak frequency increased as the measurement-to-delivery interval decreased. Receiver operating characteristic curve analysis gave high positive and negative predictive values for both term and preterm delivery. At term, the average power density spectrum peak frequency was significantly higher for the 24-or-fewer-hours-to-delivery group than for the more-than-24-hours-to-delivery group, whereas at preterm, the average power density spectrum peak frequency was significantly higher in the 4-or-fewer-days-to-delivery group than in the more-than-4-days-to-delivery group (P < .05). CONCLUSION Transabdominal uterine electromyography predicts delivery within 24 hours at term and within 4 days preterm. This methodology offers many advantages and benefits that are not available with present uterine monitoring systems.

Amniotic septostomy for the treatment of twin oligohydramnios-polyhydramnios sequence

Objective: To report our experience with intentional puncture of the intervening membrane (‘septostomy’) for the treatment of the twin oligohydramnios-polyhydramnios sequence (TOPS). Methods: 12 patients were diagnosed with TOPS based on ultrasonographic findings. A 20- to 22-gauge spinal needle was used to puncture the membrane between the twins without any attempt at amnioreduction in 9 patients, while the procedure was combined with amnioreductions in 3 patients. Results: Gestational age was 23.1 ± 3.3 weeks at the time of septostomy and 31.1 ± 4.4 weeks at delivery. Rapid accumulation of fluid around the ‘stuck’ fetus occurred in all cases following a single procedure. Three of the 24 fetuses died in utero and 1 died on the fifth day of life, for a combined survival of 83.3%. In the survivors, the septostomy to delivery interval ranged between 0.6 and 13 weeks (mean ± SD 8.3 ± 4.8). Conclusion: Amniotic septostomy is a promising new method for the management of TOPS and is associated with survival rates that are better than, or comparable to, more invasive modalities. A multicenter trial comparing septostomy to other modalities is warranted.

Non-invasive transabdominal uterine electromyography correlates with the strength of intrauterine pressure and is predictive of labor and delivery.

Objective: The study was conducted to investigate whether the strength of uterine contractions monitored invasively by intrauterine pressure catheter could be determined from transabdominal electromyography (EMG) and to estimate whether EMG is a better predictor of true labor compared to tocodynamometry (TOCO). Study design: Uterine EMG was recorded from the abdominal surface in laboring patients simultaneously monitored with an intrauterine pressure catheter (n = 13) or TOCO (n = 24). Three to five contractions per patient and corresponding electrical bursts were randomly selected and analyzed (integral of intrauterine pressure; integral, frequency, amplitude of contraction curve on TOCO; burst energy for EMG). The Mann–Whitney test, Spearman correlation and receiver operator characteristics (ROC) analysis were used as appropriate (significance was assumed at a value of p < 0.05). Results: EMG correlated strongly with intrauterine pressure (r = 0.764; p = 0.002). EMG burst energy levels were significantly higher in patients who delivered within 48 h compared to those who delivered later (median [25%/75%]: 96 640 [26 520–322 240] vs. 2960 [1560–10 240]; p < 0.001), whereas none of the TOCO parameters were different. In addition, burst energy levels were highly predictive of delivery within 48 h (AUC = 0.9531; p < 0.0001). Conclusion: EMG measurements correlated strongly with the strength of contractions and therefore may be a valuable alternative to invasive measurement of intrauterine pressure. Unlike TOCO, transabdominal uterine EMG can be used reliably to predict labor and delivery.

Instrumentation for the diagnosis of term and preterm labour.

The problems associated with labor during pregnancy are among the most important health issues facing physicians. Understanding the role of the uterus and cervix in labor and developing methods to control their function is essential to solving problems relating to labor. At the moment, only crude, inaccurate and subjective methods are used to assess changes in the uterus and cervix that occur in preparation for or during labor. In the past several years, we have developed noninvasive methods to quantitatively evaluate the uterus and cervix based respectively on recording of uterine electrical signals from the abdominal surface (uterine EMG) and measurement of light-induced cervical collagen fluorescence (LIF) with an optical device (Collascope). The methods are rapid and allow assessment of uterine contractility and cervical ripening. Studies in rats and humans indicate that uterine and cervical function can be successfully monitored during pregnancy using these approaches and that these techniques might be used in a variety of conditions associated with labor to better define management. The potential benefits of the proposed instrumentation and methods include a reducing the rate of preterm delivery, improving maternal and perinatal outcome, monitoring treatment, decreasing cesarean section rate and improving research methods to understand uterine and cervical function.

Anxiety symptoms during pregnancy and postpartum.

This cross-sectional study compared the distribution of anxiety symptoms among pregnant, non-pregnant, and postpartum women of lower socioeconomic status. Participants were 807 women who were pregnant (24–36 weeks), postpartum (2–8 weeks), or not pregnant. Anxiety and depressive symptoms were assessed by the state-trait anxiety index and the Beck depression inventory, respectively. English and Spanish versions of the instrument were available. Group differences in anxiety were evaluated using analysis of variance. Multivariate regression was performed to evaluate differences in anxiety while controlling for marital status, education, race/ethnicity, employment, cohabitation, income, parity, history of depression/anxiety, and depressive symptoms. Anxiety scores were lower among postpartum women relative to pregnant and non-pregnant women (both P < 0.001), who did not differ (P = 0.99). After controlling for depressive symptoms and patient characteristics, anxiety remained lowest among postpartum women. Additionally, history of depression/anxiety and depressive symptoms were significant predictors of anxiety in the multivariate analysis. Comparatively low anxiety and depressive symptoms were observed among women who were 2–8 weeks postpartum. Anxiety symptoms that occur postpartum may not appear until later in the postpartum period.

Zika Virus and Pregnancy: A Review of the Literature and Clinical Considerations.

The latest Zika virus (ZIKV) outbreak has reached epidemic proportions as it spreads throughout South and Central America. In November 2015, the Brazilian Ministry of Health reported a 20-fold increase in the number of cases of neonatal microcephaly, which corresponds geographically and temporally to the ZIKV outbreak. Case reports have provided some evidence of a causal link between maternal ZIKV infection, fetal microcephaly, and intracranial calcifications. The sparse data regarding ZIKV in pregnancy come solely from case reports and personal communications, and recommendations for management of ZIKV exposure during pregnancy are rapidly evolving. Our objective is to review and synthesize the current literature regarding ZIKV as it pertains to pregnancy and provide some assistance to clinicians who may have to manage a pregnant patient with potential exposure to ZIKV. We will also explore certain aspects of related viruses in pregnancy in hopes to shed light on this little-known topic.

Roles of potassium channels and nitric oxide in modulation of uterine contractions in rat pregnancy

OBJECTIVE We sought to study the involvement of potassium channels in the inhibition by nitric oxide of spontaneous contractions in isolated uterine rings from midterm and term pregnant rats. STUDY DESIGN Uterine rings from Sprague-Dawley rats at midterm and term gestation were used for isometric tension recording. The inhibition of spontaneous contractile activity by potassium channel openers and nitric oxide was studied in the absence and presence of potassium channel inhibitors. RESULTS The adenosine triphosphate-dependent potassium channel opener levcromakalim inhibited spontaneous contractions in rings from both midterm and term pregnant rats in a concentration-dependent manner, and the effects were significantly attenuated by pretreatment with selective inhibitor of the adenosine triphosphate-dependent potassium channel inhibitor glibenclamide. The opener of calcium-dependent potassium channel NS 1619 inhibited spontaneous contractions in rings from midterm but significantly less so in rings from term pregnant rats in a concentration-dependent manner, and the effect was significantly attenuated by pretreatment with potassium channel inhibitors tetraethylammonium and tetrabutylammonium but not with glibenclamide. Rings from midterm and term pregnant rats were more sensitive to the inhibitory effect of levcromakalim compared with NS 1619. Nitric oxide donor diethylamine-nitric oxide inhibited spontaneous contractions in rings from midterm but significantly less in rings from term pregnant rats in a concentration-dependent manner, and the effect was attenuated by tetraethylammonium and tetrabutylammonium but not by glibenclamide. CONCLUSIONS There is gestational age-dependent refractoriness to calcium-dependent potassium but not adenosine triphosphate-dependent potassium channel opener-induced inhibition of spontaneous contractile activity of isolated rat uterine rings. Nitric oxide inhibits uterine contractions by opening of calcium-dependent potassium channels in pregnant rat myometrium. Refractoriness to nitric oxide toward term may result from decreased probability to open or number of calcium-dependent potassium channels.

Changes in light-induced fluorescence of cervical collagen in guinea pigs during gestation and after sodium nitroprusside treatment

Abstract Lightinduced fluorescence (LIF) of collagen was used to investigate in vivo changes in cervical collagen in guinea pigs during gestation and following sodium nitroprusside treatment. Natural fluorescence of collagen is due to collagen cross-linking molecules that connect single collagen fibers and therefore provide rigidity of the cervical stroma. LIF of cervical collagen was measured from the surface of the exocervix in anesthetized nonpregnant and timed pregnant guinea pigs at different times of gestation with an instrument designed in our lab (Collascope™). Measurements were also performed in guinea pigs at midgestation before and 8 hours after intracervical treat ment with sodium nitroprusside. Collagen fluorescence decreased significantly as pregnancy progressed, reached lowest values at delivery, and increased gradually postpartum. Treatment with sodium nitroprusside, but not with the vehicle, caused a significant decrease in LIF (p = 0.007). We conclude, that LIF changes in the cervix reflect the gradual cervical softening (ripening) during pregnancy and the return to the rigid state of the cervix postpartum. Cervical softening during pregnancy, and after sodium nitroprusside treatment, is associated with a decrease in collagen cross-links. Measurements of LIF can be used to investigate cervical softening in vivo.

Determination of placental growth factor (PlGF) levels in healthy pregnant women without signs or symptoms of preeclampsia

OBJECTIVE To identify a reference range for placental growth factor (PlGF) in normotensive women without symptoms or signs of preeclampsia. STUDY DESIGN Comprising the study cohort were 247 term pregnancies without preeclampsia or adverse neonatal outcomes from 16 sites in the US and Canada. Serial plasma samples were collected in 6 gestational age (GA) intervals between 20+0 and 40+0weeks. Non-parametric percentiles of the distribution of PlGF were estimated in each GA interval and a parametric model was developed to describe the distribution of PlGF as a continuous smooth function of GA (from 20 to 40weeks) in normal healthy pregnancy. Demographic and clinical factors influencing PlGF levels were also examined. RESULTS There were 1366 evaluable samples collected from 247 subjects (242, 238, 226, 223, 222, and 215 samples in each GA interval, 20-24, 24-29, 29-32, 32-35, 35-37, and 37-40weeks, respectively). The 5th percentile of PlGF was 76.4, 141.1, 139.3, 65.5, 31.7, and 23.4pg/mL in each respective GA interval. The distribution of PlGF is approximately log normal with parameters that vary continuously as a function of GA. PlGF distribution is weakly dependent on maternal age, race/ethnicity, parity, and maximum systolic blood pressure (taken between weeks 20 and 24). Although statistically significant, these factors did not modify PlGF levels by more than ±15%. CONCLUSION These data provide a valid reference range for PlGF in normal pregnancy.

The effect of an endothelin antagonist on blood pressure in a rat model of preeclampsia

OBJECTIVE We attempted to determine the role of endothelin in a previously characterized animal model of preeclampsia by studying the effect of a specific endothelin antagonist, BQ123, on blood pressure. STUDY DESIGN A preeclampsia-like condition was induced by infusing pregnant rats with the nitric oxide synthase inhibitor N(G)-nitro-L -arginine methyl ester. Osmotic minipumps were inserted subcutaneously into timed pregnant Harlan-Sprague-Dawley rats on day 17 of pregnancy (term, 22 days). The pumps were loaded to continuously deliver either vehicle (control group) or N(G)-nitro-L -arginine methyl ester 50 mg/d, either alone or with BQ123 at 0.5 mg/d. In a similar but separate experiment, the dose of BQ123 was increased to 1 mg/d. Blood pressure was measured with the tail-cuff method before pump insertion and then daily until postpartum day 2. RESULTS Except for a decrease on the day after pump insertion, BQ123 0.5 mg/d had no significant effect on the hypertension induced by N(G)-nitro-L -arginine methyl ester. At the higher dose, however, BQ123 significantly attenuated the increase in blood pressure induced by N(G)-nitro-L -arginine methyl ester during most of the study period. CONCLUSION The effect of nitric oxide inhibition can be successfully attenuated by the use of an endothelin antagonist, thereby supporting the role of endothelin in the hypertension described with the preeclampsialike condition seen in pregnant rats.