Hemoglobin A1c as a Substitute for Oral Glucose Testing in Early Pregnancy Screening.

OBJECTIVE: Current recommendations for individuals with risk factors for gestational diabetes mellitus (GDM) call for screening in early pregnancy. However, there is currently no clear consensus on a specific screening modality. This study evaluates whether a hemoglobin A1c (HbA1c) screening in individuals with risk factors for gestational diabetes (GDM) could be used instead of an early 1-hour glucose challenge test (GCT). We hypothesized that the HbA1c could replace 1-hour GCT in early pregnancy evaluation STUDY DESIGN: This is a prospective observational trial at a single tertiary referral center of women with at least one risk factor for GDM who were screened at <16 weeks of gestation with both 1-hour GCT or HbA1c. Exclusion criteria include: previous diagnosis of diabetes mellitus, multiple gestation, miscarriage, or missing delivery information. The diagnosis of GDM was made by a 3-hour 100-g glucose tolerance test, using the Carpenter-Coustan criteria (at least two results >94, 179, 154, and 139 mg/dL for fasting, 1-, 2-, and 3-hour values, respectively), 1-hour GCT > 200 mg/dL, or HbA1c > 6.5%. RESULTS: A total of 758 patients met inclusion criteria. A total of 566 completed a 1-hour GCT and 729 had an HbA1c collected. The median gestational age at testing was 91/7 weeks (range: 40/7-156/7 weeks]. Twenty-one participants were diagnosed with GDM at <16 weeks' GA. The receiver operating characteristic (ROC) curves identified the optimal valves for a positive screen for an HbA1c > 5.6%. The HbA1c had a sensitivity of 84.2%, a specificity of 83.3%, and a false positive rate of 16.7% (p < 0.001). The area under the ROC curve for the HbA1c was 0.898. Gestational age of delivery was slightly earlier with individuals with an elevated HbA1c but no other changes in delivery or neonatal outcomes. Contingent screening improved specificity (97.7%) and decreased false positive rate to 4.4%. CONCLUSION: HbA1c may be a good assessment in early pregnancy for gestational diabetes. KEY POINTS: · HbA1c is a rational assessment in early pregnancy.. · An HbA1c > 5.6% is associated with gestational diabetes.. · Contingent screening limits the need for additional testing..

Third Trimester Ultrasound Stratifies Risk of Peripartum Complications in Pregnancies Complicated by Impaired Glucose Tolerance.

OBJECTIVE: The objective of our study was to investigate the effect of impaired glucose metabolism (IGM) and ultrasound (US) findings consistent with hyperglycemia on maternal and neonatal outcomes. STUDY DESIGN: This was a retrospective case-control study of singleton, nonanomalous pregnancies with an elevated 1-hour glucose screening test (GST) completed after 23 weeks of gestation. IGM was defined as a 1-hour GST of >130, but less than two abnormal values on 3-hour glucose tolerance test (GTT). Gestational diabetes was defined as two or more abnormal values on 3-hour GTT. Ultrasound evidence of hyperglycemia was defined as abdominal circumference >95th centile and/or polyhydramnios. Individuals with IGM were divided into those with ultrasound evidence of hyperglycemia (impaired glucose metabolism consistent with ultrasound findings [IGM-US]) and those without IGM. Maternal demographics, delivery outcomes (gestational age at delivery, delivery mode, shoulder dystocia, lacerations), postpartum hemorrhage, and neonatal outcome (birth weight centile [BW%], neonatal intensive care unit admission, hypoglycemia, and glucose) were recorded. Composite morbidity was tabulated. Delivery and neonatal outcome variables were compared in individuals with IGM-US, IGM, and gestational diabetes mellitus (GDM). Odds ratios were calculated and adjusted for maternal age, BMI, and gestational weight gain. RESULTS: A total of 637 individuals with an abnormal 1-hour GST were included (122 with IGM-US, 280 with IGM, and 235 with GDM). When compared to the IGM group, IGM-US had higher rates of cesarean delivery and BW% > 90th centile at delivery (adjusted odds ratio [aOR]: 1.7 [1.1-2.8] and aOR: 5.9 [2.7-13.0], respectively). Individuals with GDM also demonstrated similar rates with BW% > 90% but not cesarean section(aOR: 3.9 [1.8-8.5] and aOR: 1.4 [0.9-2.1], respectively). The remaining maternal and fetal outcomes were similar. CONCLUSION: Women with impaired glucose tolerance should have a third-trimester ultrasound to identify an increased risk of perinatal complications. KEY POINTS: · Women with elevated blood glucose screening should be evaluated with third-trimester ultrasound to identify risks for perinatal morbidity.. · The third-trimester ultrasound identifies individuals at risk for cesarean section.. · Counseling should be completed with individuals with polyhydramnios or accelerated growth..

Polyhydramnios or Excessive Fetal Growth Are Markers for Abnormal Perinatal Outcome in Euglycemic Pregnancies.

OBJECTIVE: This study aims to investigate the perinatal outcome of fetuses with polyhydramnios and/or accelerated growth among women with a normal oral glucose challenge test (oGCT). METHODS: Singleton, nonanomalous pregnancies with an oGCT(< 130 mg/dL) at 24 to 28 weeks, who subsequently demonstrate polyhydramnios (amniotic fluid index > 24 cm or maximum vertical pocket > 8 cm) and/or accelerated growth (abdominal circumference > 95th percentile) on two-third trimester examinations were studied. Maternal demographics, delivery, and neonatal information were recorded. Cases were compared with a reference group (normal oGCT with neither abnormal third-trimester growth nor polyhydramnios). RESULTS: A total of 282 pregnancies were in the study group, and 663 were in the reference group. Deliveries in the study group were at a higher risk for birth weight (BW)% > 90%, standard deviation, and postpartum hemorrhage when compared with the reference group (adjusted odds ratio: 2.3-5.6). Pregnancies complicated by both polyhydramnios and accelerated fetal growth were significantly more likely to result in a BW% > 90% (odds ratio [OR]: 18.5; 95% confidence interval [CI]: 8.9-38.6) and PPH (OR: 4.2; 95% CI: 2.4-7.6). CONCLUSION: Pregnancies with normal oGCT that develop polyhydramnios and accelerated growth are at higher risk for maternal and neonatal complications. Isolated polyhydramnios without accelerated growth increases the risk for delivery complications but not neonatal morbidity.

First-trimester prediction of small-for-gestational age neonates incorporating fetal Doppler parameters and maternal characteristics.

OBJECTIVE: First-trimester screening for subsequent delivery of a small-for-gestational-age (SGA) infant typically focuses on maternal risk factors and uterine artery (UtA) Doppler. Our aim is to test if incorporation of fetal umbilical artery (UA) and ductus venosus (DV) Doppler improves SGA prediction. STUDY DESIGN: Prospective screening study of singletons at 11-14 weeks. Maternal characteristics, serum concentrations of pregnancy-associated plasma protein-A (PAPP-A) and free ß-human chorionic gonadotropin are ascertained and UtA Doppler, UA, and DV Doppler studies are performed. These parameters are tested for their ability to predict subsequent delivery of a SGA infant. RESULTS: Among 2267 enrolled women, 191 (8.4%) deliver an SGA infant. At univariate analysis women with SGA neonates are younger, more frequently African-American (AA), nulliparous, more likely to smoke, have lower PAPP-A and free ß-human chorionic gonadotropin levels. They have a higher incidence of UtA Doppler bilateral notching, higher mean UtA Doppler-pulsatility index z-scores (P < .001) and UA pulsatility index z-scores (P = .03), but no significant difference in DV-pulsatility index z-scores or in the incidence of abnormal qualitative UA and DV patterns. Multivariate logistic regression analysis identifies nulliparity and AA ethnicity (P < .001), PAPP-A multiple of the median and bilateral notching (P < .05) as determinants of SGA infant. Predictive sensitivity was low; receiver operating characteristic curve analysis yields areas under the curve of 0.592 (95% confidence interval, 0.548-0.635) for the combination of UtA Doppler and UA pulsatility index z-scores. CONCLUSION: Delivery of a SGA infant is most frequent in nulliparous women of AA ethnicity. Despite the statistical association with UtA Doppler first-trimester SGA prediction is poor and not improved by the incorporation of fetal Doppler.

Marginal placental cord insertion: the need for follow up?

OBJECTIVE: The objectives of this study were (1) to estimate the association between marginal placental cord insertion (PCI) and small for gestational age (SGA) and other adverse perinatal outcomes and (2) to determine if pregnancy-associated plasma protein A (PAPP-A) levels was altered in these patients. METHODS: It was a retrospective cohort study of singleton pregnancies undergoing ultrasound between 2016 and 2018. Marginal PCI was defined as a distance of ≤2 cm from placental edge to PCI site, visualized in both sagittal and transverse planes, and diagnosed between 16 and 32 weeks. Velamentous PCI were excluded. The primary outcome was SGA, defined as birthweight below 10th percentile for gestational age. Pregnancies with marginal PCI were compared to those with normal PCI with respect to maternal characteristics, PAPP-A levels and adverse perinatal and delivery outcomes. RESULTS: The incidence of marginal PCI was 4.2% (76/1819). Compared to those with a normal PCI, patients with a marginal PCI were more likely to be nulliparous and less likely to be African American or morbidly obese (p < .05). SGA rate was similar between the groups (17.6% vs. 18.1%). There was a trend toward an increased incidence of oligohydramnios, polyhydramnios and breech presentation in patients with marginal PCI; however, these did not reach statistical significance. The incidence of low PAPP-A level was comparable between the groups (18.4% vs. 14.3%, p > .05). CONCLUSION: Our study did not demonstrate any increase in adverse pregnancy outcomes in the presence of marginal PCI. These findings may provide reassurance for counseling patients with this sonographic finding.

Prolonged early antenatal indomethacin exposure is safe for fetus and neonate.

Objective: To evaluate fetal and neonatal safety of early-onset long-term antenatal indomethacin treatment (LIT) for short cervix.Methods: In this cohort study, women started LIT for short cervix (<25 mm) before completing 25 weeks. They followed a standardized regiment of oral indomethacin: 100 mg loading, 50 mg qid for 48 h, 25 mg qid until delivery or at 32 weeks gestational age (GA), whichever comes first. Weekly monitoring for oligohydramnios and ductus arteriosus (DA) constriction included confirmation of compliance with treatment/dose. This approach is established in our clinical practice. To identify LIT complications separate from prematurity, each neonate exposed to LIT were matched to two unexposed neonatal controls within ±3 days of GA of delivery and birth weight of ±10%. Odds ratios for neonatal variables included pulmonary hemorrhage, patent DA (PDA) requiring medical or surgical correction, necrotizing enterocolitis (NEC), spontaneous intestinal perforation (SIP), intraventricular hemorrhage (IVH) grade III-IV, other intracranial hemorrhage (ICH), neonatal mortality, calculated individually, and for total composite morbidity. Statistical determinants of neonatal morbidity were assessed using binary logistic regression. Exposure to LIT, maternal age, parity, BMI, GA at delivery, birth-weight (BW), neonatal gender, cord artery pH, and 5-min Apgar score were independent variables.Results: 166 LIT cases were matched with 332 controls. LIT median duration was 49 (3-108) days. Mean delivery GA was 34 weeks. LIT was stopped for 5 patients (2.9%) with oligohydramnios and 1 (0.6%) with DA constriction, without consequent morbidity. 71 cases (43%) completed LIT, stopping at 32 weeks. 95 stopped early for preterm premature ruptures of membranes (PPROM) (20%), active labor (11%) or patient choice (22%). Odds of any individual complication did not differ between treated cases and controls. LIT was not a statistical determinant of composite morbidity or any individual neonatal problem.Conclusion: Continuous early-onset indomethacin exposure, up to 15 weeks antenatally, did not increase fetal or neonatal complications. This level of safety is permissive to a randomized trial of indomethacin for the treatment of short cervix.

The role of fetal growth restriction in the association between Down syndrome and perinatal mortality.

Objective: Down syndrome (DS) is associated with significant risk of perinatal mortality. We hypothesize that this association is primarily mediated through the effects of fetal growth restriction (FGR).Methods: This was a retrospective cohort analysis using the US Natality Database from 2011 to 2013. Analysis was limited to singleton nonanomalous pregnancies or confirmed DS pregnancies without severe structural anomalies between 24 and 42 w in gestation. The risk of stillbirth (SB) associated with DS was estimated using both Cox proportional Hazard (HR) regression and accelerated failure time (AFT) methods. The risk of neonatal mortality was estimated using logistic regression analyses. Mediation analysis was then performed to estimate the effect of small for gestational age (SGA), defined as birthweight ≤10th percentile for gestational age, on perinatal mortality associated with DS. All regression models were selected using backward stepwise elimination method. The final regression models included adjustment for maternal age, hypertension, and diabetes.Results: The final cohort included 2446 DS cases among 9,804,718 births. The overall SB rate was 223.6/1000 births in DS group and 4.7/1000 births without DS (p < .001, adjusted hazard ratio (aHR): 58.25; 95% CI [53.44,63.49]). Based on the AFT model, DS survival-to-delivery rate is 4.3 times lower (TR: 0.23; 95% CI [0.22,0.24]). Thirty-five percentage of the effect of DS on stillbirth was mediated through SGA (% mediation:35.1%; 95% CI [33.7,36.4]). The rate of neonatal mortality among DS was 69.0/1000 births compared with 2.8/1000 births without DS (p < .001, adjusted odds ratio (aOR): 27.16; 95% CI: [22.63,32.60]). Only 11.6% of the effect of DS on neonatal deaths was mediated through SGA (%mediation:11.6%; 95% CI [8.4,10.6]).Conclusion: Over one-third of overall stillbirths were mediated through SGA. Routine surveillance of fetal growth and standard SGA surveillance protocols may reduce the risk of perinatal mortality in DS pregnancies. Conversely, it is important to point out that these surveillance strategies may not be effective two-third of the cases not affected by growth restriction.

Adverse perinatal outcomes associated with trial of labor after cesarean section at term in pregnancies complicated by maternal obesity.

INTRODUCTION: Obesity is associated with higher risks for intrapartum complications. Therefore, we sought to determine if trial of labor after cesarean section (TOLAC) will lead to higher maternal and neonatal complications compared to repeat cesarean section (RCD). METHODS: This was a retrospective cohort analysis of singleton nonanomalous births between 37 and 42 weeks GA complicated by maternal obesity (body mass index (BMI) ≥ 30 kg/m2) and history of one or two previous cesarean deliveries. Outcomes were compared between TOLAC and RCD. The maternal outcomes of interest included blood transfusion, uterine rupture, hysterectomy, and intensive care unit admission. Neonatal outcomes of interest included 5-minute Apgar score <7, prolonged assisted ventilation, neonatal intensive care unit admission, neonatal seizures, and neonatal death. RESULTS: There were 538,264 pregnancies included. Compared with RCD, TOLAC was associated with an absolute increase in the following neonatal outcomes: low 5-min Apgar score (0.6%, p < .001), neonatal intensive care unit (NICU) admission (0.8%, p < .001), neonatal seizure (0.1 per 1000 births, p = .037), and neonatal death (0.2 per 1000 births, p = .028). Additionally, TOLAC was associated with an absolute increase in following maternal outcomes: blood transfusion (0.1%, p < .001), uterine rupture (0.18%, p < .001) and ICU admission (0.1%, p = .011). CONCLUSIONS: TOLAC among obesity pregnancies at term increases the risk of maternal and neonatal complications compared with RCD.

Anaphylactoid syndrome of pregnancy immediately after intrauterine pressure catheter placement.

A 35-year-old multipara woman underwent intrauterine pressure catheter placement during labor. Immediately afterwards, she had severe dyspnea develop, became unresponsive, and had a prolonged fetal bradycardia. During emergency cesarean section, she required cardiopulmonary resuscitation repetitively. She then had disseminated intravascular coagulopathy develop and underwent hysterectomy. Anaphylactic reaction may be associated with intrauterine pressure catheter placement.

QUAD versus cfDNA in an urban population in the second trimester for detection of trisomy 21: a cost sensitivity analysis.

OBJECTIVE: To compare the unit cost of noninvasive prenatal testing (cell-free DNA [cfDNA]) in an urban population who did not have first-trimester screening as a primary screening tool for trisomy 21 (T21) to multiple marker screening (QUAD). METHODS: Retrospective study of all QUAD screens performed at a single center from 2013 to 2015. All QUAD screen performed between 15 and 21 weeks were included in the study. Exclusion criteria were patients without anatomy scans or delivery information. Utilizing our population characteristics, we extrapolated to determine the cost of QUAD with additional screening (cfDNA and amniocentesis) versus QUAD for this entire population. RESULTS: 590 QUAD screens were performed during the study time period. After ultrasound correction of gestational age, 5.9% (35) were screen positive. Within this cohort, 51.4% (18) patients underwent cfDNA and 11.4% (4) had invasive testing. No cases of T21 were identified. It would be cost equivalent to offer cfDNA as a primary screen for T21 at less than $360.54 to the entire population regardless of a priori risk status. Invasive procedures were reduced by 55.4%. CONCLUSIONS: cfDNA is an acceptable option for second-trimester screening and as a primary screen eliminates the need for multi-step screening preserving valuable healthcare resources.

Association of Maternal Obesity With Maternal and Neonatal Outcomes in Cases of Uterine Rupture.

OBJECTIVE: To describe the risk of adverse outcomes associated with uterine rupture in the setting of maternal obesity. METHODS: This was a retrospective cohort analysis of singleton nonanomalous neonates born after uterine rupture between 34 and 42 weeks of gestation. We derived data from the U.S. Natality Database from 2011 to 2014. Maternal prepregnancy body mass index (BMI) was categorized according to the World Health Organization classification. The rates of neonatal and maternal complications were calculated for each BMI class. Multivariable logistic regression analysis was used to estimate the risks of these complications among obese pregnancies compared with normal-weight pregnancies. RESULTS: There were 3,942 cases of uterine rupture identified among 15,860,954 births (0.02%) between 2011 and 2014. Of these, 2,917 (74%) met inclusion criteria for analysis. There was an increased risk of low 5-minute Apgar score (22.9% compared with 15.9%; adjusted odds ratio [OR] 1.49 [1.19-1.87]), neonatal intensive care unit admission (31% compared with 24.6%; adjusted OR 1.51 [1.23-1.85]), and seizure (3.7% compared with 1.9%; adjusted OR 1.80 [1.05-3.10]) in obese compared with normal-weight pregnancies. The rate of prolonged assisted ventilation was 8.5% compared with 6.2% (P=.13), which, after adjustment for confounders, was a statistically significant difference (adjusted OR 1.47 [1.05-2.07]). The rate of neonatal death was similar (12.4 compared with 6.5/1,000 births; adjusted OR 2.03 [0.81-5.05]). The rates of various maternal complications were similar between groups. CONCLUSION: In the setting of uterine rupture, maternal obesity moderately increases the risks of low Apgar score, neonatal intensive care unit admission, prolonged ventilation, and seizure. Risk of maternal complications and the risk of neonatal death, however, are similar to risks in patients of normal BMI.

First-trimester risk factors for preeclampsia development in women initiating aspirin by 16 weeks of gestation.

OBJECTIVE: The residual risk of preeclampsia in high-risk women on aspirin prophylaxis exceeds that of low-risk populations, and this study aimed to identify first-trimester maternal characteristics associated with aspirin prophylaxis failure. METHODS: This is a nested cohort study of prospectively enrolled women with verified initiation of risk-indicated aspirin prophylaxis by 16 weeks of gestation. First-trimester maternal history, demographics, anthropometry, ultrasound parameters, and serum analytes were compared between women who developed preeclampsia and those who did not. Blood pressure measurements were classified as prehypertension or hypertension according to the Joint National Committee on Hypertension guidelines. Chi square, nonparametric, and logistic regression analyses were used to determine the contributors to preeclampsia development. RESULTS: Six hundred fourteen women prospectively enrolled at 9-14 weeks of gestation initiated aspirin by 16 weeks of gestation. The 59 (9.6%) women who developed preeclampsia were more likely to have chronic hypertension, diabetes, and obesity and had higher first-trimester blood pressure and lower serum pregnancy-associated plasma protein-A concentrations (all P<.05). Having first-trimester Joint National Committee on Hypertension prehypertension or hypertension was associated with a 2.18-fold increased risk of developing preeclampsia, whereas normotension was associated with a reduction of risk of 56%. CONCLUSION: Women who develop preeclampsia while taking aspirin prophylaxis are more likely to have elevated first-trimester blood pressures. Conversely, first-trimester normotension is associated with a reduced risk of preeclampsia.

First trimester maternal characteristics, Doppler parameters and serum analytes after preeclampsia.

OBJECTIVE: To evaluate the impact of prior preeclampsia on first trimester assessment in subsequent pregnancy. METHODS: A total of 1283 parous patients were prospectively enrolled at 9-14 weeks of gestation. Maternal biophysical characteristics, ultrasound parameters and placental analytes were compared between women with and without prior preeclampsia. RESULTS: There is no association between prior preeclampsia and the first trimester ultrasound parameters or placental analytes studied. The effects of prior preeclampsia in subsequent pregnancy are exaggerated by increasing parity and are predominantly blood pressure-related, independent of other cardiovascular risk factors. CONCLUSION: There is a potential role for lifestyle modification and stricter pregnancy blood pressure control in patients with prior preeclampsia.

Duration of the second stage of labor while wearing a dental support device: a pilot study.

AIM: Developing a method of maximizing maternal expulsive effort should be of great value in reducing the number of cesarean sections or instrumental deliveries. Various investigations have shown that use of a dental support device (DSD) increases the isometric strength of different muscle groups. The aim of our study was to investigate the role of a DSD in second stage of pushing. METHODS: Nulliparous women with an uncomplicated singleton pregnancy course were randomly assigned either to a DSD group or to a non-device group. Duration of the second stage of labor was evaluated. Rates of cesarean section or instrumental delivery indicated for failure to descend in the second stage of labor were also evaluated. Satisfaction scores for the DSD group were evaluated (range 1-5). RESULTS: Sixty-four subjects were enrolled in the study. Cesarean section and instrumental delivery were performed for 12 (18.8%) and 5 (7.8%) patients, respectively. There was no difference in obstetrical and neonatal demographics between the two groups. Among 64 enrolled patients, 38 (59.3%) were evaluated for the second stage of labor (n = 19 for each group). Duration of the second stage of labor in the DSD group was significantly shorter than in the non-device group: (median 19 min (interquartile interval, IQI, 9) vs 31 min (IQI, 23)), P < 0.001. One patient in the non-device group required a vacuum extraction for failure to descend. The mode of satisfaction score for the DSD group was 5 (59.3%). CONCLUSION: Wearing a dental support device may shorten the second stage of labor, and may decrease the number of failures to descend requiring operative intervention. CLINICAL TRIAL REGISTRATION: NCT00629369.

Staircase sign: a newly described uterine contraction pattern seen in rupture of unscarred gravid uterus.

Although extremely rare, rupture of an unscarred gravid uterus poses significant morbidity and mortality to both fetus and mother. In the past, loss of uterine contraction was thought to be characteristic of uterine rupture, while recent evidence shows that uterine contraction pattern is not associated with uterine rupture. We report two cases of rupture in the unscarred term uterus. Both patients were multiparous and denied any past medical complications, previous cesarean delivery or myomectomy. Uterine rupture occurred in the latent phase of labor at 1 cm dilation (Case 1) and during an intravenous oxytocin infusion after three doses of intravaginal misoprostol (Case 2). Case 2 required cesarean hysterectomy and blood transfusion. Case 1 was monitored with an external tocodynamometer, while Case 2 was monitored with an internal pressure transducer. External monitoring demonstrated the classic sign of complete loss of uterine tone. In contrast, internal monitoring demonstrated an increase in uterine resting tone. Both techniques revealed a stepwise gradual decrease in contraction amplitude followed by sudden onset of profound and prolonged fetal bradycardia (staircase sign). In cases of uterine rupture, differing baseline characteristics between contraction patterns were dependent on uterine monitoring technique. In both techniques a stepwise gradual decrease in contraction amplitude was followed by prolonged fetal bradycardia.

Pushing in labor: performance and not endurance.

OBJECTIVE: It is believed that delivery is faster if women are instructed to voluntarily bear down in synchrony with their uterine contractions. Confronted by the large variance in the duration of the second stage of labor, many clinicians attribute a "fast" or a "short" expulsion time solely to the patient's willingness to cooperate or to the strength of epidural anesthesia if it is a factor. Yet, knowledge of pushing performance and the factors affecting it remain limited. We investigated the maternal, fetal, and labor characteristics that influence the maternal "pushing performance" and sought to design a predictive index that prospectively identified "high" versus "low" pushing performers. STUDY DESIGN: Intrauterine pressure (IP) was prospectively measured during the second stage of labor in 52 women recruited at one North American hospital. Recordings were begun after documentation of full cervical dilatation and descent of the fetal head to +2 station (on a -3/+3 scale). Each woman acted as her own control, received epidural anesthesia, and was alert and responsive throughout the study. Pushing (closed glottis technique) was performed in a standardized fashion. Multivariate analysis with linear regression was applied to identify significant associations between maternal, fetal, or labor characteristics as the independent variables and the percent increase in IP consequent to active pushing as the dependent variable. RESULTS: Women in labor increase their IP 62% by actively pushing with a contraction during the second stage. A scattergram of the individual percent increase above the baseline IP integral revealed that for some women, pushing more readily increased their IP than it did for others (range, 0% to 192%). The percent increase was best calculated by a linear combination of myometrial thickness, estimated fetal weight, the maternal body mass index, and the obstetric need for labor augmentation (P =.007, r = 0.52, power = 0.975). A 66% change in IP provided the best separation between high and low pushing performance. Myometrial thickness provided the single strongest contribution to the regression equation's predictive value (P =.01, r = -0.36). A myometrial thickness of 6 mm had a specificity of 88% (but only 53% sensitivity) for the identification of women able to increase their IP by 66% over baseline. CONCLUSIONS: In women in labor who have received epidural anesthesia, the efficiency with which maternal expulsive efforts are converted into increased IP is directly related to the patient's body mass index but inversely related to myometrial thickness, the sonographic estimate of fetal weight, and the need for labor augmentation.

The effect of fundal pressure manoeuvre on intrauterine pressure in the second stage of labour.

OBJECTIVE: To investigate the relationship between intrauterine pressure and the application of a standardised fundal pressure manoeuvre, and to determine the maternal, fetal and labour characteristics that modulate the relationship. DESIGN: Prospective measurement of intrauterine pressure during the second stage of labour. SETTING: North American university hospital. POPULATION: Forty full-term women in spontaneous labour were studied during the second stage. Each woman acted as her own control. All women laboured with requested epidural analgesia. METHODS: A fundal pressure manoeuvre was performed so as to standardise the level of force and the surface area of application. Intrauterine pressure was measured using a sensor-tip catheter. Five interventions were analysed: 1. valsalva during a uterine contraction; 2. fundal pressure and valsalva during a contraction; 3. fundal pressure during a contraction without valsalva; 4. fundal pressure in the absence of uterine contractions; and 5. valsalva in the absence of uterine contractions. RESULTS: Women in the second stage of labour transiently increased their expulsive force (as reflected by intrauterine pressure) by 86% of their baseline contraction using valsalva and fundal pressure simultaneously. The efficiency by which both contraction-enhancing manoeuvres increased intrauterine pressure was directly related to gestational age and inversely related to myometrial thickness. CONCLUSION: Fundal pressure applied under controlled conditions significantly increases intrauterine pressure in some, but not all women. Simultaneous measurement of intrauterine pressure, to maintain feedback during application will create a 'controlled environment' for the obstetrician and reassurance that this manoeuvre can be applied in a controlled fashion. Future delineation of the group of women that could benefit from fundal pressure, as well as the group that is refractory is essential to avoid unnecessary or delayed operative interventions.