Maximum Vertical Pocket Research Articles

Paradoxical scalloped placenta with polyhydramnios in twin–twin transfusion syndrome

Objective. To describe the paradoxical occurrence of a scalloped placenta in the presence of polyhydramnios and assess its clinical significance in pregnancies complicated by twin–twin transfusion syndrome (TTTS) treated with laser therapy.Methods. All patients who underwent laser therapy for TTTS between January 2003 and April 2004 were studied. TTTS was diagnosed and staged using the Quintero staging system. Normally the placenta is characterized by undulations of the fetal-placental surface visible by ultrasound (scalloped placenta). Patients with polyhydramnios will typically have a flattened, smooth, non-scalloped placenta. Operative tapes were reviewed and placental type assigned. Pre-, intra-, and postoperative characteristics of each study patient were obtained.Results. Fifteen of 120 patients (12.5%) were noted to have a scalloped placenta despite having polyhydramnios. There was no difference in mean gestational age at laser treatment (20.3 ± 0.5 vs. 19.6 ± 0.6 weeks, p = 0.66) or in stage (p = 0.07) between the two groups. The median and range preoperative maximum vertical pocket (MVP) in the recipient gestational sac differed significantly between the scalloped and non-scalloped patients (8.3 (8–12) vs. 10.5 (8–17), p = 0.001). All 15 patients (100%) with a scalloped placenta required an amnioinfusion to expose all vascular anastomoses, while amnioinfusion was necessary in only 28 of the 105 patients (26.7%, p < 0.001) with a non-scalloped placenta. Postoperative patent placental vessel was identified by surgical pathology in 6.7% of the scalloped placenta group vs. 1.9% of the non-scalloped placenta group (p = NS).Conclusion. The definition of TTTS requires an MVP ≥8 cm in the recipient sac. Most patients will have a flattened placenta as a result of polyhydramnios in this sac. Our data show that a paradoxical scalloped placenta may still be present in approximately 12.5% of patients. This preoperative sonographic finding alerts to the potential need for amnioinfusion during laser therapy for TTTS to disclose all vessels to avoid missing placental vascular anastomoses. Amniocenteses should be avoided if possible in patients considering laser therapy to minimize the likelihood of iatrogenic placental scalloping.

Sequential selective laser photocoagulation of communicating vessels in twin–twin transfusion syndrome

Objective. We have previously described the selective laser photocoagulation of communicating vessels (SLPCV) technique for the treatment of twin–twin transfusion syndrome (TTTS). Because TTTS is thought to result from a net transfer of blood from the donor twin to the recipient twin, we hypothesized that lasering the arteriovenous anastomoses from the donor to the recipient (AVDRs) first (sequential SLPCV or SQLPCV) would result in an improved hemodynamic status and decreased likelihood of intrauterine fetal demise of the donor twin (IUFD-D).Materials and methods. The diagnosis of TTTS was made by ultrasound showing the combined presence of a maximum vertical pocket ≥ 8 cm in one sac and ≤2 cm in the other in a monochorionic/diamniotic twin pregnancy. Triplet pregnancies and monoamniotic pregnancies were excluded. Severity of TTTS was assessed using the Quintero staging system. All vascular anastomoses were endoscopically identified and classified as AVDR (AV from donor to recipient), AVRD (AV from recipient to donor), arterio-arterial (AA), or veno-venous (VV). The surgical procedure was coded as SQLPCV if all AVDRs were lasered first. Outcome measures included intrauterine fetal demise and perinatal survival.Results. One hundred and ninety-three TTTS patients (137 SQLPCV, 56 SLPCV) underwent surgery from May 2003 to August 2005. Gestational age at surgery or at delivery, Stage, patent anastomoses, or persistent/reverse TTTS were not different between the groups. IUFD-D was significantly lower in the SQLPCV than in the SLPCV group (7.3% vs 21.4%, respectively, p = 0.005). Dual perinatal survival was significantly higher in the SQLPCV than in the SLPCV group (73.7% vs 57.1%, respectively, p = 0.02), although the incidence of at least one survivor was not different between the groups (90.5% vs 87.5%, respectively). Logistic regression showed SQLPCV, but not placental location, operating time or number of anastomoses to be significantly associated with a decreased likelihood of IUFD-D (p = 0.007).Conclusion. SQLPCV is associated with a decreased likelihood of IUFD-D and an increased rate of dual survivors compared to SLPCV. SQLPCV represents both an anatomical and functional surgical approach to the laser treatment of twin–twin transfusion syndrome.

P11.07: Which amniotic fluid related variable, amniotic fluid index or maximal vertical pocket, is best predictor of successful external cephalic version?

P11.07: Which amniotic fluid related variable, amniotic fluid index or maximal vertical pocket, is best predictor of successful external cephalic version?

Surgical management of twin reversed arterial perfusion sequence

The purpose of this study was to review our experience in the management of twin reversed arterial perfusion sequence to derive management recommendations. All patients with twin reversed arterial perfusion sequence who were seen for consultation between 1993 and 2004 were studied. Criteria for umbilical cord occlusion included abdominal circumference of the twin reversed arterial perfusion fetus that was more than or equal to the pump twin, polyhydramnios (maximum vertical pocket > or = 8 cm), abnormal Doppler studies or hydrops of the pump twin, or monoamniotic twins. Various surgical and access techniques for umbilical cord occlusion were used as they were developed. Seventy-four patients with twin reversed arterial perfusion sequence were studied. Sixty-five patients were considered surgical candidates, of which 51 patients underwent umbilical cord occlusion attempt. The overall perinatal survival for surgical candidates who had umbilical cord occlusion was 65% (33/51 patients) versus 42.9% (6/14 patients) for the surgical candidates who did not undergo umbilical cord occlusion (P = .1). However, perinatal outcomes in surgical patients were significantly better than expectantly treated surgical candidates if the dividing membrane was not disrupted purposely (22/28 patients; 78.5%; P = .02). Surgery within the sac of the twin reversed arterial perfusion fetus was feasible in 23.5% of patients and was associated with no incidence of premature rupture of membranes, with 83% perinatal survival, and with a significantly greater gestational age at delivery (36 weeks). There were no significant differences in perinatal outcome relative to the specific surgical technique that was used. Surgical management of twin reversed arterial perfusion sequence is indicated in high-risk patients. The surgical approach and the surgical technique should be tailored to the specific clinical presentation, preferably by performing the surgery within the sac of the twin reversed arterial perfusion sequence fetus and avoiding disruption of the dividing membrane.

The NICHD-MFMU antibiotic treatment of preterm PROM study: Impact of initial amniotic fluid volume on pregnancy outcome

The purpose of this study was to evaluate the associations between measured amniotic fluid volume and outcome after preterm premature rupture of membranes (PROM). This was a secondary analysis of 290 women, with singleton pregnancies, who participated in a trial of antibiotic therapy for preterm PROM at 24(0) to 32(0) weeks. Each underwent assessment of the 4 quadrant amniotic fluid index (AFI) and a maximum vertical fluid pocket (MVP) before randomization. The impact of low AFI (< 5.0 cm) and low MVP (< 2.0 cm) on latency, amnionitis, neonatal morbidity, and composite morbidity (any of death, RDS, early sepsis, stage 2-3 necrotizing enterocolitis, and/or grade 3-4 intraventricular hemorrhage) was assessed. Logistic regression controlled for confounding factors including gestational age at randomization, GBS carriage, and antibiotic study group. Low AFI and low MVP were identified in 67.2% and 46.9% of women, respectively. Delivery occurred by 48 hours, 1 and 2 weeks in 32.4%, 63.5% and 81.7% of pregnancies, respectively. Both low AFI and low MVP were associated with shorter latency (P < .001), and with a higher rate of delivery at 48 hours, 1, and 2 weeks (P = .02 for each). However, neither test offered significant additional predictive value over the risk in the total population. Low AFI and low MVP were not associated with increased amnionitis. After controlling for other factors, both low MVP and low AFI were associated with shorter latency (P < or = .002), increased composite morbidity (P = .03), and increased RDS (P < or = .01), but not with increased neonatal sepsis (P = .85) or pneumonia (P = .53). Alternatively, after controlling for fluid volume, gestational age, and GBS carriage, the antibiotic study group had longer latency, and suffered less common primary outcomes and neonatal sepsis. Oligohydramnios should not be a consideration in determining which women will be candidates for expectant management or antibiotic treatment when it is identified at initial assessment of preterm PROM remote from term.

P09.10: Fetoscopic laser ablation of the placental vascular equator in twin–twin transfusion syndrome

tissue. The laser ablation was followed by an amnioreduction to a maximum vertical pocket of 5 cms in the recipient sac. Results: All patients for whom laser was chosen as therapy are included in the analysis. To date we have 37 completed cases, 29 of whom have delivered. One patient required two laser procedures and in one patient laser was not performed, as amniotic fluid was too turbid secondary to a prior amniocentesis. Mean gestational age (GA) at therapy was 21.9 weeks and mean GA at delivery was 33.2 weeks. Survival data is as follows:

P12.06: Assessment of cervical length prior to laser treatment for twin–twin transfusion syndrome

The purpose of this study was to assess the prognostic value of cervical length (CL) in twin–twin transfusion syndrome (TTTS) patients treated with laser therapy (selective laser photocoagulation of communicating vessels, SLPCV). The study period ranged between January 2000 and July 2003. TTTS was diagnosed if the maximum vertical pocket (MVP) measured ≥ 8 cm in one sac and ≤ 2 cm in the other. CL was assessed pre-op by transabdominal and/or transvaginal ultrasound. Preterm labor symptoms (PTL) were assigned if patients had regular uterine contractions that required tocolytic therapy. Data was recorded prospectively. Statistical significance was determined if p < 0.05. A total of 233 patients with TTTS underwent SLPCV during the study period. The mean preop CL was 4.04 ± .7 cm. CL was indirectly correlated with the MVP in the recipient twin's sac (r = − .139, p <.05), but was not correlated with gestational age at delivery (GAdel) nor survival. Patients with PTL (n = 32) had a shorter CL compared to asymptomatic patients (3.53 ± .81 vs. 4.05 ± .71 cm, p <.05), but this was not clinically significant in terms of GAdel nor survival outcomes. Twenty-two patients (9.4%) had a preoperative CL ≤ 2.5 cm, of which 19 underwent cervical cerclage. There was no difference in GAdel [30.4 ± 5.6 (95% CI 27.9–33.0) vs. 31.7 ± 5.1 (95% CI 31.0–32.5) weeks, p = .27] nor at least one survivor (86.6 vs. 88.7%, p = .73) between patients with preoperative CL ≤ 2.5 cm versus those with CL > 2.5 cm. This study showed no correlation between CL and perinatal outcome in TTTS patients treated with SLPCV. The results must be viewed with caution, as the subjects represent those patients stable enough to undergo SLPCV, and all patients with a CL < 2.5 cm were requested to undergo a cervical cerclage. Further analysis is needed to account for selection bias.

The cocoon sign: a potential sonographic pitfall in the diagnosis of twin - twin transfusion syndrome.

To investigate the frequency and clinical importance of the cocoon sign in twin-twin transfusion syndrome (TTTS). Charts and ultrasound images of all pregnancies with TTTS that underwent selective laser photocoagulation of communicating vessels at our institution over a 1-year period were retrospectively reviewed for a cocoon sign. TTTS had been diagnosed and prospectively staged if monochorionicity was suspected and the maximum vertical pocket (MVP) of amniotic fluid in one gestational sac was >/=8 cm, while the MVP in the other gestational sac was </=2 cm. The cocoon sign was diagnosed when there was an ultrasound finding of a donor twin with severe oligohydramnios enveloped by dividing membranes and connected to the uterine wall by a laminar stalk of these membranes. The cocoon sign was noted in 9/58 (15.5%) cases. There were no differences in gestational age and stage of TTTS upon presentation, gestational age at delivery or number of neonatal survivors between the groups of TTTS cases with and those without a cocoon sign. One patient in the cocoon group had been misdiagnosed because the donor twin's MVP was measured from the donor's tethered membranes to the posterior wall of the uterus within the recipient's sac. The cocoon sign is present in at least 15% of patients with TTTS. Its recognition is important to avoid misdiagnosis of TTTS. The practical implications and potential complications of this sonographic sign are discussed.

Stage-based treatment of twin-twin transfusion syndrome

Objective: The purpose of this study was to compare the outcomes of patients with twin-twin transfusion syndrome who were treated with either serial amniocentesis or selective laser photocoagulation of communicating vessels according to disease severity (stage). Study Design: Centers that were experienced in the treatment of twin-twin transfusion syndrome were invited to share stage-based perinatal outcome data. All patients met basic standard sonographic criteria for twin-twin transfusion syndrome (polyhydramnios maximum vertical pocket, ≥8 cm; oligohydramnios maximum vertical pocket, ≤2 cm). Gestational age at first treatment was <27 weeks of gestation. Results: Three centers submitted stage-based data, for a total of 173 patients (serial amniocentesis, 78 patients from all 3 centers) and 95 selective laser photocoagulation of communicating vessels (1 center). The distribution of patients by stage was similar in the two groups. Successful pregnancy outcome (at least 1 surviving infant) was correlated inversely with stage in the serial amniocentesis but not in the selective laser photocoagulation of communicating vessels group and was significantly lower in the serial amniocentesis (66.7%) than in the selective laser photocoagulation of communicating vessels group (83.2%). Neurologic morbidity was related directly to stage in the serial amniocentesis group but not in the selective laser photocoagulation of communicating vessels group and was significantly higher in the serial amniocentesis (24.4%) than in the selective laser photocoagulation of communicating vessels (4.2%) group. Intact neurologic survival (at least 1 surviving infant without neurologic morbidity) was significantly lower in the serial amniocentesis group than in the selective laser photocoagulation of communicating vessel group (51.3% vs 78.9%), particularly in stage III and stage IV (23.5% vs 72.7% in stage IV). Patients who were treated with selective laser photocoagulation of communicating vessels were 2.4 times more likely to have at least one survivor than those treated with serial amniocentesis. Conclusion: Our study suggests a relationship between perinatal morbidity and mortality rates and stage in serial amniocentesis but not in selective laser photocoagulation of communicating vessel-treated twin-twin transfusion syndrome patients. These findings could be used to tailor the treatment of twin-twin transfusion syndrome. A clinical trial to confirm these results is being organized by our research groups. (Am J Obstet Gynecol 2003;188:1333-40.)

An aggressive interventional protocol for early midtrimester premature rupture of the membranes using gelatin sponge for cervical plugging

Objective: This study was performed to evaluate a protocol for treatment of previable premature rupture of membranes (PROM) that includes the administration of gelatin sponge to retard the loss of fluid from the amniotic cavity. Study Design: Women with PROM at ≤21 weeks' gestation with a structurally normal singleton; having no evidence of infection, active bleeding, or labor; and a maximum vertical fluid pocket of less than 1.5 cm were candidates. Interventions included hospital admission, amnioinfusion, cervical cerclage, administration of gelatin sponge (Gelfoam) into the amniotic cavity, antibiotic administration, and perioperative tocolysis. Weekly assessment of fluid status was performed and if oligohydramnios returned, patients were offered repeat amnioinfusion. Results: Fifteen women with PROM at 17.9 ± 2.2 weeks' gestation (range 13-21 weeks) underwent this protocol. Spontaneous PROM was diagnosed in 14 patients and one had iatrogenic PROM after fetoscopy. Eight fetuses reached a viable gestational age (≥24 weeks, 53%), with six of these newborn infants surviving to hospital discharge (30%) and two suffering intrauterine death. The average gestational age of delivery for survivors was 31.8 ± 4.3 weeks, range 25 to 36 weeks. Talipes equivarus was observed in three survivors (50%). Bilateral hip dysplasia and torticollis were also diagnosed in two infants. Respiratory distress syndrome was diagnosed in all cases delivered at less than 32 weeks but was not observed thereafter. No adverse sequelae have been attributed to gelatin sponge exposure. Conclusion: The observed survival rate with this interventional approach in a population at highest risk for pregnancy loss justifies further study of this treatment strategy. This protocol may not reduce the rate of musculoskeletal abnormalities. (Am J Obstet Gynecol 2002;187:1143-6.)

Amnioreduction versus septostomy in twin-twin transfusion syndrome

Objective: The purpose of this study was to compare treatment outcomes in pregnancies affected with twin-twin transfusion syndrome. Treatment consisted of serial amnioreduction or septostomy. Study Design: A retrospective review of patients who were diagnosed with twin-twin transfusion syndrome from June 1998 to June 2000 was conducted. Diagnosis was based on polyhydramnios (maximal vertical pocket, >8 cm) in conjunction with an enlarged fetal bladder, oligohydramnios (maximal vertical pocket, <2 cm) with nonvisualization of the fetal bladder, and documentation of a single placenta. Data evaluated were gestational age at enrollment and delivery, prolongation of gestation, and number of surviving fetuses by treatment modality. Results: There were 7 patients in the amnioreduction group and 7 patients in the septostomy group. The mean gestational age at enrollment for amnioreduction was 21.0 weeks and for septostomy was 18.0 weeks (P =.01). There were 67% 2-twin survivors in the septostomy group (P = not significant), but an overall equal number of survivors (78%) in both treatment groups. The rate of no surviving twins was equal (14%) in both groups. Pregnancy was prolonged an average of 12 weeks in the septostomy group and 6.5 weeks in the amnioreduction group (P =.007). The average gestational age at delivery was 27.5 weeks for the amnioreduction group and 30.0 weeks for the septostomy group (P =.08). Conclusion: The prolongation of pregnancy from diagnosis to delivery was statistically significant for septostomy when compared to amnioreduction. Although not statistically significant, there appears to be a trend toward increasing gestational age at delivery with septostomy. Further randomized studies are warranted for septostomy as a treatment modality in twin-twin transfusion syndrome. (Am J Obstet Gynecol 2001;185:1044-7.)

Selective Versus Non-Selective Laser Photocoagulation of Placental Vessels in Twin-to-Twin Transfusion Syndrome

Objective We have recently described a surgical technique for the treatment of twin-to-twin transfusion syndrome (TTTS) that allows precise identification of vascular anastomoses (selective laser photocoagulation of communicating vessels, or S-LPCV). The purpose of this study was to compare S-LPCV with the previous non-selective technique (NS-LPCV) that targeted all vessels crossing the dividing membrane. Materials and Methods Patients with TTTS were treated with NS-LPCV from May 1994 to June 1997 and with S-LPCV from July 1997 to December 1999. TTTS was defined as polyhydramnios of ≥8 cm maximum vertical pocket (MVP) in the recipient twin and oligohydramnios of ≤2 cm MVP in the donor twin. Outcome was measured as survival per number of pregnancies and per number of fetuses together with limited morbidity data. Results NS-LPCV was used in 18 patients and 74 were treated with S-LPCV. Three patients interrupted their pregnancies electively after surgery (S-LPCV) and were removed from further analysis. Survival of at least one fetus was higher in S-LPCV (83.1%) than in NS-LPCV (61.1%) (P = 0.04), mostly due to a lower rate of dual intra-uterine fetal demise in S-LPCV (5.6%) than in NS-LPCV (22%) (P = 0.05). There were more hydropic fetuses in the NS-LPCV group (27%) than in the S-LPCV group (5.4%), but this difference did not account for the results. There was no difference in the survival per number of fetuses between the two groups. Conclusions S-LPCV represents an important evolution in the surgical treatment of TTTS. The use of this technique by all centers should allow better comparison of fetal survival and morbidity rates. S-LPCV should be the standard technique in trials comparing amniocentesis versus laser for the treatment of severe TTTS. Copyright © 2000 International Society of Ultrasound in Obstetrics and Gynecology

Staging of Twin-Twin Transfusion Syndrome

The purpose of this study was to evaluate the prognostic value of sonographic and clinical parameters to develop a staging classification of twin-twin transfusion syndrome (TTTS). Severe TTTS was defined as the presence of polyhydramnios (maximum vertical pocket of > or = 8 cm) and oligohydramnios (maximum vertical pocket of < or = 2 cm). Nonvisualization of the bladder in the donor twin (-BDT) and absence of presence of hydrops was also noted. The middle cerebral artery, umbilical artery, ductus venosus, and umbilical vein in both fetuses were assessed with pulsed Doppler. Critically abnormal Doppler studies (CADs) were defined as absent/reverse end-diastolic velocity in the umbilical artery, reverse flow in the ductus venosus, or pulsatile flow in the umbilical vein. TTTS was staged as follows: stage I, BDT still visible; stage II, BDT no longer visible, no CADs; stage III, CADs; stage IV, hydrops; stage V, demise of one or both twins. Laser photocoagulation of communicating vessels (LPCV) or umbilical cord ligation was performed depending on the severity of the condition. The study was approved by the Institutional Review Board of St. Joseph's Hospital in Tampa and by the Fetal Therapy Board at Hutzel Hospital, Detroit, and all patients gave informed consent. A total of 80 of 108 referred patients met criteria for surgery, but only 65 were treated surgically: 48 with LPCV and 17 with umbilical cord ligation. Complete Doppler data were obtainable in 41 of 48 LPCV patients. Survival rates by stage for one or two fetuses were statistically different (chi-squared analysis = 12.9, df = 6, p = 0.044). Neither percent size discordance nor gestational age at diagnosis were predictive of outcome. Staging of TTTS using the proposed criteria has prognostic significance. This staging system may allow comparison of outcome data of TTTS with different treatment modalities.

Amniotic fluid volume and onset of labor in physiological pregnancy.

We measure, by means of ultrasound, the amniotic fluid volume (expressed as maximal vertical pocket or MVP) in 646 normal pregnancies at the 39th gestational week. Our aim is to evaluate the possible correlation between MVP and onset of the labor. In a 2-week follow-up, the onset of the labor is considered the "event" variable in a time-dependent statistical analysis. Univariate analysis (Kaplan-Meier algorithm) describes a different trend in predicting the onset of labor when a stratification of MVP < 50 and > or = 50 mm was performed (chi2 = 7.91 p < 0.0049 with 1 df, Breslow-Gehan test). The first category was comprised of 496 fetuses with a median (min-max) MVP of 39 mm (25-49), the second category of 150 fetuses with a MVP of 57 mm (50-100). The results suggest that lower levels of MVP are associated to a higher percentage of the onset of labor. Furthermore, in our measurement, performed at the 39th gestational week, the correlation with the events is higher within the 40th gestational week. In fact, at 7 days from the amniotic fluid measurement, the onset of labor and the subsequent delivery is observed in 80.65 and 73.00% of the cases when they are stratified according to MVP < 50 and > or = 50 mm. At the end of the follow-up, instead, the percentage of "events" is similar, 88.10 and 86.67%, respectively. Adjustment for covariates (Cox analysis), as well as maternal age, neonatal weight, and obstetrics history, show an odds ratio (95% C.I.) of 2.08 (1.61-2.69) for MVP, using the above cutoff level. In physiological pregnancy, lower levels of amniotic fluid at term correlated to a higher probability of the onset of labor.

Isolated hydramnios at term gestation and the occurrence of peripartum complications

Objective: To determine if hydramnios at term gestation is an independent risk factor for poor pregnancy outcome and perinatal death. Study design: The study population consisted of 60 702 patients with singleton gestation who delivered at term (>37 weeks). Patients were classified into two groups according to the presence or the absence of hydramnios. Hydramnios was diagnosed in the presence of an amniotic fluid index greater than 25 cm or of a maximum vertical pocket of amniotic fluid of at least 8 cm or by subjective assessment. Logistic regression analysis was used to evaluate the unique contribution of hydramnios to fetal death and to perinatal and maternal morbidity. Results: The prevalence of hydramnios was 1211/60 702 (2%). Patients with hydramnios had a higher incidence of complications than those with a normal amount of amniotic fluid: cesarean section (22.8 vs. 8.5%, P<0.01), antepartum death (0.6 vs. 0.2%, P<0.005), postpartum death (2.8 vs. 0.4%, P<0.01), abruptio placenta (0.9 vs. 0.3%, P<0.001), fetal distress (6.1 vs. 3.65%, P<0.0015), meconium-stained amniotic fluid (17.8 vs. 15%, P<0.001), low Apgar score at 5 min (2.95 vs. 1%, P<0.01), malpresentation (6.8 vs. 2.9%, P<0.01), clinical chorioamnionitis (0.3 vs. 0.1%, P<0.05), prolapse of cord (2.2 vs. 0.3%, P<0.01), and large-for-gestational-age infant (LGA) (23.8 vs. 8.1%, P<0.01). When adjusted for confounding variables, the presence of hydramnios remained strongly associated with perinatal mortality (odds ratio 5.5 (95% CI 3.2–9.3)) and neonatal and maternal morbidity (odds ratios 2.1 (CI 1.1–3.7) and 2.3 (CI 1.9–2.7), respectively). Conclusions: (1) Hydramnios at term is an independent risk factor for perinatal death; (2) Fetal surveillance is warranted in patients with hydramnios even in the absence of other known risk factors for adverse pregnancy outcome.

Effects of maternal smoking on amniotic fluid volume and fetal urine output.

The purpose of this study was to assess the effects of maternal smoking on amniotic fluid volume and fetal urine output. Seventeen women (10 smokers and 7 non-smokers) were serially assessed through pregnancy. Smoking status was determined by self-report and carbon monoxide manometry. Amniotic fluid volume was assessed by sonographically measuring the maximum vertical pocket, the amniotic fluid index, and the two dimensions of the largest pockets. The coronal area formula was used to calculate bladder volume at 5-minute intervals for 20 minutes. Urine output was calculated from serial measurements of bladder volume. The mean gestational age of the first session was 26.8 (2.7) weeks, of the second session 32.4 (1.6) weeks, and of the last session 36.9 (2.1) weeks. In the univariate analysis there were no differences between smokers and non-smokers at any of the three visits for gestational age, fetal weight, maximum vertical pocket, amniotic fluid index, two-dimensional maximum pocket, and urine output. In the regression model, while controlling for gestational age, smoking status could not predict significant differences in any parameter. Maternal smoking does not appear to affect either amniotic fluid volume or fetal urine output.

Daily antenatal testing in women with severe preeclampsia

OBJECTIVE: Our purpose was to determine whether daily antenatal testing in the expectant management of severe preeclampsia remote from term prevents stillbirth or neonatal compromise at birth. STUDY DESIGN: We reviewed the medical records of 68 women with severe preeclampsia remote from term who underwent expectant management with daily fetal testing until delivery. On admission each patient had reassuring nonstress testing (absence of persistent severe variable or late decelerations), biophysical profile (≥6), and amniotic fluid volume (≥2 cm maximal vertical pocket before 32 weeks or amniotic fluid index ≥5 after 32 weeks). RESULTS: There were no stillbirths. Twenty-one patients (31%) had nonreassuring testing necessitating delivery. Two neonatal deaths occurred as a result of complications of prematurity. There were no statistical differences in the cord arterial pH ( p = 0.93) or in the 1- and 5-minute Apgar scores ( p = 0.18 and p = 0.88, respectively) between those with normal and abnormal antenatal testing. CONCLUSIONS: Because optimizing neonatal outcome is the only reason to prolong pregnancy in women with severe preeclampsia, confirmation of fetal well-being is mandatory. Because neither stillbirths nor fetal compromise at birth occurred in patients undergoing daily antenatal testing, we recommend daily testing in patients with severe preeclampsia managed expectantly.

Amniotic Fluid Assessment

Amniotic fluid assessment is a tool for the evaluation of fetal well-being. Because of the uterine cavity being irregular direct evaluation is difficult and subsequently, indirect techniques have been utilized. The three ultrasound techniques currently used for the evaluation of amniotic fluid include 1) maximum vertical pocket, 2) subjective assessment, and 3) amniotic fluid index. A review of these techniques show that the amniotic fluid index technique is valid, and the subjective technique and the amniotic fluid index technique appear to have a good inter- and intraobserver variability. All three techniques have been shown to predict peripartum morbidity and mortality when they define decreased amniotic fluid. Amniotic fluid volume is a weak predictor of morbidity and should be used in conjunction with other fetal biophysical variables to predict perinatal outcome.

Intraobserver reliability of amniotic fluid volume estimation by two techniques: amniotic fluid index vs. maximum vertical pocket.

We evaluated the intraobserver agreement of two techniques of amniotic fluid assessment: amniotic fluid index and maximum vertical pocket. The intraobserver variation of the two forms of amniotic fluid assessment was obtained by evaluating amniotic fluid prior to fetal biometry (post-biometry value) and after fetal biometry (pre-biometry value). Between January and June 1990, this amniotic fluid assessment was by the maximum vertical pocket technique, and between July and December 1990, by the amniotic fluid index technique. In the Grace Maternity Hospital, Vancouver, 352 subjects were evaluated by the maximum vertical pocket technique, and 184 subjects by the amniotic fluid index technique.Amniotic fluid volumes were categorized into normal, oligohydramnios, and polyhydramnios, and the pre-biometry and post-biometry categories of amniotic fluid index and maximum vertical pocket techniques were compared by kappa statistics. The maximum vertical pocket technique showed poor intraobserver agreement (kappa = 0.33), but the amniotic fluid index technique showed good agreement (kappa = 0.72). With the poor reproducibility of the maximum vertical pocket technique in assessing extremes of amniotic fluid volume, it is difficult to support its use as a component of fetal assessment.

Abnormal second-trimester ultrasounds: an indication for karyotype.

There are limited data on the risks of aneuploidy for normal-appearing fetuses with amniotic fluid volume (AFV) abnormalities. The purpose of this study was to determine the relative risks of aneuploidy associated with second-trimester abnormal AFVs and fetal structural anomalies in a cohort of 2,823 singleton, viable fetuses. Compared to gravidas younger than 35 with normal ultrasounds, normal fetuses had an increased incidence of aneuploidy with polyhydramnios, increased AFV, i.e. subjectively increased but normal by maximum vertical pocket (MVP) and/or amniotic fluid index (AFI), oligohydramnios, and decreased AFV, i.e. subjectively decreased but normal by MVP and/or AFI. These included: increased AFV [odds ratio = 12.9, 95% confidence interval (CI) = 4.1-39.4], polyhydramnios (odds ratio = 4.6, CI = 0.6-36.8), and decreased AFV (odds ratio = 3.8, CI = 1.1-13.1). There were no aneuploidies among the 28 normal fetuses with oligohydramnios. Anomalous fetuses had a markedly increased incidence of aneuploidy (odds ratio = 13.4, CI = 7.2-24.9). We conclude that fetal structural anomalies as well as isolated AFV abnormalities were associated with an increased risk for aneuploidy.