Effectiveness of preventive B-Lynch sutures in patients at a high risk of postpartum hemorrhage.

AIM: We aimed to evaluate the clinical outcomes and adverse events of preventive B-Lynch suture performed during cesarean section in patients at a high risk of postpartum hemorrhage. METHODS: This retrospective observational study included patients who underwent a cesarean section and the B-Lynch suture at a tertiary perinatal medical center between January 2019 and May 2021. The B-Lynch sutures were placed preventively before excessive blood loss occurred in patients with uterine atony, placental position abnormality (placenta previa and low-lying placenta), placenta accreta, thrombocytopenia, coagulopathy, and other risk factors of bleeding. Partial compression sutures for bleeding points and vaginal gauze packing were placed if required. RESULTS: The B-Lynch suture was performed in 38 patients, and hysterectomy was avoided in all patients. Only one patient required intrauterine balloon tamponade as an additional treatment 5 days after the cesarean section. No apparent postoperative bleeding occurred within 2 h after the cesarean section in 35 patients (92%), and blood transfusion was avoided in 14 patients (37%). Thirty-three adverse events occurred in 23 patients; these included an inflammatory response, hematomas, retained products of conception, and ileus in one, two, and two patients, respectively. In most cases, the events were not severe and were unrelated to the procedure. In one patient, a second-look operation was performed and no complications were observed in the uterus and abdominal cavity. CONCLUSIONS: Preventive B-Lynch suture seemed effective and safe after a short-term observation. When excessive bleeding is expected during a cesarean section, an early introduction of this procedure is recommended.

Long-Term Outcomes of 92 Cases of Fetal Hydrothorax Including Thoracoamniotic Shunting.

BACKGROUND: There have been no previous reports on the postnatal course, especially long-term outcomes, of fetal hydrothorax patients, including those treated with thoracoamniotic shunting (TAS) using a double-basket catheter.The outcomes of cases from a single center are reported. METHODS: Cases of fetal hydrothorax managed at our center between 2005 and 2015 were enrolled retrospectively. TAS was performed if indicated. Long-term outcomes such as cerebral palsy, developmental disabilities, and others were analyzed. RESULTS: Ninety-two cases of fetal hydrothorax were included. The causes were primary chylothorax, transient abnormal myelopoiesis, cardiac disease, pulmonary sequestration, mediastinal neoplasm, and infection. TAS was performed in 36 cases. Early neonatal death occurred in 19 cases. The 28-day survival rates for all cases and for TAS cases were 70% (48/69) and 72% (26/36), respectively. Of the cases that underwent TAS, one was treated with home oxygen therapy, one was diagnosed with cerebral palsy and severe intellectual disability, and five were diagnosed with mild or moderate developmental disabilities. CONCLUSIONS: The results showed that the survival rate and long-term outcomes of cases with hydrothorax have improved as TAS has become more prevalent. The reasons for these results need to be elucidated, and efforts are needed to further improve outcomes.

Case of resuscitation from cardiac failure by intrauterine transfusion after single fetal death in monochorionic twin pregnancy.

In case of a single fetal death in monochorionic twin pregnancy, the surviving fetus is thought to become hypovolemic. However, there is no report of any evidence of fetal circulatory insufficiency in such cases. We present a case of a single fetal death in a monochorionic twin pregnancy with type III selective intrauterine growth restriction that involved low fractional shortening, high myocardial performance index, elevated pulsatility index in the middle cerebral artery and fetal ascites. After immediate intrauterine transfusion, each parameter improved promptly. The surviving baby grew up without cardiac and neurological complications. To the best of our knowledge, this is the first report on transient circulatory insufficiency and decreased cardiac function in the surviving fetus.

Amnioinfusion for variable decelerations caused by umbilical cord compression without oligohydramnios but with the sandwich sign as an early marker of deterioration.

We report prophylactic amnioinfusion (AI) for variable decelerations in umbilical cord compression without oligohydramnios as an early sign of deterioration. We performed a transabdominal AI in cases without oligohydramnios using the ultrasonography findings of umbilical cord compression (i.e. sandwich sign [SWS]) and variable decelerations (VD) in a foetal heart rate. Thirteen cases and 21 AIs were analysed. Nine (69%) cases were of a foetal growth restriction and 4 (31%) had umbilical hyper-coiled cords. VD frequency (p < .0001), umbilical artery pulsatility index (PI) (p < .01) and ductus venous PI (0.66 vs. 0.48; p < .05) significantly decreased, and an umbilical venous (UV) flow volume (121 vs. 197 ml/min/kg; p < .05) significantly increased after AI. The umbilical artery diastolic blood flow abnormalities and UV pulsation improved. In conclusion, AI improves the umbilical cord compression even without oligohydramnios. The SWS is an important marker of deterioration to severe oligohydramnios and latent foetal damage. IMPACT STATEMENT What is already known on this subject? Antepartum variable decelerations due to umbilical cord compression are significantly associated with the deceleration in labour. In particular, foetal hypoxia leads to other adverse events such as foetal distress, hypoxic-ischemic encephalopathy, and pulmonary arterial hypertension after birth. Amnioinfusion has been shown to be effective in patients who also have oligohydramnios. What do the results of this study add? Amnioinfusion may be effective in the cases with ultrasonography findings of umbilical cord compression (i.e. sandwich sign) and in cases with variable decelerations in foetal heart rate, but without oligohydramnios. What are the implications of these findings for clinical practice and/or further research? Amnioinfusion may be helpful to prevent adverse events including oligohydramnios and anhydroamnios.

Hypercoiled cord can cause a reversible abnormal Doppler in ductus venosus in cases of fetal growth restriction.

AIM: Although an absent or reversed a-wave in ductus venosus (DV-RAV) is reported to be the terminal finding of fetal growth restriction (FGR), we have seen DV-RAV that disappears within a short span of time in some FGR cases with a hypercoiled cord. The purpose of this study was to investigate the relationship between hypercoiled cord and reversible DV-RAV in FGR. METHODS: This was a retrospective study of 499 FGR cases, including 14 with DV-RAV. Transabdominal amnioinfusion (AI) was performed when oligohydramnios was severe (maximum vertical pocket <2 cm) and/or variable deceleration was detected. DV-RAV that disappeared quickly was defined as 'temporary DV-RAV'. DV-RAV that continued until delivery or fetal death (FD) was defined as 'persistent DV-RAV'. A hypercoiled cord was defined as one with an umbilical coiling index >0.6 antenatally or >0.3 postnatally. Clinical characteristics and clinical courses of the two types of DV-RAV were compared. RESULTS: DV-RAV disappeared after AI in all five cases in which temporary DV-RAV was identified. The incidence of a hypercoiled cord was significantly higher among temporary DV-RAV cases (100%) than among persistent DV-RAV cases (14.3%; P = 0.015). The time from detection of DV-RAV to delivery or FD was significantly longer among temporary DV-RAV cases (4.5 weeks) than among persistent DV-RAV cases (0.7 weeks; P = 0.027). CONCLUSION: Temporary DV-RAV is suspected to be related to the combination of a hypercoiled cord and oligohydramnios. DV-RAV may not be always be a terminal finding in FGR with a hypercoiled cord.

Can measurement of maternal anti-cytomegalovirus immunoglobulin-M antibody levels be used to screen for cytomegalovirus infection in embryos and fetuses?

AIMS: Our study aims to estimate whether measurement of maternal anti-cytomegalovirus immunoglobulin-M antibody (CMV-IgM) levels are useful as a screening method for achieving early detection of congenital CMV infection. MATERIAL AND METHODS: Levels of maternal CMV-IgM were measured by enzyme immunoassay in all (n =2865) pregnant women who visited our hospital in the first trimester during the period from January 2005 to December 2009. RESULTS: Among them, 21 individuals (0.73%) had a CMV-IgM titer of ≥0.08 and were judged to be CMV-IgM-positive. Informed consent was obtained from all 21 individuals to perform the confirmation test that quantifies the levels of cytomegalovirus DNA (CMV-DNA) in amniotic fluid by real-time polymerase chain reaction. However, only one (0.03%) of the 21 individuals was CMV-DNA-positive (CMV-DNA concentration, 1.0 × 10(4) copies/ml). CONCLUSION: In order to detect congenital CMV infection in early pregnancy, it is considered appropriate to use ultrasound for close examination of embryo or fetal symptoms indicative of CMV instead of performing serological screening based on CMV-IgM.

Analysis about the influence on the fetus infected with parvovirus B19 using amniotic erythropoietin and troponin-T.

OBJECTIVE: We tried to identify the influence on the fetus infected with parvovirus B19 (PB19) and retrospectively analyze the severity of fetal infection. METHODS: Twenty pregnant women who developed maternal PB19 infection were included in this study. A total of 20 amniotic fluid samples were collected for measurement of PB19-DNA, erythropoietin (Epo) and troponin-T (TnT). RESULTS: Of the 5 fetuses with hydrops, 2 were rescued by fetal therapy. Significant differences between groups were found for Epo and TnT: Epo 107.1 ± 45.3 mU/ml and TnT 0.040 ± 0.028 ng/ml (mean ± standard deviation) for the symptomatic fetus group; and Epo 18.9 ± 13.7 mU/ml and TnT 0.008 ± 0.014 ng/ml for the asymptomatic fetus group (p = 0.043 for both variables). Setting Epo ≥50 mU/ml as the predictor of disease onset resulted in an Odds ratio of 56.0, with a 95 % confidence interval of 7.68-1,108.76. CONCLUSION: The study has determined an amniotic Epo level of ≥50 mU/ml as a factor of the influence on the fetus infected with PB19. The measurement of amniotic Epo level combined with amniotic TnT level is effective for determining the severity of fetal hypoxia.

Magnetic resonance imaging pelvimetric measurements as predictors for emergent cesarean delivery in obstructed labor.

Objective: This study aimed to investigate the usefulness of various magnetic resonance imaging (MRI) pelvimetric parameters for predicting emergent cesarean delivery due to obstructed labor. Study design: This was a prospective observational study. MRI pelvimetry was performed in cases of a clinically suspected maternal narrow pelvis, maternal short stature, fetal overgrowth, and abnormal placental position. MRI pelvimetry was performed at 34.7 ± 4.2 gestational weeks using a 1.5 T MRI system. The pelvic inlet angle, pelvic inclination, obstetric conjugate, sacral outlet diameter (SOD), and coccygeal pelvic outlet were measured in the sagittal section. The interspinous diameter and intertuberous diameter were measured in coronal sections. Fetal anomalies, cesarean deliveries before the onset of labor, and non-reassuring fetal status were excluded from the analysis. Results: MRI pelvimetry was performed in 154 patients. After excluding 76 cases, including 19 cases of absolute cephalopelvic disproportion, 78 cases of trial of labor were included. Of these, 63 were vaginal deliveries and 15 were emergent cesarean deliveries due to obstructed labor. The cut-off value for body mass index (BMI) was 22.2, with an area under the curve (AUC) of 0.69, for predicting obstructed labor. The cut-off value for the SOD was 10.7 cm with an AUC of 0.69. BMI alone had a sensitivity of 80%, specificity of 66%, positive predictive value (PPV) of 36%, and negative predictive value (NPV) of 93%. When BMI and SOD were combined, sensitivity was 53%, specificity was 90%, PPV was 57%, and NPV was 89%. The odds ratio for emergent cesarean delivery was 5.42 (95% confidence interval 1.06-27.6, p = 0.041) if the SOD was less than the cut-off value in the binomial logistic regression analysis in cases with an BMI > 22. Conclusion: We confirmed that MRI pelvimetry was a reliable tool for better patient selection for obstructed labor. The SOD was the best predictor of obstructed labor, with a cut-off value of 10.7 cm for women with a low BMI.

Umbilical cord length affects the efficacy of amnioinfusion for repetitive variable deceleration during labor.

OBJECTIVES: Although amnioinfusion (AI) for repetitive variable deceleration has been reported to reduce the frequency of variable deceleration and cesarean section (CS) rate, CS is sometimes unavoidable even after therapeutic AI. The purpose of this study was to investigate prenatal factors related to the efficacy of therapeutic AI during labor. METHODS: This retrospective study investigated 80 singleton pregnancies that underwent transcervical therapeutic AI for repetitive variable deceleration during labor. AI was performed with 500 mL of warmed saline through an intrauterine pressure catheter by gravity infusion. Prenatal factors related to emergency CS for fetal distress even after therapeutic AI were investigated. RESULTS: Emergency CS was performed for 12 of the 80 cases due to fetal distress. Z-score for umbilical cord length was significantly smaller in the CS group (-0.68 SD) than in the vaginal delivery group (0.15 SD, p < .001). No CSs were performed in cases with Z-score for umbilical cord length >-0.05 SD. No significant differences between CS and vaginal delivery groups were seen in gestational age at delivery, cervical dilatation at AI, birth weight, Z-score of birth weight, incidence of the nuchal cord or incidence of abnormal umbilical cord insertion. CONCLUSIONS: Therapeutic AI for repetitive variable deceleration was considered useful, in many cases avoiding emergency CS. Short umbilical cord length (lower Z-score) was related to emergency CS after therapeutic AI for repetitive variable deceleration. Umbilical cord length may offer an important factor for assessing the risk of fetal distress that is difficult to avoid, if methods to accurately determine umbilical cord length can be developed.

Transabdominal amnioinfusion: An evaluation of its adverse events.

OBJECTIVE: Transabdominal amnioinfusion is beneficial in oligohydramnios, which has high fetal mortality and does not improve with observation alone. However, there are few reports on the maternal adverse events of transabdominal amnioinfusion. This study aimed to evaluate the adverse events of amniocentesis with transabdominal amnioinfusion. STUDY DESIGN: This study is a retrospective cohort study at a single tertiary perinatal center in Japan. A total of 313 procedures in 126 patients who underwent amniocentesis for transabdominal amnioinfusion at our tertiary perinatal institution were evaluated using the Common Terminology Criteria for Adverse Events (CTCAE). Adverse events were retrospectively examined using a 5-grade evaluation based on the CTCAE. Procedurally, a 21-23-G percutaneous transhepatic cholangiography drainage (PTCD) needle was advanced under ultrasound guidance into the amniotic fluid cavity with a gravity-fed infusion of warm saline solution. RESULTS: No maternal deaths were recorded. Only two maternal/fetal adverse events occurred, and grade 4 fetal adverse events requiring pregnancy termination were observed in seven cases. Fetal death occurred in five cases, all with severe oligohydramnios and premature rupture of the membranes. No placental abruption or bleeding occurred before or after delivery. CONCLUSION: Adverse events during transabdominal amnioinfusion were successfully analyzed using CTCAE. We also provided new terminology for evaluating adverse events during amnioinfusion. Our results may encourage obstetricians to perform amnioinfusion in difficult situations, with less concern for severe maternal or fetal adverse events.

Accumulation of fetal IgG in immunoglobulin injection into the fetal abdominal cavity is proven.

OBJECTIVE: There have been a number of studies on immunoglobulin injection into fetuses or mothers during pregnancy for the treatment of congenital cytomegalovirus infection. However, no study has examined the effect of injected immunoglobulin on fetal hemodynamics. In this study, we examined the effect of immunoglobulin injection on fetal hemodynamics by retrospectively measuring the concentrations of several igg subclasses in stored umbilical cord blood sera collected during fetal therapy. METHODS: Five patients who underwent immunoglobulin injection into the fetal abdominal cavity (IFAC) as a fetal therapy during pregnancy were included in this study. Frozen-stored umbilical venous blood samples collected from these patients during IFAC were measured for serum concentrations of each IgG subclass. RESULTS: The largest change was observed in the IgG2 concentration, with a mean increase of 221% following IFAC. The IgG4 concentration also showed a mean increase of 63%. In contrast, the concentration of IgG1, which has the strongest physiological activity of all IgG subclasses examined, only exhibited an overall mean increase of 1.4%. CONCLUSION: Our results confirmed that immunoglobulins are incorporated into the fetal circulation following IFAC.

[The impact of systematic lymphadenectomy for early-stage ovarian carcinomas].

Among the 161 cases of pT1 ovarian cancer treated at our hospital during the last 25 years, the impact of systematic lymphadenectomy was evaluated in 93 cases of the pT1N0M0 group(N0 group), 59 cases of the pT1NxM0(Nx group), and 9 cases of the pT1N1M0(N1 group). Significantly greater relapse-free survival(RFS)and overall survival(OS)were observed in 108 cases of the N0+N1 group compared to the Nx group(p=0. 006, p=0. 02). Multivariate analysis showed that systematic lymphadenectomy was a significant prognostic factor(hazard ratio 0. 473(95%CI, 0. 235-0. 951; p=0. 036). The present study suggested the systematic lymphadenectomy had a significant therapeutic effect on pT1 stage ovarian cancers.

Changes in the Intra-Amniotic Pressure following Transabdominal Amnioinfusion during Pregnancy.

OBJECTIVE: The aim of the article was to investigate the changes in intra-amniotic pressure following transabdominal amnioinfusion during pregnancy. DESIGN: This retrospective study included 19 pregnant women who underwent transabdominal amnioinfusion during pregnancy to relieve umbilical cord compression and improve the intrauterine environment or to increase the accuracy of ultrasonography. MATERIALS AND METHODS: We measured and analyzed the changes in intra-amniotic pressure, single deepest pocket, and the amniotic fluid index before and after amnioinfusion. We also determined the incidence of maternal or fetal adverse events, such as preterm premature rupture of membranes, preterm delivery, fetal death within 48 h, placental abruption, infection, hemorrhage, and peripheral organ injury. RESULTS: A total of 41 amnioinfusion procedures were performed for 19 patients. The median gestational age during the procedure was 24.3 weeks. The median volume of the injected amniotic fluid was 250 mL. The median single deepest pocket and amniotic fluid index after amnioinfusion were significantly higher than those before amnioinfusion (4.0 cm vs. 2.65 cm; p < 0.001 and 13.4 cm vs. 6.0 cm; p < 0.001). However, the median (range) intra-amniotic pressure after amnioinfusion was not significantly different compared to that before amnioinfusion (11 mm Hg vs. 11 mm Hg; p = 0.134). Maternal or fetal adverse events were not observed following amnioinfusion. CONCLUSION: Intra-amniotic pressure remained unchanged following amnioinfusion. The complications associated with increased intra-amniotic pressure are not likely to develop if the amniotic fluid index and/or single deepest pocket remains within the normal range after amnioinfusion. Studies of groups with and without complications are warranted to clarify the relationship between the intra-amniotic pressure and incidence of complications.

Successful amnioinfusion for severe fetal growth restriction with umbilical cord complications: two case reports.

BACKGROUND: There is no established treatment for fetal growth restriction during pregnancy. We report two cases that represent an example of an amnioinfusion-based management strategy for severe fetal growth restriction with umbilical cord complications. CASE PRESENTATION: We encountered two cases of fetal growth restriction with abnormal fetal Doppler velocity. In one case, fetal ultrasound revealed a hypercoiled umbilical cord with a single umbilical artery and oligohydramnios, while fetal Doppler revealed a reversed end-diastolic flow in the umbilical artery and reversed a-waves of the ductus venosus. Umbilical cord compression was confirmed at 22 weeks and 2 days of gestation, and nine amnioinfusions were performed to relieve the umbilical cord compression. A cesarean section was performed at 31 weeks and 2 days of gestation because of severe preeclampsia. The Asian infant is now a normally developed 6-month-old. In another Asian case, fetal ultrasound revealed a hypercoiled cord, while fetal Doppler revealed a reversed end-diastolic flow in the umbilical artery and intermittent reversed a-waves of the ductus venosus. Umbilical cord compression was confirmed at 24 weeks and 5 days of gestation, and seven amnioinfusions were performed. A cesarean section was performed at 31 weeks and 1 day of gestation because of nonreassuring fetal status. At the age of 1 month, the Asian infant was stable on respiratory circulation. In both cases, fetal Doppler findings improved significantly following amnioinfusions. CONCLUSIONS: Amnioinfusion is a symptomatic treatment for umbilical cord compression. However, to determine the therapeutic effect of amnioinfusion, complete resolution of the umbilical cord compression should be ascertained by ultrasonography.

Comparison of bilateral and unilateral umbilical artery diastolic blood flow abnormalities in monochorionic diamniotic twin pregnancies.

Aim: Our study aimed to clarify the prognosis of bilateral and unilateral umbilical artery end-diastolic blood flow abnormalities (BFAs) in monochorionic diamniotic twin pregnancies.Methods: Monochorionic diamniotic twin pregnancies were classified into bilateral (group 1), unilateral (group 2), and no (group 3) umbilical artery end-diastolic BFAs. After the usual obstetric management, short- and long-term prognoses were analyzed.Results: A total of 171 monochorionic diamniotic twins were analyzed and classified into group 1 (13 twins, 7.6%), 2 (12 twins, 7.0%), and 3 (146 twins, 85.4%). Gestational age at delivery was significantly lower in group 1 than in groups 2 and 3 (median, 29.3, 35.6, and 35.6 weeks, respectively; p < .01 and p < .001). The survival rate of fetuses with BFAs was significantly lower in group 1 than in group 2 (23.0% [3/13] versus 100% [12/12]; p < .001). However, the survival rate of the co-twin was not significantly different between groups 1 and 2 (84.6% [11/13] versus 100% [12/12]; p = .48). The survival rate of both fetuses was significantly lower in group 1 than in groups 2 and 3 (53.8% [14/26], 100% [24/24], and 98.6% [288/292], respectively; both p < .001). In cases with fetal therapy, the survival rate of both fetuses tended to be lower in group 1 than in group 2 (44.4% [8/18] versus 83.3% [10/12]; p = .05). In cases without fetal therapy, the gestational age at delivery tended to lower in group 1 than in group 2 and was significantly lower than in group 3 (median, 29.1, 35.6, 35.6 weeks, respectively; p = .05 and p < .05). The survival rate of fetuses with BFA tended to be lower in group 1 than in group 2 (50.0% [2/4] versus 100% [12/12]; p = .05). The survival rate of the co-twin was not significantly different between groups 1 and 2 (100% [4/4] versus 100% [12/12]; p = 1). The survival rate of both fetuses tended to be lower in group 1 than in group 2 and was significantly lower than in group 3 (75% [6/8], 100% [24/24], and 99.2% [278/280], respectively; p = .05 and p < .01).Conclusions: In monochorionic diamniotic twin pregnancies, bilateral umbilical artery end-diastolic BFAs demonstrated a poor prognosis. However, unilateral abnormalities exhibited a good prognosis similar to that in twins with normal umbilical artery blood flow. If such abnormalities are detected during a routine checkup, the umbilical artery pulse wave on the other side should be examined.

Cardiomegaly of the larger twin in monochorionic twin pregnancies warrants neonatal intensive care even without twin-to-twin transfusion syndrome.

OBJECTIVES: Some monochorionic twin pregnancies need intensive cardiac management even in the absence of twin-to-twin transfusion syndrome after birth. The purpose of this study was to investigate risk factors related to persistent hypotension requiring cardiotonic agent use among monochorionic twin pregnancies without twin-to-twin transfusion syndrome. STUDY DESIGN: This was a retrospective study of 316 monochorionic twin pregnancies without twin-to-twin transfusion syndrome (632 babies). All cases were treated in the neonatal intensive care unit. Hypotension was defined as mean arterial blood pressure below the norm for gestational age. Decreased left ventricular ejection fraction was defined as a value <60%. Dopamine, dobutamine and phosphodiesterase III inhibitor were used as cardiotonic agents for hypotension persisting even after adequate infusion. RESULTS: Among the 632 cases, 33 (5.2%) needed cardiotonic agents for persistent hypotension. The frequency of persistent hypotension with decreased left ventricular ejection fraction was significantly higher among larger twins (4.4%) than among smaller twins (0.6%, p = 0.0038). In larger twins, multivariate analysis showed that Z-score for cardiothoracic area ratio (odds ratio, 2.31; p < 0.001), tricuspid regurgitation (odds ratio, 6.34; p = 0.015) and gestational age at delivery (odds ratio, 0.66; p < 0.001) correlated with persistent hypotension. In smaller twins, univariate analysis showed gestational age at delivery, birth weight, Z-score for birth weight and Z-score for cardiothoracic area ratio of the larger twin were related to persistent hypotension. Concentration of brain natriuretic peptide in the umbilical vein in larger and smaller twins were significantly correlated (coefficient of correlation = 0.792, p < 0.001). CONCLUSIONS: In monochorionic twin pregnancies, attention needs to be given to cardiac size along with amniotic fluid and fetal growth. Both larger and smaller twins carry risks of persistent hypotension after birth. Close observation is needed, especially in cases where the larger twin displays cardiomegaly despite absence of twin-to-twin transfusion syndrome.

Relationship between higher intra-amniotic pressures in polyhydramnios and maternal symptoms.

OBJECTIVES: Our study aimed to analyze the differences in intra-amniotic pressures in patients with polyhydramnios with and without symptoms. STUDY DESIGN: We recruited patients with pregnancies in which amnioreduction was performed for polyhydramnios in the Department of Fetal-Maternal Medicine at Nagara Medical Center between April 2017 and August 2018. Amnioreduction was performed for severe polyhydramnios with maternal symptoms [symptomatic group] or polyhydramnios without maternal symptoms [asymptomatic group] such as abdominal distension, dyspnea, or threatened premature labor. We measured the intra-amniotic pressure after every 200 ml volume reduction during the amnioreduction. RESULTS: A total of 27 patients who underwent amnioreduction were classified into symptomatic (66.7%, 18/27) and asymptomatic (33.3%, 9/27) groups. Gestational age, amniotic fluid index at the time of amnioreduction, and the volume of amniotic fluid removed were not significantly different between the symptomatic and asymptomatic groups [median 32.4 weeks vs. 33.1 weeks, median 38.0 cm vs. 39.0 cm, and median 1500 ml vs. 2500 ml, respectively]. However; the intra-amniotic pressure before amnioreduction was significantly higher in the symptomatic group than in the asymptomatic group [median 15.0 mmHg (range, 10-27) vs. 10.0 mmHg (range, 6.0-13); p < 0.005]. After amnioreduction, these pressures decreased significantly to median 9.0 mmHg (range, 5.0-13) (p < 0.001) in the symptomatic and 7.0 mmHg (range, 4.0-11) (p < 0.05) in the asymptomatic group. The median intra-amniotic pressure gradually decreased and reached a plateau during the amnioreductions in both groups. CONCLUSIONS: With polyhydramnios, the intra-amniotic pressure was significantly higher in the symptomatic group than in the asymptomatic group. Therefore, uterine pressure tolerance might vary according to the individual. In addition, intra-amniotic pressure monitoring might enhance the safety during amnioreduction procedures to avoid drastic and potentially harmful pressure changes.