Polyhydramnios

Window to the Womb: Amniotic Fluid and Postnatal Outcomes

Amniotic fluid volumes are tightly regulated, and amniotic fluid derangement can indicate maternal complications or fetal abnormalities. Ultrasound estimate of amniotic fluid provides a tool to evaluate the maternal-fetal-placental interface in real-time. Oligohydramnios and polyhydramnios are associated with adverse maternal and neonatal outcomes. Oligohydramnios is associated with adverse maternal and neonatal outcomes including cesarean delivery, operative vaginal delivery, induction of labor, postpartum hemorrhage, small for gestational age neonate, intrauterine demise, neonatal death, NICU admission, and APGAR less than 7 at. 5 minutes of life Polyhydramnios is associated with adverse outcomes including cesarean delivery, induction of labor, placental abruption, shoulder dystocia, cord prolapse, postpartum hemorrhage, intrauterine fetal demise, NICU admission, neonatal death, APGAR less than 7 at 5 minutes of life, large for gestational age neonate, and respiratory distress syndrome. Therefore, Amniotic fluid should be evaluated when maternal or fetal well-being is in question.

Term Idiopathic Polyhydramnios, and Labor Complications

Background and Aim: Polyhydramnios is associated with an increased risk of various adverse pregnancy outcomes, yet complications during labor have not been sufficiently studied. We assessed the labor and perinatal outcomes of idiopathic polyhydramnios during term labor. Methods: Retrospective cohort study at a tertiary medical center between 2010 and 2014. Women with idiopathic polyhydramnios defined as an amniotic fluid index (AFI) greater than 24 cm or a deep vertical pocket (DVP) > 8 cm (cases) were compared with women with a normal AFI (5-24 cm) (controls). Statistics: Descriptive, means ± SDs, medians + IQR. Comparisons: chi-square, Fisher's exact test, Mann-Whitney Test, multivariate logistic models. Results: During the study period 11,065 women had ultrasound evaluation completed by a sonographer within two weeks of delivery. After excluding pregnancies complicated by diabetes (pre-gestational or gestational), fetal anomalies, IUFD, multifetal pregnancies, elective cesarean deliveries (CD) or missing data, we included 750 cases and 7000 controls. The degree of polyhydramnios was mild in 559 (75.0%) cases (AFI 24-30 cm or DVP 8-12 cm), moderate in 137 (18.0%) cases (30-35 cm or DVP 12-15 cm) and severe in 54 (7.0%) cases (AFI >35 cm or DVP > 15 cm). Idiopathic polyhydramnios was associated with a higher rate of CD 9.3% vs. 6.2%, p = 0.004; a higher rate of macrosomia 22.8% vs. 7.0%, p < 0.0001; and a higher rate of neonatal respiratory complications 2.0% vs. 0.8%, p = 0.0001. A multivariate regression analysis demonstrated an independent relation between polyhydramnios and higher rates of CD, aOR 1.62 (CI 1.20-2.19 p = 0.002) and composite adverse neonatal outcome aOR 1.28 (CI 1.01-1.63 p = 0.043). Severity of polyhydramnios was significantly associated with higher rates of macrosomia and CD (p for trend <0.01 in both). Conclusions: The term idiopathic polyhydramnios is independently associated with macrosomia, CD and neonatal complications. The severity of polyhydramnios is also associated with macrosomia and CD.

Diagnosis and management of Bartter syndrome: executive summary of the consensus and recommendations from the European Rare Kidney Disease Reference Network Working Group for Tubular Disorders

Bartter syndrome is a rare inherited salt-losing renal tubular disorder characterized by secondary hyperaldosteronism with hypokalemic and hypochloremic metabolic alkalosis and low to normal blood pressure. The primary pathogenic mechanism is defective salt reabsorption predominantly in the thick ascending limb of the loop of Henle. There is significant variability in the clinical expression of the disease, which is genetically heterogenous with 5 different genes described to date. Despite considerable phenotypic overlap, correlations of specific clinical characteristics with the underlying molecular defects have been demonstrated, generating gene-specific phenotypes. As with many other rare disease conditions, there is a paucity of clinical studies that could guide diagnosis and therapeutic interventions. In this expert consensus document, the authors have summarized the currently available knowledge and propose clinical indicators to assess and improve quality of care.

Novel Computerized Analytic Technique for Quantification of Amniotic Fluid Volume in Fetal MRI

OBJECTIVE. Fetal MRI is increasingly used in the evaluation of suspected congenital anomalies. Assessment of amniotic fluid volume (AFV) is crucial, but no automated quantitative technique is currently available for MRI. The purpose of this study was to develop and evaluate an analytic technique for quantifying AFV in fetal MRI. MATERIALS AND METHODS. Two MRI phantoms containing known quantities of synthetic amniotic fluid were created. A 3D steady-state free precession sequence was used for 1.5-T MRI of the phantoms and as part of a standard clinical fetal MRI protocol. Software was developed and used to retrospectively calculate AFV for the phantom and 20 clinical MRI examinations. Times to completion were recorded. AFV was also calculated by a manual hand-tracing method. To evaluate performance, paired t tests were used to compare computer-generated measurements with known phantom volumes. Intraclass correlation coefficients were calculated to assess agreement between computer-generated and manual measurements. RESULTS. There was no significant difference between computer-generated measurements of known AFV in the MRI phantoms (p > 0.11). When the software program was applied to the clinical MRI examinations, the mean time to complete AFV measurement was 110 seconds. There was excellent reliability between total AFV calculated by the two software users and by means of manual measurements (intraclass correlation coefficient, 0.995; p < 0.01). CONCLUSION. The computerized analysis evaluated in this study rapidly and accurately quantifies AFV in fetal MRI. The results are concordant with known phantom volumes and manual measurements. The technique is promising for objective MRI evaluation of AFV and has the potential to improve prenatal diagnosis and management.

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.

Risk Factors for Adverse Fetal Outcome in Hemodialysis Pregnant Women

Introduction

Pregnancy in women on dialysis is associated with a higher risk of adverse events, and the best care for this population remains to be established.

Methods

In this series, we aimed to identify factors associated with the risk of adverse fetal outcomes among 93 pregnancies in women on hemodialysis. Dialysis dose was initially assigned according to the presence of residual diuresis, body weight, and years on dialysis. Subsequent adjustments on dialysis dose were performed according to several parameters.

Results

The overall successful delivery rate was 89.2%, with a dialysis regimen of 2.6 ± 0.7 h/d, 15.4 ± 4.0 h/wk, and mean weekly standard urea Kt/V of 3.3 ± 0.6. In the logistic models, preeclampsia, lupus, primigravida, and average midweek blood urea nitrogen (BUN) level were positively related to the risk of a composite outcome of perinatal death or extreme prematurity, whereas polyhydramnios was inversely related to it. In multivariable linear regression, preeclampsia, polyhydramnios, primigravida, average midweek BUN, and residual diuresis remained significantly and independently related to fetal weight, which is a surrogate marker of fetal outcome. An average midweek BUN of 35 mg/dl was the best value for discriminating the composite outcome, and BUN ≥35 mg/dl was associated with a significant difference in a Kaplan-Meier curve (P = 0.01).

Conclusion

Our results showed that a good fetal outcome could be reached and that preeclampsia, lupus, primigravida, residual diuresis, polyhydramnios, and hemodialysis dose were important variables associated with this outcome. In addition, we suggested that a midweek BUN <35 mg/dl might be used as a target for adjusting dialysis dose until hard data were generated.

Outcome of pregnancy in women diagnosed with idiopathic polyhydramnios

INTRODUCTION

Polyhydramnios is present in approximately 2% of pregnancies and it has been associated with a variety of adverse pregnancy outcomes.

OBJECTIVES

The aim of our study was to evaluate the association between polyhydramnios and adverse pregnancy outcomes.

METHODS

This was a retrospective case control study of 288 singleton pregnancies delivered in the Rotunda Hospital, Dublin, between 2013 and 2014. Polyhydramnios was defined as: (i) amniotic fluid index (AFI) ≥ 25 cm; (ii) maximal vertical pocket (MVP) of ≥8 cm; and (iii) a gestational age-specific threshold for AFI. Demographic information, obstetric and neonatal outcomes were obtained by review of hospital databases. Exclusion criteria included gestational or pre-existing diabetes, multiple pregnancy, carrying a fetus with structural or chromosomal abnormalities, Rhesus factor isoimmunisation, and TORCH screen positive. Outcomes were compared with outcomes of those without polyhydramnios.

RESULTS

A total of 8798 deliveries occurred during the study period. The frequency of polyhydramnios was 1.6%. One hundred and forty-four women were selected in each group. There was no significant difference in preterm deliveries, low birth weight, low Apgar score at one minute and five minutes and perinatal mortality. However, increase in caesarean delivery rate (43.1% vs 21.5%), number of fetal distresses (17.4% vs 6.9%) and number of neonatal intensive care unit (NICU) admissions (17.4% vs 4.9%) were observed in our study.

CONCLUSION

In conclusion, idiopathic polyhydramnios is associated with specific adverse outcomes, such as higher rate of caesarean delivery, fetal distress and NICU admissions. Therefore, close surveillance of these pregnancies is required, especially near term.

Outcomes From Polyhydramnios With Normal Ultrasound

OBJECTIVE

To investigate the short- and long-term outcomes of children from pregnancies complicated with polyhydramnios, defined as amniotic fluid index (AFI) >24 cm, and with a normal detailed ultrasound examination.

METHODS

This retrospective cohort study examined 134 children aged 4 to 9 years with polyhydramnios and normal detailed ultrasound examination during pregnancy compared with 268 controls with normal AFI and normal detailed ultrasound examination matched for maternal age, year of delivery, gestational week at delivery, and presence or absence of diabetes. The primary outcome was the rate of malformations diagnosed postnatally. Additional outcomes were obstetrics outcomes, genetic syndromes, and neurodevelopment.

RESULTS

Polyhydramnios was associated with increased risk for cesarean delivery (CD) and birth weight >90th percentile. This elevation in CD was attributed to increased rate of elective CD due to suspected macrosomia. Polyhydramnios was associated with increased risk for congenital malformations (n = 25 [19%] compared with 27 [10%], respectively; P = .016) without a statistically significant increase in the rate of major malformations (11 [8%] vs. 10 [4%]; P = .057). Genetic syndromes were more prevalent in the polyhydramnios group (5 [3.7%] vs. 2 [0.75%]; P = .043), as were neurologic disorders and developmental delay (9.7% vs. 3%; P = .004).

CONCLUSIONS

Despite a normal detailed ultrasound examination, polyhydramnios is associated with increased rate of fetal malformations, genetic syndromes, neurologic disorders, and developmental delay, which may be diagnosed only after birth.

Renal Artery Doppler Findings in the Patients with Polyhydramnios before and after the Conservative Treatment

OBJECTIVE

The aim of this study was to evaluate the foetal renal blood flow with colour Doppler ultrasonography. Patients with polyhydramnios were investigated for the foetal renal artery pulsatility index (PI) at the beginning of the treatment, and after the conservative treatment in those who reached the normal amniotic fluid index.

MATERIALS AND METHODS

In this prospective study, 39 foetuses with polyhydramnios were evaluated at gestational weeks 26 to 36. The foetal development parameters, right and left foetal renal artery PIs, and amniotic fluid index were measured at the beginning of the treatment in all of these patients. Of these patients, 19 who responded to the conservative treatment were also revaluated when their amniotic fluid index reached normal levels, and statistical analyses were performed for the renal artery PIs before and after the treatment.

RESULTS

In this study, 19 patients fulfilled the inclusion criteria as patients with polyhydramnios who responded to conservative treatment. For these patients, the mean foetal renal artery PI was 2.08 (range 1.5-3.0) at the first sonographic examination, and the mean foetal renal artery PI was 1.94 (range 1.53-2.69) after the conservative treatment. However, there was no statistically significant difference between these two groups (p=0.117).

CONCLUSION

In this study, no statistically significant difference was found in the foetal renal artery PIs of the patients with polyhydramnios before and after the conservative treatment. These results suggest that the renal artery blood flow may not have any effect on the renal artery PI; therefore, these findings indicate that the renal artery PI cannot be used as a marker in the evaluation of polyhydramnios.

Polyhydramnios: Causes, Diagnosis and Therapy

Polyhydramnios is defined as a pathological increase of amniotic fluid volume in pregnancy and is associated with increased perinatal morbidity and mortality. Common causes of polyhydramnios include gestational diabetes, fetal anomalies with disturbed fetal swallowing of amniotic fluid, fetal infections and other, rarer causes. The diagnosis is obtained by ultrasound. The prognosis of polyhydramnios depends on its cause and severity. Typical symptoms of polyhydramnios include maternal dyspnea, preterm labor, premature rupture of membranes (PPROM), abnormal fetal presentation, cord prolapse and postpartum hemorrhage. Due to its common etiology with gestational diabetes, polyhydramnios is often associated with fetal macrosomia. To prevent the above complications, there are two methods of prenatal treatment: amnioreduction and pharmacological treatment with non-steroidal anti-inflammatory drugs (NSAIDs). However, prenatal administration of NSAIDs to reduce amniotic fluid volumes has not been approved in Germany. In addition to conventional management, experimental therapies which would alter fetal diuresis are being considered.

Maximal amniotic fluid index as a prognostic factor in pregnancies complicated by polyhydramnios

OBJECTIVES

Polyhydramnios is present in approximately 2% of pregnancies and has been associated with a variety of adverse pregnancy outcomes. Our aim was to evaluate the association between the maximal amniotic fluid index (AFI) and the frequency of specific adverse outcomes.

METHODS

This was a retrospective chart review of 524 singleton pregnancies diagnosed with polyhydramnios and delivered in a single tertiary referral center between 2003 and 2008. Polyhydramnios was defined as either AFI ≥ 25 cm or a maximum vertical pocket (MVP) ≥ 8 cm even in the presence of AFI < 25 cm. The cohort was stratified into four groups based on the maximal AFI noted during the pregnancy: < 25 cm but with MVP ≥ 8 cm; 25-29.9 cm; 30-34.9 cm; and ≥ 35 cm. Data were collected to determine the frequency of the following adverse pregnancy outcomes: prenatally diagnosed congenital anomalies, fetal aneuploidy, preterm delivery, Cesarean delivery, low birth weight, 5-min Apgar score < 7 and perinatal mortality.

RESULTS

Higher AFI was associated with a statistically significant increase in the frequency of adverse pregnancy outcomes. The most severe form of polyhydramnios, as based on the maximal AFI (≥ 35 cm; n = 67), was associated with the highest rates of prenatally diagnosed congenital anomalies (79%), preterm delivery (46%), small-for-gestational-age neonate (16%), aneuploidy (13%) and perinatal mortality (27%). No significant association between degree of polyhydramnios and adverse outcome was demonstrated in cases of idiopathic polyhydramnios (n = 253).

CONCLUSIONS

There is an association between the frequencies of a variety of adverse pregnancy outcomes and the severity of polyhydramnios as reflected by the maximal AFI.

Prenatal pharmacotherapy for fetal anomalies: a 2011 update

Fetal therapy can be defined as any prenatal treatment administered to the mother with the primary indication to improve perinatal or long-term outcomes for the fetus or newborn. This review provides an update of the pharmacological therapies that are solely directed at the fetus with anomalies and outlines a future transcriptomic approach. Fetal anomalies targeted with prenatal pharmacotherapy are a heterogeneous group of structural, endocrine, and metabolic conditions, including congenital cystic adenomatoid malformation (CCAM), congenital adrenal hyperplasia, congenital heart block, fetal tachyarrhythmias, inborn errors of metabolism, fetal thyroid disorders, and polyhydramnios. To date, the majority of pharmacotherapies for fetal anomalies have been evaluated only in retrospective, uncontrolled studies. The way forward will be with an evidence-based approach to prenatal pharmacological interventions.

Neuroblastoma presented with polyhydramniosis

Neuroblastoma is the most common extracranial solid tumor in pediatric age group. Clinical presentation of neuroblastoma is mostly related to origin of the tumor, extent of disease, and the presence of paraneoplastic syndromes. Here the authors report a neonate with neuroblastoma with an atypical presentation, diagnosed with postnatal abdominal ultrasonography performed due to polyhydramniosis in her mother during pregnancy.

Influence of polyhydramnios on perinatal outcome in pregestational diabetic pregnancies

OBJECTIVE

This study was carried out to evaluate the perinatal outcomes of pregnancy with pregestational diabetes mellitus complicated by polyhydramnios.

METHODS

This was a retrospective study of singleton pregnancies, with an antepartum diagnosis of polyhydramnios, seen at the maternal fetal medicine department of Mater Mothers' Hospital, a tertiary-level facility. All pregnancies in women with pregestational diabetes with a singleton pregnancy beyond 24 weeks of gestation, from 1996 to 2006, were reviewed (n = 314), and pregnancies complicated by polyhydramnios were identified (n = 59). Pregnancy outcomes of women whose pregnancy was complicated with polyhydramnios were compared to those without this complication.

RESULTS

The incidence of polyhydramnios in the study population was 18.8%. Women with polyhydramnios had increased hemoglobin A1c (HbA1c) levels throughout the pregnancy, and the difference was significant during the prepregnancy period and in the third trimester (P = 0.003 and P = 0.025, respectively). Significantly more mothers in the polyhydramnios group delivered preterm (54.2% vs. 33.3%, P = 0.004), the majority of which were iatrogenic preterm deliveries (44.1%). More pregnancies with polyhydramnios were delivered by Cesarean section (83.0% vs. 62%; P = 0.006), with the majority being performed electively in both groups (79.6% and 70.3%, respectively). Regardless, there were no significant differences in perinatal mortality rates, congenital abnormality rates, the incidences of low Apgar score, acidemia, hypoglycemia requiring intravenous therapy, phototherapy and ventilatory needs between the babies of the two groups.

CONCLUSION

Pregestational diabetic pregnancy with polyhydramnios is associated with poor diabetic control. Despite this, there is no significant increase in adverse perinatal outcome in these pregnancies, apart from a higher iatrogenic preterm birth rate.

Clinical features of polyhydramnios associated with fetal anomalies

The purpose of this study was to examine the clinical features of pregnancy complicated by polyhydramnios associated with fetal anomalies. Sixty-nine patients with a singleton pregnancy complicated by polyhydramnios were retrospectively analyzed. Based on prenatal ultrasonographic findings, 13 cases were considered to have idiopathic polyhydramnios and the remaining 56 cases were associated with fetal anomalies. Between these two groups, no significant difference was found in the gestational weeks when polyhydramnios developed. However, significant difference was noted in the maximum amniotic fluid index (AFI) values during the pregnancy period; 25.4 +/- 2.7 cm in the former, and 30.6 +/- 8.9 cm in the latter (P = 0.0004). In all of 13 cases with idiopathic polyhydramnios, AFI values remained less than 30 cm until delivery. Twenty-two patients (39%) with fetal anomalies required a prenatal treatment such as amnioreduction and tocolysis, whereas only one patient (7.7%) with idiopathic polyhydramnios needed tocolysis therapy (P = 0.03). There was a significant risk of premature delivery with fetal anomalies (35.6 +/- 3.9 weeks' gestation vs. 38.8 +/- 1.5 weeks' gestation, P = 0.004) because of refractory polyhydramnios, rupture of membranes, non-reassuring fetal status, and intrauterine fetal death, and although most infants with idiopathic polyhydramnios were appropriate-for-dates, many of the infants with congenital anomalies were small-for-dates. Significant risk of fetal anomalies should be considered in pregnant women with severe polyhydramnios (AFI > or = 30 cm), an increased trend of amniotic fluid during the pregnancy period, polyhydramnios requiring a prenatal treatment, or fetal growth restriction. On the other hand, based on our experience, a fetus without these conditions seems to have a low risk of congenital anomalies even if polyhydramnios is noted.

Hydramnios and small for gestational age are independent risk factors for neonatal mortality and maternal morbidity

OBJECTIVE

The objective was to evaluate the contribution of hydramnios and small for gestational age (SGA) as a combined pathology to maternal and neonatal morbidity and mortality.

METHODS

The study population consisted of 192 SGA neonates with hydramnios, 5,515 SGA neonates with a normal amount of amniotic fluids, 3,714 appropriate for gestational age (AGA) neonates with polyhydramnios and 83,763 AGA neonates with a normal amount of amniotic fluid. A cross-sectional population based study was designed between the four study groups. Multiple logistic regression analysis was used to assess the contribution of these abnormalities and different risk factors to maternal and perinatal complications.

RESULTS

The combination of hydramnios/SGA was found to be an independent risk factor for perinatal mortality (OR 20.55; CI 12.6-33.4). Congenital anomalies, prolapse of cord, hydramnios, SGA and grand multiparity were also independent risk factors for perinatal mortality. Independent risk factors for neonatal complications were prolapse of umbilical cord (OR 4.13; 95% CI 1.48-11.5), hydramnios/SGA (OR 2.72; 95% CI 1.81-4.07), chronic hypertension (OR 2.45; 95% CI 1.02-5.9), congenital malformations (OR 1.93; 95% CI 1.14-3.24) and SGA (OR 1.47; 95% CI 1.07-2). Significant independent risk factors for medical interventions during labor were fetal distress (OR 198.46; 95% CI 47.27-825.27), GDM Class B-R (OR 21.22; 95% CI 2.34-192.25), GDM class A (OR 4.64; 95% CI 2.62-8.21), severe pregnancy-induced hypertension (PIH; OR 7.74; 95% CI 2.35-25.42), hydramnios (OR 1.95; 95% CI 1.3-2.91), hydramnios/SGA (OR 1.84; 95% CI 1.12-3.02) and malpresentation (OR 1.56; 95% CI 1.32-1.84).

CONCLUSION

The combination of hydramnios and SGA is an independent risk factor for perinatal mortality and maternal complications. We suggest that the growth restriction of these fetuses is responsible for the neonatal complications, while the hydramnios contributes mainly to maternal complications.

Amniotic fluid index in normal pregnancy: an assessment of gestation specific reference values among Indian women

AIM

To obtain a gestational reference range for the amniotic fluid index (AFI) among Indian women.

METHODS

An analysis of AFI estimations was undertaken in 517 Indian women with normal pregnancy between 16 and 42 weeks of gestation. It was a prospective, cross-sectional study conducted in a university teaching hospital. Women with fetal anomalies, pregnancy-induced hypertension, diabetes mellitus, and other maternal complications were excluded from the study. The median, the 5th and the 95th percentile values were calculated for each gestational week and these values were compared with other studies.

RESULTS

The median reached its peak at the 27th week of gestation. We observed approximately 6 cm as the lower limit of normal (5th percentile) and approximately 18 cm (95th percentile) as upper limit of normal AFI at term for our population, whereas in the Caucasian population, the values were approximately 7 cm and approximately 20 cm, respectively. All gestation specific AFI values were lower in the studied population of Indian women compared with other studies on Caucasian population (P < 0.01 for 5th percentile & P < 3.26 x 10(-7) for 95th percentile), but slightly higher than the Chinese population.

CONCLUSION

Amniotic fluid index values differ in different populations. We standardized the reference values for normal AFI in Indian women. We found that they are lower in the population studied compared with reported values in the Caucasian population, but slightly higher than the Chinese population.

Uterine artery Doppler velocimetry in patients with idiopathic hydramnios

OBJECTIVE

To evaluate the role of overdistended uterus on the uterine artery (UA) blood flow velocimetry by comparing UA Doppler in patients with idiopathic hydramnios to patients with normal amniotic fluid (AF) volume.

METHODS

Pulsatility index (PI) of both UAs was determined prospectively between 26 and 41 weeks of gestation in 72 consecutive pregnant women with singleton pregnancies and idiopathic hydramnios and in 72 pregnant women with normal AF volume. Hydramnios was defined as an AF index (AFI) above 24 cm. A normal amount of AF was defined as an AFI of 6-24 cm. Patients with known fetal structural or chromosomal anomalies and those with diabetes mellitus were excluded.

RESULTS

No significant differences were observed between the groups with regard to maternal age, gravidity, and gestational age at examination. Gestational age at delivery and accordingly birth weight were significantly lower in patients with hydramnios compared to those with a normal AFI (34.9 +/- 2.1 vs. 39.1 +/- 1.2, p < 0.001; 2,508 +/- 399 vs. 2,995 +/- 420, p < 0.001, respectively). No significant differences were noted between right UA PI (0.73 +/- 0.3 in the hydramnios group vs. 0.71 +/- 0.2 in the control group; p = 0.091) and left UA PI (0.91 +/- 0.3 in the hydramnios group vs. 0.84 +/- 0.3 in the control group; p = 0.131) of both groups.

CONCLUSION

UA velocimetry in patients with idiopathic hydramnios was not significantly different from those with a normal AF volume.

Gestational diabetes complicated by hydramnios was not associated with increased risk of perinatal morbidity and mortality

OBJECTIVE

To determine whether gestational diabetes (GDM) complicated with hydramnios is associated with higher rates of perinatal morbidity and mortality than those with normal amniotic fluid (AFI).

STUDY DESIGN

A case control study of 368 pregnant women with GDM was conducted between January 1995 and December 1996. The study group consisted of 184 women with hydramnios (AFI>25 cm) that were matched for maternal age, parity, and gestational age to 184 women with gestational diabetes and normal AFI. A Student's t-test, McNemar test and logistic regression test were used to compare the two groups.

RESULTS

Both groups were under strict metabolic control; mean glucose levels of 5.2+/-2.4 mmol/l in the study group and 5.5+/-2.4 mmol/l in the controls (P>0.05). There were no significant differences between groups in the rates of severe preeclampsia, premature rupture of membranes (PROM), cesarean section rate, intrauterine growth restriction (IUGR), antepartum fetal death, fetal distress, prolapse of umbilical cord and placenta abruption. Even though the prevalence of large for gestational age (LGA) and birth weight were significantly higher in the study group (31 versus 19% and 3441+/-477 versus 3232+/-554 g, respectively), the prevalence of neonatal trauma was the same in both groups (2.6%). There was no significant difference in the Apgar scores (1 and 5 min), newborn hypoglycemia, metabolic acidosis and hyperbilirubinemia.

CONCLUSIONS

Hydramnios in women with GDM was not associated with increased risk of perinatal morbidity and mortality.

Polyhydramnios and arterio-arterial placental anastomoses may beneficially affect monochorionic twin pregnancies

Our objective was to appraise whether an increased amniotic fluid pressure by polyhydramnios can beneficially affect monochorionic twins that are haemodynamically connected by arterio-venous plus arterio-arterial placental anastomoses. We assessed the effects of polyhydramnios in monochorionic twin placentas, combining (a) data from previous in vitro placental perfusion experiments in singleton term placentas under simulated normal and increased amniotic fluid pressures with (b) logical deduction from observations made in monochorionic twins. Our hypothesis is that in monochorionic placentas, an increased amniotic fluid pressure increases the placental microvascular resistance but not the resistance of placental chorionic plate arteries. Hence, an increased amniotic fluid pressure increases the microvascular resistance of the joint cotyledon, the arterio-venous resistance, but not the arterioarterial resistance. This proposed mechanism reduces arterio-venous but not oppositely directed arterio-arterial transfusion. Therefore, reversal of the normal direction of net foeto-foetal transfusion may develop, which will reduce the circulatory imbalance that evolved between the monochorionic foetal twins. In contrast, in monochorionic twins connected by unidirectional or bidirectional arterio-venous anastomoses reversal of the normal direction of net foeto-foetal transfusion will not occur. In conclusion, reversal of the normal direction of net foeto-foetal transfusion, induced by polyhydramnios, is protective against the onset and severity of twin-twin transfusion syndrome in monochorionic twins connected by arterio-venous plus arterio-arterial anastomoses, but not by unidirectional or bidirectional arterio-venous anastomoses.