The association between isolated oligohydramnios at term and pregnancy outcome

Oligohydramnios at term in the high-risk population - how severe is severe?

OBJECTIVES

The term oligohydramnios is linked to pregnancy complications. We previously presented the outcome of the low-risk population (no pregnancy complications) with term oligohydramnios. This study aims to address the high-risk group (Any maternal complication during pregnancy, such as gestational diabetes, pre-gestational diabetes, chronic hypertension, preeclampsia, anemia, asthma, obesity, and multi parity.).

METHODS

This retrospective cohort study of 1,114 singleton term (≥37), oligohydramnios (AFI <50 mm) pregnancies from Shamir Medical Center between 2017 and 2021. Compering the low-risk to high-risk groups with subdivision by severity of oligohydramnios.

RESULTS

A total of 211 subjects (19 %) were high-risk cases and 903 (81 %) low-risk cases. Comparing these two groups, subjects of the high-risk group were older (31.34 ± 5.85 vs. 29.51 vs. 4.96), had earlier gestational age at delivery 39.53 ± 1.18 vs. 40, had higher mean AFI (35 ± 12.7 vs. 33 ± 14.5), were subject to more labor inductions (81 vs. 69.7 %), and CS rate (19.9 vs. 12.4 %). Logistic regression revealed a need for more cesarean sections in the high-risk group. Additionally, more labor inductions and a higher risk of negative fetal outcomes.

CONCLUSIONS

This study highlights the importance of considering pregnancy risk factors when we are approaching oligohydramnios in high-risk pregnancies.

Is Obesity a Risk Factor for Disorders of Amniotic Fluid?

OBJECTIVES

Prior studies show conflicting evidence as to whether obesity in the absence of other medical or pregnancy-related conditions contributes to amniotic fluid disorders. The purpose of this study is to determine the association between late-pregnancy obesity with oligohydramnios (amniotic fluid index [AFI] ≤5 cm or maximum vertical pocket [MVP] <2 cm) and/or polyhydramnios (AFI ≥24 cm or MVP ≥8 cm).

METHODS

This is a retrospective cohort study of 961 women with singleton gestations who had one or more obstetrical ultrasounds at a single institution at 36 0/7 weeks gestation or beyond between August 1, 2015, and May 1, 2020. Patients were included if they had valid pregnancy dating and a documented AFI and/or MVP. Patients were categorized based on body mass index or BMI (eg, normal, overweight, Class I Obesity, Class II Obesity, or Class III Obesity).

RESULTS

A total of 6.2% of patients met criteria for oligohydramnios based on AFI, MVP or both (n = 60). There was no significant association between oligohydramnios and increasing BMI, regardless of obesity class (P = .21). In terms of polyhydramnios, 5.6% of patients met criteria based on AFI, MVP, or both (n = 54). Similarly, there was also no significant association between polyhydramnios and increasing BMI, regardless of obesity class (P = .66).

CONCLUSIONS

Elevated maternal BMI was not significantly associated with disorders of amniotic fluid, regardless of the severity of obesity.

Maternal and perinatal outcomes of oligohydramnios in late term and post term pregnancies at public hospitals in Ethiopia: a cross-sectional study

BACKGROUND

The prevalence of oligohydramnios ranges from 12 to 14% after 41 weeks to as high as 30% in post term pregnancies. Oligohydramnios poses a dilemma in the choice of mode of labor and delivery in a setup where there is lack of continuous electronic fetal monitoring during labor. The condition also puts the mother at risks of operative interventions and cesarean delivery. We aimed to asses the maternal and perinatal outcomes in pregnancies with oligohydramnios in late term and post term pregnancy in this study.

METHODS

A cross-sectional study was conducted among mothers with diagnosis of oligohydramnios after 40+ 6 weeks of gestation at four hospitals at four public hospitals in Addis Ababa, Ethiopia from May 1, 2021 to September 30, 2021. Data were collected using structured questionnaire. Logistic regression were performed to assess factors associated with the adverse maternal and perinatal outcomes.

RESULTS

From a total of 142 mothers with oligohydramnios in late term and post tem pregnancies, 40.8% delivered through cesarean section. Spontaneous labor and elective cesarean section were more likely to occurr in parous women (AOR 2.5, 95% CI 1.06-6.04, p = 0.04), but with less likely in those with secondary level education (AOR 0.13, 95% CI 0.02-0.74, p = 0.02). There was no statistically significant difference in adverse outcomes between those who had induction of labor and those who had either spontaneous labor or had elective cesarean section.

CONCLUSIONS

The adverse maternal and perinatal outcomes in late term and post term pregnancies with oligohydramnios may not be different among different modes of delivery. Induction of labor can be safe in these particular group of women with intermittent auscultation with fetoscope in a setup where continuous electronic fetal monitoring is not readily available.

Meconium-stained amniotic fluid

Green-stained amniotic fluid, often referred to as meconium-stained amniotic fluid, is present in 5% to 20% of patients in labor and is considered an obstetric hazard. The condition has been attributed to the passage of fetal colonic content (meconium), intraamniotic bleeding with the presence of heme catabolic products, or both. The frequency of green-stained amniotic fluid increases as a function of gestational age, reaching approximately 27% in post-term gestation. Green-stained amniotic fluid during labor has been associated with fetal acidemia (umbilical artery pH <7.00), neonatal respiratory distress, and seizures as well as cerebral palsy. Hypoxia is widely considered a mechanism responsible for fetal defecation and meconium-stained amniotic fluid; however, most fetuses with meconium-stained amniotic fluid do not have fetal acidemia. Intraamniotic infection/inflammation has emerged as an important factor in meconium-stained amniotic fluid in term and preterm gestations, as patients with these conditions have a higher rate of clinical chorioamnionitis and neonatal sepsis. The precise mechanisms linking intraamniotic inflammation to green-stained amniotic fluid have not been determined, but the effects of oxidative stress in heme catabolism have been implicated. Two randomized clinical trials suggest that antibiotic administration decreases the rate of clinical chorioamnionitis in patients with meconium-stained amniotic fluid. A serious complication of meconium-stained amniotic fluid is meconium aspiration syndrome. This condition develops in 5% of cases presenting with meconium-stained amniotic fluid and is a severe complication typical of term newborns. Meconium aspiration syndrome is attributed to the mechanical and chemical effects of aspirated meconium coupled with local and systemic fetal inflammation. Routine naso/oropharyngeal suctioning and tracheal intubation in cases of meconium-stained amniotic fluid have not been shown to be beneficial and are no longer recommended in obstetrical practice. A systematic review of randomized controlled trials suggested that amnioinfusion may decrease the rate of meconium aspiration syndrome. Histologic examination of the fetal membranes for meconium has been invoked in medical legal litigation to time the occurrence of fetal injury. However, inferences have been largely based on the results of in vitro experiments, and extrapolation of such findings to the clinical setting warrants caution. Fetal defecation throughout gestation appears to be a physiologic phenomenon based on ultrasound as well as in observations in animals.

Magnitude and associated factors of adverse perinatal outcomes among women with oligohydramnios at 3rd trimester at University of Gondar comprehensive specialized hospital, North West Ethiopia

Background

Oligohydramnios is a pregnancy condition characterized by low volume of amniotic fluid. Based on ultrasound measurement, it is defined as a single maximum vertical pocket of liquor less than 2 cm or summation of four quadrants vertical pockets of liquor measurement less than 5 cm. It is associated with multiple adverse perinatal outcomes (APO) and complicates 0.5%-5% of pregnancies.

Objective

To assess magnitude and associated factors of adverse perinatal outcome among women with oligohydramnios at 3rd trimester at University of Gondar Comprehensive Specialized Hospital, North West Ethiopia.

Methods

Institution based cross-sectional study was employed from April 1 to September 30, 2021 in which 264 participants were involved. All women with oligohydramnios at 3rd trimester who meet the inclusion criteria were included. Semi- structured questionnaire was used for data collection after Pre-tested. Collected data was checked for completeness; clarity then coded and entered using Epi data version 4.6.0.2 then exported to STATA version 14.1 for analysis.

Result

The magnitude of APO was 46.6% (95%CI: 40.5-52.7%). Null parity [AOR =  2.2, 95%CI (1.2-4.2)], presence of hypertensive disorders of pregnancy (HDP) [AOR = 4.9, 95%CI (2.0-12.1)] and presence of intrauterine growth restriction (IUGR) [AOR = 8.4, 95%CI (3.5-20.2)] were found to be predictors of APO.

Conclusion

Third trimester oligohydramnios is associated with APO. The presence of HDP, IUGR and being nulliparous were predictors of APO.

Impact of Thin Meconium on Delivery and Early Neonatal Outcomes

Several reports regarding the effects of thin meconium on maternal and neonatal outcomes are contradictory. This study evaluated the risk factors and obstetrical outcomes during deliveries complicated with thin meconium. This retrospective cohort study included all women with a singleton pregnancy, who underwent trial of labor >24 weeks of gestation, in a single tertiary center, over a six-year period. Obstetrical, delivery, and neonatal outcomes were compared between deliveries with thin meconium (thin meconium group) to deliveries with clear amniotic fluid (control group). Included in the study were 31,536 deliveries. Among them 1946 (6.2%) were in the thin meconium group and 29,590 (93.8%) were controls. Meconium aspiration syndrome was diagnosed in eight neonates in the thin meconium group and in none of the controls (0.41%, p < 0.001). In multivariate logistic regression analysis, the following adverse outcomes were found to be independently associated with increased odds ratio (OR) for thin meconium: intrapartum fever (OR 1.37, 95% CI 1.1-1.7), instrumental delivery (OR 1.26, 95% CI 1.09-1.46), cesarean delivery for non-reassuring fetal heart rate (OR 2.0, 95% CI 1.68-2.46), and respiratory distress requiring mechanical ventilation (OR 2.06, 95% CI 1.19-3.56). Thin meconium was associated with adverse obstetrical, delivery, and neonatal outcomes that should receive extra neonatal care and alert the pediatrician.

Isolated oligohydramnios in previous pregnancy is a risk factor for a placental related disorder in subsequent delivery

BACKGROUND

We aimed to assess the association between isolated oligohydramnios in previous pregnancy and the incidence of placental related complications in subsequent pregnancy.

METHODS

This was a retrospective cohort study of live singleton births from a single university affiliated medical center during an eleven-year period of women with two subsequent deliveries at our center. An analysis of outcomes was performed for all second deliveries, comparing women for whom their first delivery was complicated by isolated oligohydramnios (previous oligohydramnios group), and women without isolated oligohydramnios in their first delivery (control group). Patients for whom their first delivery was complicated by small for gestational age, pregnancy induced hypertension and preterm birth were excluded. The study groups were compared for obstetric and early neonatal outcomes, recurrence of oligohydramnios and a composite of placental related pregnancy complications.

RESULTS

A total of 213 in the previous oligohydramnios group and 5348 in the control group were compared. No differences were found between the groups in maternal age, body mass index, smoking and comorbidities. Gestational age at delivery was, 39.6 ± 1.3 vs. 39.3 ± 1.4 weeks, p = 0.006, in the previous oligohydramnios and controls respectively, although preterm birth rate was similar between the groups. The previous oligohydramnios group had a significantly higher incidence of oligohydramnios in second delivery, aOR 3.37, 95%CI 1.89-6.00, small for gestational age neonates, aOR 1.94, 95% CI 1.16-3.25, and overall placental related disorders of pregnancy, aOR 2.13, 95%CI 1.35-3.35.

CONCLUSION

Pregnancies complicated by isolated oligohydramnios are associated with an increased risk of placental related disorders in subsequent pregnancy. Isolated oligohydramnios may be the first sign of placental insufficiency and an independent manifestation of the placental related complications spectrum.

Vaginal fluid index - The fifth amniotic pocket

OBJECTIVE

The forebag is a pocket of amniotic fluid preceding the fetal presenting part. Herein we describe the feasibility of transvaginal measurements of the forebag and assess its correlation with the standard amniotic fluid index (AFI).

METHODS

A prospective study was carried out between January 2019 and July 2020. Eligible cases were women with singletons, vertex presentation, and normal AFI at term. We assessed the implementation and acceptance of a novel process in the clinical practice setting. Feasibility was assessed by using transvaginal ultrasound to measure the three orthogonal planes of the forebag. The vaginal fluid index (VFI) was defined as the volume composite of the three orthogonal planes. Correlations of the forebag measurements with both AFI and maximal vertical pocket were then calculated.

RESULTS

In total, 292 out of 305 (95.7%) women were enrolled. All participants completed both transabdominal and transvaginal ultrasound, of which the vaginal pocket was demonstrated in 266 (91.1%) cases. We found significant correlations, in both nulliparas and multiparas, between the vaginal pocket measurements and the VFI to both the AFI and maximal vertical pocket measurements (R = 0.38, P < 0.001; R = 0.3, P < 0.001, respectively).

CONCLUSION

We introduced a new ultrasound variable, the VFI, with a high feasibility rate. This may provide invaluable information for future decision making around the time of delivery.

Hourly fetal urine production rate in isolated oligohydramnios at term

OBJECTIVE

The aim of this study was to evaluate the hourly fetal urine production rate (HFUPR) via three-dimensional ultrasonography in women with isolated oligohydramnios and compare with normal pregnant women at term.

MATERIALS AND METHODS

This was a prospective observational cohort study of 112 women from 34 to 40 6/7 weeks' gestation. They were classified into three groups according to the amniotic fluid index (AFI) and ultrasonographic estimated fetal weight (EFW) as isolated oligohydramnios (defined as AFI below 5% and appropriate EFW corresponding to gestational age) (n = 34) and IUGR (defined as EFW below 5% corresponding to gestational age irrespective amniotic fluid) (n = 17), and normal pregnancy (n = 61). HFUPR was measured using three-dimensional virtual organ computer-aided analysis. Adverse perinatal outcomes in all participants were examined.

RESULTS

There was no significant difference in HFUPR between patients with isolated oligohydramnios and women with normal pregnancies (median, 40.0 mL/h [interquartile range [IQR] 31.0-66.5] vs. 48.6 [31.5-81.2], p = 0.224). HFUPR was significantly decreased in the IUGR group (13.8 mL/h [IQR 10.1-24.8]), compared to the normal pregnancy group (p<0.001) and the isolated oligohydramnios group (p<0.001). HFUPR was significantly decreased in neonates with adverse perinatal outcomes compared to the control (24.7 mL/h [IQR 13.4-47.4] vs. 43.6 [29.8-79.0], p = 0.016).

CONCLUSION

HFUPR was not decreased in patients with isolated oligohydramnios but was decreased in patients with IUGR when compared to normal controls at term.

Universal late pregnancy ultrasound screening to predict adverse outcomes in nulliparous women: a systematic review and cost-effectiveness analysis

BACKGROUND

Currently, pregnant women are screened using ultrasound to perform gestational aging, typically at around 12 weeks' gestation, and around the middle of pregnancy. Ultrasound scans thereafter are performed for clinical indications only.

OBJECTIVES

We sought to assess the case for offering universal late pregnancy ultrasound to all nulliparous women in the UK. The main questions addressed were the diagnostic effectiveness of universal late pregnancy ultrasound to predict adverse outcomes and the cost-effectiveness of either implementing universal ultrasound or conducting further research in this area.

DESIGN

We performed diagnostic test accuracy reviews of five ultrasonic measurements in late pregnancy. We conducted cost-effectiveness and value-of-information analyses of screening for fetal presentation, screening for small for gestational age fetuses and screening for large for gestational age fetuses. Finally, we conducted a survey and a focus group to determine the willingness of women to participate in a future randomised controlled trial.

DATA SOURCES

We searched MEDLINE, EMBASE and the Cochrane Library from inception to June 2019.

REVIEW METHODS

The protocol for the review was designed a priori and registered. Eligible studies were identified using keywords, with no restrictions for language or location. The risk of bias in studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool. Health economic modelling employed a decision tree analysed via Monte Carlo simulation. Health outcomes were from the fetal perspective and presented as quality-adjusted life-years. Costs were from the perspective of the public sector, defined as NHS England, and the costs of special educational needs. All costs and quality-adjusted life-years were discounted by 3.5% per annum and the reference case time horizon was 20 years.

RESULTS

Umbilical artery Doppler flow velocimetry, cerebroplacental ratio, severe oligohydramnios and borderline oligohydramnios were all either non-predictive or weakly predictive of the risk of neonatal morbidity (summary positive likelihood ratios between 1 and 2) and were all weakly predictive of the risk of delivering a small for gestational age infant (summary positive likelihood ratios between 2 and 4). Suspicion of fetal macrosomia is strongly predictive of the risk of delivering a large infant, but it is only weakly, albeit statistically significantly, predictive of the risk of shoulder dystocia. Very few studies blinded the result of the ultrasound scan and most studies were rated as being at a high risk of bias as a result of treatment paradox, ascertainment bias or iatrogenic harm. Health economic analysis indicated that universal ultrasound for fetal presentation only may be both clinically and economically justified on the basis of existing evidence. Universal ultrasound including fetal biometry was of borderline cost-effectiveness and was sensitive to assumptions. Value-of-information analysis indicated that the parameter that had the largest impact on decision uncertainty was the net difference in cost between an induced delivery and expectant management.

LIMITATIONS

The primary literature on the diagnostic effectiveness of ultrasound in late pregnancy is weak. Value-of-information analysis may have underestimated the uncertainty in the literature as it was focused on the internal validity of parameters, which is quantified, whereas the greatest uncertainty may be in the external validity to the research question, which is unquantified.

CONCLUSIONS

Universal screening for presentation at term may be justified on the basis of current knowledge. The current literature does not support universal ultrasonic screening for fetal growth disorders.

FUTURE WORK

We describe proof-of-principle randomised controlled trials that could better inform the case for screening using ultrasound in late pregnancy.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42017064093.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 15. See the NIHR Journals Library website for further project information.

Isolated oligohydramnios - should induction be offered after 36 weeks?

OBJECTIVE

Isolated oligohydramnios (IO) - oligohydramnios in the absence of maternal or gestational comorbidity is debated as an indication for induction of labor. Previous meta-analyses regarding perinatal outcomes of IO at term have yielded conflicting results. We aimed to investigate the neonatal outcomes among gestations with IO delivered at 36°^/7-39^6/7.

METHODS

The study cohort included all women undergoing a trial of labor between during 2011 and 2019 of a singleton gestation with cephalic presentation between 36°^/7 and 40°^/7. We allocated the study groups into women with IO and those with normal amniotic fluid volume. Neonatal outcomes were compared between the groups and in relation to gestational age and induction of labor.

RESULTS

Overall, there were 529/17,709 (3.0%) IO cases. IO was associated with maternal age <25 years (OR [95% CI] 1.62 (1.20-2.20), p = .001). Induction of labor was more common with IO (OR [95% CI] 1.33 (1.05-1.69) p = .01. IO was associated with preterm delivery (OR [95% CI] 1.81 (1.36-2.40), p < .001). The rate of neonatal adverse outcome did not differ between study groups. Overall composite adverse neonatal outcome occurred among 1,399/17,709 (7.9%) deliveries. Adverse neonatal outcome was associated with induction of labor (OR [95% CI] 1.61 (1.40-1.86), p < .001) and low birth weight (OR [95% CI] 7.41 (6.27-8.75), p < .001). When Stratified by gestational age, neonatal adverse outcome did not differ between IO and no IO groups. When examining cases of induction of labor per gestational age, induction of labor at 36 weeks among IO gestations, was associated with adverse neonatal outcome as compared to no IO group (OR [95% CI] 5.7 (1.23-26.3), p = .04).

CONCLUSIONS

Induction of labor in gestations complicated by IO at 36 weeks gestational age is associated with an increased risk for adverse neonatal outcome. Our study results adds to the current literature regarding outcomes of IO and time of delivery.

SYNOPSIS

Induction of labor in gestations complicated by IO at 36 weeks gestational age is associated with an increased risk for adverse neonatal outcome.

Management of isolated oligohydramnios in Korea: a questionnaire-based study of clinical practice patterns among the members of the Korean Society of Maternal Fetal Medicine

Objective

The aim of this survey was to investigate the recommendations and clinical practice patterns of the Korean Society of Maternal and Fetal Medicine (KSMFM) members, regarding management of isolated oligohydramnios (IO).

Methods

From December 2018 to February 2019, questionnaires were e-mailed to the KSMFM members at 257 institutes that are listed by the Korean Statistical Information Services (KOSIS) as suitable labor premises. Responses to the seven questions on the management of IO, from diagnosis to treatment, were evaluated.

Results

A total of 72 KSMFM members responded to this survey. Nearly all participants (90.1%) used the amniotic fluid index (AFI) as the primary method for estimating amniotic fluid volume. The majority of the participants (73.6%) believed that IO was a risk factor for adverse pregnancy outcomes, including abnormal fetal heart rate (73.6%), need for cesarean delivery (58.3%), intrauterine fetal demise (52.8%), and meconium aspiration syndrome (50%). Almost 70% of the participants believed that induction of labor might decrease perinatal morbidities, and that late-preterm to early-term period (36–38 gestational weeks) was a suitable timeframe for delivery, if the fetus was sufficiently grown and antenatal testing revealed reassuring results. Less than half of the participants (47.2%) believed that maternal oral or intravenous hydration was a useful intervention for IO management.

Conclusions

KSMFM members preferred labor induction at late-preterm to early-term, to decrease perinatal morbidity in cases of IO, although it was still uncertain whether labor induction improved the outcomes. Further prospective studies are needed regarding IO management.

The association between isolated oligohydramnios at term and placental pathology in correlation with pregnancy outcomes

INTRODUCTION

Isolated term oligohydramnios (ITO) is an obstetrical complication of which the etiology, management, and clinical importance are controversial. In attempt to deepen our understanding, we aimed to study placental pathology and pregnancy outcomes in pregnancies complicated by ITO.

MATERIALS AND METHODS

- Maternal demographics, neonatal outcomes, and placental histopathology reports of all pregnancies complicated by ITO at 37^0/7 to 41^0/7 weeks were reviewed. Excluded were cases complicated by hypertensive disorders, intrauterine fetal growth restriction, placental abruption, and deliveries of undiagnosed small for gestational age neonates. Results were compared between the ITO group and a control group matched for gestational age and mode of delivery. Placental lesions were classified according to the current "Amsterdam" criteria. Composite adverse neonatal outcome was defined as one or more of the following early complications: neonatal intensive care unit admission, sepsis, blood transfusion, phototherapy, respiratory morbidity, cerebral morbidity, necrotizing enterocolitis, or death.

RESULTS

The study group included 108 patients with ITO that were compared to matched controls. Placentas from the ITO group were characterized by higher rates of placental weights <10th centile (p < 0.001), abnormal cord insertion (p < 0.001), and maternal vascular malperfusion (MVM) lesions (p < 0.001). Neonates from the ITO group had lower birth weights (p < 0.002), and worse composite adverse neonatal outcome (p = 0.028) compared to controls.

CONCLUSION

- The current study demonstrates higher rates of placental MVM lesions, and worse neonatal outcome in pregnancies complicated by ITO. These novel findings suggest that ITO should be seen as part of the "placental insufficiency" spectrum.

Are Congenital Urinary Tract Abnormalities Linked to Maternal Methylenetetrahydrofolate Reductase Polymorphisms in Fetuses of Intentionally Terminated Pregnancies with Oligo- or Anhydramnios ?

OBJECTIVE

We aimed to evaluate fetuses of terminated pregnancies with oligo-or anhydramnios (OAH) to further investigate the association between maternal methylenetetrahydrofolate reductase (MTHFR) polymorphisms and fetal urinary tract malformations.

MATERIALS AND METHODS

This retrospective study included 16 pregnancies with OAH (with normal fetal karyotype) that were intentionally terminated before 22nd gestational week. Fetal autopsy was performed in all cases. We evaluated cases for presence of DNA methylation pathway-related gene polymorphisms.

RESULTS

We demonstrated that renal abnormalities and disorders exist in 75% of the cases. Pulmonary system anomalies and single umbilical artery were the most frequently observed associated abnormalities. Polymorphisms with known reduced MTHFR activity were found in 81.8% (9/11) of the cases.Association between urinary system abnormalities and polymorphisms with known reduced MTHFR activity was observed in 88.8% (8/9) of the cases.

CONCLUSION

Physicians should keep in mind that polymorphisms with known reduced MTHFR activity may be associated with urinary tract abnormalities and OAH.

Is pregnancy associated plasma protein-A (PAPP-A) a marker for adverse perinatal outcomes in preterm isolated oligohydramnios cases?

OBJECTIVE

Isolated oligohydramnios is defined as an amniotic fluid index below five centimeter with no other coexisting condition. There are still controversies about the management and pregnancy outcomes. A marker predicting these is crucial. Low pregnancy associated plasma protein-A levels were reported to be related with adverse pregnancy outcomes. We aimed to determine the role of first trimester pregnancy associated plasma protein-A for poor outcomes in preterm isolated oligohydramnios cases.

MATERIAL AND METHODS

Fifty-one patients with singleton pregnancies diagnosed as isolated oligohydramnios at 28/0-36/6 weeks of gestation and 110 gestational age matched healthy controls between January and December 2015 were included. Maternal age, gestational age at delivery, mode of delivery, indication for cesarean section, Apgar scores at first and fifth minutes, birth weight, neonatal intensive care unit admission and mortality were recorded. Pregnancy associated plasma protein-A levels were compared between groups and its role in adverse perinatal outcomes was evaluated.

RESULTS

Pregnancy associated plasma protein-A levels and pregnancy outcomes were similar in two groups (p > 0.050) except birth weight, gestational age at delivery and presence of fetal distress. Pregnancy associated plasma protein-A levels did not differ in terms of delivery mode, presence of fetal distress, first and fifth minutes Apgar scores and neonatal intensive care unit admission (p = 0.323,0.650,0.990,0.112,0.853). Also, it was not determined as a risk factor for cesarean section, presence of fetal distress, low Apgar scores and neonatal intensive care unit admission.

CONCLUSION

Pregnancy associated plasma protein-A, a well-known prognostic factor for some of high risk pregnancy conditions, may not be used as a marker in preterm isolated oligohydramnios cases.

Oligohydramnios in complicated and uncomplicated pregnancy: a systematic review and meta-analysis

OBJECTIVE

To evaluate adverse pregnancy outcomes in singleton pregnancies diagnosed with oligohydramnios through a systematic review and meta-analysis of controlled trials.

METHODS

We searched electronic databases via OVID, EBSCO, Web of Science, Google Scholar and others from 1980 to 2015. Prospective and retrospective studies with a control group were included. Two authors independently reviewed the abstracts from the literature search. Inclusion criteria were: studies in English, singleton pregnancy, normal fetal anatomy, intact membranes and oligohydramnios determined by the amniotic fluid index (AFI) technique. We stratified the meta-analysis into two groups according to risk: high risk including studies of oligohydramnios with comorbid conditions (e.g. hypertension) and low risk including studies of isolated oligohydramnios.

RESULTS

Fifteen trials met the inclusion criteria. Nine were high-risk and six were low-risk studies, including 8067 and 27 526 women, respectively. Compared with women with normal AFI, those with isolated oligohydramnios had significantly higher rates of an infant with meconium aspiration syndrome (relative risk (RR), 2.83; 95% CI, 1.38-5.77), Cesarean delivery for fetal distress (RR, 2.16; 95% CI, 1.64-2.85) and admission to the neonatal intensive care unit (NICU) (RR, 1.71; 95% CI, 1.20-2.42). Patients with oligohydramnios and comorbidities were more likely to have an infant with low birth weight (RR, 2.35; 95% CI, 1.27-4.34). However, rates of 5-min Apgar score < 7 (RR, 1.85; 95% CI, 0.69-4.96), NICU admission (RR, 2.09; 95% CI, 0.80-5.45), meconium-stained amniotic fluid (RR, 1.32; 95% CI, 0.62-2.81) and Cesarean delivery for fetal distress (RR, 1.65; 95% CI, 0.81-3.36) were similar to those for women with normal AFI. Stillbirth rates were too low to analyze in the meta-analysis.

CONCLUSIONS

This review helps to delineate which adverse outcomes are increased with oligohydramnios in low-risk pregnancy (NICU admission, Cesarean delivery for fetal distress and meconium aspiration syndrome), but does not provide enough data to determine the optimal timing of delivery in such cases. Oligohydramnios in complicated pregnancy is associated with an increased risk of delivery of an infant with low birth weight, but this may be confounded by the comorbid condition. Therefore, in high-risk pregnancy, management should be dictated by the comorbid condition and not the presence of oligohydramnios. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Breech presentation at term and associated obstetric risks factors-a nationwide population based cohort study

PURPOSE

The aim of this study was to estimate whether breech presentation at term was associated with known individual obstetric risk factors for adverse fetal outcome.

METHODS

This was a retrospective, nationwide Finnish population-based cohort study. Obstetric risks in all breech and vertex singleton deliveries at term were compared between the years 2005 and 2014. A multivariable logistic regression model was used to determine significant risk factors.

RESULTS

The breech presentation rate at term for singleton pregnancies was 2.4%. The stillbirth rate in term breech presentation was significantly higher compared to cephalic presentation (0.2 vs 0.1%). The odds ratios (95% CIs) for fetal growth restriction, oligohydramnios, gestational diabetes, a history of cesarean section and congenital fetal abnormalities were 1.19 CI (1.07-1.32), 1.42 CI (1.27-1.57), 1.06 CI (1.00-1.13), 2.13 (1.98-2.29) and 2.01 CI (1.92-2.11).

CONCLUSIONS

The study showed that breech presentation at term on its own was significantly associated with antenatal stillbirth and a number of individual obstetric risk factors for adverse perinatal outcomes. The risk factors included oligohydramnios, fetal growth restriction, gestational diabetes, history of caesarean section and congenital anomalies.

Amniotic Fluid Assessment: Amniotic Fluid Index Versus Maximum Vertical Pocket

Amniotic fluid assessment is vital to fetal well-being. Accurately diagnosing an amniotic fluid abnormality can aid in the proper management of a pregnancy at risk for an adverse outcome. Sonography is the most common way to assess amniotic fluid volume throughout a pregnancy; however, the most accurate technique, amniotic fluid index or maximum vertical pocket, is yet to be determined. Dye-dilution techniques are the most accurate way to measure amniotic fluid volume, but they are invasive and can be performed only at the time of a cesarean delivery. Multiple studies have been performed to determine the accuracy of the amniotic fluid index and maximum vertical pocket methods when diagnosing amniotic fluid volume abnormalities. Based on the studies reviewed in this article, neither method stands out as superior to the other when it comes to diagnosing amniotic fluid abnormalities during pregnancy. However, the maximum vertical pocket should also always be considered when an amniotic fluid abnormality is suspected because the amniotic fluid index overdiagnoses amniotic fluid abnormalities, leading to increased rates of pregnancy intervention and the potential for adverse pregnancy outcomes.

Isolated Oligohydramnios at Term as an Indication for Labor Induction: A Systematic Review and Meta-Analysis

OBJECTIVE

To investigate whether isolated oligohydramnios at term is associated with increased rates of perinatal morbidity and mortality and whether induction of labor in term pregnancies with isolated oligohydramnios is superior to conservative management in reducing perinatal morbidity and mortality.

STUDY DESIGN

We searched databases from inception to May 2015. We included studies that evaluated isolated oligohydramnios at term and perinatal outcome. Each outcome was analyzed separately, performing a comparative analysis between the study and control groups.

RESULTS

Twelve studies were included with 35,999 women: 2,414 (6.7%) with isolated oligohydramnios and 33,585 (93.29%) with normal amniotic fluid index. Patients with isolated oligohydramnios had significantly higher rates of labor induction [odds ratio (OR) 7.56, confidence interval (CI) 4.58-12.48] and Cesarean sections (OR 2.07, CI 1.77-2.41). There were higher rates of an Apgar score <7 at 1 and 5 min (OR 1.53, CI 1.03-2.26, and OR 2.01, CI 1.3-3.09, respectively) and admission to the neonatal intensive care unit (OR 1.47, CI 1.17-1.84). There were no significant differences in cord pH <7.1 and meconium-stained amniotic fluid. In the single randomized trial comparing induction of labor with expectant management, no differences were found in any significant maternal or neonatal outcomes.

CONCLUSION

Isolated oligohydramnios at term is associated with significantly higher rates of labor induction, Cesarean sections, and short-term neonatal morbidity.

An Update on Maternal Hydration Strategies for Amniotic Fluid Improvement in Isolated Oligohydramnios and Normohydramnios: Evidence from a Systematic Review of Literature and Meta-Analysis

OBJECTIVE

Several trials aimed at evaluating the efficacy of maternal hydration (MH) in increasing amniotic-fluid-volume (AFV) in pregnancies with isolated oligohydramnios or normohydramnos have been conducted. Unfortunately, no evidences support this intervention in routine-clinical-practice. The aim of this systematic-literature-review and meta-analysis was to collect all data regarding proposed strategies and their efficacy in relation to each clinical condition for which MH-therapy was performed with the aim of increasing amniotic-fluid (AF) and improving perinatal outcomes.

MATERIALS AND METHODS

A systematic literature search was conducted in electronic-database MEDLINE, EMBASE, ScienceDirect and the Cochrane-Library in the time interval between 1991 and 2014. Following the identification of eligible trials, we estimated the methodological quality of each study (using QADAS-2) and clustered patients according to the following outcome measures: route of administration (oral versus intravenous versus combined), total daily dose of fluids administered (<2000 versus >2000), duration of hydration therapy: (1 day, >1 day but <1 week, >1 week), type of fluid administered (isotonic versus hypotonic versus combination).

RESULTS

In isolated-oligohydramnios (IO), maternal oral hydration is more effective than intravenous hydration and hypotonic solutions superior to isotonic solutions. The improvement in AFV appears to be time-dependent rather than daily-dose dependent. Regarding normohydramnios pregnancies, all strategies seem equivalent though the administration of hypotonic-fluid appears to have a slightly greater effect than isotonic-fluid. Regarding perinatal outcomes, data is fragmentary and heterogeneous and does not allow us to define the real clinical utility of MH.

CONCLUSIONS

Available data suggests that MH may be a safe, well-tolerated and useful strategy to improve AFV especially in cases of IO. In view of the numerous obstetric situations in which a reduced AFV may pose a threat, particularly to the fetus, the possibility of increasing AFV with a simple and inexpensive practice like MH-therapy may have potential clinical applications. Considering the various strategies of maternal hydration implemented in the treatment of IO, better results were observed when treatment was based on a combination of intravenous (for a period of 1 day) and oral (for a period of at least 14 days) hypotonic fluids (≥2000ml).