Perinatal outcome of oligohydramnios without associated premature rupture of membranes and fetal anomalies

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 and long-term neurological morbidity of the offspring

This study aimed to assess the association between maternal-isolated oligohydramnios (IO) and offspring long-term neurological complications. A population-based retrospective cohort study was conducted, including all births at a single tertiary medical center in Israel between the years 1991 and 2014. Multiple pregnancies and potential pregnancy complications associated with oligohydramnios were excluded. The computerized obstetrical database was linked with the computerized dataset of all pediatric hospitalizations of the same medical center. Evaluation of cumulative neurological-associated hospitalizations rate over time was compared using a Kaplan-Meier survival curve. The Weibull survival parametric model was conducted to assess the neurological-associated hospitalization risk in the presence of IO, while accounting for potential confounders. A total of 190,259 pregnancies were included in the study, of which 4063 (2.13%) pregnancies were complicated with IO. Total neurological-related hospitalizations were significantly more common in the IO group (3.7% in the IO group and 3.0% in the comparison group, p = 0.005). Pervasive developmental disorder, movement disorders, developmental disorders, and degenerative and demyelization disorders were all specific neurological diagnoses significantly more common in the exposed group. The survival curve demonstrated a significantly higher cumulative hospitalization rate in the exposed group (log-rank p = 0.001). Using a multivariate model adjusting for gestational age, maternal age, and labor induction, an independent association between IO and long-term neurological morbidity of the offspring was observed (adjusted hazard ratio 1.203; 95% CI 1.02-1.42). In summary, a significant association was found between pregnancies complicated by IO and long-term neurological morbidity of the offspring.

Oligohydramnios increases the risk of respiratory hospitalization in childhood: a population-based study

BACKGROUND

Pulmonary hypoplasia is associated with reduced lung function in infancy. The aim of this study was to evaluate the hypothesis that children exposed to oligohydramnios display an increased risk of hospitalization for respiratory illness by using a population-based matched-cohort design.

METHODS

We used three nationwide population-based data sets to identify 5,228 women who gave birth during 2004 to 2007 and were diagnosed with oligohydramnios during the third trimester of pregnancy. A cohort of 20,912 unaffected pregnant women was matched with these cases, according to neonatal sex and gestational age, maternal age and education, and level of prenatal care. Respiratory hospitalization and respiratory failure were defined using discharge diagnostic codes.

RESULTS

Oligohydramnios-exposed children had an 8% higher incidence rate of respiratory hospitalization and an 80% higher incidence rate of respiratory failure, compared with children without oligohydramnios exposure. This risk remained after adjusting for all potential risk factors. Cox regression analyses indicated that the adjusted hazard ratios of respiratory hospitalization and respiratory failure were 1.07 (95% confidence interval (CI): 1.01-1.15; P = 0.030) and 2.20 (95% CI: 1.26-3.84; P = 0.005), respectively.

CONCLUSION

Children exposed to oligohydramnios during the third trimester of pregnancy display an increased risk of hospitalization for respiratory illness.

Which is the safer method of labor induction for oligohydramnios women? Transcervical double balloon catheter or dinoprostone vaginal insert

OBJECTIVE

To compare the effectiveness and safety of two cervical ripening methods in term primiparous women with unfavorable cervices and oligohydramnios.

METHODS

Women (126 cases) with oligohydramnios [amniotic fluid index (AFI) ≤5 cm] and a low Bishop Score (≤6) were assigned randomly to use double balloon catheter (mechanical method group, 67 cases) or dinoprostone 10 mg controlled-release vaginal insert (pharmacological method group, 59 cases) for induction of labor. The study's primary outcome was caesarean section rate (CSR). The secondary outcome measures included maternal and neonatal morbidity, an incremental changes in Bishop Score, and intrapartum interventions.

RESULTS

There was no significant difference between the mechanical method group and the pharmacological method group in CSR and change in Bishop Score. Tacysystole, non-reassuring fetal heart patterns, and cases of newborn umbilical-cord arterial blood pH<7.1 were significantly lower with the mechanical method compared with the pharmacological method (p < 0.05). More patients needed additional intervention in the mechanical method group.

CONCLUSIONS

Both methods resulted in a similar CSR. Double balloon catheter resulted in fewer labor complications, but more frequent use of oxytocin and amniotomy. Compared with dinoprostone vaginal insert, double balloon catheter use may be less problematic in women with oligohydramnios.

Short-term outcome among term singleton infants with intrapartum oligohydramnios

AIM

To evaluate rates of early short-term neonatal complications among term singleton newborn infants with oligohydramnios.

METHODS

Retrospective data were collected on 456 term infants with prenatal diagnosis of oligohydramnios and on matched controls, including information on maternal condition and on infant perinatal complications.

RESULTS

Infants in the study group were born with lower birthweight and were SGA compared with those in the control group. Rates of renal malformations were significantly higher in the study group compared with the controls (15-3.3% and 3-0.7%, respectively; p = 0.007). Among the severe oligohydramnios subgroup (Amniotic Fluid Index <2), renal anomalies were even more prevalent compared to other infants with oligohydramnios and to the controls (6-9.8%, 9-2.3% and 3-0.7%, respectively; p < 0.001). The incidence of skeletal deformities (developmental dislocation of hip and torticollis) was higher among the study group.

CONCLUSION

Term infants with oligohydramnios that was detected near birth are associated with a greater prevalence of renal malformations (mostly mild hydronephrosis) as well as congenital torticollis and developmental dislocated hips compared with controls. Postnatal renal evaluation should be considered in infants with severe oligohydramnios.

The ultrasound estimation of amniotic fluid volume in diamniotic twin pregnancies and prediction of peripartum outcomes

OBJECTIVE

To determine ultrasonic estimations of amniotic fluid in diamniotic twins across gestation using the single deepest pocket (SDP) technique and correlate volumes to intrapartum and neonatal outcomes.

STUDY DESIGN

Prospective observational study using diamniotic dichorionic and diamniotic monochorionic pregnancies. Intrapartum and neonatal outcomes were evaluated.

RESULTS

Between April 2004 and April 2006, 299 women were recruited. There was no significant relationship between SDP and gestational age. Statistically significant differences by SDP groups (for low, normal, and high volumes) include preterm delivery (P = .043; 56, 62, and 86%), abnormal labor tracing (P = .013; 5, 8, and 27%), fetal labor intolerance (P = .026; 6, 9, and 27%), Apgar scores at 5 minutes (P = .028; 17, 10, and 27%) and any neonatal complications (P = .002; 28, 21, and 55%).

CONCLUSION

The SDP is constant between 17 and 37 weeks. Fetal labor intolerance and adverse neonatal outcomes are greater in a twin with hydramnios.

An amniotic fluid index < or =5 cm within 7 days of delivery in the third trimester is not associated with decreasing umbilical arterial pH and base excess

OBJECTIVE

To determine if an amniotic fluid index (AFI) < or =5.0 cm within 7 days of delivery in the third trimester is associated with decreasing umbilical arterial pH and base excess.

STUDY DESIGN

Cases for this retrospective cohort study were all pregnancies > or =26 weeks with intact membranes and an AFI < or =5.0 cm within 7 days of delivery between 11/99 and 7/02. Multiple gestations, aneuploid, and anomalous fetuses were excluded. Controls with an AFI >5.0 cm within 7 days of delivery were matched to each case within 1 week by gestational age. For a control group with a mean+/-SD umbilical arterial pH of 7.26+/-0.07 and alpha=0.05, a sample size of 100 would have a power of 99% to detect a difference with a study group whose mean was 7.20. Data were compared using paired Student's t-test, Mann-Whitney, Fisher's exact, chi(2) and risk ratios with 95% confidence intervals.

RESULTS

In all, 131 neonates with an AFI < or =5.0 cm were matched to 131 controls with an AFI >5 cm. There was no difference in gestational age (37.6+/-3.0, 37.7+/-3.0 weeks) or birth weight (2897+/-810, 2762+/-788 g). There was no difference in umbilical artery pH (7.25+/-0.07, 7.26+/-0.07) or base excess (-3.32+/-2.59, -2.83+/-2.45 mmol/l), even in small for gestational age (SGA) infants in both groups. There was no difference in the number of SGA neonates, 5-minute Apgar <7, respiratory distress syndrome, necrotizing enterocolitis, or neurologic morbidity. Linear regression showed no correlation between AFI and either umbilical arterial pH (r=-0.00047, SE=0.001, p=0.63) or base excess (r=-0.029, SE=0.037, p=0.428).

CONCLUSION

An AFI < or =5.0 cm measured within 7 days of delivery in the third trimester is not associated with decreasing umbilical arterial pH and base excess.

Effect of maternal oral hydration on amniotic fluid index in women with pregnancy-induced hypertension

OBJECTIVE

To evaluate the effect of maternal oral hydration on amniotic fluid index (AFI) in women with pregnancy-induced hypertension.

METHODS

Five women with pregnancy-induced hypertension and five normotensive gravidae at 32-37 weeks gestation with normal AFI (8-18cm) were hydrated by oral intake of 2L of water over 1 h. Both groups were similar in age, parity and gestation. Repeat AFI was measured in all women after 3 h. The differences between pre- and post-hydration AFI in the two groups were analyzed with Student's t-test for statistical significance.

RESULTS

Maternal oral hydration resulted in a significant increase in AFI in both hypertensive and normotensive gravidae (1.7cm and 3.48cm, respectively). However, the extent of increase was significantly lower in the hypertensive group (P = 0.03).

CONCLUSION

Pregnancy-induced hypertension adversely affects the increase in amniotic fluid volume with maternal hydration. This observation is of clinical relevance in the management of oligohydramnios associated with pregnancy-induced hypertension.