Oligohydramnios, small for gestational age and pregnancy outcomes: an analysis using precise measures

Amniotic fluid content in children with kidney and urinary tract anomalies determines pre- and postnatal development

BACKGROUND

Renal oligohydramnios (ROH) describes an abnormally low volume of amniotic fluid (AF) during pregnancy. ROH is mostly caused by congenital fetal kidney anomalies. The ROH diagnosis frequently implies an increased risk of peri- and postnatal fetal mortality and morbidity. The present study aimed to evaluate the impact of ROH on pre-and postnatal development in children with congenital kidney anomalies.

METHODS

This retrospective study included 168 fetuses with anomalies in the kidney and urinary tract. Based on the amount of AF measured by ultrasound, patients were divided into three groups: normal amniotic fluid (NAF), amniotic fluid in the lower normal range (LAF), and ROH. These groups were compared with respect to prenatal sonographic parameters, perinatal outcomes, and postnatal outcomes.

RESULTS

Among the 168 patients with congenital kidney anomalies, 26 (15%) had ROH, 132 (79%) had NAF, and 10 (6%) had LAF. Of the 26 families affected by ROH, 14 (54%) decided to terminate pregnancy. Of 10 live-born children in the ROH group, 6 (60%) survived the observation time; of these, 5/6 presented with chronic kidney disease, stages I-III, at their last examination. The main differences in postnatal development between the ROH group and the NAF and LAF groups were: restricted height and weight gain, respiratory issues, complicated feeding, and the presence of extrarenal malformations.

CONCLUSIONS

ROH is not a mandatory indicator of severe postnatal kidney function impairment. However, children with ROH have complicated peri-and postnatal periods, due to the presence of concomitant malformations, which must be considered in prenatal care. A higher resolution version of the Graphical abstract is available as Supplementary information.

Diagnostic Tests in the Prediction of Neonatal Outcome in Early Placental Fetal Growth Restriction

Background and Objectives: Monitoring pregnancies with fetal growth restriction (FGR) presents a challenge, especially concerning the time of delivery in cases of early preterm pregnancies below 32 weeks. The aim of our study was to compare different diagnostic parameters in growth-restricted preterm neonates with and without morbidity/mortality and to determine sensitivity and specificity of diagnostic parameters for monitoring preterm pregnancies with early preterm fetal growth restriction below 32 weeks. Materials and Methods: Our clinical study evaluated 120 cases of early preterm deliveries, with gestational age ≤ 32 + 0 weeks, with prenatally diagnosed placental FGR. All the patients were divided into three groups of 40 cases each based on neonatal condition,: I-Neonates with morbidity/mortality (NMM); II-Neonates without morbidity with acidosis/asphyxia (NAA); III-Neonates without neonatal morbidity/acidosis/asphyxia (NWMAA). Results: Amniotic fluid index (AFI) was lower in NMM, while NWMAA had higher biophysical profile scores (BPS). UA PI was lower in NWMAA. NWMAA had higher MCA PI and CPR and fewer cases with CPR <5th percentile. NMM had higher DV PI, and more often had ductus venosus (DV) PI > 95th‱ or absent/reversed A wave, and pulsatile blood flow in umbilical vein (UV). The incidence of pathological fetal heart rate monitoring (FHRM) was higher in NMM and NAA, although the difference was not statistically significant. ROC calculated by defining a bad outcome as NMM and a good outcome as NAA and NWMAA showed the best sensitivity in DV PIi. ROC calculated by defined bad outcome in NMM and NAA and good outcome in NWMAA showed the best sensitivity in MCA PI. Conclusions: In early fetal growth restriction normal cerebral blood flow strongly predicts good outcomes, while pathological venous blood flow is associated with bad outcomes. In fetal growth restriction before 32 weeks, individualized expectant management remains the best option for the optimal timing of delivery.

Trends of change in the individual contribution of risk factors for small for gestational age over more than 2 decades

PURPOSE

Over the past years, the prevalence of various risk factors for small for gestational age (SGA) neonates has changed. Little is known if there was also a change in the specific contribution of these risk factors to the prevalence of SGA. We aim to identify trends in the specific contribution of various risk factors for SGA by observing their odds ratios (ORs) throughout different time periods.

METHODS

A nested case-control study was conducted. The ORs for selected known risk factors for SGA occurring in three consecutive 8-year intervals between 1988 and 2014 (T1 - 1988-1996; T2 - 1997-2005; T3 - 2006-2014) were compared. Data were retrieved from the medical centre's computerized perinatal database. Multivariable logistic regression models were constructed and ORs were compared to identify the specific contribution of independent risk factors for SGA along the study period.

RESULTS

During the study period, 285,992 pregnancies met the study's inclusion criteria, of which 15,013 (5.25%) were SGA. Between 1988 and 2014, the incidence of SGA increased from 2.6% in 1988 to 2.9% in 2014. Using logistic regression models, nulliparity, maternal age, gestational age, hypertensive disorders of pregnancy, oligohydramnios and pre-gestational diabetes mellitus were found to be independently associated with SGA. While the adjusted ORs (aOR) of hypertensive disorders of pregnancy and pre-gestational diabetes mellitus had increased, aORs for nulliparity, maternal age and gestational age had remained stable over time. Oligohydramnios had demonstrated a mixed trend of change over the time.

CONCLUSION

In our study, the specific contribution of factors associated with SGA had changed over time. Having a better understating of the changes in the specific contribution of different risk factors for SGA may enable obstetricians to provide consultations.

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.

Persistent Pulmonary Hypertension of the Newborn in Late Preterm and Term Infants in California

BACKGROUND AND OBJECTIVES

There are limited epidemiologic data on persistent pulmonary hypertension of the newborn (PPHN). We sought to describe the incidence and 1-year mortality of PPHN by its underlying cause, and to identify risk factors for PPHN in a contemporary population-based dataset.

METHODS

The California Office of Statewide Health Planning and Development maintains a database linking maternal and infant hospital discharges, readmissions, and birth and death certificates from 1 year before to 1 year after birth. We searched the database (2007-2011) for cases of PPHN (identified by International Classification of Diseases, Ninth Revision codes), including infants ≥34 weeks' gestational age without congenital heart disease. Multivariate Poisson regression was used to identify risk factors associated with PPHN; results are presented as risk ratios, 95% confidence intervals.

RESULTS

Incidence of PPHN was 0.18% (3277 cases/1 781 156 live births). Infection was the most common cause (30.0%). One-year mortality was 7.6%; infants with congenital anomalies of the respiratory tract had the highest mortality (32.0%). Risk factors independently associated with PPHN included gestational age <37 weeks, black race, large and small for gestational age, maternal preexisting and gestational diabetes, obesity, and advanced age. Female sex, Hispanic ethnicity, and multiple gestation were protective against PPHN.

CONCLUSIONS

This risk factor profile will aid clinicians identifying infants at increased risk for PPHN, as they are at greater risk for rapid clinical deterioration.

A randomized controlled study of the efficacy of 4 weeks of supplementation with ω-3 polyunsaturated fatty acids in cases of unexplained oligohydramnios

OBJECTIVE

To investigate the effect of ω-3 fatty acids on amniotic fluid volume and uterine artery blood flow after 4 weeks of treatment.

STUDY DESIGN

A randomized clinical trial was conducted on 140 participants with unexplained oligohydramnios at Woman's Health Hospital, Assiut University, Egypt. Participants were randomly assigned to ω-3 plus capsules or placebo. Categorical variables were analyzed by means of the χ² test, whereas continuous variables were analyzed by means of the independent-sample T-test between the two groups.

RESULTS

One hundred and forty women were recruited. There was significant improvement in the amniotic fluid index (AFI) in the ω-3 plus group in comparison with the placebo group (P=0.001). Moreover, there were significant decreases in the systolic/diastolic ratio (P=0.01), resistance index (P=0.041) and pulsatility index (P=0.002) of the uterine arteries in the ω-3 plus group when comparing baseline values with those after 4 weeks.

CONCLUSION

The results suggest that ω-3 fatty acids may have a role in the increase in AFI in cases of unexplained oligohydramnios. This effect may be secondary to the increase in uterine blood flow.

Perinatal outcomes with isolated oligohydramnios at term pregnancy

AIMS

To compare the outcomes of term gestations with oligohydramnios in the absence of other underlying disorders and term gestations with normal amniotic fluid.

METHODS

A retrospective analysis of obstetric outcomes in 27,708 term pregnancies. We compared three groups: labor induced because of oligohydramnios, spontaneous onset of labor with normal amniotic fluid, and labor induced because of late term pregnancy with normal amniotic fluid. We excluded pregnancies with maternal or fetal diseases or disorders potentially related with amniotic fluid alterations. The main outcome measures were mode of delivery, neonatal birth weight, umbilical artery blood pH, Apgar scores and neonatal discharge status.

RESULTS

Compared to spontaneous labor, induction of labor because of oligohydramnios was associated with a higher risk of cesarean delivery and small size of the fetus for gestational age (SGA). Compared to induction because of late term pregnancy there were no significant differences in neonatal, although neonates had a higher risk of being SGA.

CONCLUSION

The only perinatal outcome for which the risk was higher in term pregnancies with isolated oligohydramnios was SGA. The systematic induction of labor in these pregnancies should be questioned.

Clustering and classical analysis of clinical and placental phenotypes in fetal growth restriction and constitutional fetal smallness

This study aims to determine whether placental examination can be used to distinguish between pathologic fetal growth restriction (FGR) and constitutional fetal smallness. Data were extracted from a clinicoplacental database of high risk pregnancies during the period 1994-2013. These data were used to compare the 590 consecutive cases having birth weights below the 10th percentile with the 5201 remaining cases having gestational ages ≥20 weeks. The authors analyzed 20 clinical and 46 placental phenotypes using classical statistics, clustering analysis, and multidimensional scaling. Of the low-birth-weight babies, the following types of cases were compared: Four categories of placental phenotypes (those with features of poor uteroplacental perfusion, postuterine placental pathology, chronic inflammation, and a mixed category) better defined the presumably true FGR than did the clinical phenotypes. Maternal smoking and oligohydramnios were associated with fewer abnormal placental phenotypes than were maternal hypertensive diseases and abnormal Dopplers. Early-onset cases of fetal smallness clustered with placental features of poor uteroplacental perfusion, whereas late onset cases did not. Placental examination helps to retrospectively distinguish constitutionally small fetuses from those that are pathologically growth restricted. The latter correlate best with the clinical risk for FGR and with early-onset FGR. This correlation may have prognostic significance for the child and for future pregnancies, since hypoxic placental lesions can occur without clinical risk factors but with a tendency to recur in future pregnancies.

Correlation of ultrasound estimated with dye-determined or directly measured amniotic fluid volume revisited

BACKGROUND/AIMS

To examine the relationship of the amniotic fluid index (AFI) and single deepest pocket (SDP) with an AFV as modelled by Brace or Magann.

METHODS

AFI and SDP were evaluated for their correlation with an actual AFV using the Spearman correlation coefficient.

RESULTS

482 AFI and 468 SDP pregnancies were evaluated. There was a significant association between the AFI and SDP and an actual AFV (p < 0.0001). The AFI range of 5.1-20 was better correlated than 5.1-24 for normal AFVs Brace (κ = 0.175) and Magann (κ = 0.356) versus 5.1-24 (κ = 0.150 and κ = 0.319), respectively. The agreement level t for the AFI (κ = 0.175) and SDP (κ = 0.126) using Brace was slight and for the AFI (κ = 0.356) and SDP (κ = 0.295) using Magann was fair.

CONCLUSIONS

Both the AFI and SDP were correlated with actual AFV using both models. AFI of 5.1-20 better categorizes normal volumes. Although the Magann model correlates AFI/SDP and AFV better, the superiority is minimal.

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.

Amniotic fluid as a vital sign for fetal wellbeing

Introduction: Amniotic fluid, once thought to merely provide protection and room for necessary movement and growth for the fetus, is now understood to be a highly complex and dynamic system that is studied as a data point to interpret fetal wellbeing. Methods: Assessment of amniotic fluid volume is now routine when performing a sonographic evaluation of fetal status and is an important consideration in the assessment and management of perinatal morbidity and mortality.1,2 In this review, we will cover the dynamics that affect amniotic fluid volume, review methods for measurement and quantification of volume, review definitions for normative data as related to neonatal outcomes, and provide evidence based guidance on the workup and management options for oligoydramnios and polyhydramnios in singleton and twin pregnancies. Conclusions: When abnormalities of fluid exist, appropriate workup to uncover the underlying etiology should be initiated as adverse fetal outcomes are sometimes associated with these variations from normalcy.