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

Amnioinfusion compared with expectant management in oligohydramnios with intact amnions in the second and early third trimesters

INTRODUCTION

Treatment of oligohydramnios in the mid-trimester is challenging, because of the high incidence of adverse perinatal outcomes mainly due to bronchopulmonary dysplasia. Antenatal amnioinfusion has been proposed as a possible treatment for oligohydramnios with intact amnions, but there are few relevant studies. This study aimed to evaluate the effectiveness of transabdominal amnioinfusion in the management of oligohydramnios without fetal lethal malformations in the second and early third trimesters.

MATERIAL AND METHODS

It is a historical cohort study. A total of 79 patients diagnosed with oligohydramnios at 18-32 weeks gestation were enrolled. In the amnioinfusion group (n = 39), patients received transabdominal amnioinfusion with the assistance of real-time ultrasound guidance. In the expectant group (n = 41), patients were treated with 3000 mL of intravenous isotonic fluids daily. The perioperative complications and perinatal outcomes were analyzed.

RESULTS

Compared with the expectant group, the delivery latency was significantly prolonged, and the rate of cesarean delivery was significantly reduced in the amnioinfusion group (p < 0.05). Although the rate of intrauterine fetal death was significantly reduced, the incidence of spontaneous miscarriage, premature rupture of membranes (PROMs), and threatened preterm labor were significantly higher in the amnioinfusion group than in the expectant group (p < 0.05). There was no significant difference in terms of perinatal mortality (28.9% vs. 41.4%, p > 0.05). Multivariate logistic regression revealed that amnioinfusion (odds ratio [OR] 0.162, 95% confidence interval [CI] 0.04-0.61, p = 0.008) and gestational age at diagnosis (OR 0.185, 95% CI 0.04-0.73, p = 0.016) were independently associated with neonatal adverse outcomes. Further subgrouping showed that amnioinfusion significantly reduced the frequency of bronchopulmonary hypoplasia for patients ≤26 weeks (26.7% vs. 75.0%, p = 0.021). The rates of other neonatal complications were similar in both groups.

CONCLUSIONS

Amnioinfusion has no significant effect on improving the perinatal mortality of oligohydramnios in the second and early third trimesters. It may lead to a relatively high rate of PROM and spontaneous abortion. However, amnioinfusion may significantly improve the latency period, the rate of cesarean delivery, and neonatal outcomes of oligohydramnios, especially for women ≤26 weeks with high risk of neonatal bronchopulmonary hypoplasia.

Fetal growth restriction, neonatal morbidity and placental pathology in dichorionic twins-a comparison of twin-specific versus singleton growth charts‏‏

INTRODUCTION

Fetal growth restriction (FGR) in dichorionic diamniotic (DCDA) twin gestations is a known complication associated with adverse neonatal outcomes. The international guidelines have no consensus on whether to use singleton or twin-specific growth charts. Thus, we aimed to compare growth charts in correlation with pregnancy outcomes and placental histopathology.

METHODS

The medical files of all DCDA twin deliveries between 2010 and 2020 were reviewed. Birthweight percentile for gestational age (GA) for each individual neonate was assigned using the updated local singleton and twin-specific growth chart. We then divided the study population into two groups, neonates that were FGR based on the local singleton charts (FGR-singleton group) versus FGR on both twin-specific and singleton charts (FGR-twin group). Placental lesions were classified as lesions related to maternal or fetal malperfusion lesions (MVM, FVM), vascular and villous changes, and inflammatory lesions.

RESULTS

Overall, 185 neonates met the inclusion criteria. The FGR-twin group (59/185) had a higher rate of PE, lower GA at delivery, lower birthweight, and a higher rate of neonatal composite adverse outcomes compared to the FGR-singleton group. Moreover, placental pathology of the FGR-twin group demonstrated a higher rate of MVM lesions (p = 0.035).

DISCUSSION

In our cohort, neonates considered FGR based on twin-specific charts had worse neonatal outcomes with underlying placental insufficiency demonstrated by a higher rate of placental malperfusion vascular lesions. Our findings support using a twin-specific chart to diagnose FGR that is more clinically relevant.

Amniotic Fluid Disorders: From Prenatal Management to Neonatal Outcomes

Amniotic fluid volume assessment has become standard in the surveillance of fetal well-being, especially in high-risk pregnancies. Amniotic fluid disorders are a frequent and important topic in fetal and perinatal medicine. However, although important advances have been achieved, many important and challenging questions remain unanswered to date. An abnormally low amniotic fluid volume, referred to as oligohydramnios, has been traditionally considered a possible indicator of placental insufficiency or fetal compromise and is associated with an increased rate of obstetric interventions. An excess of amniotic fluid, referred to as polyhydramnios, may be secondary to fetal or maternal conditions and has been associated with a variety of adverse pregnancy outcomes, especially when it is severe. The ultrasonographic detection of an amniotic fluid disorder should prompt a proper workup to identify the underlying etiology. Data on the association of isolated oligohydramnios or idiopathic polyhydramnios with adverse obstetric and perinatal outcomes are conflicting. While the management of secondary oligohydramnios is usually guided by the underlying condition, the management of isolated oligohydramnios is poorly defined. Similarly, the management of idiopathic and secondary polyhydramnios is not yet standardized. There is an urgent need for randomized clinical trials to provide stronger recommendations on the management of these two common conditions.

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.

Amniotic-Umbilical-to-Cerebral Ratio - A Novel Ratio Combining Doppler Parameters and Amniotic Fluid Volume to Predict Adverse Perinatal Outcome in SGA Fetuses At Term

PURPOSE

 Introduction of a novel ratio - the amniotic-umbilical-to-cerebral ratio (AUCR) - to predict adverse perinatal outcome in SGA fetuses at term and comparison of its predictive accuracy with established parameters.

MATERIALS AND METHODS

 This retrospective cohort study included 165 singleton pregnancies with SGA fetuses (birth weight < 10^th percentile) at term. Cases with planned vaginal delivery and documented pulsatility indices (PI) of the umbilical artery (UA), middle cerebral artery (MCA), and single deepest pocket (SDP) were included. CPR was calculated as the ratio between MCA PI and UA PI, UCR as the ratio between UA PI and MCA PI. AUCR was defined as follows: SDP/(UA PI/MCA PI). Adverse perinatal outcomes were defined as operative intervention (OI), OI due to fetal distress, admission to the neonatal intensive care unit (NICU), and composite adverse perinatal outcome (CAPO). Associations between Doppler parameters and these outcomes were estimated using regression analyses.

RESULTS

 OI was statistically significantly associated with UCR, SDP, and AUCR, whereas no association was observed for UA PI, MCA PI, and CPR. Fetuses requiring OI due to fetal distress revealed a significantly higher UA PI and UCR as well as a lower MCA PI, CPR, and AUCR. With regard to NICU admission and CAPO, a significantly higher UA PI and lower CPR were found. Furthermore, a significant association was shown for SDP, UCR, and AUCR. AUCR achieved the best area under the curve for all outcome parameters.

CONCLUSION

 AUCR leads to an improvement in the prediction of unfavorable outcome in SGA fetuses at term. Furthermore, results of our study show that UCR might be superior to CPR.

The effect of maternal intravenous hydration on amniotic fluid index in oligohydramnios

Objective

Assessing amniotic fluid determines an important dimension of fetal health. Significant relationships of oligohydramnios, which occurs in 1–2% of pregnancies, with abnormal pregnancy outcomes such as intrauterine growth retardation (IUGR), fetal anomalies, umbilical cord compression, fetal distress, preterm childbirth, meconium-stained amniotic fluid, perinatal mortality and cesarean section necessitate the measurement of amniotic fluid volume in many prenatal fetal health assessments.

Amniotic fluid volume may significantly fluctuate between different gestational ages. Reduced uteroplacental perfusion can cause oligohydramnios by decreasing fetal renal blood flow and urine output. The appropriate management of isolated term oligohydramnios (ITO) is controversial. This study was performed aimed to assess the effect of maternal intravenous hydration on amniotic fluid index in oligohydramnios.

Result

Forty-eight hours after completing fluid therapy, statistically significant differences were observed in the mean AFI in the intervention group (4.06 ± 0.33) and the control group (3.61 ± 0.35) (P < 0.0001) and also between the intervention group (0.532 ± 0.45) and the controls (−0.036 ± 0.18) (P < 0.0001).

Conclusion

The results of the present study suggested that maternal intravenous hydration significantly increases AFI in women with oligohydramnios.

Umbilical cord diameter in the prediction of foetal growth restriction: a cross sectional study

This was a cross sectional study with a prospective design conducted from October 2018 to October 2019. We recruited patients at risk for FGR and normal pregnant women. Each patient had ultrasound examination for the umbilical cord diameter in the 28th, 32nd, 36th, and the 40th week, Foetal growth restriction developed in 10/76 (13.2%) patients in the at risk group. The umbilical cord diameter was significantly lower in the at risk group (1.8 ± 0.2 versus 2.0 ± 0.2 in the control group with a p value of <.001). The umbilical cord diameter was highly predictive for the occurrence of FGR at each antenatal care visit as well as at delivery. We concluded that the umbilical cord diameter was a significant predictor of foetal growth restriction when applied through the antenatal care visits. It is a simple and easy method causing no distress for the patients.IMPACT STATEMENTWhat is already known on this subject? Conflicting results exist regarding the predictive role of the umbilical cord in foetal growth restriction.What do the results of this study add? Foetal umbilical cord diameter was correlated significantly to foetal weight and had a significant predictive role in the prediction of FGR. The cut off values for the umbilical cord diameter in women with FGR were not evaluated before.What are the implications of these findings for clinical practice and/or further research? Comparing the ultrasound findings with histopathologic examination of the umbilical cord and the placentas would be recommended.

Dynamic thiol/disulphide homeostasis and ischemic modified albumin levels in isolated oligohydramnios

OBJECTIVE

Oligohydramnios is defined as amniotic fluid index in ultrasonographic measurement is less than 5 percentile according to gestational age, the amniotic fluid volume is ≤ 5 cm, or if the single deepest dial is < 2 cm. The condition of oligohydramnios that not with fetal structural/chromosomal abnormalities, intrauterine growth retardation, intrauterine infection and maternal disease is described as isolated oligohydramnios (IO). The aim of this study is to examine whether oxidative stress and reactive oxygen species (ROS) have a place in the pathophysiology of IO.

MATERIALS AND METHODS

In this prospective case-control study, a total of 126 participants were included. The patient group consisted of 65 patients who were diagnosed IO, and the control group consisted of 61 healthy normal pregnants. Native thiol (-SH), total thiol (-SH + -SS), dynamic disulfide (-SS), IMA values from maternal serum were measured and compared between groups.

RESULTS

Maternal serum -SH and -SH + -SS values were significantly lower in the IO group than in the control group (409.47 ± 55.36 μmol/L vs. 437.40 ± 48.68 μmol/L, p = 0.03 and 457.40 ± 63.01 μmol/L vs. 484.59 ± 52.75 μmol/L, p = 0.01). In the IO group when -SS/-SH and -SS/-SH + -SS ratio was found to be statistically significantly higher than control group (5.84 ± 1.1 vs 5.41 ± 0.71, p = 0.01 and 5.2 ± 0.88 vs 4.8 ± 0.58, p = 0.01), -SH/-SH + -SS ratio was significantly lower (89.56 ± 1.7 vs 90.24 ± 1.16, p = 0.01). There was no significant difference in terms of -SS value (p = 0.66). IMA value was significantly higher in the IO group than control group (0.76 ± 0.10 ABSU vs 0.68 ± 0.06, p < 0.01). It is seen as a result of ROC analysis that -SH, -SH + -SS, -SS/-SH, -SS/-SH + -SS, -SH/-SH + -SS and IMA values have a diagnostic value for IO (p < 0.05).

CONCLUSION

The thiol/disulfide balance shifted towards oxidative stress in IO compared to control group. So oxidative stress and ROS have a place in the pathophysiology of IO.

Placental pathology: Pathways leading to or associated with perinatal brain injury in experimental neurology, special issue: Placental mediated mechanisms of perinatal brain injury

Perinatal brain injury is a multifactorial process. In utero placental physiology plays a major role in neuroprotection and the normal development of the fetal central nervous system. Advances in placental pathology have clarified several specific mechanisms of injury and the histologic lesions most strongly associated with them. This review provides an updated summary of the relevant placental anatomy and physiology, the specific placental pathways leading to brain injury, the revised Amsterdam classification system for placental pathology, and the known associations of specific placental lesions with subtypes of adverse neurologic outcomes.

Four major patterns of placental injury: a stepwise guide for understanding and implementing the 2016 Amsterdam consensus

The Amsterdam classification system defines four major patterns of placental injury, maternal vascular malperfusion, fetal vascular malperfusion, acute chorioamnionitis, and villitis of unknown etiology, and lists the histologic findings that characterize each. However, there continues to be uncertainty regarding specific definitions, histologic mimics, grading and staging, and what combination of findings is required to diagnose each pattern of injury in a reproducible fashion. The purpose of this review is to clarify some of these issues by suggesting a stepwise approach to more fully realize the potential of this new classification system. In our view, the critical steps for correctly identifying and communicating each pattern of injury are (1) familiarity with the underlying pathophysiology and known clinical associations, (2) incorporation of important gross findings, (3) learning to recognize underlying architectural alterations and defining features at low power, (4) using higher magnification to narrow the differential diagnosis and assess severity (grading) and duration (staging), and (5) adopting a template for generating standardized placental reports that succinctly provide useful information for patient care and research applications.

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.

Oligohydramnios: how severe is severe?

OBJECTIVE

To investigate whether the severity of isolated oligohydramnios at term is associated with increased rates of adverse perinatal outcome.

STUDY DESIGN

A retrospective study conducted in a single medical center from 2017 to 2019. All low-risk pregnancies with incidental isolated oligohydramnios at term were included. The degree of oligohydramnios was arbitrarily classified into mild (AFI = 41-50 mm), moderate (AFI = 21-40 mm) and severe (AFI = 0-20 mm).

RESULT

A total of 610 women were included: 202 with a mild (33.1%), 287 moderate (47.0%), and 121 severe oligohydramnios (19.8%). Non-reassuring monitor requiring immediate delivery and worse composite neonatal outcome were more common among severe than mild or moderate oligohydramnios (14.0% and 6.4%, 7.3% respectively; p = .039 and 19.8%, 10.9% and 11.8%, respectively; p = .048).

CONCLUSION

Low-risk pregnancies with isolated severe oligohydramnios at term have a higher tendency toward non-reassuring fetal monitoring requiring prompt delivery and adverse neonatal outcomes, this calls for close intrapartum surveillance.