Amar Bhide

Recent advances in the management of placenta previa.

Purpose of review Despite the widespread and routine use of ultrasound to make the diagnosis of placenta previa, evidence-based classification and management strategies have failed to evolve over the years. The purpose of this review is to present the current evidence supporting the screening, diagnosis and management of placenta previa. Recent findings The prevalence of placenta previa is significantly overestimated due to the practice of routine mid-pregnancy scan, and many women currently undergo a repeat scan in late pregnancy for placental localization. Recent reports support limiting third-trimester scans to only those cases where the placental edge either reaches or overlaps the internal cervical os at 20-23 weeks of pregnancy. In some cases of mid-trimester placenta previa, the placental edge is more likely to ‘migrate’ than others, and it appears that ultrasound may be useful to predict this process. At term, women with placental edge within 2 cm of the internal cervical os require a Caesarean section for delivery, whereas an attempt at vaginal birth is appropriate if this distance is more that 2 cm. Ultrasound also has a role in the diagnosis and management of both vasa previa and placenta accreta. Summary This review addresses screening for placenta previa. A simple and pragmatic ultrasound classification of placenta previa and low-lying placenta is proposed. Caesarean section is recommended for delivery in cases of placenta previa. Women with a low-lying placenta have at least 60% chance of a vaginal birth, but should be monitored for post-partum haemorrhage. Vasa previa is a rare complication but antenatal diagnosis is possible. It should particularly be suspected in in-vitro fertilization conceptions, and where the placental edge covers the os in mid-pregnancy but recedes later on. Prenatal diagnosis of placenta accreta should be based on the placental lacunae signs rather than the absence of retro-placental clear space.

Prenatal diagnosis of non‐immune hydrops fetalis: what do we tell the parents?

The aim of this study is to outline the aetiology and outcome of a series of fetuses with non‐immune hydrops (NIH), detected prenatally. The findings are compared with a comprehensive review of recent reports.

The association between fetal Doppler and admission to neonatal unit at term

OBJECTIVEnFetal cerebroplacental ratio is emerging as a better proxy than birthweight for placental insufficiency and as a marker of fetal compromise at term. The extent to which these fetal Doppler changes are related to neonatal outcomes has not been systematically assessed. The main aim of this study was to evaluate the association between estimated fetal weight percentile, cerebroplacental ratio recorded at 34(+0)-35(+6) weeks gestation, and neonatal unit admission at term.nnnSTUDY DESIGNnThis was a retrospective cohort study in a tertiary referral center over an 11 year period from 2002 to 2012. The umbilical artery pulsatility index (PI), middle cerebral artery PI, and cerebroplacental ratio were recorded at 34(+0)-35(+6) weeks. Weight values were converted into percentiles and Doppler parameters into multiples of the median (MoM), adjusting for gestational age. Logistic regression analysis was performed to identify, and adjust for, potential confounders.nnnRESULTSnWe identified 2518 pregnancies in which a scan was performed at 34(+0)-35(+6) weeks and delivery occurred at or beyond 37 weeks. In the 2485 pregnancies included in the analysis, the umbilical artery PI MoM was significantly higher, and the middle cerebral artery PI and cerebroplacental ratio MoM significantly lower in the babies requiring neonatal unit admission (P < .05). However, the estimated fetal weight percentile was not significantly different between those who required neonatal unit admission and those who did not (P = .087). According to multivariate logistic regression, cerebroplacental ratio MoM (odds ratio, 0.39; 95% confidence interval, 0.19-0.79; P = .008) and gestational age at delivery (odds ratio, 0.70; 95% confidence interval, 0.61-0.80; P < .001) were significantly associated with the risk of neonatal unit admission, whereas maternal age and birthweight percentile were not (P = .183 and P = .460, respectively). Irrespective of birthweight or estimated fetal weight percentile, the fetal cerebroplacental ratio appears to be a better predictor of the need for neonatal unit admission (P < .001).nnnCONCLUSIONnLower cerebroplacental ratio and gestational age at delivery, but not fetal size, were independently associated with the need for admission to the neonatal unit at term in a high-risk patient group. The extent to which fetal hemodynamic assessment could be used to predict perinatal morbidity and optimize the timing of delivery merits further investigation.

Association between first-trimester maternal serum pregnancy-associated plasma protein-A and obstetric complications.

This study aimed to investigate the relationship between maternal serum pregnancy‐associated plasma protein‐A (PAPP‐A) in the first trimester of pregnancy and the development of preeclampsia (PE), early PE, small‐for‐gestational age (SGA) fetus and preterm delivery (PD).

Ultrasound-guided interstitial laser therapy for the treatment of placental chorioangioma

BACKGROUND Placental chorioangioma is a relatively rare malformation with potential to cause fetal hydrops and even death. We describe ultrasound-guided interstitial laser as a modality for treating chorioangiomas of the placenta. CASE The patient presented at midgestation with placental chorioangioma resulting in fetal cardiomegaly. Interstitial laser was performed under local anesthesia on two occasions and resulted in arrest of flow through the tumor feeder vessel. CONCLUSION Interstitial laser therapy in a patient with placental chorioangioma resulted in a successful outcome.

Prenatal ultrasound diagnosis and outcome of placenta previa accreta after cesarean delivery: a systematic review and meta-analysis

BACKGROUND: Women with a history of previous cesarean delivery, presenting with a placenta previa, have become the largest group with the highest risk for placenta previa accreta. OBJECTIVE: The objective of the study was to evaluate the accuracy of ultrasound imaging in the prenatal diagnosis of placenta accreta and the impact of the depth of villous invasion on management in women presenting with placenta previa or low‐lying placenta and with 1 or more prior cesarean deliveries. STUDY DESIGN AND DATA SOURCES: We searched PubMed, Google Scholar, clinicalTrials.gov, and MEDLINE for studies published between 1982 and November 2016. STUDY ELIGIBILITY CRITERIA: Criteria for the study were cohort studies that provided data on previous mode of delivery, placenta previa, or low‐lying placenta on prenatal ultrasound imaging and pregnancy outcome. The initial search identified 171 records, of which 5 retrospective and 9 prospective cohort studies were eligible for inclusion in the quantitative analysis. STUDY APPRAISAL AND SYNTHESIS METHODS: The studies were scored on methodological quality using the Quality Assessment of Diagnostic Accuracy Studies tool. RESULTS: The 14 cohort studies included 3889 pregnancies presenting with placenta previa or low‐lying placenta and 1 or more prior cesarean deliveries screened for placenta accreta. There were 328 cases of placenta previa accreta (8.4%), of which 298 (90.9%) were diagnosed prenatally by ultrasound. The incidence of placenta previa accreta was 4.1% in women with 1 prior cesarean and 13.3% in women with ≥2 previous cesarean deliveries. The pooled performance of ultrasound for the antenatal detection of placenta previa accreta was higher in prospective than retrospective studies, with a diagnostic odds ratios of 228.5 (95% confidence interval, 67.2–776.9) and 80.8 (95% confidence interval, 13.0–501.4), respectively. Only 2 studies provided detailed data on the relationship between the depth of villous invasion and the number of previous cesarean deliveries, independently of the depth of the villous invasion. A cesarean hysterectomy was performed in 208 of 232 cases (89.7%) for which detailed data on management were available. Positive correlations were found in the largest prospective studies between the cumulative rates of the more invasive forms of accreta placentation and the sensitivity and specificity of ultrasound imaging but not with diagnostic odds ratio values. We found no data on the ultrasound screening of placenta accreta at the routine midtrimester ultrasound examination from the nonexpert ultrasound units. CONCLUSION: Planning individual management for delivery is possible only with accurate evaluation of prenatal risk of accreta placentation in women presenting with a low‐lying placenta/previa and a history of prior cesarean delivery. Ultrasound is highly sensitive and specific in the prenatal diagnosis of accreta placentation when performed by skilled operators. Developing a prenatal screening protocol is now essential to further improve the outcome of this increasingly more common major obstetric complication.

Systematic review and meta-analysis of isolated posterior fossa malformations on prenatal ultrasound imaging (part 1): nomenclature, diagnostic accuracy and associated anomalies.

To explore the outcome in fetuses with prenatal diagnosis of posterior fossa anomalies apparently isolated on ultrasound imaging.

Screening for pre‐eclampsia by using changes in uterine artery Doppler indices with advancing gestation

The aim of the study was to assess the relationship of changes in uterine artery (UtA) Doppler pulsatility indices (PI) between first and second trimesters and the subsequent development of pre‐eclampsia.

Discordance in fetal biometry and Doppler are independent predictors of the risk of perinatal loss in twin pregnancies

OBJECTIVEnImpaired fetal growth might be better evaluated in twin pregnancies by assessing the intertwin discordance rather than the individual fetal size. The aim of this study was to investigate the prediction of perinatal loss in twin pregnancy using discordance in fetal biometry and Doppler.nnnSTUDY DESIGNnThis was a retrospective cohort study in a tertiary referral center. The estimated fetal weight (EFW), umbilical artery (UA) pulsatility index (PI), middle cerebral artery (MCA) PI, cerebroplacental ratio (CPR), and their discordance recorded at the last ultrasound assessment before delivery or demise of one or both fetuses were converted into centiles or multiples of the median (MoM). The discordance was calculated as the larger value-smaller value/larger value. A logistic regression analysis was performed to identify, and adjust for, potential confounders. The predictive accuracy was assessed using receiver-operating characteristic curve analysis.nnnRESULTSnThe analysis included 620 (464 dichorionic diamniotic and 156 monochorionic diamniotic) twin pregnancies (1240 fetuses). Perinatal loss of one or both fetuses complicated 16 pregnancies (2.6%). The combination of EFW discordance and CPR discordance had the best predictive performance (area under the curve, 0.96; 95% confidence interval, 0.92-1.00) for perinatal mortality. The detection rate, false-positive rate, positive likelihood ratio, and negative likelihood ratio were 87.5%, 6.7%, 13.08, and 0.13, respectively. The EFW centile, EFW below the 10th centile (small for gestational age), UA PI discordance, MCA PI discordance, and MCA PI MoM were significantly associated with the risk of perinatal loss on univariate analysis, but these associations became nonsignificant after adjusting for other confounders (P = .097, P = .090, P = .687, P = .360, and P = .074, respectively). The UA PI MoM, CPR MoM, EFW discordance, and CPR discordance were all independent predictors of the risk of perinatal loss, even after adjusting for potential confounders (P = .022, P = .002, P < .001, and P = .010, respectively).nnnCONCLUSIONnEFW discordance and CPR discordance are independent predictors of the risk of perinatal loss in twin pregnancies. Their combination could identify the majority of twin pregnancies at risk of perinatal loss. These findings highlight the importance of discordance in Doppler indices of fetal hypoxia, as well as fetal size, in assessing the risk of perinatal mortality.

First trimester uterine artery Doppler in women with previous pre-eclampsia.

Objective. To assess the role of first trimester uterine artery Doppler in pregnancies previously complicated by pre‐eclampsia. Design and setting. Case‐control study in two tertiary referral hospitals. Sample. A total of 56 singleton pregnancies in women with a previous pregnancy complicated by pre‐eclampsia (Group 1). For each case, two parous controls (Group 2) and two nulliparous controls (Group 3) with normal pregnancy outcome were matched. Methods. Doppler examination of the uterine arteries at 11–14 weeks’ gestation. Main outcome measures. Mean uterine artery resistance index (UtARI) and notching. Pregnancy outcome. Results. UtARI did not vary significantly between the three groups (0.73, 0.70 and 0.71, respectively). Women in Group 1 had a significantly higher prevalence of uterine artery notching than those in Group 2 (73 vs 57%, p = 0.04). In Group 1, the UtARI and prevalence of notching was not significantly increased when pregnancies were subsequently complicated by pre‐eclampsia (p = 0.60 and 0.61, respectively). However, in 12 pregnancies requiring delivery before 37 weeks due to pre‐eclampsia, fetal growth restriction, abruption or intrauterine fetal death, the UtARI was significantly higher than in the 44 pregnancies with normal outcome (p = 0.04). A combination of UtARI and notching showed sensitivities up to 75% and negative predictive values up to 88% for adverse outcome before 37 weeks. Conclusions. In pregnancies following a previous gestation complicated by pre‐eclampsia, first trimester uterine artery Doppler findings are similar to those observed in nulliparous women. In these high‐risk women, a combination of UtARI and notching can predict the risk of adverse outcome before 37 weeks.