Evaluation of classic and novel ultrasound signs of placenta accreta spectrum

OBJECTIVES

Improvement in the antenatal diagnosis of placenta accreta spectrum (PAS) would allow preparation for delivery in a referral center, leading to decreased maternal morbidity and mortality. Our objectives were to assess the performance of classic ultrasound signs and to determine the value of novel ultrasound signs in the detection of PAS.

METHODS

This was a retrospective cohort study of women with second-trimester placenta previa who underwent third-trimester transvaginal ultrasound and all women with PAS in seven medical centers. A retrospective image review for signs of PAS was conducted by three maternal-fetal medicine physicians. Classic signs of PAS were defined as placental lacunae, bladder-wall interruption, myometrial thinning and subplacental hypervascularity. Novel signs were defined as small placental lacunae, irregular placenta-myometrium interface (PMI), vascular PMI, non-tapered placental edge and placental bulge towards the bladder. PAS was diagnosed based on difficulty in removing the placenta or pathological examination of the placenta. Multivariate regression analysis was performed and receiver-operating-characteristics (ROC) curves were generated to assess the performance of combined novel signs, combined classic signs and a model combining classic and novel signs.

RESULTS

A total of 385 cases with placenta previa were included, of which 55 had PAS (28 had placenta accreta, 11 had placenta increta and 16 had placenta percreta). The areas under the ROC curves for classic markers, novel markers and a model combining classic and novel markers for the detection of PAS were 0.81 (95% CI, 0.75-0.88), 0.84 (95% CI, 0.77-0.90) and 0.88 (95% CI, 0.82-0.94), respectively. A model combining classic and novel signs performed better than did the classic or novel markers individually (P = 0.03). An increasing number of signs was associated with a greater likelihood of PAS. With the presence of 0, 1, 2 and ≥ 3 classic ultrasound signs, PAS was present in 5%, 24%, 57% and 94% of cases, respectively.

CONCLUSIONS

We have confirmed the value of classic ultrasound signs of PAS. The use of novel ultrasound signs in combination with classic signs improved the detection of PAS. These findings have clinical implications for the detection of PAS and may help guide the obstetric management of patients diagnosed with these placental disorders. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

A randomized trial of the bactericidal effects of chlorhexidine vs povidone-iodine vaginal preparation

BACKGROUND

Precesarean vaginal preparation significantly reduces postpartum infections. Although povidone-iodine is the most commonly used vaginal antiseptic, evidence suggests that chlorhexidine gluconate may be more effective.

OBJECTIVE

We aimed to compare the bactericidal effect of chlorhexidine gluconate and povidone-iodine on vaginal bacterial colony counts in pregnancy.

MATERIALS AND METHODS

We conducted a prospective randomized controlled trial of vaginal preparation with 0.5% chlorhexidine gluconate vs 10% povidone-iodine vs saline in women undergoing cesarean delivery at ≥34 weeks' gestation. Women in labor or those with ruptured membranes, chorioamnionitis, abnormal placentation, or allergy to study agents were excluded. Vaginal specimens were collected aseptically in the operating room immediately before and 5-10 minutes after vaginal cleansing with 3 sterile sponge sticks. Our primary outcome was postintervention aerobic and anaerobic bacterial colony counts, assessed by blinded investigators. Two-way analysis of variance with simple-effects analysis and Tukey post hoc test were used for multiple group comparisons. Secondary outcomes included baseline colony counts, change in colony counts, adverse events, and maternal infections.

RESULTS

A total of 29 women consented and underwent vaginal preparation with chlorhexidine gluconate (n=10), povidone-iodine (n=9), or saline (n=10). Groups were similar with respect to maternal age, body mass index, race, ethnicity, parity, group B streptococcus status, and gestational age. There were no differences in baseline colony counts. Vaginal preparation with povidone-iodine resulted in lower aerobic and anaerobic colony counts compared with chlorhexidine gluconate and saline (P≤.01 and P≤.0001, respectively). Povidone-iodine eliminated more than 99.9% of bacteria, whereas chlorhexidine gluconate and saline eliminated more than 99% and 95% of bacteria, respectively. Although all agents decreased aerobic and anaerobic bacterial counts, 0.5% chlorhexidine gluconate was no more effective than saline in reducing anaerobic bacteria. There were no reported adverse effects or postpartum infections.

CONCLUSION

Compared with 0.5% chlorhexidine gluconate, 10% povidone-iodine was more effective in reducing vaginal bacterial colony counts before cesarean delivery.

Effect of Delayed vs Immediate Umbilical Cord Clamping on Maternal Blood Loss in Term Cesarean Delivery: A Randomized Clinical Trial

IMPORTANCE

The American College of Obstetricians and Gynecologists recommends a delay in umbilical cord clamping in term neonates for at least 30 to 60 seconds after birth. Most literature supporting this practice is from low-risk vaginal deliveries. There are no published data specific to cesarean delivery.

OBJECTIVE

To compare maternal blood loss with immediate cord clamping vs delayed cord clamping in scheduled cesarean deliveries at term (≥37 weeks).

DESIGN, SETTING, AND PARTICIPANTS

Randomized clinical trial performed at 2 hospitals within a tertiary academic medical center in New York City from October 2017 to February 2018 (follow-up completed March 15, 2018). A total of 113 women undergoing scheduled cesarean delivery of term singleton gestations were included.

INTERVENTIONS

In the immediate cord clamping group (n = 56), cord clamping was within 15 seconds after birth. In the delayed cord clamping group (n = 57), cord clamping was at 60 seconds after birth.

MAIN OUTCOMES AND MEASURES

The primary outcome was change in maternal hemoglobin level from preoperative to postoperative day 1, which was used as a proxy for maternal blood loss. Secondary outcomes included neonatal hemoglobin level at 24 to 72 hours of life.

RESULTS

All of the 113 women who were randomized (mean [SD] age, 32.6 [5.2] years) completed the trial. The mean preoperative hemoglobin level was 12.0 g/dL in the delayed and 11.6 g/dL in the immediate cord clamping group. The mean postoperative day 1 hemoglobin level was 10.1 g/dL in the delayed group and 9.8 g/dL in the immediate group. There was no significant difference in the primary outcome, with a mean hemoglobin change of -1.90 g/dL (95% CI, -2.14 to -1.66) and -1.78 g/dL (95% CI, -2.03 to -1.54) in the delayed and immediate cord clamping groups, respectively (mean difference, 0.12 g/dL [95% CI, -0.22 to 0.46]; P = .49). Of 19 prespecified secondary outcomes analyzed, 15 showed no significant difference. The mean neonatal hemoglobin level, available for 90 neonates (79.6%), was significantly higher with delayed (18.1 g/dL [95% CI, 17.4 to 18.8]) compared with immediate (16.4 g/dL [95% CI, 15.9 to 17.0]) cord clamping (mean difference, 1.67 g/dL [95% CI, 0.75 to 2.59]; P < .001). There was 1 unplanned hysterectomy in each group.

CONCLUSIONS AND RELEVANCE

Among women undergoing scheduled cesarean delivery of term singleton pregnancies, delayed umbilical cord clamping, compared with immediate cord clamping, resulted in no significant difference in the change in maternal hemoglobin level at postoperative day 1.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03150641.

Fetal growth velocity in diabetics and the risk for shoulder dystocia: a case-control study

INTRODUCTION

Shoulder dystocia complicates up to 3% of vaginal births. The clinical ability to predict shoulder dystocia is limited, especially among diabetic women. We sought to evaluate if fetal growth trajectory measured from ultrasonographic (US) estimated fetal weight (EFW) percentiles was associated with increased risk for shoulder dystocia.

METHODS

We performed a case-control study among women diagnosed with diabetes at a single institution between 2005 and 2015. Two diabetic controls without shoulder dystocia based on the year of delivery were included for each woman with a shoulder dystocia. Women with a single EFW measurement, delivery by cesarean, or multiple gestation were excluded. Demographic and US data were collected. Fetal growth trajectory was calculated from EFW measurements in the last two growth ultrasound scans performed closest to delivery. We compared the odds of EFW percentile change per week above specific thresholds for shoulder dystocia cases versus controls. The following cutoffs were generated: a mean percentile per week increase of > 0%, ≥ 0.5%, ≥ 1%, and ≥ 2%. Among those with EFW percentile changes that decreased (<0%), we evaluated whether odds of an abdominal circumference (AC) > 75th percentile or an EFW > 75th percentile was higher for women with shoulder dystocia. The primary exposure was increased growth trajectory. Secondary outcomes included analysis of the following adverse neonatal outcomes: (i) low 5 minutes Apgar score, (ii) rates of NICU admission, and (iii) neonatal demise.

RESULTS

Of 3954 diabetics, we identified 68 cases with shoulder dystocia and 136 controls who did not have shoulder dystocia. Women who experienced a shoulder dystocia were more likely to be of advanced maternal age as compared to those without a shoulder dystocia (41.9% versus 23.5, p = .01); all other demographic characteristics were similar between groups. At growth trajectory cutoffs of > 0%, ≥ 0.5%, ≥ 1%, and ≥ 2% per week, odds ratios were increased among shoulder dystocia cases versus controls (OR = 1.8, 95% confidence interval (CI) = 0.9-3.3; OR = 1.6, 95% CI = 0.8-3.2; OR = 1.7, 95% CI = 0.7-3.9; and OR = 1.8, 95% CI = 0.6-5.3; respectively); however, this was not statistically significant. For women with fetal growth trajectories that decreased (< 0%), shoulder dystocia was associated with increased odds of fetal AC > 75th percentile and overall growth > 75th percentile (OR = 3.3, 95% CI = 1.5-7.1, OR = 4.8, 95% CI = 1.3-17.4, respectively). There was no difference in neonatal outcomes between shoulder dystocia cases and controls.

CONCLUSION

Future research is required to determine if fetal growth velocity proves to be a useful tool in identifying women at increased risk for shoulder dystocia. Larger studies are required for precise estimates of risk, and associated neonatal outcomes.