Can the Pfannenstiel skin incision length be adjusted according to the fetal head during elective cesarean delivery?

Objective

The study aims to determine whether the Pfannenstiel skin incision can be adjusted according to the fetal head's occipitofrontal diameter (OFD) during primary cesarean delivery.

Background

Eligible 114 nulliparous women delivered at term by cesarean section in which Pfannenstiel skin incision was performed according to the OFD of the fetal head between June 2017 and September 2021 were included. Excluded cases were non-vertex presentations, all emergency cesarean sections, severe preeclampsia, women in an active phase of the first stage of labor and second stage of labor, placenta previa and low-lying placenta, multiple pregnancies, and uncontrolled gestational diabetes mellitus.

Results

Among 114 eligible nulliparous women, the mean OFD was 116.1 ± 7.2 (99-138) mm, and the measurement of the Pfannenstiel skin incision length, which was performed according to the OFD was found to be 122.8 ± 9.2 (100-155) mm. The difference between OFD and Pfannenstiel incision kept remained within 10 mm in 90 (82.5.2%), 10-20 mm in 17 (15.5%), and more than 20 mm in two women (1.8%). This technique was successful in 109 (95.6%) out of 114 women without extending the skin incision. In five women, skin incision needed to be extended up to 38 mm. In 10 women (8.7%), the rectus abdominis muscle was cut partially to deliver the fetal head. The mean fetal umbilical artery pH was 7.33 ± 0.05. No neonatal hypoxia was encountered in the study.

Conclusion

Pfannenstiel skin incision can be adjusted according to the OFD with minimal margins of error. This technique may provide better cosmetic results by avoiding unnecessarily prolonged incisions with similar newborn outcomes.

Clinical Trial Registration

Clinicaltrials.gov, identifier [NCT05632796].

Diagnostic accuracy of fetal choroid plexus length to head biometry ratio at 11 to 13 weeks for open spina bifida

BACKGROUND

Open spina bifida is a major congenital anomaly with an estimated incidence of <1 in 1000. The diagnosis of open spina bifida is usually made during the second trimester, but first-trimester detection rate of spina bifida is increasingly reported. Recently, the mean choroid plexus length to occipitofrontal diameter ratio was reported to be increased in fetuses with open spina bifida. The ratio reflects the so-called dry brain effect caused by cerebrospinal fluid leakage and expansion of the choroid plexus into the lateral ventricles. The mean choroid plexus length to occipitofrontal diameter ratio appears to be a promising tool for early detection of open spina bifida, but its diagnostic accuracy is yet to be determined in a large cohort.

OBJECTIVE

This study aimed to assess the predictive accuracy of mean choroid plexus length to occipitofrontal diameter ratio recorded at 11 to 13 weeks' gestation for the detection of open spina bifida.

STUDY DESIGN

This was a retrospective cohort of patients treated in a tertiary referral center. Fetuses in which open spina bifida was detected at 16 to 24 weeks' gestation and normal fetuses were included in the cohort. Biparietal diameter and occipitofrontal diameter were measured in an axial view. The length of choroid plexus was measured along its longest diameter in the same plane. Ultrasound images were examined offline, and the operator was blinded to the clinical diagnosis. The predictive accuracy was evaluated using the area under the curve and positive and negative predictive values.

RESULTS

We included 3300 pregnant women, of whom 24 (0.73%) had the fetuses affected by open spina bifida. The area under the curve values were 0.921 for mean choroid plexus length to occipitofrontal diameter ratio and 0.933 for its multiple of the median. Mean choroid plexus length to biparietal diameter ratio indicated similar results, with area under the curve values of 0.928 and 0.931 for raw ratio and multiple of the median ratio models, respectively. The optimal cutoffs of the mean choroid plexus to occipitofrontal diameter ratio and multiple of the median ratios were 0.662 and 1.263, respectively. The optimal mean choroid plexus to occipitofrontal diameter ratio and multiple of the median ratio cutoffs provided a positive predictive value of 90.9% and a negative predictive value of 99.6%. The number of affected spinal segments was significantly higher in fetuses with a ratio above 0.662 (P=.022).

CONCLUSION

The mean choroid plexus length to occipitofrontal diameter ratio at 11 to 13 weeks' gestation is a promising tool for the prenatal detection of open spina bifida.

Discrepancy in fetal head biometry between ultrasound and MRI in suspected microcephalic fetuses

Background Microcephaly is one of the most common fetal structural abnormalities, and prenatal microcephaly is considered a group I malformation of cortical development diagnosed according to ultrasound (US) skull measurements. Purpose To evaluate the agreement between fetal head US and magnetic resonance imaging (MRI) biometric measurements of suspected microcephalic fetuses. Material and Methods This institutional review board-approved retrospective study with waived informed consent included 180 pregnant women and was conducted at our medical center from March 2011 to April 2013. Biparietal diameter (BPD) and occipitofrontal diameter (OFD) results of fetal head US normograms were compared to normograms for MRI. We used Pearson and Spearman rho non-parametric correlation coefficients to assess the association between two quantitative variables, paired t-test for paired quantitative variables, and McNemar test for paired qualitative variables. Results The average BPD but not the average OFD percentiles in fetal head US differed significantly from the MRI results ( P < 0.0001). When looking at the accepted microcephaly threshold, both BPD and OFD percentiles differed significantly from MRI ( P < 0.0001 and P < 0.004, respectively). There was no correlation between US-measured skull biometry and MRI-measured brain biometry. Estimated cerebrospinal fluid volumes were significantly lower in the study group compared to 120 fetuses with normal findings in prenatal head US and MRI. Also, we have created a MRI-based normogram of fetal head circumference and gestational age. Conclusion The diagnosis of microcephaly by US alone may be insufficient and ideally should be validated by MRI before a final diagnosis is established.

Scientific basis for standardization of fetal head measurements by ultrasound: a reproducibility study

OBJECTIVE

To compare the standard methods for ultrasound measurement of fetal head circumference (HC) and biparietal diameter (BPD) (outer-to-outer (BPDoo) vs outer-to-inner (BPDoi) caliper placement), and compare acquisition of these measurements in transthalamic (TT) vs transventricular (TV) planes.

METHODS

This study utilized ultrasound images acquired from women participating in the Oxford arm of the INTERGROWTH-21(st) Project. In the first phase of the study, BPDoo and BPDoi were measured on stored images. In the second phase, real-time measurements of BPD, occipitofrontal diameter (OFD) and HC in TT and TV planes were obtained by pairs of sonographers. Reproducibility of measurements made by the same (intraobserver) and by different (interobserver) sonographers, as well as the reproducibility of caliper placement and measurements obtained in different planes, was assessed using Bland-Altman plots.

RESULTS

In Phase I, we analyzed ultrasound images of 108 singleton fetuses. The mean intraobserver and interobserver differences were < 2% (1.34 mm) and the 95% limits of agreement were < 5% (3 mm) for both BPDoo and BPDoi. Neither method for measuring BPD showed consistently better reproducibility. In Phase II, we analyzed ultrasound images of 100 different singleton fetuses. The mean intraobserver and interobserver differences were < 1% (2.26 mm) and the 95% limits of agreement were < 8% (14.45 mm) for all fetal head measurements obtained in TV and TT planes. Neither plane for measuring fetal head showed consistently better reproducibility. Measurement of HC using the ellipse facility was as reproducible as HC calculated from BPD and OFD. OFD by itself was the least reproducible of all fetal head measurements.

CONCLUSIONS

Measurements of BPDoi and BPDoo are equally reproducible; however, we believe BPDoo should be used in clinical practice as it allows fetal HC to be measured and compared with neonatal HC. For all head measurements, TV and TT planes provide equally reproducible values at any gestational age, and HC values are similar in both planes. Fetal head measurement in the TT plane is preferable as international standards in this plane are available; however, measurements in the TV plane can be plotted on the same standards. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.