This pilot study examined the use of early HbA1c in screening for gestational diabetes mellitus and adverse pregnancy outcomes in Singapore. One hundred and fifty-one pregnant women with a gestational age of under 14 weeks had an HbA1c test measured with their antenatal bloods prior to a second trimester oral glucose tolerance test. Patient characteristics and pregnancy outcome data were collected. Gestational diabetes mellitus prevalence was 11%. A receiver operating characteristic curve showed an HbA1c level of 5.2% (33 mmol/mol), had an 82% sensitivity, 72% specificity, 97% negative predictive value and 27% positive predictive value to predict gestational diabetes mellitus. Women with HbA1c of 5.2% (33 mmol/mol) or over 5.2% (33 mmol/mol) were older, had higher BMI and were less likely to be Chinese than those with HbA1c less than 5.2% (33 mmol/mol). There was no difference in pregnancy outcomes. Early HbA1c less than 5.2% (33 mmol/mol) may be useful to exclude low-risk Singaporean women from further testing, while those with HbA1c of 5.2% (33 mmol/mol) or greater would still need a oral glucose tolerance test between 24 and 28 weeks’ gestation.
Background
To investigate whether the existing surgical technique for uterine closure at repeat lower segment Caesarean section (LSCS) can be modified to achieve adequate residual myometrial thickness (RMT) to ensure scar integrity and reduce complications in future pregnancy.
Methods
Women with a significant scar defect at repeat LSCS had the anterior uterine wall closed by a single experienced obstetrician with a technique focused on recognition, mobilisation and apposition of the retracted myometrial edges at the boundary of the defect. This was aimed at anatomical restoration of the lower segment. The RMT at the scar area was assessed by postnatal pelvic ultrasound scan at three months.
Results
Thirty women with a history of at least one previous CS, incidentally found to have a large defect at operation underwent the technique with prior consent. A postnatal scan showed a mean residual myometrial thickness of 8.4 mm (SD ±1.3 mm; range 5.6–11.0 mm). The average operating time was 91 mins and the average blood loss 728 ml. Two women who underwent the repair have gone on to have a further uneventful CS.
Conclusion
This modified technique resulted in scan evidence of an RMT indicative of uterine wall stability postnatally and offers the potential for reducing the risk of rupture and placenta accreta spectrum (PAS) in future pregnancy.
What are the novel findings of this work?In pregnant women with previous Cesarean section, assessment of the lower uterine segment scar on transvaginal ultrasound at the time of first-trimester aneuploidy screening is accurate and feasible. This screening strategy can identify reliably women at high risk of subsequent development of placenta accreta spectrum disorder.
What are the clinical implications of this work?Routine first-trimester assessment of the location of the lower uterine segment scar in women with prior Cesarean section may become part of early risk assessment for placenta accreta spectrum disorder. Implementation of such a scanning protocol should help plan optimal multidisciplinary management of high-risk pregnancies while reassuring the vast majority of women with previous Cesarean section.
Objective
We previously described a technique for repair of the myometrial defect at repeat Caesarean section which increases residual myometrial thickness thereby potentially reducing future niche-related complications. Here we describe how this technique can be modified for use for placenta accreta spectrum disorders, in line with emerging evidence that this is more a disorder of myometrial deficiency than morbid adherence.
Design
The surgical performance of peripartum hysterectomy was compared with that of the modified technique in all women having repeat Caesarean delivery for placenta accreta spectrum disorder in a tertiary unit in Singapore between December 2019 and October 2021.
Methods
Modification of the original technique involved the systematic delivery of the placenta starting from its most posterior attachment after uterine exteriorization. This is followed by the identification, mobilization, and apposition of the boundaries of myometrial defects as described previously.
Results
Ten women had Caesarean hysterectomy and ten had Caesarean section using the modified approach. Age and gestational age at delivery were similar for the two groups. Women in the modified technique group had had fewer prior Caesarean sections and had a lower body mass index. Operating time, estimated blood loss and need for transfusion were all lower in the myometrial repair group but without statistical significance. There were no visceral injuries in the repair group but there was one bladder injury in the hysterectomy group.
Conclusion
The modified approach provides an effective alternative to peripartum hysterectomy with favourable surgical profile and allows uterine conservation with restoration of myometrial thickness.
Introduction: An antenatal scoring system for vaginal birth after caesarean section (VBAC)
categorises patients into a low or high probability of successful vaginal delivery. It enables counselling
and preparation before labour starts. The current study aims to evaluate the role of Grobman nomogram
and the Kalok scoring system in predicting VBAC success in Singapore.
Methods: This is a retrospective study on patients of gestational age 37 weeks 0 day to 41 weeks
0 day who underwent a trial of labour after 1 caesarean section between September 2016 and
September 2017 was conducted. Two scoring systems were used to predict VBAC success, a nomogram
by Grobman et al. in 2007 and an additive model by Kalok et al. in 2017.
Results: A total of 190 patients underwent a trial of labour after caesarean section, of which 103
(54.2%) were successful. The Kalok scoring system (AUC [area under the curve] 0.740) was a better
predictive model than Grobman nomogram (AUC 0.664). Patient’s age odds ratio [OR] 0.915, 95%
CI [confidence interval] 0.844–0.992), body mass index at booking (OR 0.902, 95% CI 0.845–0.962),
and history of successful VBAC (OR 4.755, 95% CI 1.248–18.120) were important factors in
predicting VBAC.
Conclusion: Neither scoring system was perfect in predicting VBAC among local women. Further
customisation of the scoring system to replace ethnicity with the 4 races of Singapore can be made to
improve its sensitivity. The factors identified in this study serve as a foundation for developing a
population-specific antenatal scoring system for Singapore women who wish to have a trial of VBAC.
Keywords: Antenatal scoring system, caesarean section, obstetrics and gynaecology, trial of labour after
caesarean section, vaginal birth after caesarean section
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