Admission cardiotocography: A hospital based validation study

The association between undetected small-for-gestational age and abnormal admission cardiotocography: A registry-based study

OBJECTIVE

To assess the association between undetected small-for-gestational age (SGA) fetuses and abnormal admission cardiotocography (admCTG) in a low-risk population.

DESIGN

An observational study.

SETTING

Four hospitals in Stockholm-Gotland, Sweden.

SAMPLE

A cohort of 127 461 deliveries between 1 February 2012 and 15 June 2020.

METHODS

This cohort was linked to the Swedish Neonatal Quality Register. Pregnancies were designated as high or low risk at the time of admission to the labour ward according to pre-defined risk measures. SGA was defined as a birthweight at or below the tenth centile and at or below the third centile for gestational age.

MAIN OUTCOME MEASURES

The main outcome was the proportion of undetected SGA by admCTG (normal or abnormal). The secondary outcome was a composite severe adverse neonatal outcome for fetuses born less than 6 hours after admission (Apgar score <4 at 5 minutes, hypoxic-ischaemic encephalopathy grade of 2-3, neonatal seizures and neonatal death).

RESULTS

The rate of abnormal admCTG was 4.9%. The proportion of SGA at or below the tenth centile was higher in the abnormal admCTG group than in the normal admCTG group, 18.6% versus 9.7% (odds ratio 2.1, 95% CI 1.9-2.3). Abnormal admCTG and SGA (≤10th) was associated with a more than 20-fold increased risk of an adverse outcome compared with normal admCTG and non-SGA (adjusted odds ratio 23.7, 95% CI 9.8-57.3). The latter had a risk of 1/2000 of an adverse outcome.

CONCLUSIONS

In this low-risk population, undetected SGA fetuses were more prone to having abnormal admCTG and had a substantially higher risk of severe adverse neonatal outcomes.

Multimodal Deep Learning for Predicting Adverse Birth Outcomes Based on Early Labour Data

Cardiotocography (CTG) is a widely used technique to monitor fetal heart rate (FHR) during labour and assess the health of the baby. However, visual interpretation of CTG signals is subjective and prone to error. Automated methods that mimic clinical guidelines have been developed, but they failed to improve detection of abnormal traces. This study aims to classify CTGs with and without severe compromise at birth using routinely collected CTGs from 51,449 births at term from the first 20 min of FHR recordings. Three 1D-CNN and LSTM based architectures are compared. We also transform the FHR signal into 2D images using time-frequency representation with a spectrogram and scalogram analysis, and subsequently, the 2D images are analysed using a 2D-CNNs. In the proposed multi-modal architecture, the 2D-CNN and the 1D-CNN-LSTM are connected in parallel. The models are evaluated in terms of partial area under the curve (PAUC) between 0-10% false-positive rate; and sensitivity at 95% specificity. The 1D-CNN-LSTM parallel architecture outperformed the other models, achieving a PAUC of 0.20 and sensitivity of 20% at 95% specificity. Our future work will focus on improving the classification performance by employing a larger dataset, analysing longer FHR traces, and incorporating clinical risk factors.

Is there a relation between stillbirth and low levels of vitamin D in the population? A bi-national follow-up study of vitamin D fortification

BACKGROUND

Stillbirth has been associated with low plasma vitamin D. Both Sweden and Finland have a high proportion of low plasma vitamin D levels (< 50 nmol/L). We aimed to assess the odds of stillbirth in relation to changes in national vitamin D fortification.

METHODS

We surveyed all pregnancies in Finland between 1994 and 2021 (n = 1,569,739) and Sweden (n = 2,800,730) with live or stillbirth registered in the Medical Birth Registries. The mean incidences before and after changes in the vitamin D food fortification programs in Finland (2003 and 2009) and Sweden (2018) were compared with cross-tabulation with 95% confidence intervals (CI).

RESULTS

In Finland, the stillbirth rate declined from ~ 4.1/1000 prior to 2003, to 3.4/1000 between 2004 and 2009 (odds ratio [OR] 0.87, 95% CI 0.81-0.93), and to 2.8/1000 after 2010 (OR 0.84, 95% CI 0.78-0.91). In Sweden, the stillbirth rate decreased from 3.9/1000 between 2008 and 2017 to 3.2/1000 after 2018 (OR 0.83, 95% CI 0.78-0.89). When the level of the dose-dependent difference in Finland in a large sample with correct temporal associations decreased, it remained steady in Sweden, and vice versa, indicating that the effect may be due to vitamin D. These are observational findings that may not be causal.

CONCLUSION

Each increment of vitamin D fortification was associated with a 15% drop in stillbirths on a national level. If true, and if fortification reaches the entire population, it may represent a milestone in preventing stillbirths and reducing health inequalities.

Cardiotocography and Clinical Risk Factors in Early Term Labor: A Retrospective Cohort Study Using Computerized Analysis With Oxford System

OBJECTIVE

The role of cardiotocography (CTG) in fetal risk assessment around the beginning of term labor is controversial. We used routinely collected clinical data in a large tertiary hospital to investigate whether infants with "severe compromise" at birth exhibited fetal heart rate abnormalities in their first-hour CTGs and/or other clinical risks, recorded as per routine care.

MATERIALS AND METHODS

Retrospective data from 27,927 parturitions (single UK tertiary site, 2001-2010) were analyzed. Cases were included if the pregnancy was singleton, ≥36 weeks' gestation, cephalic presentation, and if they had routine intrapartum CTG as per clinical care. Cases with congenital abnormalities, planned cesarean section (CS), or CS for reasons other than "presumed fetal compromise" were excluded. We analyzed first-hour intrapartum CTG recordings, using intrapartum Oxford System (OxSys) computer-based algorithms. To reflect the effect of routine clinical care, the data was stratified into three exclusive groups: infants delivered by CS for "presumed fetal compromise" within 2 h of starting the CTG (Emergency CS, n = 113); between 2 and 5 h of starting the CTG (Urgent CS, n = 203); and the rest of deliveries (Others, n = 27,611). First-hour CTG and clinical characteristics were compared between the groups, sub-divided to those with and without severe compromise: a composite outcome of stillbirth, neonatal death, neonatal seizures, encephalopathy, resuscitation followed by ≥48 h in neonatal intensive care unit. Two-sample t-test, X² test, and Fisher's exact test were used for analysis.

RESULTS

Compared to babies without severe compromise, those with compromise had significantly higher proportion of cases with baseline fetal heart rate ≥150 bpm; non-reactive trace; reduced long-term and short-term variability; decelerative capacity; and no accelerations in the first-hour CTG across all groups. Prolonged decelerations(≥3 min) were also more common. Thick meconium and small for gestational age were consistently more common in compromised infants across all groups. There was more often thick meconium, maternal fever ≥38 C, sentinel events, and other clinical risk factors in the Emergency CS and Urgent CS compared to the Others group.

CONCLUSION

A proportion of infants born with severe compromise had significantly different first-hour CTG features and clinical risk factors.