Prelabor short-term variability in fetal heart rate by computerized cardiotocogram and maternal fetal doppler indices for the prediction of labor outcomes

Prediction of labour outcomes using prelabour computerised cardiotocogram and maternal and fetal Doppler indices: A prospective cohort study

OBJECTIVES

To investigate the association and the potential value of prelabour fetal heart rate short-term variability (STV) determined by computerised cardiotocography (cCTG) and maternal and fetal Doppler in predicting labour outcomes.

DESIGN

Prospective cohort study.

SETTING

The Prince of Wales Hospital, a tertiary maternity unit, in Hong Kong SAR.

POPULATION

Women with a term singleton pregnancy in latent phase of labour or before labour induction were recruited during May 2019-November 2021.

METHODS

Prelabour ultrasonographic assessment of fetal growth, Doppler velocimetry and prelabour cCTG monitoring including Dawes-Redman CTG analysis were registered shortly before induction of labour or during the latent phase of spontaneous labour.

MAIN OUTCOME MEASURES

Umbilical cord arterial pH, emergency delivery due to pathological CTG during labour and neonatal intensive care unit (NICU)/special care baby unit (SCBU) admission.

RESULTS

Of the 470 pregnant women invited to participate in the study, 440 women provided informed consent and a total of 400 participants were included for further analysis. Thirty-four (8.5%) participants underwent emergency delivery for pathological CTG during labour. A total of 6 (1.50%) and 148 (37.00%) newborns required NICU and SCBU admission, respectively. Middle cerebral artery pulsatility index (MCA-PI) and MCA-PI z-score were significantly lower in pregnancies that required emergency delivery for pathological CTG during labour compared with those that did not (1.23 [1.07-1.40] versus 1.40 [1.22-1.64], p = 0.002; and 0.55 ± 1.07 vs. 0.12 ± 1.06), p = 0.049]. This study demonstrated a weakly positive correlation between umbilical cord arterial pH and prelabour log10 STV (r = 0.107, p = 0.035) and the regression analyses revealed that the contributing factors for umbilical cord arterial pH were smoking (p = 0.006) and prelabour log10 STV (p = 0.025).

CONCLUSIONS

In pregnant women admitted in latent phase of labour or for induction of labour at term, prelabour cCTG STV had a weakly positive association with umbilical cord arterial pH but was not predictive of emergency delivery due to pathological CTG during labour.

Can Fetal Heart Lie? Intrapartum CTG Changes in COVID-19 Mothers

Background

COVID-19 infection has raised multiple concerns in pregnant mothers; many questioned the risk of vertical transmission and the implication on the feto-maternal outcome. Cardiotocogrm (CTG) is the principal method to observe intrapartum fetal well-being. This paper aims to verify intrapartum CTG changes seen in seropositive COVID-19 mothers versus healthy controls and looks into their relation to subsequent delivery mode and neonatal outcome.

Methods

A case-control study recruited 90 pregnant women at the labor word of AL Yarmouk Teaching Hospital. All were term pregnancy admitted for delivery. They were grouped into 2: seropositive COVID-19 confirmed by real-time RT-PCR test (30/90) and healthy controls (60/90). We recorded their demographic criteria, laboratory results, CTG changes, delivery mode, and indication.

Results

COVID-19 cases showed significantly higher pulse rate, temperature, and leukocyte counts. Cesarian deliveries (CS) were higher in cases versus healthy controls (70 % vs. 53.3 %) and P = 0.45. Analysis of the CS indications showed that abnormal fetal heart tracing accounts for 33.3 % versus 15.6 % (P-value = 0.015) for cases versus healthy controls. 60 % of COVID-19 cases exhibited abnormal CTG changes versus 19.4 % in healthy controls. These changes were primarily fetal tachycardia and reduced variabilities.

Conclusions

The higher incidence of abnormal CTG in COVID-19 cases, alongside infection signs and symptoms, underlies the exaggerated inflammatory reactions inside the pregnant mother. These inflammatory reactions are the main causes of CTG changes and higher CS rates. Therefore, obstetricians are advised to optimize the maternal condition to rectify reactive CTG changes rather than proceeding into urgent CS.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13224-022-01663-6.

Association of fetal heart rate short term variability pattern during term labor with neonatal morbidity and small for gestational age status

OBJECTIVE

To assess the association of fetal heart rate short-term variability (STV) pattern during term labor with both neonatal composite morbidity (cord blood pH ≤ 7.10 and/or neonatal intensive care unit admission and/or Apgar score at 5 min <7) and small for gestational age (SGA) status.

STUDY DESIGN

Retrospective cohort in a single academic institution between January 2016 and December 2018. A total of 1896 women that delivered a singleton during labor in cephalic presentation after 37 weeks of gestation were included (948 women with SGA neonates and 948 women with appropriate weight for gestational age (AGA) neonates that were matched to women with SGA neonates based on maternal age, parity, induction of labor, gestational diabetes, gestational age at delivery and a history of one cesarean section using propensity score matching). STV was compared at labor onset (cervical dilation ≤ 4 cm), in the first stage of labor (cervical dilation = 6 cm) and in the second stage of labor (cervical dilation = 10 cm). A generalized linear mixed model was used to assess the association between SGA status, neonatal composite morbidity and STV.

RESULTS

After adjustment for maternal origin, term, gestational diabetes, labor length, SGA status was not associated with any change in STV during labor (mean adjusted STV: -0.20 ms, 95 %CI[-0.58-0.17], p = 0.284 at labor onset, 0.29 ms, 95 %CI[-0.1- 0.68], p = 0.155, in the first stage of labor and 0.36 ms, 95 %CI[-0.02-0.74], p = 0.065 in the second stage of labor). In case of neonatal composite morbidity mean adjusted STV was lower in the first stage of labor (mean adjusted STV: -1.29 ms, 95 %CI[-2.1 - -0.43], p = 0.003) and in the second stage of labor (mean adjusted STV: -1.15 ms, 95 %CI[-1.96 - -0.34], p = 0.005). The results were similar with the addition of delivery mode and meconium-stained amniotic fluid in the model or non-reassuring fetal heart rate and meconium-stained amniotic fluid.

CONCLUSIONS

This work suggests that STV decrease during term labor is associated with fetal well-being, independently of fetal weight. This suggests that further prospective studies should consider the evaluation of this parameter in the prediction of neonatal compromise.

Uterine contraction frequency in the last hour of labor: how many contractions are too many?

OBJECTIVE

Increased frequency of uterine contractions is a component in the cluster of causal conditions that can lead to fetal hypoxia and acidosis and increase the risk for neonatal neurologic injury. For most international obstetrical societies, 5 contractions per 10 min averaged over 30 min is considered as the upper limit of normal uterine activity. We hypothesize that it might be safer to adopt an upper limit of 4 contractions per 10 min.

METHODS

We reviewed our 1970's research database containing 475 patients with closely monitored and well-documented labor and neonatal assessments that included cord blood (CB) pH, base excess (BE), and continuous recording of neonatal heart rate (NHR). Using data segregated by the proportion of the last hour before delivery when uterine contraction frequency (UCF) exceeded 4 and 5 contractions per 10 min respectively, we evaluated outcomes (CB BE, pH, Apgar scores at 1 min, the status of NHR at 16 min after birth, and the proportion of births that did not the result from normal spontaneous vaginal deliveries (NSVDs). ANOVA established relationships between UCF cutoffs and these outcomes. Our sample size is sufficiently large to provide the ability of UCF, per se, to accurately detect an alpha region of .05 88% of the time with an effect size of .15.

RESULTS

During the last hour prior to delivery, a UCF cutoff at 4 contractions per 10 min performed better than a UCF cutoff at 5 contractions per 10 min to enable the earlier identification of risks for abnormal outcomes. The longer UCF was increased, the worse were the outcomes that were measured, and the region >4 but ≤5 contractions identifies the beginnings of worsening conditions in a variety of measures of poor outcomes.

CONCLUSION

Lowering the recommended threshold for UCF from 5 to 4 contractions per 10-minute period as averaged over 30 min facilitates earlier detection of potentially compromised fetuses and is also an important contributor to a multicomponent contextualized approach to risk assessment.