Does nuchal cord at birth increase the risk for cerebral palsy?

In utero Exposure to Maternal Diabetes and the Risk of Cerebral Palsy: A Population-based Cohort Study

BACKGROUND

Evidence on the effects of in utero exposure to maternal diabetes on cerebral palsy (CP) in offspring is limited. We aimed to examine the effects of pregestational (PGDM) and gestational diabetes (GDM) separately on CP risk and the mediating role of increased fetal size.

METHODS

In a population-based study, we included all live births in Ontario, Canada, between 2002 and 2017 followed up through 2018 (n = 2,110,177). Using administrative health data, we estimated crude and adjusted associations between PGDM or GDM and CP using Cox proportional hazards models to account for unequal follow-up in children. For the mediation analysis, we used marginal structural models to estimate the controlled direct effect of PGDM (and GDM) on the risk of CP not mediated by large-for-gestational age (LGA).

RESULTS

During the study period, 5,317 children were diagnosed with CP (187 exposed to PGDM and 171 exposed to GDM). Children of mothers with PGDM showed an increased risk (hazard ratio [HR]: 1.84 [95% confidence interval (CI): 1.59, 2.14]) after adjusting for maternal sociodemographic and clinical factors. We found no associations between GDM and CP (adjusted HR: 0.91 [0.77, 1.06]). Our mediation analysis estimated that LGA explained 14% of the PDGM-CP association.

CONCLUSIONS

In this population-based birth cohort study, maternal pregestational diabetes was associated with increased risk of CP, and the increased risk was not substantially mediated by the increased fetal size.

Association of placental and umbilical cord characteristics with cerebral palsy: national cohort study

OBJECTIVES

Cerebral palsy (CP) is a group of movement disorders usually diagnosed in childhood. A substantial proportion are thought to be caused by antenatal events. Abnormalities of the umbilical cord and placenta are associated with an increased risk of adverse neonatal outcomes, but it is unclear whether these conditions also carry an increased risk of CP. We aimed to determine whether abnormalities of the umbilical cord or placenta are associated with CP and assess if these associations differ by sex of the child or gestational age at birth.

METHODS

We performed a national cohort study by linking data from The Medical Birth Registry of Norway with other national registries. All liveborn singletons born between 1999 and 2017 (n = 1 087 486) were included and followed up until the end of 2019. Diagnoses of CP were provided by the Norwegian National Insurance Scheme and the Norwegian Patient Register. We used generalized estimating equations and multilevel log binomial regression to calculate relative risks (RR), adjusted for year of birth, and stratified analyses were carried out based on sex and gestational age at birth. Exposures were abnormal umbilical cord (velamentous or marginal insertion, single umbilical artery (SUA), knots and entanglement), and placental abnormalities (retained placenta, placental abruption and previa).

RESULTS

A total of 2443 cases with CP (59.8% males) were identified. Velamentous cord insertion (adjusted RR (aRR), 2.11 (95% CI, 1.65-2.60)), cord knots (aRR, 1.53 (95% CI, 1.15-2.04)) and placental abnormalities (placenta previa (aRR, 3.03 (95% CI, 2.00-4.61)), placental abruption (aRR, 10.63 (95% CI, 8.57-13.18)) and retained placenta (aRR, 1.71 (95% CI, 1.32-2.22))) carried an increased risk of CP. Velamentous cord insertion was associated with CP regardless of gestational age or sex. A retained placenta was associated with a 2-fold increased risk for CP in males, while the associations of SUA and cord knot with CP were significant only among females.

CONCLUSIONS

The detection of placental and umbilical cord abnormalities may help identify children at increased risk of CP. The associations between placental or umbilical cord abnormalities and the risk of CP do not vary substantially with gestational age at birth or sex of the child. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

The evaluation of the antepartum and intrapartum risk factors in predicting the risk of birth asphyxia

PURPOSE

This study aimed to determine the related antepartum and intrapartum factors of birth asphyxia among neonates born in a tertiary referral hospital.

METHODS

A total of 45 singleton pregnant women who delivered live births with a gestational age of ≥35 weeks and their neonates who suffered from birth asphyxia from June 2016 to June 2021 were included in this retrospective study. Data regarding maternal demographic features, maternal laboratory values, pregnancy complications, and obstetric and neonatal outcomes were collected.

RESULTS

Significant risk factors associated with birth asphyxia were nulliparity (odds ratio [OR] = 5.357, 95% confidence interval [CI] = 2.169-24.950, p = 0.001), placental abruption (OR = 8.667, 95% CI = 2.223-33.784, p = 0.002), intrauterine growth restriction (OR = 1.394, 95% CI = 1.109-8.631, p = 0.012), the prolonged second stage of labor (OR = 6.121, 95% CI = 2.120-17.595, p = 0.001), meconium-stained amniotic fluid (OR = 7.615, 95% CI = 2.394-24.223, p = 0.001), bloody amniotic fluid (OR = 9.423, 95% CI = 2.885-35.232, p = 0.001), the presence of FHR category II (OR = 12.083, 95% CI = 7.081-48.849, p <0.001) and FHR category III before labor (OR = 15.500, 95% CI = 8.394-56.176, p <0.001).

CONCLUSION

We identified that nulliparity, placental abruption, intrauterine growth restriction, the prolonged second stage of labor, meconium-stained or bloody amniotic fluid, and FHR tracings categories II and III were significantly associated with birth asphyxia.

The Relationship between Nuchal Cord and Adverse Obstetric and Neonatal Outcomes: Retrospective Cohort Study

Objective: The twisting of the umbilical cord around the fetal neck is a common phenomenon in the delivery room, and despite the lack of univocal evidence of its negative impact on perinatal events, it causes anxiety and stress in patients. The aim of the study was to assess the prevalence of nuchal cord and its impact on adverse obstetric and neonatal outcomes. Methods: We conducted a retrospective cohort study. All patients who gave birth in the clinic within one year (n = 1467) were included in the study group. We compared the prevalence of nuchal cord in distinct subgroups of patients. In the next stage, we estimated the chance of specific perinatal outcomes and compared the neonatal outcomes between groups with and without nuchal cord. Results: Nuchal cord was present in 24% of labors. It was twice as common among patients giving birth vaginally (32.14%) than among patients giving birth by a caesarean section (16.78%, p < 0.001). Nuchal cord was also more frequent in births with meconium-stained amniotic fluid (33.88% vs. 23.34%, p = 0.009). In the group of patients with nuchal cord, we observed a slight increase in the risk of a non-reassuring fetal heart rate trace (OR = 1.55, CI 95% 1.02−2.36) as an indication of the completion of labor by caesarean delivery. We did not note an increase in the risk of completing natural childbirth by vacuum extraction. In the group of nuchal cord patients, there was a higher chance of a serious or moderate neonatal condition in the first minute of life (Apgar 0−7 points) (OR = 2.00, 95% CI = 1.14−3.49). Conclusions: Nuchal cord increases the risk of a caesarean delivery due to a non-reassuring fetal heart rate trace. Nuchal cord increases the chance of a reduced Apgar score (0−7 points) in the first minute of life. The observed relationships do not translate to neonatal arterial blood gas testing.

The perils of true knot of the umbilical cord: antepartum, intrapartum and postpartum complications and clinical implications

BACKGROUND

True knot of the umbilical cord (TKUC) is found in 0.3-2.1% of pregnancies and is associated with an increased risk of adverse perinatal outcomes.

METHODS

A retrospective cohort study including all singleton pregnancies delivered from 2011 to 2019 was performed. Diagnosis of TKUC was made postnatally, immediately after delivery of the baby. Comparison was made between pregnancies with and without TKUC regarding maternal, fetal and neonatal adverse outcome.

RESULTS

Overall, 867/85,541 (1%) pregnancies were diagnosed with TKUC. Maternal age, BMI, gravidity and parity were significantly higher in pregnancies with TKUC as well as higher rate of induction of labor, meconium-stained amniotic fluid, and delivery prior to 37 weeks. The rate of cesarean deliveries due to non-reassuring-fetal monitor was significantly higher in pregnancies with TKUC. Overall, there were 2.5% IUFD in pregnancies with TKUC vs. 1% in pregnancies without TKUC (p < 0.001). Importantly, the rate of IUFD prior to 37 weeks of gestation was not significantly higher in the group with TKUC, however, the rate of IUFD after 37 weeks of gestation was 10 folds higher in fetuses with TKUC, 0.9% vs. 0.08% (p < 0.001). Significantly, more neonates with TKUC needed phototherapy or suffered from hypoglycemia. There were no differences in the 5 min Apgar scores, admission to the NICU and number of days of hospitalization.

CONCLUSION

Pregnancies complicated with TKUC are associated with a tenfold higher risk of IUFD beyond 37 weeks of gestation. To the results of this study suggest that it would be prudent to induce labor around 37 weeks of gestation in pregnancies with prenatal diagnosis of TKUC. It may be warranted to use continuous fetal monitoring during labor and delivery in those cases were antenatal diagnosis of TKUC is made.

Identifying the Critical Threshold for Long-Term Pediatric Neurological Hospitalizations of the Offspring in Preterm Delivery

We opted to investigate whether a critical threshold exists for long-term pediatric neurological morbidity, and cerebral palsy (CP), in preterm delivery, via a population-based cohort analysis. Four study groups were classified according to their gestational age at birth: 24–27.6, 28–31.6, 32–36.6 weeks and term deliveries, evaluating the incidence of long-term hospitalizations of the offspring due to neurological morbidity. Cox proportional hazard models were performed to control for confounders. A Kaplan–Meier survival curve was used to compare the cumulative neurological morbidity incidence for each group. A total of 220,563 deliveries were included: 0.1% (118) occurred at 24–27.6 weeks of gestation, 0.4% (776) occurred at 28–31.6 weeks of gestation, 6% (13,308) occurred at 32–36.6 weeks of gestation and 93% (206,361) at term. In a Cox model, while adjusting for confounders, delivery before 25 weeks had a 3.9-fold risk for long-term neurological morbidity (adjusted HR (hazard ratio) = 3.9, 95% CI (confidence interval) 2.3–6.6; p < 0.001). The Kaplan–Meier survival curve demonstrated a linear association between long-term neurological morbidity and decreasing gestational age. In a second Cox model, adjusted for confounders, infants born before 25 weeks of gestation had increased rates of CP (adjusted HR = 62.495% CI 25.6–152.4; p < 0.001). In our population, the critical cut-off for long-term neurological complications is delivery before 25 weeks gestation.

Current Perspectives of Prenatal Sonographic Diagnosis and Clinical Management Challenges of Nuchal Cord(s)

Umbilical cord accidents preceding labor are uncommon. In contrast, nuchal cords are a very common finding at delivery, with reported incidences of a single nuchal cord of approximately between 20% and 35% of all singleton deliveries at term. Multiple loops occur less frequently, with reported incidence rates inverse to the number of nuchal cords involved. Rare cases of up to 10 loops of nuchal cord have been reported. While true knots of the umbilical cord have been associated with a 4–10-fold increased risk of stillbirth, nuchal cord(s) are most often noted at delivery of non-hypoxic non-acidotic newborns, without any evidence of subsequent adverse neonatal outcome. Prior to ultrasound, nuchal cords were suspected clinically following subtle (spontaneous or evoked) electronic fetal heart rate changes. Prenatal sonographic diagnosis, initially limited to real-time gray-scale ultrasound, currently entails additional sonographic modalities, including color Doppler, power Doppler, and three-dimensional sonography, which have enabled increasingly more accurate prenatal sonographic diagnoses of nuchal cord(s). In contrast to true knots of the umbilical cord (which are often missed at sonography, reflecting the inability to visualize the entire umbilical cord, and hence are often incidental findings at delivery), nuchal cord(s), reflecting their well-defined and sonographically accessible anatomical location (the fetal neck), lend themselves with relative ease to prenatal sonographic diagnosis, with increasingly high sensitivity and specificity rates. While current literature supports that single (and possibly double) nuchal cords are not associated with increased adverse perinatal outcome, emerging literature suggests that cases of ≥3 loops of nuchal cords or in the presence of a coexisting true knot of the umbilicus may be associated with an increased risk of stillbirth or compromised neonatal status at delivery. This commentary will address current perspectives of prenatal sonographic diagnosis and clinical management challenges associated with nuchal cord(s) in singleton pregnancies.

The effect of nuchal cord on perinatal mortality and long-term offspring morbidity

OBJECTIVE

To evaluate perinatal and long-term cardiovascular and respiratory morbidities of children born with nuchal cord.

STUDY DESIGN

A large population-based cohort analysis of singleton deliveries was conducted. Maternal and birth characteristics, as well as cardiovascular and respiratory morbidity incidence were evaluated. Kaplan-Meier survival curves were used to compare cumulative hospitalization incidence between groups. Cox regression models were used to control for possible confounders and follow-up length.

RESULTS

243,682 deliveries were included. Of them, 34,332 (14.1%) were diagnosed with nuchal cord. Perinatal mortality rate was comparable between groups (0.5 vs. 0.6%, p = 0.16). Kaplan-Meier survival curves demonstrated no significant differences in cumulative cardiovascular or respiratory morbidity incidence between groups (log rank p = 0.69 and p = 0.10, respectively). Cox regression models reaffirmed a comparable risk for hospitalization between groups (aHR = 0.99 (95% CI 0.85-1.14, p = 0.87) and aHR = 0.97 (95% CI 0.92-1.02, p = 0.28).

CONCLUSIONS

Nuchal cord is not associated with higher rate of perinatal mortality nor long-term cardiorespiratory morbidity.