Association of placental weight with cerebral palsy: population-based cohort study in Norway

Two-dimensional (2D) placental ultrasound measurements - The correlation with placental volume measured by magnetic resonance imaging (MRI)

INTRODUCTION

Information about placental size in ongoing pregnancies may aid the identification of pregnancies with increased risk of adverse outcome. Placental volume can be measured using magnetic resonance imaging (MRI). However, this method is not universally available in antenatal care. Ultrasound is the diagnostic tool of choice in pregnancy. Therefore, we studied whether simple two-dimensional (2D) ultrasound placental measurements were correlated with placental volume measured by MRI.

METHODS

We examined a convenience sample of 104 ongoing pregnancies at gestational week 27, using both ultrasound and MRI. The ultrasound measurements included placental length, width and thickness. Placental volume was measured using MRI. The correlation between each 2D placental ultrasound measurement and placental volume was estimated by applying Pearson's correlation coefficient (r).

RESULTS

Mean placental length was 17.2 cm (SD 2.1 cm), mean width was 14.7 cm (SD 2.1 cm), and mean thickness was 3.2 cm (SD 0.6 cm). Mean placental volume was 536 cm3 (SD 137 cm3). The 2D ultrasound measurements showed poor correlation with placental volume (placental length; r = 0.27, width; r = 0.37, and thickness r = 0.13).

DISCUSSION

Simple 2D ultrasound measurements of the placenta were poorly correlated with placental volume and cannot be used as proximate measures of placental volume. Our finding may be explained by the large variation between pregnancies in intrauterine placental shape.

Placental size at gestational week 27 and 37: The associations with pulsatility index in the uterine and the fetal-placental arteries

INTRODUCTION

Fetal growth restriction is known to be related to decreased fetal and placental blood flow. It is not known, however, whether placental size is related to fetal and placental blood flow. We studied the correlations of intrauterine placental volume and placental-fetal-ratio with pulsatility index (PI) in the uterine arteries, fetal middle cerebral artery, and umbilical artery.

METHODS

We followed a convenience sample of 104 singleton pregnancies, and we measured placental and fetal volumes using magnetic resonance imaging (MRI) at gestational week 27 and 37 (n = 89). Pulsatility index (PI) was measured using Doppler ultrasound. We calculated cerebroplacental ratio as fetal middle cerebral artery PI/umbilical artery PI and placental-fetal-ratio as placental volume (cm3)/fetal volume (cm3).

RESULTS

At gestational week 27, placental volume was negatively correlated with uterine artery PI (r = -0.237, p = 0.015, Pearson's correlation coefficient), and positively correlated with fetal middle cerebral artery PI (r = 0.247, p = 0.012) and cerebroplacental ratio (r = 0.208, p = 0.035). Corresponding correlations for placental-fetal-ratio were -0.273 (p = 0.005), 0.233 (p = 0.018) and 0.183 (p = 0.064). Umbilical artery PI was not correlated with placental volume. At gestational week 37, we found weaker and no significant correlations between placental volume and the pulsatility indices.

CONCLUSIONS

Our results suggest that placental size is correlated with placental and fetal blood flow at gestational week 27.

The association of placental pathology and neurodevelopmental outcomes in patients with neonatal encephalopathy

BACKGROUND

Studies conflict on how acute versus chronic placental pathology impacts outcomes after neonatal encephalopathy from presumed hypoxic-ischemic encephalopathy (HIE). We examine how outcomes after presumed HIE vary by placental pathology categories.

METHODS

We performed retrospective chart review for neonates with presumed HIE, regardless of severity, focusing on 50 triads for whom placental specimens were available for re-review. Placentas were categorized as having only acute, any chronic, or no lesions. Primary outcomes included in-hospital morbidity/mortality and long-term neurodevelopmental symptoms. Secondary outcomes assessed neonatal MRI and EEG.

RESULTS

Demographics did not differ between groups. Forty-seven neonates were treated with therapeutic hypothermia. Placental acuity category was not associated with primary or secondary outcomes, but clinical and/or histopathological chorioamnionitis was associated with abnormal EEG background and post-neonatal epilepsy (16.7%, n = 3 with chorioamnionitis versus 0%, n = 0 without chorioamnionitis, p = 0.04).

CONCLUSIONS

When grouped by acute, chronic, or absent placental lesions, we observed no association with in-hospital, neurodevelopmental, MRI, or EEG outcomes. When reanalyzed by the presence of chorioamnionitis, we found that chorioamnionitis appeared to be associated with a higher risk of EEG alterations and post-neonatal epilepsy. Despite our limited sample size, our results emphasize the critical role of placental examination for neuroprognostication in presumed HIE.

IMPACT

Neonatal encephalopathy presumed to result from impaired fetal cerebral oxygenation or blood flow is called hypoxic ischemic encephalopathy (HIE). Prior studies link placental pathology to various outcomes after HIE but disagree on the impact of acute versus chronic pathology. Our study determines that neurodevelopmental outcomes, in-hospital outcomes, injury on MRI, and EEG findings in patients with HIE are not differentially associated with acute versus chronic placental pathology. Chorioamnionitis is associated with an increased risk of abnormal EEG patterns and post-neonatal epilepsy. Histopathologic chorioamnionitis without clinical symptoms is common in HIE, emphasizing the crucial role of placental pathology for neuroprognostication.

Placental weights of neonates born with symptomatic congenital syphilis

Background

Syphilis during pregnancy remains an important global health concern causing miscarriage, stillbirth, preterm birth and neonatal death. As part of the fetal infection, placental changes occur which may include a heavier placenta than expected.

Methods

A cohort of 50 neonates with symptomatic congenital syphilis has previously been described. This cohort was admitted to Groote Schuur neonatal unit in Cape Town South Africa from 2011 to 2013. For this study, the placental weights of the neonates were analyzed and compared to population based placental centiles.

Results

There was data for 37 placentae. Heavy placentae (>90th centile) occurred in 76% of placentae in the study. All 6 infants with birth weights ≥2,500 g had heavy placentae. There was no correlation between placental centile and death.

Conclusion

Heavy placenta are an important and frequent finding with symptomatic congenital syphilis, especially in the larger neonates.

Automatic placental and fetal volume estimation by a convolutional neural network

INTRODUCTION

We aimed to develop an artificial intelligence (AI) deep learning algorithm to efficiently estimate placental and fetal volumes from magnetic resonance (MR) scans.

METHODS

Manually annotated images from an MRI sequence was used as input to the neural network DenseVNet. We included data from 193 normal pregnancies at gestational week 27 and 37. The data were split into 163 scans for training, 10 scans for validation and 20 scans for testing. The neural network segmentations were compared to the manual annotation (ground truth) using the Dice Score Coefficient (DSC).

RESULTS

The mean ground truth placental volume at gestational week 27 and 37 was 571 cm³ (Standard Deviation (SD) 293 cm³) and 853 cm³ (SD 186 cm³), respectively. Mean fetal volume was 979 cm³ (SD 117 cm³) and 2715 cm³ (SD 360 cm³). The best fitting neural network model was attained at 22,000 training iterations with mean DSC 0.925 (SD 0.041). The neural network estimated mean placental volumes at gestational week 27-870 cm³ (SD 202 cm³) (DSC 0.887 (SD 0.034), and to 950 cm³ (SD 316 cm³) at gestational week 37 (DSC 0.896 (SD 0.030)). Mean fetal volumes were 1292 cm³ (SD 191 cm³) and 2712 cm³ (SD 540 cm³), with mean DSC of 0.952 (SD 0.008) and 0.970 (SD 0.040). The time spent for volume estimation was reduced from 60 to 90 min by manual annotation, to less than 10 s by the neural network.

CONCLUSION

The correctness of neural network volume estimation is comparable to human performance; the efficiency is substantially improved.

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.

Placental pathology and neonatal encephalopathy

Neonatal encephalopathy (NE) is an important cause of neonatal morbidity and mortality worldwide; however, there remain gaps in our knowledge about its pathogenesis. The placenta has been implicated in the pathogenesis of this disease but conclusive evidence related to the placental factors that influence it is sparse. This review aims to outline the current knowledge on the role of the placenta with particular attention to its role in NE as a consequence of hypoxia-ischemia. A total of 26 original articles/review papers were used to compile this review. Three themes were identified from these publications: fetal vascular malperfusion including umbilical cord pathology, inflammatory changes in the placenta, and maternal vascular malperfusion including placental weight. These features were identified as being significant in the development of NE. Advancing our understanding of this relationship between placental pathology and NE may facilitate the development of additional antenatal screening to better identify at-risk fetuses. We highlight areas for further research through antenatal screening and placental histology.

Effect of third trimester maternal vitamin D levels on placental weight to birth weight ratio in uncomplicated pregnancies

OBJECTIVES

Vitamin D has critical role for the fetal and placental development. Today, placental weight (PW), fetal birth weight (BW), and the PW/BW ratio are used as markers of fetal development. The aim of this study is to evaluate the relationship between vitamin D levels and these markers in uncomplicated pregnancies.

METHODS

This study included 108 women with uncomplicated pregnancies, defined as full-term and healthy pregnancies without perinatal complications. Vitamin D levels <12 ng/mL were classified as deficient, 12-20 ng/mL as insufficient, and >20 ng/mL as normal. Postnatal BW and PW were compared according to maternal serum vitamin D levels.

RESULTS

Maternal age, maternal height, maternal weight, body mass index, nulliparity, gestational age at delivery, mode of delivery, and fetal gender were similar between groups. Postnatal BW, PW, fetal height at birth, and fetal head circumference parameters were similar between the groups. The PW/BW ratio was 21.77±2.20 in the vitamin D deficient group, 21.20±2.40 in the insufficient group, and 19.98±2.37 in the normal group (p=0.012). In addition, there was a significant negative correlation between vitamin D level and the PW/BW ratio (p=0.012, r=0.031).

CONCLUSIONS

Our results indicated that PW/BW ratio which is the marker for prediction adverse perinatal outcomes were significantly increased in the presence of vitamin D deficiency and insufficiency.

Effect of gestational weight gain on placental weight: A single tertiary referral center study of Japanese women

AIM

The effect of gestational weight gain on placental weight has not been elucidated. We aimed to examine the effect of body weight gain during pregnancy on the Japanese standardized z-score of placental weight, based on the pre-pregnancy body mass index.

METHODS

This retrospective cohort study included Japanese women with singleton pregnancies who gave birth during 2013-2019 at Ohta Nishinouchi Hospital. Participants (n = 3610) were categorized by their pre-pregnancy body mass index: G1 (<18.5 kg/m² ), G2 (18.5 to <20.0 kg/m² ), G3 (20.0 to <23.0 kg/m² ), G4 (23.0 to <25.0 kg/m² ), and G5 (≥25.0 kg/m² ). Multiple linear regression analysis was used to identify associations between insufficient or excessive gestational weight gain in each body mass index category and z-score of placental weight, with adjustments for maternal age, assisted reproductive technology, and maternal pre-pregnancy conditions, such as hypertension, diabetes mellitus, myoma uteri, and uterine anomalies.

RESULTS

Among the 3610 women assessed, 479, 692, 1292, 435, and 711 were in G1-G5, respectively. In G1, G3, and G4, excessive weight gain increased the placental weight z-score ([B: 0.50, 95% confidence interval [CI]: 0.23-0.76], [B: 0.19, 95% CI: 0.19-0.33], and [B: 0.18, 95% CI: 0.10-0.26]). Insufficient weight gain decreased the placental weight z-score in G3 (B: -0.19, 95% CI: -0.33 to -0.06) and G4 (B: -0.21, 95% CI: -0.29 to -0.13) women.

CONCLUSION

The effect of weight gain during pregnancy on placental size varies by pre-pregnancy body mass index. This result may guide personalized pre-conception counseling to improve the outcomes of offspring.

Placental volume in gestational week 27 measured by three-dimensional ultrasound and magnetic resonance imaging

INTRODUCTION

Ultrasound is the diagnostic tool of choice in pregnancy. We lack valid ultrasound methods for placental size measurements. Our aim was therefore to compare three-dimensional (3D) ultrasound with magnetic resonance imaging (MRI) for measurements of placental volume.

MATERIAL AND METHODS

We measured placental volume by 3D ultrasound and MRI in 100 unselected pregnancies at 27 weeks of gestation (25⁺⁴ -28⁺⁴  weeks). The 3D ultrasound acquisitions were analyzed offline, and the placental outline was manually traced using the virtual organ computer-aided analysis (VOCAL) 30° rotational technique. The MRI examinations included a T2-weighted gradient echo sequence in the sagittal plane, with 5-mm slices through the entire uterus. The placental outline was manually traced in each slice. The correlation between 3D ultrasound and MRI placental volumes was estimated by intraclass correlation coefficients. Bland-Altman analysis was applied to visualize systematic bias and limits of agreement, in which the ratio MRI placental volume/3D ultrasound placental volume was plotted against the average of the two methods.

RESULTS

The intraclass correlation coefficient between 3D ultrasound and MRI measurements was 0.49 (95% confidence interval 0.33-0.63). In general, 3D ultrasound measured smaller placental volumes (median 373 cm³ , interquartile range 309-434 cm³ ) than MRI (median 507 cm³ , interquartile range 429-595 cm³ ) and the systematic bias was 1.44. The 95% limits of agreement between the two methods were wide (0.68-2.21).

CONCLUSIONS

We found poor to moderate correlation between 3D ultrasound and MRI placental volume measurements. Generally, 3D ultrasound measured smaller placental volumes than MRI, suggesting that 3D ultrasound failed to visualize the entire placenta. Our findings may hopefully contribute to the improvement of ultrasound methods for placental measurements.

Associations of prenatal heavy metals exposure with placental characteristics and birth weight in Hangzhou Birth Cohort: Multi-pollutant models based on elastic net regression

BACKGROUND

The human placenta is vulnerable to environmental pollutants, but the associations between exposure to multiple, correlated metals and placental characteristics have not been studied.

METHODS

The current study population was derived from the Hangzhou Birth Cohort Study. Whole blood and urine samples were collected from mothers during 20-28 gestational week. The concentrations of 11 metals in blood and 11 metals in urine were evaluated by inductively coupled plasma mass spectrometry. The data on placental characteristics and birth weight were retrieved from medical records. The elastic net (ENET) model combined with unpenalized regression model was employed to estimate the relationship between levels of metals and placental characteristics (placental weight, chorionic disc area, chorionic disc eccentricity, placental thickness, placental-fetal birth weight ratio) and birth weight. Mediation analysis was performed to explore the mediated effect of placenta on the association of prenatal metals exposure with birth weight.

RESULTS

Among 512 participants with urine metal levels, the ENET model retained Cadmium (Cd) and Selenium (Se) for placental weight. Further unpenalized regression model including Cd and Se simultaneously showed that one-unite increased natural-logarithm (ln)-transformed urine creatinine corrected (CC) Cd levels was associated with reductions in placental weight of -7.2 g (95% confidence interval (CI): -14.0, -0.4). Among 483 participants with blood metal levels, similarly, blood Cd levels were negatively associated with placental weight (β = -7.5, 95% CI: -17.0, 1.9). Furthermore, mediation analysis demonstrated that urine CC-Cd level was associated with a 21.3 g decrease (95% CI: -42.0, -2.5, p = 0.024) in birth weight through a reduction in placental weight, while blood Cd levels presented a negative association at borderline significance.

CONCLUSION

Our findings suggest a mediation effect of the placenta in the relationship between prenatal Cd exposure and lower birth weight. Additional studies with repeated assessment of exposure and more placental parameters are warranted to confirm this relationship.

Placental Weight and Risk of Neonatal Death

This study examines the association of placental weight with the risk of prenatal death using data from the Medical Birth Registry of Norway.

The Placenta in Neonatal Encephalopathy: A Case-Control Study

OBJECTIVE

We assessed whether specific histologic placental lesions were associated with risk for neonatal encephalopathy, a strong predictor of death or cerebral palsy.

STUDY DESIGN

Case-control study of singletons with gestational ages ≥35 weeks. Data were abstracted from a prospectively collected database of consecutive births at a hospital in which placental samples from specified sites are collected and stored for all inborn infants. Placentas of infants with neonatal encephalopathy were compared with randomly selected control infants (ratio of 1:3). Placental histologic slides were read by a single experienced perinatal pathologist unaware of case status, using internationally recommended definitions and terminology. Findings were grouped into inflammatory, maternal, or fetal vascular malperfusion (FVM) and other lesions.

RESULTS

Placental samples were available for 73 of 87 (84%) cases and 253 of 261 (97%) controls. Delivery complications and gross placental abnormalities were more common in cases, of whom 4 died. Inflammation and maternal vascular malperfusion did not differ, and findings consistent with global FVM were more frequent in case (20%) than control (7%) placentas (P = .001). There was a trend toward more segmental FVM and high-grade FVM (fetal thrombotic vasculopathy) among cases. Some type of FVM was observed in 24% of placentas with neonatal encephalopathy. In infants with both neonatal encephalopathy and placental FVM, more often than in infants with neonatal encephalopathy without FVM, electronic fetal monitoring tracings were considered possibly or definitely abnormal (P = .028).

CONCLUSIONS

Vascular malperfusion of subacute or chronic origin on the fetal side of the placenta was associated with increased risk of neonatal encephalopathy.

Relationship between birth weight to placental weight ratio and major congenital anomalies in Japan

Recent studies have indicated that birth weight to placental weight (BW/PW) ratio is related to perinatal outcomes, but the effect of congenital abnormalities on BW/PW ratio remains unclear. We performed this study to elucidate correlations between BW/PW ratio and congenital abnormalities. Subjects were 735 singleton infants born at 34–41 weeks of gestation admitted to our center between 2010 and 2016. Of these, 109 infants (15%) showed major congenital anomalies. Major congenital anomalies and subgroups were diagnosed according to European Surveillance of Congenital Anomalies criteria. The primary outcome was the association between BW/PW ratio and major congenital anomaly, and secondary outcomes were the distribution pattern of BW/PW ratio with major anomalies and by major anomaly subgroups in each categorization (<10th percentile, 10–90th percentile, or >90th percentile) of BW/PW ratio. BW/PW ratio was not associated (P = 0.20) with presence (adjusted mean BWPW ratio = 5.02, 95% confidence interval [CI] 4.87–5.18) or absence (adjusted mean BW/PW ratio = 4.91, 95%CI 4.85–4.97) of major anomalies, after adjusting for gestational age and sex. Proportions of infants with major anomalies according to BW/PW ratio categories were as follows: 12% in <10th percentile, 15% in 10–90th percentile, and 25% in >90th percentile of BW/PW ratio. Among major anomalies of the nervous system, congenital heart defects, and orofacial clefts, BW/PW ratio showed equally distributed trend across the three BW/PW ratio categories, but showed unequally distributed trend for anomalies of the digestive system, other anomalies/syndromes, or chromosomal abnormalities. BW/PW ratio was not associated with major congenital anomaly, and was distributed diffusely according to major anomaly subgroups. Major anomalies may tend to aggregate in the 90th percentile of the BW/PW ratio.

Maternal concentrations of human chorionic gonadotropin (hCG) and risk for cerebral palsy (CP) in the child. A case control study

BACKGROUND

Intrauterine conditions may be important in the development of cerebral palsy in the child. The hormone, human chorionic gonadotropin (hCG), is synthesized in the placenta, and hCG plays an important role in placental angiogenesis and development. Thus, maternal hCG concentrations may be an indicator of placental function and thereby the intrauterine environment for the offspring. We studied the associations of maternal concentrations of hCG during pregnancy with cerebral palsy in the child.

METHODS

We performed a case-control study nested within a cohort of 29,948 pregnancies in Norway during 1992-1994. Cases were all women within the cohort who gave birth to a singleton child with cerebral palsy diagnosed before five years of age (n = 63). Controls were a random sample of women with a singleton child without cerebral palsy (n = 182).

RESULTS

The adjusted odds ratio (OR) for cerebral palsyin the child was 0.78 (95% CI: 0.55-1.10) per log-transformed unit of maternal hCG in the 1 st trimester, and the OR was 1.42 (95% CI: 0.94-2.16) in the 2nd trimester. Thus, women who did not have high hCG concentrations in the 1 st trimester and low hCG concentrations in the 2nd trimester, had increased risk for giving birth to a child with cerebral palsy. Adjustments were made for pregnancy week of serum sampling, maternal age and parity.

CONCLUSIONS

The abnormal hCG concentrations in pregnancies with cerebral palsy in the offspring, could suggest placental factors as causes of cerebral palsy.

Placental Chorangiosis: Increased Risk for Cesarean Section

We describe a patient with Class C diabetes who presented for nonstress testing at 36 weeks and 4 days of gestation with nonreassuring fetal heart tones (NRFHT) and oligohydramnios. Upon delivery, thrombosis of the umbilical cord was grossly noted. Pathological analysis of the placenta revealed chorangiosis, vascular congestion, and 40% occlusion of the umbilical vein. Chorangiosis is a vascular change of the placenta that involves the terminal chorionic villi. It has been proposed to result from longstanding, low-grade hypoxia in the placental tissue and has been associated with such conditions such as diabetes, intrauterine growth restriction (IUGR), and hypertensive conditions in pregnancy. To characterize chorangiosis and its associated obstetric outcomes we identified 61 cases of “chorangiosis” on placental pathology at Henry Ford Hospital from 2010 to 2015. Five of these cases were omitted due to lack of complete records. Among the 56 cases, the cesarean section rate was 51%, indicated in most cases for nonreassuring fetal status. Thus, we suggest that chorangiosis, a marker of chronic hypoxia, is associated with increased rates of cesarean sections for nonreassuring fetal status because of long standing hypoxia coupled with the stress of labor.

Motor vehicle crashes during pregnancy and cerebral palsy during infancy: a longitudinal cohort analysis

OBJECTIVES

To assess the incidence of cerebral palsy among children born to mothers who had their pregnancy complicated by a motor vehicle crash.

DESIGN

Retrospective longitudinal cohort analysis of children born from 1 April 2002 to 31 March 2012 in Ontario, Canada.

PARTICIPANTS

Cases defined as pregnancies complicated by a motor vehicle crash and controls as remaining pregnancies with no crash.

MAIN OUTCOME

Subsequent diagnosis of cerebral palsy by age 3 years.

RESULTS

A total of 1 325 660 newborns were analysed, of whom 7933 were involved in a motor vehicle crash during pregnancy. A total of 2328 were subsequently diagnosed with cerebral palsy, equal to an absolute risk of 1.8 per 1000 newborns. For the entire cohort, motor vehicle crashes correlated with a 29% increased risk of subsequent cerebral palsy that was not statistically significant (95% CI -16 to +110, p=0.274). The increased risk was only significant for those with preterm birth who showed an 89% increased risk of subsequent cerebral palsy associated with a motor vehicle crash (95% CI +7 to +266, p=0.037). No significant increase was apparent for those with a term delivery (95% CI -62 to +79, p=0.510). A propensity score-matched analysis of preterm births (n=4384) yielded a 138% increased relative risk of cerebral palsy associated with a motor vehicle crash (95% CI +27 to +349, p=0.007), equal to an absolute increase of about 10.9 additional cases per 1000 newborns (18.2 vs 7.3, p=0.010).

CONCLUSIONS

Motor vehicle crashes during pregnancy may be associated with an increased risk of cerebral palsy among the subgroup of cases with preterm birth. The increase highlights a specific role for traffic safety advice in prenatal care.