Epidemiology of stillbirth and fetal central nervous system injury

Understanding the associations and significance of fetal movements in overweight or obese pregnant women: a systematic review

INTRODUCTION

Presentation with decreased fetal movement (DFM) is associated with fetal growth restriction and stillbirth. Some studies report that DFM is frequent among overweight or obese mothers. We aimed to determine the significance and associations of fetal movements in women of increased body size.

MATERIAL AND METHODS

This systematic review was conducted in accordance with the PRISMA statement and the protocol was registered with PROSPERO (CRD42016046352). Major databases were explored from inception to September 2017, using a predefined search strategy. We restricted inclusion to studies published in English and considered studies of any design that compared fetal movements in women of increased and normal body size. Two authors independently extracted data and assessed quality.

RESULTS

We included 23 publications from 19 observational studies; data were extracted from 10 studies. Increased maternal body size was not associated with altered perception of fetal movement (four studies, 95 women, very low-quality evidence), but was associated with increased presentation for DFM (two cohort studies, 20 588 women, OR 1.56, 95% CI 1.27-1.92: three case-control studies, 3445 women, OR 1.32, 95% CI 1.12-1.54; low-quality evidence). Among women with DFM, increased maternal body size was associated with increased risk of stillbirth and fetal growth restriction (one study, 2168 women, very low-quality evidence).

CONCLUSIONS

This systematic review identified limited evidence that women with increased body size are more likely to present with DFM but do not have impaired perception of fetal movements. In women with DFM, increased body size is associated with worse pregnancy outcome, including stillbirth.

Risk of cerebral palsy among the offspring of immigrants

BACKGROUND

Cerebral palsy (CP) has a multifactorial etiology, and placental vascular disease may be one major risk factor. The risk of placental vascular disease may be lower among some immigrant groups. We studied the association between immigrant status and the risk of CP.

METHODS

We conducted a population-based retrospective cohort study of all singleton and twin livebirths in Ontario between 2002-2008, and who survived ≥28 days after birth. Each child was assessed for CP up to age 4 years, based on either a single inpatient or ≥2 outpatient pediatric diagnoses of CP. Relative to non-immigrants (n = 566,668), the risk of CP was assessed for all immigrants (n = 177,390), and further evaluated by World region of origin. Cox proportional hazard ratios (aHR) were adjusted for maternal age, income, diabetes mellitus, obesity, tobacco use, Caesarean delivery, year of delivery, physician visits, twin pregnancy, preterm delivery, as well as small- and large-for-gestational age birthweight.

RESULTS

There were 1346 cases of CP, with a lower rate among immigrants (1.45 per 1000) than non-immigrants (1.92 per 1000) (aHR 0.77, 95% confidence interval [CI] 0.67 to 0.88). Mothers from East Asia and the Pacific (aHR 0.54, 95% CI 0.39 to 0.77) and the Caribbean (aHR 0.58, 95% CI 0.37 to 0.93) were at a significantly lower risk of having a child with CP. Whether further adjusting for preeclampsia, gestational hypertension, placental abruption or placental infraction, or upon using a competing risk analysis that further accounted for stillbirth and neonatal death, these results did not change.

CONCLUSIONS

Immigration and ethnicity appear to attenuate the risk of CP, and this effect is not fully explained by known risk factors.

Third trimester fetal demise occurring at time of delivery: correlation of autopsy findings and placental pathology with emphasis on antenatal central nervous system injury

OBJECTIVE

Third trimester fetal deaths occurring in the hospital at the time of delivery are unusual. We report an autopsy series of such cases with emphasis on neuropathological injury and other lesions predating delivery.

METHODS

We identified autopsies performed on third trimester fetuses documented to be alive shortly before delivery, but that expired during, or very close to, time of delivery, and we correlate autopsy and placental findings. Fetuses with major congenital anomalies were excluded.

RESULTS

Ten cases were identified (6 term, 4 preterm). All were delivered by cesarean section and had attempted resuscitation. Established or recent brain injury was identified in 9 of 10 cases, including 3 with established neuronal damage and 1 with periventricular leukomalacia. Additional autopsy findings included thymic involution in eight (five mild; three severe), myocardial infarcts in two; intrathoracic petechiae in five, and ascites or pleural or pericardial effusions in six. Severe thymic involution and myocardial infarcts correlated with established brain injury. Placental lesions adaptive to decreased oxygenation (increased nucleated red blood cells or villous hypervascularity) were seen in five cases and correlated with established brain injury. Acute chorioamnionitis with funisitis was present in one, and chronic inflammatory placental lesions were present in six.

CONCLUSIONS

These findings indicate brain injury predated the time period immediately before delivery in 9 of 10 fetuses, and in the fetuses with established brain injury the onset of acute illness was possibly >72 h before delivery.

Fetal central nervous system injury in third trimester stillbirth: a clinicopathologic study of 63 cases

We report the neuropathologic findings and clinicopathologic associations in 63 3rd trimester singleton stillborn fetuses. All were ≥ 28 weeks estimated gestational age (EGA) with complete autopsies, including placental examination. Fetuses with chromosomal abnormalities, major congenital anomalies, and intrapartum demise were excluded. The cases were divided into those with abruption (n  =  12) and those with unexplained fetal demise (n  =  51). The latter group was then subdivided by gestational age with 3 subgroups (preterm 28 to < 32 weeks EGA (n  =  16), preterm 32 to <37 weeks EGA (n  =  13), and term 37-41 weeks EGA (n  =  22). Each group was further subdivided as appropriate-for-gestational age/large-for-gestational age (AGA/LGA) or small-for-gestational age (SGA). Placental lesions were also evaluated and correlated with brain lesions. Established or recent injury involving gray or white matter was seen in 88% of the fetuses with unexplained demise versus 42% with abruption (P  =  0.001). The most common form of brain injury was established gray matter damage, seen in 65% of the fetuses with unexplained demise versus 25% with abruption (P  =  0.021), the most common pattern being established pontosubicular neuronal necrosis plus established neuronal necrosis in other sites. There was no significant difference in the frequency of brain injury between the SGA fetuses and AGA/LGA fetuses or between the unexplained stillbirth preterm and term subgroups, and there was no unequivocal correlation between placental lesions and brain lesions. Brain injury, most frequently established gray matter damage, is seen in the majority of stillborn infants with unexplained demise, indicating that the brain injury predates the period immediately before death.

Stillbirth as a risk factor for subsequent infant mortality

BACKGROUND

Infant mortality is an important indicator of the health and wellness of a society. Multiple risk factors for infant mortality have been identified and investigated; however, the influence of prior pregnancy experience on subsequent infant mortality is under-researched.

AIMS

To examine the association between stillbirth in the first pregnancy and risk for infant mortality in the second pregnancy in a large population-based dataset.

STUDY DESIGN

Population-based, retrospective cohort study

SUBJECTS

Missouri maternally linked cohort data files were utilized from 1989 through 2005. Analyses were restricted to women who had two singleton pregnancies during the study period.

OUTCOME MEASURES

The exposure was stillbirth in the first pregnancy, while the primary outcome was infant mortality in the second pregnancy.

RESULTS

Women who experienced stillbirth in their first pregnancy were more likely to be of advanced age, black, and obese and had higher rates of pregnancy-related complications (p<0.01). Previous stillbirth was associated with an elevated risk for subsequent infant mortality (AHR=2.51, 95% CI: 1.73-3.65) and neonatal mortality (AHR=3.04, 95% CI: 1.99-4.65), after adjustment for socio-demographic variables and pregnancy complications. Risk estimates for mortality in the second pregnancy were most profound among black mothers with a history of stillbirth in the first pregnancy [risk for infant mortality: (AHR=2.68, 95% CI: 1.41-5.09) and neonatal death: (AHR=4.25, 95% CI: 2.34-7.60)].

CONCLUSIONS

Women with prior stillbirth bear elevated risks for subsequent infant mortality. Women's previous childbearing experiences could serve as important criteria in determining appropriate interconception strategies to improve subsequent feto-infant health and survival.

Reference ranges for Doppler assessment of uterine artery resistance and pulsatility indices in dichorionic twin pregnancies

OBJECTIVES

To construct reference ranges of uterine artery Doppler parameters against gestation in twin pregnancies and to present charts of the pulsatility index (PI) and resistance index (RI) for clinical use.

METHODS

This was an observational study of the uterine circulation in 557 women with dichorionic twin pregnancies at 17-38 weeks' gestation. Uterine artery measurements were performed by color and pulsed Doppler imaging. The uterine artery PI and RI were calculated as a mean of both sides. Reference ranges were constructed by regression of each index on gestational age. For this purpose, a regression model with fractional polynomials was fitted to the data. Furthermore, the presence of uterine artery notching was recorded.

RESULTS

New reference curves and tables of percentiles of the uterine artery PI and RI are presented. The calculated indices both showed a significant decrease with gestational age. Compared with singleton values, mean twin PI values were lower during the whole course of pregnancy. The prevalence of bilateral notching was 4.6% at 17-19 weeks' gestation and 3.1% at 20-24 weeks.

CONCLUSIONS

Uterine artery Doppler indices in twin pregnancies are lower than in singleton pregnancies. Therefore, the use of uterine artery reference ranges adapted to twin gestations seems more appropriate for identifying low- and high-risk groups.