Available via license: CC BY-NC-ND
Content may be subject to copyright.
Received: 13 April 2021
-
Revised: 12 September 2021
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Accepted: 7 October 2021
DOI: 10.1002/pd.6072
ORIGINAL ARTICLE
Severe fetal ventriculomegaly: Fetal morbidity and mortality,
caesarean delivery rates and obstetrical challenges in a large
prospective cohort
Alex O. Start
1,2
|Gillian A. Ryan
1,2
|Barbara Cathcart
2
|Heather Hughes
2
|
Shane Higgins
1,2
|Siobhan Corcoran
1,2
|Jennifer Walsh
1,2
|Stephen Carroll
2
|
Rhona Mahony
2
|Darach Crimmins
3,4
|John Caird
3
|Gabrielle Colleran
4,5
|
Peter McParland
1,2
|Fionnuala M. McAuliffe
1,2
1
UCD Perinatal Research Centre, University
College Dublin, The National Maternity
Hospital, Dublin, Ireland
2
Fetal Medicine Department, The National
Maternity Hospital, Dublin, Ireland
3
Neurosurgery Department, Children's
University Hospital, Dublin, Ireland
4
UCD School of Medicine, University College
Dublin, Dublin, Ireland
5
Radiology Department, The National
Maternity Hospital, Dublin, Ireland
Correspondence
Fionnuala McAuliffe, UCD Perinatal Research
Centre, University College Dublin, The
National Maternity Hospital, Dublin, Ireland.
Email: Fionnuala.mcauliffe@ucd.ie
Abstract
Introduction: Severe fetal ventriculomegaly (VM) is defined as an enlargement of
the atria of the lateral cerebral ventricles (Vp) of greater than 15 mm. While it is
well established that it confers significant risk of morbidity and mortality to the
neonate, there is limited information pertaining to the caesarean delivery rates and
the obstetric management of these complex cases. The aim of this study was
twofold: firstly, to determine survival rates in fetuses with severe VM, and secondly
to determine the caesarean delivery rates in continuing pregnancies. We explore
the obstetric challenges associated with these difficult cases.
Methods: This was a prospective observational study of patients with antenatal
severe VM, attending the Department of Fetal Medicine, National Maternity Hos-
pital, Dublin, Ireland, from 1st January 2011 to 31st July 2020. Data were obtained
from the hospital database and those with severe VM (Vp >15 mm) were identified.
The rates of chromosomal abnormalities, the survival rates and the caesarean de-
livery (CD) rates for the overall group were then determined. The data were then
further sub‐divided into two groups: 1. Vp <20 mm and 2. Vp >20 mm, and the
results compared. Statistical analysis was performed using the Chi‐Square test.
Results: A total of N=95 pregnancies with severe VM were included for analysis, of
which additional structural abnormalities on ultrasound were apparent in 67/95
(70.5%) and 28/95 (29.5%) had isolated severe VM. Chromosomal abnormalities
were diagnosed in 15/95 (15.8%) of cases, with (2/28) 7.1% in the isolated SVM
group versus (13/67) 19.4% in the non‐isolated SVM group. The overall survival rate
(excluding TOP) was 53/74 (71.6%), with 20/23 (86.9%) in the isolated SVM group.
The overall CD rate was 47/72 (65.3%), which was significantly higher than the CD
for the hospital during the same time period of 25.4% (P<0.01).
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© 2021 The Authors. Prenatal Diagnosis published by John Wiley & Sons Ltd.
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1
The data were subdivided into Vp <20 and Vp >20 and those with a Vp >20 had
higher rates of additional intracranial findings on ultrasound (Vp <20 13/41 (31.7%)
versus Vp >20 32/54 (59.3%) (P<0.05)) and macrocrania (Vp <20 14/41 (34.1%)
versus Vp >20 35/54 (64.8%) (P<0.05)). No significant difference was observed in
the overall survival or CD rates between the two groups.
Conclusion: In conclusion this study reports significant fetal morbidity and mortality
with severe VM with high CD rates observed in this cohort. Significant challenges
exist in relation to the obstetric management and counseling of parents regarding
an often uncertain neonatal prognosis. In continuing pregnancies with significant
macrocrania delivery plans should be individualized to improve neonatal outcomes
where possible and minimize harm to the mother.
Key points
What's already known about this topic?
�Severe ventriculomegaly is associated with fetal morbidity and mortality
�There is paucity of data on the outcomes of Vp >20 mm versus Vp <20 mm
�There is limited information about caesarean delivery rates of these cases
What does this study add?
�The overall survival (excluding TOP) was 71%
�No differences were observed in overall survival or CD rates between Vp >20 mm versus
Vp <20 mm
�The overall caesarean delivery rates were 65% in this cohort
1
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INTRODUCTION
Prenatal counseling in cases of severe fetal ventriculomegaly (VM) is
often challenging. While it is well established that is confers a sig-
nificant risk of morbidity and mortality to the neonate, despite a
generally poor prognosis, it is often difficult to accurately quantify
antenatally the infant outcome as there can be poor correlation
between brain imaging and subsequent neurodevelopment antena-
tally.
1
Severe VM is typically classified as Vp >15 mm
2
and is
diagnosed via antenatal ultrasound by measuring the atria of the
lateral ventricles (Vp).
3
Additional structural and chromosomal/ge-
netic abnormalities are commonly reported in cases of SVM.
4,5
Studies have reported high rates of additional abnormalities of 58% ‐
65%,
6–8
with SVM. The incidence of aneuploidies is high >15%
9
in
the presence of other structural abnormalities, while there is a low
incidence of aneuploidy reported in fetuses with isolated SVM.
4,10–12
SVM may also be associated an underlying genetic condition or other
intracranial abnormalities including Dandy‐walker spectrum,
congenital stenosis of the aqueduct of Sylvius (presumed to be an X‐
linked disorder), agenesis of the corpus callosum, spina bifida,
obstruction of cerebrospinal fluid or as the result of a congenital
infection.
2,5,13,14
While the findings of associated genetic and structural abnor-
malities negatively impact prognosis, the long‐term disability and
mortality rate in isolated SVM is also disproportionally high. A 2018
systematic review and meta‐analysis reported a 12% mortality rate in
isolated SVM
15
with mild/moderate disability in 18.6% and severe
disability in 39.6%.
15
What is perhaps less frequently appreciated and discussed is the
increased caesarean delivery (CD) associated with an antenatal
finding of SVM. For those who continue the pregnancy, severe VM
can progress and in turn cause significant macrocrania, which can
result in increased maternal morbidity, as CD is more likely to be
indicated secondary to an enlarging head circumference (HC).
13,16
Fetal surgical options including cephalocentesis
17,18
and fetal
venticulo‐amniotic shunts
19,20
have been reported to decompress the
fetal head in order to facilitate delivery. However, their role in the
management of this condition is controversial and at present ante-
natal procedures for ventriculomegaly are not accepted practice due
to lack of evidence to support them.
17,20
With regards to optimal timing and mode of delivery there is
limited data pertaining to mild and moderate VM and even less
guidance to direct management in cases of severe VM. There is a
paucity of data on the CD rates in this cohort. To that end, the aim of
this study was twofold: to examine the outcomes of fetuses diag-
nosed with SVM antenatally, and secondly to determine the CD rates
in continuing pregnancies. There are minimal data comparing the
outcomes of fetuses diagnosed with varying degrees of severe VM.
Therefore, the study cohort was subdivided this group into two
clinical groups; 1. those with a Vp <20 mm (Vp <20) and 2. those
2
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ET AL.
with a Vp >20 mm (Vp >20) to determine if a difference in perinatal
outcome exists between them.
2
|
METHODS
This was a prospective observational study with Institutional Ethical
Approval of patients referred with suspected fetal VM to the
Department of Fetal Medicine, National Maternity Hospital, Dublin,
Ireland, from 1st January 2011 to 31st July 2020. The department is
a tertiary referral center for the Republic of Ireland with onsite fetal
MRI facilities and a dedicated national fetal neurosurgical clinic
where patients are seen jointly by fetal medicine and pediatric
neurosurgery.
1
All patients with suspected ventriculomegaly are seen
by a fetal medicine consultant within one week of being referred. The
patients are offered prenatal genetic diagnosis, fetal MRI and are
then counseled regarding the likely prognosis and pregnancy options
are discussed including the options to continue the pregnancy and to
terminate the pregnancy where appropriate. All patients in this
cohort were offered amniocentesis. From 2014 non‐invasive pre‐
natal screening was available in our unit as an option for those
who elected not to have invasive testing. A fetal brain MRI is offered
after a detailed anatomical and neurosonographic examination by a
maternofetal medicine specialist, following discussion with the per-
forming Pediatric Radiologist. Ventriculomegaly is the most common
indication for fetal MRI in our institution. Prior to August 2016 fetal
MRI facilities were not available in the hospital and all patient
referred with ventriculomegaly prior to this may not have been
offered the option of fetal MRI. For those after 2016 all patients with
severe ventriculomegaly, where aneuploidy was not suspected, were
offered a fetal MRI for further investigation. They were then
reviewed again in the fetal neurosurgical clinic where a further
detailed ultrasound was performed, and the patients were counseled
by both a fetal medicine consultant and a pediatric neurosurgeon.
Data were entered into the hospital database prospectively by
a specialist fetal medicine midwife, and those with severe
VM (>15 mm) were identified. Patients were excluded where there
was a multiple pregnancy, where the Vp measurement did not meet
the above diagnostic criteria for severe ventriculomegaly and those
with a subsequent diagnosis of a neural tube defect/spina bifida were
also excluded from the analysis. The data were assessed to determine
the average gestational age at diagnosis and whether VM was uni-
lateral or bilateral. The rates of chromosomal abnormalities, the
survival rates and the CD rates for the overall group was then
determined. The data were then further sub‐divided into two distinct
groups as described above, 1. Vp <20 and 2. Vp >20, and the results
compared between the two groups. Statistical analysis performed
using the Chi‐Square test or students t‐Test as appropriate.
3
|
RESULTS
A total of N=95 singleton pregnancies with confirmed SVM were
included for analysis. The maternal demographics are presented in
Table 1. The median gestational age at diagnosis was 24 weeks and
1 day (range 16 weeks and 6 days to 38 weeks and 5 days). VM was
bilateral in 86/95 (90.5%) of cases and unilateral in 9/95 (9.5%) of
cases. Additional structural abnormalities on ultrasound were
apparent in 67/95 (70.5%) cases, of which 47.4% had additional
intracranial findings only and 28/95 (29.5%) had apparently isolated
TABLE 1Maternal demographic
Average maternal age (range) 31.7 years
Range (19–45 years)
BMI (SD) 26.26 (5.6) kg/m
2
Nationality
Irish 77/95 (81.05%)
EU 10/95 (10.53%)
Non‐EU 8/95 (8.42%)
Median gestation at diagnosis (range) 24 +1 week (16 +6 weeks to 38 +5 weeks)
Range
Median gestation at delivery (range) 38 +4 weeks (30 +3 weeks to 42 +4 weeks)
Range
Median maternal parity (range) 1
Range (0–7)
Bilateral ventriculomegaly 86
Unilateral ventriculomegaly 9
Abbreviations: BMI, Body Mass Index; EU, European Union; SD, Standard Deviation.
START ET AL.
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3
SVM on ultrasound. Amniocentesis was performed in 46/95 (48.4%)
and 10/95 (10.5%) had non‐invasive prenatal screening and a further
12/95 (12.6%) had postnatal genetic investigations after neonatal
review and genetics input where appropriate. There were 37/95
(38.9%) where no karyotype or chromosomal microarray were per-
formed. In the overall group chromosomal abnormalities were sub-
sequently diagnosed in 15/95 (15.8%) of cases (Table 2), with a rate of
15/58 (25.9%) in those that availed of diagnostic testing. Genetic
abnormalities were confirmed in 2/28 (7.1%) of the isolated SVM
group versus 13/67 (19.4%) in the non‐isolated SVM group. These
included trisomy 21 n=4, trisomy 18 n=2, triploidy n=1, X‐Linked
hydrocephalus (L1 CAM) n=1, mutation in PP2RIA gene n=1,
chromosome 7q36 mutation n=1, mutation in ISPD gene n=1 and
other single gene disorders n=4. There was one case of congenital
CMV in this cohort. A total of 59/95 (62.1%) had fetal MRIs per-
formed, with additional intracranial information was provided in 46/
59 (78%) of these. Of the n=36 that did not have a fetal MRI per-
formed the reasons included: maternal spinal rods (n=1), termination
of pregnancy (n=13), IUD (n=1), confirmed genetic cause (n=3),
additional significant structural abnormalities (n=5), no documented
reason (n=11). In the group with no documented reason why an MRI
was not performed, 7 were diagnosed with SVM after 33 weeks'
gestation (range 33 to 38 weeks and 5 days). Of these 7, one was
delivered the next day. Of the remaining six cases, the patients
attended the hospital from 2012 to 2016, when MRI was not available
on site, and this may have influenced the decision not to perform
antenatal MRI in the third trimester in these cases. There was one
confirmed case of Fetal Neonatal Alloimmune Thrombocytopenia
(FNAIT) in this cohort with underlying intra‐ventricular hemorrhage
present on antenatal MRI. Table 3outlines the most likely final
diagnosis for all patients after completion of investigations.
The overall survival rate was 53/95 (55.8%). In utero demise was
reported in 2 cases and in 21 cases couples opted for termination of
pregnancy. However, after exclusion of those who opted for termi-
nation of pregnancy (TOP) n=21/95 (22.1%) the overall survival rate
was 53/74 (71.6%), with a rate of 20/23 (86.9%) for those with iso-
lated SVM (Table 2). For those that opted for TOP the median
gestation of diagnosis of the VM was 21 weeks and 2 days (range
16 weeks and 6 days to 37 weeks and 2 days). The majority, 14/21
(66.7%), subsequently had TOP after 24 weeks of gestation. Table 4
compares the outcomes by gestational age at diagnosis of VM. Fe-
tuses where severe VM was diagnosed before 24 weeks, had an
overall higher rate of TOP and a lower survival rate than those
diagnosed from 24 to 32 weeks and those diagnosed after 32 weeks'
gestation. The overall CD rate for this group was 47/72 (65.3%). This
was significantly higher than the CD for the hospital during the same
time period which was 25.4% (P<0.01). A total of N=16 preg-
nancies delivered prior to 37 weeks gestation (16/72, 22.2%). Of
these 3/16 (18.75%) were spontaneous vaginal deliveries and 13/16
(81.25%) were iatrogenic and delivered by CD.
In our series only one patient required cephalocentesis at the time
of CD to facilitate delivery of the fetal head through a lower trans-
verse abdominal incision. This patient had CD at 36 +1 week'
gestation with an increasing HC, measuring 406 mm on ultrasound the
week prior. A lower uterine segment incision was performed and as it
was not possible to deliver the fetal head through the lower
TABLE 2Antenatal Findings, Survival and Mode of Delivery Compared between Fetuses with Vp measurements <20 mm and >20 mm
Vp <20 mm
(N=41)
Vp >20 mm
(N=54) pvalue
Overall group
(N=95)
Chromosomal abnormalities 7/41 (17.1%) 8/54 (14.8%) p=0.7 (NS) 15/95 (15.8%)
US findings
a
Isolated 16/41 (39%) 12/54 (22.2%) p=0.07 (NS) 28/95 (29.5%)
Additional intracranial 13/41 (31.7%) 32/54 (59.3%) p<0.05 45/95 (47.4%)
Extra cranial findings 12/41 (29.3%) 10/54 (18.5%) p=0.2 (NS) 22/95 (23.2%)
Additional intracranial MRI findings 9/28 (32.14%) 37/67 (55.2%) p<0.05 46/95 (48.4%)
HC >95th 14/41 (34.1%) 35/54 (64.8%) p<0.05 49/95 (51.6%)
TOP 10/41 (24.4%) 12/54 (22.2%) p=0.6 (NS) 21/95 (24.2%)
IUD =2 1/41 1/54 2/95 (2.1%)
NND 4/41 (9.8%) 15/54 (27.8%) p<0.05 19/95 (20%)
Survival (excluding TOP) 26/41 (63.4%) 27/54 (50%) p=0.19 (NS) 53/74 (71.6%)
Delivery information
CD 17/30 (56.7%) 30/42 (71.4%) p=0.19 (NS) 47/72 (65.3%)
VD 13/30 (43.3%) 12/42 (28.6%) p=0.19 (NS) 25/72 (34.7%)
Abbreviations: CD, Caesarean delivery; HC, Head circumference; IUD, In utero demise; NND, Neonatal death; NS, Not significant; TOP, Termination of
pregnancy; US, Ultrasound; VD, Vaginal delivery; Vp, Measurement of the posterior horn of the lateral ventricle.
a
US findings relate to the initial ultrasound performed by a fetal medicine specialist reported findings from this detailed assessment.
4
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transverse incision 180 ml was aspirated under direct vision with a 16
gauge needle and the fetal head was then successfully delivered
though the standard transverse uterine incision. The HC at birth was
476 mm. The baby was born alive and died at 3 h of life. In this case
there was a diagnosis of severe hydrocephalus secondary to an
intracranial tumor and an intracranial teratoma was confirmed on
postmortem examination. The were no cases of cephalocentesis per-
formed during a vaginal birth in this series. In one other case a patient
had a CD at 34 weeks' gestation after MDT discussion with fetal
medicine, pediatric neurosurgeons and the neonatal team. The HC in
this case was 400 mm on US and a decision was made to perform a CD
at this gestation in an attempt to avoid cephalocentesis as the parents
wished for the baby to be born alive and also to avoid an extended
uterine incision at a later gestation. In this case the patient had had a
prior CD and the fetus was expected to have a poor prognosis. CD was
performed through a standard lower segment incision; the fetal head
was delivered easily, and the infant demised shortly after birth. The
HC at birth was measured at 418 mm and this was the largest HC in
our cohort successfully delivered by lower uterine segment incision
that did not require additional peri‐CD drainage.
The data were then subdivided into those with Vp <20 and
those with Vp >20 and the results compared between the two
groups. These results are presented in Table 2. No significant dif-
ferences were observed in the rate of chromosomal abnormalities
between the groups. Those with a Vp >20 had a higher rates of
additional intracranial findings on ultrasound, Vp >20 32/54 (59.3%)
versus Vp <20 13/41 (31.7%), P<0.05. They also had higher rates of
macrocrania, Vp >20 35/54 (64.8%) than those in the Vp <20 group
14/41 (34.1%), P<0.05. Those with Vp >20 mm also had a higher
rate of neonatal death than those with Vp <20 mm, P<0.05
(Table 2). There was no significant difference observed in the CD
rates between the two groups.
The data were further analyzed to assess the survival rates and
CD rates in those with macrocrania (defined as HC >95th centile)
and those without (defined as HC <95th centile) and these findings
are presented in Table 5. Fetuses with a HC >95th centile had a
lower survival rate than those with a normal HC (P<0.05). They also
had significantly higher rates of CD at 86.1%, while those with a
HC<95% had a CD rate of 44.4% (P<0.05).
TABLE 3The Final Diagnosis of this Cohort after Antenatal
and Postnatal Assessment
Final diagnosis N (%)
Isolated VM 16/95 (16.8%)
Chromosomal/Genetic abnormalities 15/95 (15.8%)
CMV 1/95 (1.05%)
Additional findings 63/95 (66.3%)
Agenesis of the corpus callosum 12
Hemorrhage 11
VM +dilated third ventricle 10
Aqueduct stenosis 7
Brainstem abnormality 4
Schizencephaly 2
Walker Warburg 1
Arachnoid cyst 1
Cortical migrational anomaly +ACC 1
Encephalocele 1
Lissencephaly 1
Dandy walker malformation 1
Chiari 1 malformation 1
Enlarged CM 1
VM +Sonolucent area in right temporal lobe 1
Multiple anomalies 3
Schizencephaly +HLHS 1
Thantophoric dysplasia 1
VSD 1
Severe hydronephrosis 1
Tetralogy of fallot 1
Note: This Table givens a breakdown of the most likely final diagnosis of
each case after US imaging, MRI (as appropriate) and genetic
investigations were completed.
Abbreviations: ACC, Agenesis of the Corpus Callosum; CM, Cisterna
Magna; CMV, Cytomegalovirus; HLHS, Hypoplastic Left Heart
Syndrome; VM, Ventriculomegaly; VSD, Ventricular Septal Defect.
TABLE 4Comparison of outcomes by the gestation at diagnosis
Gestation at diagnosis
(weeks +days) Number
Gestation at delivery
(median) TOP Survival
<24 N=47 37 weeks +2 days 18/47 (38.3%) 14/47 (29.8%)
24 +0 to 32 +0N=22 37 weeks +1 day 2/22 (9.1%) 16/22 (72.7%)
>32 N=26 38 weeks +6 days 1/26 (3.8%) 23/26 (88.5%)
pvalue NS P<0.05 P<0.05
Note: This table provides the outcomes in terms of gestation at delivery, rate of TOP and the survival rates when subdivided by gestation at diagnosis of
the ventriculomegaly.
Abbreviations: NS, Not significant; TOP, Termination of pregnancy.
P<0.05 was considered statistically significant.
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5
4
|
DISCUSSION
The finding of antenatal SVM poses a number of challenges, both in
terms of obstetric management and counseling the parents regarding
an often guarded and uncertain prognosis. As alluded to above, SVM
has long been associated with adverse neonatal outcomes with a 21%
mortality rate.
3
We found an overall survival rate in this cohort of
71.6% (after exclusion of TOP), although it was significantly higher
20/23 (87%) in the isolated severe VM group versus those with
additional abnormalities 33/51 (64.7%) (P<0.05). It is frequently
described in the literature that cases of SVM associated with extra-
cranial abnormalities results in a poor outcome, with livebirth rates
as low as 30%–40%.
3,11,15
No difference was observed in the overall
survival rates between those with Vp <20 versus Vp >20, though
those in the Vp >20 group had a higher neonatal death (NND) rate of
27.8% (Table 2).
There were chromosomal abnormality rates in the SVM popu-
lation of 15.8%, with 7.1% observed in the isolated SVM group versus
19.4% in the non‐isolated SVM group, consistent with previously
reported studies.
3,10,11,15
However, it must be acknowledged that the
rate was higher, 25.9%, in those that availed of diagnostic testing.
The reasons for this variation are multifactorial. In some cases,
women choose not to have diagnostic testing, some opted for NIPS,
some opted for TOP prior to embarking on any additional genetic
testing, and in some cases additional genetic testing was not rec-
ommended postnatally after detailed neonatal assessment.
Our study confirms previous reports of high rates of additional
structural abnormalities on ultrasound of 70.6% associated with
SVM, of which 47.4% had additional intracranial findings only. Other
studies reported additional structural findings in SVM patients of
58%–65%.
6,7,15
Those in the Vp >20 group had a higher rate of
intracranial findings than those in the Vp <20 group at 59.3% versus
31.7% respectively, P<0.05. MRI has enhanced antenatal diagnosis
of fetal abnormalities in recent years.
2
US lacks the ability to detect
subtle cortical brain anomalies and MRI provides additional infor-
mation in these scenarios.
16
In this study we found fetal MRI pro-
vided additional diagnostic information in 78% of cases. MRI results
were useful to guide counseling in several respects. In 8 cases, par-
ents opted for termination of pregnancy after the MRI reported
additional findings, which included agenesis of the corpus callosum. In
4 other cases the parents chose to continue the pregnancy but with a
plan for palliative care after the birth. These included in cases of
schizencephaly, severe hemorrhage, severe Aqueduct stenosis and
one case where there were additional cerebellar findings on MRI.
Furthermore, additional MRI findings were useful to counsel patients
regarding the potential surgical treatment options that may be
required after birth, to allow families to prepare for this. Moreover,
when the MRI found no additional intracranial findings this was also
helpful for parents to make decision regarding continuing or termi-
nating the pregnancy.
Aside from the significant fetal morbidity and mortality
observed in this cohort, this study also highlights the increased
TABLE 5Survival and Mode of Delivery Compared between Fetuses with macrocrania and those with a normal head circumference on
antenatal ultrasound
HC <95th centile
n=46
HC >95th centile
N=49 pvalue
Vp >20 mm 16/46 (34.8%) 35/49 (71.4%) p<0.05
Average Vp 20.5 mm 28.5 mm p<0.05
Range (15–37.9 mm) (15–48.4 mm)
Survival (Ex‐TOP) 33/38 (86.8%) 20/36 (55.6%) p<0.05
TOP 8/46 (17.4%) 13/49 (26.5%)
IUD 2/46 (4.3%) 0/49 (0%)
NND 3/46 (8.3%) 16/49 (32.6%) p<0.05
Median parity 1 1 p=NS
Range (0–5) (0–7)
Primiparous 17/46 (34%) 24/49 (49%)
Multiparous 29/46 (63%) 25/49 (51%)
Median gestation at delivery 37 weeks +5 days 37 weeks +4 days p=NS
Range (weeks +days) (30 +3 to 41 +5) (34 +4 to 42 +4)
CD 16/36 (44.4%) 31/36 (86.1%) p<0.05
VD 20/36 (55.6%) 5/36 (13.9%) p<0.05
Abbreviations: CD, Caesarean delivery; HC, Head circumference; IUD, In utero demise; NND, Neonatal death; NS, Not significant; TOP, Termination of
pregnancy; US, Ultrasound; VD, Vaginal delivery.
6
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CD associated with an antenatal diagnosis of SVM in continuing
pregnancies. We found women with an antenatal diagnosis of
SVM had a disproportionally high CD rate of 65.3%, which was
significantly higher than the background rate in the unit during
this time period of 25.4% (P<0.01). When comparing those with
a Vp <20 and Vp >20, no significant difference was observed
between the groups in perinatal outcomes. This high rate of CD is
important to consider in counseling regarding the maternal risks
associated with a diagnosis of SVM and continuation of the
pregnancy.
21
Fetuses with severe macrocrania require individualized man-
agement to facilitate safe delivery in continuing pregnancies and to
minimize maternal morbidity where possible. The options for de-
livery for a fetus with significant macrocrania may include consid-
eration for preterm delivery to allow for safe delivery of the fetal
head, use of cephalocentesis to decompress the fetal head prior to
or during delivery or consideration of a classical CD. In our cohort
86.1% of fetuses with a HC >95th centile had a CD, which was
significantly higher than the background rate of 25.4%. There is no
evidence to suggest that preterm or CD improves maternal or
neonatal outcome in mild or moderate VM
2
although little is known
about the effects of preterm delivery on SVM fetuses, particularly
where a poor prognosis is anticipated. In select cases preterm de-
livery may be considered with worsening macrocrania in an attempt
to avoid a potentially more difficult or complex CD at term.
22,23
We
acknowledge that preterm delivery confers significant risks of pre-
maturity
13,24
and it should only be considered in cases where there
is an anticipated very poor neonatal outcome, in an effort to
decrease maternal morbidity. As alluded to above, a CD was per-
formed in one case at 34 weeks' gestation due to progressively
worsening macrocrania. Preterm delivery in this context decreased
the need for cephalocentesis or an extended uterine incision/clas-
sical incision being performed at a later gestation and allowed the
parents time with their baby.
While there have been significant advances in the diagnoses of
fetal malformations in recent years, the same improvements have
not been seen in the surgical treatments for fetal ven-
triculomegaly.
19
Fetal surgical options, including cephalocentesis
17,18
and venticulo‐amniotic shunts,
19,20
have been reported to decom-
press the fetal head in order to facilitate delivery. Due to the high
risk of fetal demise with cephalocentesis, it is now rarely performed
and is typically only used to cause decompression of the fetal head
to aid delivery and to prevent surrounding structures being com-
pressed in the fetal cranium.
25
If done successfully, cephalocentesis
can facilitate vaginal delivery or a lower segment uterine incision at
the time of CD and as such result in decreased maternal morbidity
related to delivery. In our cohort only one case with severe VM and
macrocrania required cephalocentesis peri‐CD to facilitate delivery
of the fetal head through a lower transverse uterine incision, and
thus reducing maternal morbidity in this context. Despite unfavor-
able outcomes during the early experience with in utero CSF
diversion, improvements in prenatal diagnosis and fetal surgery have
led to a renewed interest in fetal ventriculo‐amniotic fluid (VA)
shunting.
23
Several reasons have been cited to explain the historic
suboptimal outcomes and include poor patient selection and lower
quality imaging modalities.
23,26
Advance in neurosonography and
fetal MRI have improved detection of pathologies which are more
likely to be amenable to in utero shunting, such as Aqueduct Ste-
nosis.
23,27,28
Ventriculo‐amniotic shunting may improve neurologic
outcomes in selected patients and decrease maternal morbidity at
the time of delivery.
28
There is a need for further evaluation on the
topic
20
and a research agenda has been constructed, and investi-
gation is underway to determine in use in routine clinical
practice.
20,28
Extended or classical CD procedures have also been considered
as a means to facilitate delivery of the large fetal head, where it is
not possible to deliver the fetus through a low transverse incision
and are associated with increased maternal morbidity.
29
Classical
CD procedures are associated with risks of complications at both at
the time of surgery, including a risk of infection and blood loss,
28–30
and are also a cause of morbidity in subsequent pregnancies,
particularly in relation to an increased risk of uterine rupture.
28,29
In
our series we did not perform any classical CD procedures to
facilitate delivery in the context of fetal macrocrania, nor were there
any J, T incisions or any significant uterine angle tears reported in
this cohort. Other studies however have used classical CD as a
means to facilitate delivery. A 2009 retrospective study reported
the delivery of 13 out of 23 fetuses with fetal macrocrania by
classical CD from 1st March 2003 to the 30th June 2007.
13
From
this series 22% of infants died in the neonatal period, 70% went to
the neonatal intensive care unit and 8% were transferred for further
surgical management and subsequently died.
13
Given the increased
maternal morbidity, without a significant improvement in fetal
outcome, the authors are therefore of the option that classical CD
should only be considered where other means of delivery are either
unsuccessful or unacceptable.
Finally, it must be remembered there is an increased level of
psychological stress experienced by parents with the ultrasono-
graphic detection of a fetal anomaly in pregnancy.
31
The severity of
the fetal malformation and ambiguity concerning diagnosis and
prognosis, as is often the case with SVM, also increases parental
psychological distress, social dysfunction and health perception.
32
As
it has also been reported that there appears to be no correlation
between the severity of the neurologic outcomes and the prenatal
ventricular dilation on antenatal ultrasound imaging in the SVM
group,
33
this further adds to the complexities of antenatal counseling
and support should be offered to couples when faced with this
complex diagnosis.
The strengths of this study include that as this is a large tertiary
referral centre with a national fetal neurosurgical clinic.
1
A further
strength is that this is a large prospective study and delivery out-
comes were available for all pregnancies, to aide in the counseling of
women with SVM. Another strength of this study is that we
analyzed the data separately according to the degree of VM;
START ET AL.
-
7
Vp <20 mm and Vp >20 mm. The paucity of long‐term neuro-
logical follow up and developmental data in our population is a
limitation of this study and standardized short‐and longer‐term
neurodevelopmental assessment using validated, contemporary
tools and metrics is recommended and this is the topic of an
ongoing study within our department. Further limitations of this
study include the lack of comprehensive data on postpartum hem-
orrhage, maternal length or stay, previous CD procedures and the
indications for the CD including whether it was an emergency or an
elective CD.
In our study we confirmed that antenatally diagnosed SVM
confers a significant degree of both fetal morbidity and mortality.
The results also highlight the significantly increased rates of CD in
pregnancies affected by SVM. It is important therefore to tailor our
counseling appropriately not only to highlight potentially poor fetal
outcomes, but to also ensure couples are aware of the vastly
increased CD rate in this population and to offer appropriate psy-
chological support in the context of an uncertain and complex
diagnosis. This paper also highlights the significant obstetrical
challenges faced when planning delivery for fetuses with severe VM
in continuing pregnancies, and management should be individualized
to optimize neonatal outcomes while minimizing harm to the
mother.
ACKNOWLEDGMENTS
We would like to thank the families that participated in the study and
the clinical staff of National Maternity Hospital and Children's Uni-
versity Hospital at Temple Street for supporting this study.
CONFLICT OF INTEREST
The authors report no conflict of interest.
DATA AVAILABILITY STATEMENT
Data available on request from the corresponding author.
ORCID
Alex O. Start
https://orcid.org/0000-0003-0317-5642
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How to cite this article: Start AO, Ryan GA, Cathcart B, et al.
Severe fetal ventriculomegaly: fetal morbidity and mortality,
caesarean delivery rates and obstetrical challenges in a large
prospective cohort. Prenat Diagn. 2021;1‐9. https://doi.org/10.
1002/pd.6072
START ET AL.
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