Effect of Delayed Cord Clamping on Neurodevelopment at 4 Years of Age: A Randomized Clinical Trial

Abstract

Prevention of iron deficiency in infancy may promote neurodevelopment. Delayed umbilical cord clamping (CC) prevents iron deficiency at 4 to 6 months of age, but long-term effects after 12 months of age have not been reported.
To investigate the effects of delayed CC compared with early CC on neurodevelopment at 4 years of age.
Follow-up of a randomized clinical trial conducted from April 16, 2008, through May 21, 2010, at a Swedish county hospital. Children who were included in the original study (n = 382) as full-term infants born after a low-risk pregnancy were invited to return for follow-up at 4 years of age. Wechsler Preschool and Primary Scale of Intelligence (WPPSI-III) and Movement Assessment Battery for Children (Movement ABC) scores (collected between April 18, 2012, and July 5, 2013) were assessed by a blinded psychologist. Between April 11, 2012, and August 13, 2013, parents recorded their child's development using the Ages and Stages Questionnaire, Third Edition (ASQ) and behavior using the Strengths and Difficulties Questionnaire. All data were analyzed by intention to treat.
Randomization to delayed CC (≥180 seconds after delivery) or early CC (≤10 seconds after delivery).
The main outcome was full-scale IQ as assessed by the WPPSI-III. Secondary objectives were development as assessed by the scales from the WPPSI-III and Movement ABC, development as recorded using the ASQ, and behavior using the Strengths and Difficulties Questionnaire.
We assessed 263 children (68.8%). No differences were found in WPPSI-III scores between groups. Delayed CC improved the adjusted mean differences (AMDs) in the ASQ personal-social (AMD, 2.8; 95% CI, 0.8-4.7) and fine-motor (AMD, 2.1; 95% CI, 0.2-4.0) domains and the Strengths and Difficulties Questionnaire prosocial subscale (AMD, 0.5; 95% CI, >0.0-0.9). Fewer children in the delayed-CC group had results below the cutoff in the ASQ fine-motor domain (11.0% vs 3.7%; P = .02) and the Movement ABC bicycle-trail task (12.9% vs 3.8%; P = .02). Boys who received delayed CC had significantly higher AMDs in the WPPSI-III processing-speed quotient (AMD, 4.2; 95% CI, 0.8-7.6; P = .02), Movement ABC bicycle-trail task (AMD, 0.8; 95% CI, 0.1-1.5; P = .03), and fine-motor (AMD, 4.7; 95% CI, 1.0-8.4; P = .01) and personal-social (AMD, 4.9; 95% CI, 1.6-8.3; P = .004) domains of the ASQ.
Delayed CC compared with early CC improved scores in the fine-motor and social domains at 4 years of age, especially in boys, indicating that optimizing the time to CC may affect neurodevelopment in a low-risk population of children born in a high-income country.
clinicaltrials.gov Identifier: NCT01581489.

Full text

Copyright 2015 American Medical Association. All rights reserved.
Effect of Delayed Cord Clamping on Neurodevelopment
at 4 Years of Age
A Randomized Clinical Trial
Ola Andersson, MD, PhD; Barbro Lindquist, PhD; Magnus Lindgren, PhD; Karin Stjernqvist, PhD;
Magnus Domellöf, MD,PhD; Lena Hellström-Westas, MD, PhD
IMPORTANCE Prevention of iron deficiency in infancy may promote neurodevelopment.
Delayed umbilical cord clamping (CC) prevents iron deficiency at 4 to 6 months of age, but
long-term effects after 12 months of age have not been reported.
OBJECTIVE To investigate the effects of delayed CC compared with early CC on
neurodevelopment at 4 years of age.
DESIGN, SETTING, AND PARTICIPANTS Follow-up of a randomized clinical trial conducted from
April 16, 2008, through May 21, 2010, at a Swedish county hospital. Children who were
included in the original study (n = 382) as full-term infants born after a low-risk pregnancy
were invited to return for follow-up at 4 years of age. Wechsler Preschool and Primary Scale of
Intelligence (WPPSI-III) and Movement Assessment Battery for Children (Movement ABC)
scores (collected between April 18, 2012, and July 5, 2013) were assessed by a blinded
psychologist. Between April 11, 2012, and August 13, 2013, parents recorded their child’s
development using the Ages and Stages Questionnaire, Third Edition (ASQ) and behavior
using the Strengths and Difficulties Questionnaire. All data were analyzed by intention to treat.
INTERVENTIONS Randomization to delayed CC (ⱖ180 seconds after delivery) or early CC
(ⱕ10 seconds after delivery).
MAIN OUTCOMES AND MEASURES The main outcome was full-scale IQ as assessed by the
WPPSI-III. Secondary objectives were development as assessed by the scales from the
WPPSI-III and Movement ABC, development as recorded using the ASQ, and behavior using
the Strengths and Difficulties Questionnaire.
RESULTS We assessed 263 children (68.8%). No differences were found in WPPSI-III scores
between groups. Delayed CC improved the adjusted mean differences (AMDs) in the ASQ
personal-social (AMD, 2.8; 95% CI, 0.8-4.7) and fine-motor (AMD, 2.1; 95% CI, 0.2-4.0)
domains and the Strengths and Difficulties Questionnaire prosocial subscale (AMD, 0.5; 95%
CI, >0.0-0.9). Fewer children in the delayed-CC group had results below the cutoff in the ASQ
fine-motor domain (11.0% vs 3.7%; P= .02) and the Movement ABC bicycle-trail task (12.9%
vs 3.8%; P= .02). Boys who received delayed CC had significantly higher AMDs in the
WPPSI-III processing-speed quotient (AMD, 4.2; 95% CI, 0.8-7.6; P= .02), Movement ABC
bicycle-trail task (AMD, 0.8; 95% CI, 0.1-1.5; P= .03), and fine-motor (AMD, 4.7; 95% CI,
1.0-8.4; P= .01) and personal-social (AMD, 4.9; 95% CI, 1.6-8.3; P= .004) domains of the ASQ.
CONCLUSIONS AND RELEVANCE Delayed CC compared with early CC improved scores in the
fine-motor and social domains at 4 years of age, especially in boys, indicating that optimizing
the time to CC may affect neurodevelopment in a low-risk population of children born in a
high-income country.
TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01581489
JAMA Pediatr. doi:10.1001/jamapediatrics.2015.0358
Published online May 26, 2015.
Editorial
Supplemental content at
jamapediatrics.com
Author Affiliations: Department of
Women’s and Children’s Health,
Uppsala University,Uppsala, Sweden
(Andersson, Hellström-Westas); The
Habilitation Center, Hospital of
Halland, Halmstad, Sweden
(Lindquist); Department of
Psychology,Lund University, Lund,
Sweden (Lindgren, Stjernqvist);
Department of Clinical Sciences, Unit
for Pediatrics, Umeå University,
Umeå, Sweden (Domellöf).
Corresponding Author: Ola
Andersson, MD, PhD, Department of
Women’s and Children’s Health,
Uppsala University,SE-751 85
Uppsala, Sweden (ola.andersson
@kbh.uu.se).
Research
Original Investigation
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Iron deficiency is a global health issue among preschool
children that is associated with impaired neurodevelop-
ment affecting cognitive, motor, and behavioral abilities.
1,2
High growth velocity combined with limited ability to
absorb iron results in markedly reduced iron stores during
the first year of life.
3
Iron deficiency affects 5% to 25% of
preschool children in high-income countries and up to 100%
of young children in low-income countries.
4,5
Iron adminis-
tration to high-risk groups is associated with improved psy-
chomotor and cognitive development and fewer behavioral
symptoms.
6,7
Delaying umbilical cord clamping (CC) by 2 to 3 minutes
after delivery allows fetal blood remaining in the placental cir-
culation to be transfused to the newborn.
8,9
This transfusion
can expand the blood volume by 30% to 40% (25-30 mL/kg).
10
After physiologic hemolysis, hemoglobin-bound iron is trans-
ferred into iron stores. Consequently, delayed CC is associ-
ated with improved iron status at 4 to 6 monthsof age.
11,12
De-
layed CC has the potential to contribute approximately 75 mg
of iron, corresponding to more than 3 months’ requirement in
a 6- to 11-month-old infant.
13
We have previously demon-
strated a 90% reduction in iron deficiency at 4 months in
healthy full-term infants who received delayed CC with no ad-
verse neonatal effects.
14
However, there is a lack of knowl-
edge regarding the long-term effects and evidence of no harm,
causing policy makers to be hesitant to make clear recommen-
dations concerning delayed CC in full-term infants, espe-
cially in settings with rich resources.
15
We hypothesized that delayed CC and the associated re-
duction of iron deficiency during the first 4 months of life
would result in improved neurodevelopment. Therefore, we
conducted a follow-up of a randomized clinical trial
14
to as-
sess the long-term effects of delayed CC compared with early
CC on neurodevelopment at 4 years of age.
Method
Study Design
This study is a follow-up of a randomized clinical trial con-
ducted at the Hospital of Halland from April 16, 2008, through
May 21, 2010.
14
Follow-up was conducted at the same loca-
tion from April 11, 2012, through August 13, 2013. The original
trial and the follow-up study were approved by the Regional
Ethics Review Board at Lund University (protocols 41/2008 and
23/2012), and written patient consent was obtained from par-
ents separately for the study and follow-up.B oth studies were
registered with Clinicaltrials.gov (NCT01245296 and
NCT01581489). The full study protocol can be found in the trial
protocol in Supplement 1.
Randomization and Masking of the Original Trial
Full-term newborns with a gestational age of 37 to 41 weeks
were eligible if the mother was healthy, was a nonsmoker,
and had an uncomplicated pregnancy with expected vaginal
delivery. Randomization assignments (1:1), consisting of
delayed (≥180 seconds after delivery) or early (≤10 seconds
after delivery) CC, were contained in sealed, numbered,
opaque envelopes that were opened by the midwife when
delivery was imminent.
14
The mother and the midwife could
not be masked, but all staff and researchers involved in the
collection or analysis of data were blinded to the allocation
group.
Study Participants
All children included in the original study (n = 382) were eli-
gible for the follow-up. An invitation letter for the follow-up
study was sent 1 month before the child’s fourth birthday.
Procedures
The children were assessed by a psychologist (B.L.) at 48 to
51 months of age. This age was chosen to enable assessment
of cognitive function using the older-age band (4-7 years) of
the Wechsler Preschool and Primary Scale of Intelligence
(WPPSI-III).
16
This test provides composite scores that rep-
resent intellectual functioning in the following verbal and
cognitive performance domains: full-scale IQ, verbal IQ,
performance IQ, processing-speed quotient, and general
language composite. Scores are standardized to a mean (SD)
of 100 (15). A subnormal score was defined as a result lower
than 85.
Fine-motor skills were assessed by the manual dexterity
area from the Movement Assessment Battery for Children,
Second Edition (Movement ABC), which includes 3 subtests:
time for posting coins into a slot (both hands), time for bead
threading, and drawing within a bicycle trail.
17
The refer-
ence mean (SD) for each test is 10 (3). A score of less than 7
reflects performance below the 15th percentile and is
regarded as an at-risk score. The psychologist also assessed
the child’s pencil grip and classified findings as mature (static
or dynamic tripod) or immature (palmar supinate or digital
pronate).
18,19
Parents reported their child’s development using the
Ages and Stages Questionnaire, Third Edition (ASQ)
48-month questionnaire, which was translated into Swedish
(by permission from Paul H. Brookes Publishing Co).
20
The
ASQ contains 5 subdomains: communication, gross motor,
fine motor, problem solving, and personal-social, each con-
sisting of 6 items with a maximum score of 60, resulting in a
At a Glance
•Iron deficiency is associated with impaired neurodevelopment
affecting cognitive, motor, as well as behavioralabilities; delaying
umbilical cord clamping for 3 minutes reduces iron deficiency at
4 to 6 months of age.
•In a follow-up of a randomized trial, 263 children (69% of the
original study population) were assessed for neurodevelopment
at 4 years of age.
•Delayed cord clamping compared with early cord clamping
improved scores and reduced the number of children having low
scores in fine-motor skills and social domains.
•Boys, who were more prone to iron deficiency, were shown to
have the most improved results, especially in fine-motor skills.
•Optimizing the time to cord clamping may affect
neurodevelopment in a low-risk population of children born in a
high-income country.
Research Original Investigation Delayed Clamping and Neurodevelopment at 4 Yearsof Age
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maximum total score of 300 (higher scores indicate more
developmental milestones reached). Cutoff scores were cre-
ated according to the ASQ manual, and scores that were 2
SDs less than the mean score of the respective subdomain
were considered subnormal. If questionnaires were not com-
pletely answered, scores were adjusted according to the ASQ
manual.
20
Behavior was assessed using the Strengths and Difficul-
ties Questionnaire (SDQ),
21
which is directed at children aged
3 to 4 years. In the SDQ, 25 items in 5 subscales are scored. Four
of these subscales—emotional difficulties score, conduct dif-
ficulties score, hyperactivity difficulties score, and peer prob-
lems score—are added together to form a total difficulties score
(based on 20 items; maximum score, 40; higher scores indi-
cate more difficulties). The fifth subscale, the prosocial score,
is evaluated separately (5 items; maximum score, 10; higher
scores indicate better prosocial behavior). A cutoff score was
defined according to the criteria given for borderline and ab-
normal in the manual, Scoring the Informant-Rated Strengths
and Difficulties Questionnaire.
22
Outcomes
The WPPSI-III full-scale IQ was prespecified as the primary
outcome. Prespecified secondary outcomes included the
WPPSI-III composite scores (verbal IQ, performance IQ,
processing-speed quotient, and general language composite),
fine-motor skills (Movement ABC, manual dexterity area and
subtests), psychomotor development (ASQ, total and 5 subdo-
mains), and behavior (SDQ, total and subscales). Children’s
sex and gestational age at birth were prespecified confound-
ers. The child’s pencil grip was also recorded.
Statistical Analysis
This study is a follow-up of a randomized clinical trial, and the
sample size is considered fixed.
For summary statistics (Table 1), delayed CC was com-
pared with early CC with respect to maternal and newborn data
with means and SDs or numbers and percentages, as appro-
priate. An unpaired 2-tailed ttest was used for variables with
normal distribution, and categorical variables were com-
pared between groups using the Fisher exact test.
Table 1. Baseline and BackgroundCharacteristics by Intervention Group Comparing Infants With Delayed CC vs
Early CC
a
Characteristic
Delayed
CC
Early
CC
Value
b
Patients, No. Value
b
Patients, No.
Maternal data
Age, y 31.4 (4.4) 141 32.0 (4.2) 122
Weight, kg 67.6 (11.9) 141 66.9 (12.3) 119
Hemoglobin level at first antenatal
visit, g/dL
12.8 (1.1) 141 12.9 (0.9) 116
Parity (including newborn child) 1.7 (0.7) 141 1.7 (0.8) 122
College education, No. (%) 90 (66.7) 135 85 (70.2) 121
Newborn data
Male sex, No. (%) 60 (42.6) 141 57 (46.7) 122
Gestational age, wk 40.1 (1.0) 141 40.1 (1.1) 122
Apgar score, min
1 8.8 (0.8) 141 8.7 (1.0) 122
5 9.8 (0.5) 141 9.8 (0.7) 122
Measurement at birth
Weight, kg
c
3.64 (0.48) 141 3.50 (0.52) 122
Length, cm 50.9 (1.9) 141 50.6 (2.1) 120
Head circumference, cm 34.8 (1.4) 141 34.5 (1.4) 122
Umbilical cord blood sample tests
pH 7.26 (0.08) 117 7.26 (0.09) 117
Base deficit 4.8 (3.5) 116 5.1 (3.6) 116
Hemoglobin level, g/dL 16.0 (1.8) 122 16.3 (1.6) 109
Mean cell volume, fL 105 (5) 122 106 (5) 109
Ferritin level, ng/mL 225 (140) 136 232 (163) 119
Transferrin
Saturation, % 54.3 (16.6) 132 53.4 (17.6) 115
Level, mg/L 5.26 (1.85) 140 5.33 (1.96) 122
Condition1hafterbirth,No. (%)
Respiratory symptoms
d
12 (9.0) 132 8 (7.2) 111
Breastfed 95 (72.0) 131 84 (73.0) 115
Exclusively breastfed at 4 mo, No. (%) 80 (56.7) 141 64 (53.3) 120
Abbreviation: CC, umbilical cord
clamping.
SI conversion factors: Toconvert
hemoglobin to grams per liter,
multiply by 10.0;ferritin to picomoles
per liter, multiply by 2.247; and
transferrin to micromoles per liter,
multiply by 0.0123.
a
Delayed CC was defined as 180 s or
more after delivery; early CC, 10 s or
less.
b
Values are presented as mean (SD)
unless otherwise indicated.
c
Intervention groups had
significantly different birth weights
(P= .03, unpaired 2-tailed ttest).
d
Respiratory rate greater than 60
breaths per minute; presence of
nostril flaring, grunting, and/or
intercostal retractions.
Delayed Clamping and Neurodevelopment at 4 Yearsof Age Original Investigation Research
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For comparison of continuous test scores (WPPSI-III,
Movement ABC, and ASQ), the mean difference between
delayed CC and early CC was calculated and the ttest was
used for Pvalue estimation (Table 2). For ordinal scale vari-
ables from the SDQ test scores, the Mann-Whitney test was
used.
For adjusted analyses, analysis of covariancewas used for
test scores from the WPPSI-III, Movement ABC, and ASQ, and
ordinal regression analysis was used for scores from the SDQ.
Children’s sex and parents’ level of education were chosen a
priori as adjustment variables for known predictors of chil-
dren’s development, and children’s age when performing the
test was chosen a posteriori because it was significantly cor-
related with several of the outcome variables.
Test scores were dichotomized for logistic regression
analysis (Table 3); unadjusted and adjusted analyses were
conducted. Odds ratios (ORs) and 95% CIs were calculated.
To estimate an overall effect of fine-motor function,
multivariate analysis of variance (MANOVA) was used. The
MANOVA analysis was appropriate, with correlation coeffi-
cients for fine-motor outcome variables ranging from 0.2456
to 0.4221. The MANOVA analysis was conducted using the
tests that are considered most specific for fine-motor func-
tion, including the WPPSI-III processing-speed quotient,
Movement ABC manual dexterity, and ASQ fine-motor sec-
tions, with randomization as a grouping variable and sex,
parents’ level of education, and age when performing the
test as independent factors.
A subgroup analysis was conducted for sex as prespeci-
fied in the protocol. Analysis of covariance and logistic
regression were conducted using the designated adjustment
variables (eTable 1 and eTable 2 in Supplement 2). P< .05 was
considered significant for all the above-mentioned tests.
The Statistical Package for Social Sciences (SPSS) for
Windows, version 18.0 was used (SPSS Inc), and STATA, ver-
sion 10.1 (StataCorp LP) was used for MANOVA and logistic
regression analysis. All data were analyzed by intention
to treat.
Results
Study Patients
The study was conducted between April 18, 2012, and July 5,
2013 (WPPSI-III and Movement ABC). The ASQ and SDQ were
completed by parents between April 11, 2012, and August 13,
2013. Data from all 4 tests were acquired from 243 of 382 chil-
dren (63.6%) and from at least 1 test from 263children (68.8%)
(Figure 1). There was no significant difference in response rates
between the delayed- and early-CCgroups. Two responses were
excluded from the ASQ analysis because they were answered
after the defined time frame (51 months after birth). Baseline
Table 2. Neurodevelopmentat 48 Months of Age in Children Born at Term Who Were Randomized to Delayed CC or Early CC
a
Characteristic
Delayed CC Early CC Unadjusted Adjusted
b
Mean (SD) Patients, No. Mean (SD) Patients, No.
Mean Difference
(95% CI) PValue
c
Mean Difference
(95% CI) PValue
d
WPPSI-III
Full-scale IQ 117.1 (9.7) 135 117.1 (9.7) 116 0.1 (−2.4 to 2.5) 0.95 0.6 (−1.8 to 2.9) 0.65
Verbal IQ 121.2 (13.8) 136 121.7 (12.5) 116 −0.5 (−3.8 to 2.7) 0.74 0.3 (−3.0 to 3.5) 0.87
Performance 115.0 (7.9) 135 115.3 (12.5) 117 −0.3 (−2.4 to 1.7) 0.74 −0.1 (−2.1 to 1.9) 0.92
Processing-speed
quotient
100.7 (7.9) 129 98.9 (10.0) 111 1.8 (−0.5 to 4.1) 0.12 2.2 (−0.1 to 4.5) 0.06
General language
composite
112.1 (12.8) 133 112.9 (10.2) 108 −0.8 (−3.7 to 2.2) 0.62 −0.4 (−3.5 to 2.7) 0.81
Movement ABC
Manual dexterity 8.4 (2.4) 133 8.2 (2.5) 116 0.2 (−0.4 to 0.8) 0.53 0.3 (−0.2 to 0.9) 0.25
Posting coins in box 8.1 (2.7) 134 8.1 (2.7) 116 0.0 (−0.6 to 0.7) 0.92 0.3 (−0.4 to 1.0) 0.44
Bead threading 8.3 (3.1) 134 7.8 (3.4) 116 0.4 (−0.3 to 1.3) 0.28 0.5 (−0.2 to 1.3) 0.17
Drawing bicycle trail 9.3 (1.6) 133 9.1 (1.8) 116 0.2 (−0.3 to 0.6) 0.42 0.3 (−0.2 to 0.7) 0.23
ASQ
Total score 278.9 (21.6) 130 275.5 (27.6) 115 3.5 (−2.7 to 9.7) 0.27 4.7 (−1.3 to 10.6) 0.12
Communication 56.6 (5.3) 132 57.7 (5.5) 117 −1.0 (−2.4 to 0.3) 0.13 −0.9 (−2.2 to 0.5) 0.22
Motor skill
Gross 56.1 (6.5) 134 55.7 (7.9) 119 0.4 (−1.4 to 2.1) 0.07 0.2 (−1.6 to 2.0) 0.82
Fine 54.2 (7.3) 134 52.3 (9.4) 118 1.9 (−0.2 to 4.1) 0.07 2.1 (0.2 to 4.0) 0.03
Problem solving 56.1 (7.1) 134 55.8 (6.9) 117 0.3 (−1.4 to 2.1) 0.72 0.8 (−0.9 to 2.4) 0.35
Personal-social 55.5 (7.0) 135 53.1 (8.6) 119 2.4 (0.4 to 4.4) 0.02 2.8 (0.8 to 4.7) 0.006
Abbreviations: ASQ, Ages and Stages Questionnaire, Third Edition; CC, umbilical
cord clamping; Movement ABC, Movement Assessment Battery for Children,
Second Edition; WPPSI-III, Wechsler Preschool and Primary Scale of
Intelligence, Third Edition.
a
Delayed CC was defined as 180 s or more after delivery; early CC, 10 s or less.
b
Adjusted for the child’s sex, mother’s educational level, father’seducational
level, and child’s age at testing.
c
Pvalues were calculated using the ttest.
d
Pvalues were calculated using analysis of covariance.
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characteristics of participants in the follow-up did not differ
between the 2 groups (Table 1). As previously reported, birth
weights were higher in the delayed-CC group as a result of the
intervention.
14
At 4 years, there were no group differences in
the mean (SD) weight or height measurements,which were 17.3
(2.1) kg and 104 (4) cm in the delayed-CC group (n = 136) vs 17.1
(2.1) kg and 104 (4) cm in the early-CC group (n = 120) (P=.45
and P= .90, respectively).
Because the attrition rate was higher than expected,
background data were compared between participants in
the follow-up study and nonparticipants (eTable 3 in
Supplement 2). In the participant group, mothers were 1.3
years (95% CI, 0.32.2 years) older, and the infants’ mean head
circumference at birth was 0.3 cm (95% CI, 0.1-0.6 cm) less
than in the nonparticipant group. Other background data did
not differ.
Primary Outcome
Full-scale IQ did not differ between the randomization groups
for the mean scores (Table 2) or the proportion of children with
a subnormal score of less than 85 (Table 3).
Secondary Outcomes
The WPPSI-III composite scores for verbal IQ, performance IQ ,
processing-speed quotient, and general language composite
did not differ between the randomization groups (Tables 2 and
3). The groups did not differ in mean scores for fine-motor skills
as assessed by the Movement ABC manual dexterity test
(Table 2). However, for the bicycle-trail task, the proportion of
children with a score of less than 7 (ie, at risk) was signifi-
cantly lower in the delayed-CC group than in the early-CCgroup
(3.8% vs 12.9%; P= .02) (Table 3). The proportion of children
with an immature pencil grip was significantly lower in the de-
layed-CC group than in the early-CC group (13.2% vs 25.6%;
P= .01) (Table 3).
The delayed-CC group had significantly higher scores lead-
ing to significant adjusted mean differences (AMDs) in the ASQ
personal-social (AMD, 2.8; 95% CI, 0.8-4.7) and fine-motor
(AMD, 2.1; 95% CI, 0.2-4.0)domains. In the ASQ fine-motor do-
main, the proportion of children with a score 2 SDs below the
mean was lower in the delayed-CC group (3.7%) than in the
early-CC group (11.0%; P= .02). After adjusted logistic regres-
sion analysis, there were also fewer children with a score 2 SDs
below the mean in the ASQ problem-solving domain (ad-
justed OR, 0.3; 95% CI, 0.1 to <1.0). There were no differences
between groups for the total score or the other subdomains
(Tables 2 and 3).
The SDQ did not show any differences in the total diffi-
culties scale or in the 4 difficulties subscales between the 2
groups. The delayed-CC group scored higher in the prosocial
Table 3. Proportion of 4-Year-Old Children With Neurodevelopmental Test Scores Below Cutoff Levels
a
Test Score
Delayed CC Early CC Unadjusted
b
Adjusted
b,c
Value, No. (%) Patients, No. Value, No. (%) Patients, No. OR (95% CI) PValue OR (95% CI) PValue
WPPSI-III
Full-scale IQ<85 1 (0.7) 135 0 116 NA >.99 NA >.99
Verbal IQ<85 2 (1.5) 136 1 (0.9) 116 1.7 (0.2 to 19.2) .66 1.7 (0.1 to 18.7) .68
Performance 1 (0.7) 135 0 (0) 117 NA >.99 NA >.99
Processing-speed quotient
<85
2 (1.6) 129 7 (6.3) 111 0.2 (0.0 to 1.2) .07 0.2 (0.0 to 1.1) .06
General language composite
<85
4 (3.0) 133 2 (1.9) 108 1.6 (0.2 to 9.1) .57 1.3 (0.2 to 8.3) .76
Movement ABC
Manual dexterity
<7 (15th percentile)
24 (18.0) 133 30 (25.9) 116 0.6 (0.3 to 1.2) .14 0.6 (0.3 to 1.2) .15
Posting coins in box
<7 (15th percentile)
40 (29.9) 134 41 (35.3) 116 0.8 (0.5 to 1.3) .36 0.7 (0.4 to 1.2) .16
Bead threading
<7 (15th percentile)
21 (15.7) 134 23 (19.8) 116 0.8 (0.4 to 1.4) .39 0.7 (0.4 to 1.5) .41
Drawing bicycle trail
<7 (15th percentile)
5 (3.8) 133 15 (12.9) 116 0.3 (0.1 to 0.7) .01 0.3 (0.1 to 0.8) .02
ASQ
Communication <46.2 11 (8.3) 132 5 (4.3) 117 2.0 (0.7 to 6.0) .20 1.8 (0.6 to 5.8) .32
Gross motor <41.7 7 (5.2) 134 8 (6.7) 119 0.8 (0.3 to 2.2) .62 0.9 (0.3 to 3.2) .88
Fine motor <36.7 5 (3.7) 134 13 (11.0) 118 0.3 (0.1 to 0.9) .03 0.2 (0.1 to 0.8) .02
Problem solving <42.3 7 (5.2) 134 10 (8.5) 117 0.6 (0.2 to 1.6) .30 0.3 (0.1 to <1.0) .05
Personal-social <38.7 4 (3.0) 135 10 (8.4) 119 0.3 (0.1 to 1.1) .07 0.3 (0.1 to 1.2) .10
Immature pencil grip
d
18 (13.2) 136 30 (25.6) 117 0.4 (0.2 to 0.8) .01 0.4 (0.2 to 0.8) .01
Abbreviations: ASQ, Ages and Stages Questionnaire, Third Edition; CC, umbilical
cord clamping; Movement ABC, Movement Assessment Battery for Children,
Second Edition; NA, not analyzed because n = 0 in 1 group; OR , odds ratio;
WPPSI-III, Wechsler Preschool and Primary Scale of Intelligence, Third Edition.
a
The children were born at term and randomized to delayed (ⱖ180safter
delivery) or early (ⱕ10 s) umbilical CC.
b
Unadjusted and adjusted ORs were analyzed by logistic regression.
c
Adjusted for the child’s sex, mother’s educational level, father’seducational
level, and child’s age at testing.
d
Palmar supinate or digital pronate grip.
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subscale (median, 9; interquartile range, 8-10)than the early-CC
group (median, 8; interquartile range, 7-9; AMD, 0.5; 95% CI,
>0.0-0.9; P= .05).
To estimate the overall group difference in each out-
come measure, MANOVA analysis was conducted using the
subtests and subdomains as dependent variables. This
analysis demonstrated that the ASQ showed a significant
difference between randomization groups (P= .02; fit of
model, <0.0001) while the WPPSI-III, Movement ABC, and
SDQ did not.
A MANOVA analysis that included the tests considered
most specific for fine-motor function (WPPSI-III processing-
speed quotient, Movement ABC manual dexterity, and ASQ
fine motor), with randomization as a grouping variable and
sex, parents’ level of education, and age when performing
the test as independent factors, showed a significant differ-
ence between groups (P= .02; fit of model, <0.001).
Effect of Children’s Sex and Gestational Age on Outcome
In girls, there were no differences between the groups for
any of the assessments. However, boys who received
delayed CC had higher mean (SD) scores in several tasks that
involved fine-motor function, including the WPPSI-III
processing-speed quotient (AMD, 4.2; 95% CI, 0.8-7.6),
Movement ABC bicycle-trail task (AMD, 0.8; 95% CI, 0.1-1.5;
P= .03), and ASQ fine-motor score (AMD, 4.7; 95% CI, 1.0-
8.4). Furthermore, the ASQ personal-social score was higher
(AMD, 4.9; 95% CI, 1.6-8.3) in the delayed-CC group (eTable 1
in Supplement 2).
An at-risk result in the bicycle-trail task was less preva-
lent in boys who received delayed CC compared with those
who received early CC (3.6% vs 23.1%; P= .008); findings
were similar in the ASQ fine-motor domain (8.9% vs 23.6%;
P= .03). A similar trend was present for the number of boys
who had a score of less than 85 on the WPPSI-III processing-
Figure 1. CONSORT Flow Diagram
1992 Assessed for eligibility
1592 Excluded
929 Did not meet inclusion criteria
663 Declined to participate
400 Randomized
4Inclusion criteria not followed
7Excluded
3Family decided to stop participation
immediately after intervention
11 Excluded
7Inclusion criteria not followed
1Data not recorded
3Family decided to stop participation
immediately after intervention
200 Randomized to early cord clamping
(≤10 s)
200 Randomized to delayed cord clamping
(≥180 s)
166 Received randomized intervention
23 Did not receive randomized intervention
168 Received randomized intervention
25 Did not receive randomized intervention
67 Lost to follow-up (family decided to stop
participating)
52 Lost to follow-up (family decided to stop
participating)
122 Completed ≥1 test
109 Received randomized intervention
107 Received randomized intervention
117 Wechsler Preschool and Primary Scale of
Intelligence, Third Edition
104 Received randomized intervention
113 Completed all tests
108 Received randomized intervention
121 Ages and Stages Questionnaire,
Third Edition
106 Received randomized intervention
119 Strengths and Difficulties Questionnaire
107 Received randomized intervention
116 Movement Assessment Battery for
Children, Second Edition
141 Completed ≥1 test
121 Received randomized intervention
117 Received randomized intervention
136 Wechsler Preschool and Primary Scale of
Intelligence, Third Edition
112 Received randomized intervention
130 Completed all tests
116 Received randomized intervention
135 Ages and Stages Questionnaire,
Third Edition
166 Received randomized intervention
135 Strengths and Difficulties Questionnaire
116 Received randomized intervention
135 Movement Assessment Battery for
Children, Second Edition
Flowchart depicting the selection of
children randomized to either early or
delayed cord clamping at birth and
the following attrition of study
participants until the 4-year
follow-up.
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speed quotient (2.0% vs 12.5%; P=.06)(Figure 2 and eTable 3
in Supplement 2). The MANOVA of the tests that were consid-
ered most specific for fine-motor function showed a signifi-
cant interaction term for randomization by sex, indicating
that the effect of randomization depends on sex (P= .005)
and showing a highly significant difference between groups
among boys (P= .008; fit of model, 0.0033) but not among
girls (P= .80; fit of model, 0.3706). There was no significant
interaction between gestational age at birth and the interven-
tion on any of the outcomes.
Discussion
Our results indicate that delaying CC for 3 or more minutes af-
ter delivery is associated with better fine-motor function in
4-year-old children. However, in this pronounced low-risk
population, delayed CC did not have any effect on full-scale
IQ or behavior difficulties. For the whole study population, de-
layed CC was associated with a significantly higher propor-
tion of children with a mature pencil grip and with higher scores
for the ASQ personal-social and fine-motor domains as well as
for the SDQ prosocial scale. When the proportions of children
with subnormal performance on the various tasks were com-
pared, delayed CC was associated with fewer children having
a score below the normal range in the Movement ABC bicycle-
trail task and the ASQ fine-motor domain. In the ASQ personal-
social domain, 3 of the 6 items involve fine-motor skills, such
as if the child serves himself or herself, brushes his or her teeth,
and can dress himself or herself. Also, the higher proportion
of children in the early-CC group having an immature pencil
grip indicates the effect of the timing of CC on fine-motor ca-
pabilities at 4 years of age. Our findings are supported by data
from other studies that demonstrate associations between low
umbilical cord ferritin levels and poorer fine-motor skills at 5
years of age and between a low level of ferritin at 1 year and
poorer fine-motor scores at 6 years.
23,24
Previous data on the
study population demonstrated significantly higher levels of
ferritin at 4 months of age but no persisting effect of the in-
tervention on ferritin levels at 12 months.
14,25
This finding,
which indicates a period of motor development vulnerability
to low iron stores during early infancy, was also demon-
strated in a systematic review of early iron supplementation.
6
When the results were analyzed according to children’s
sex, differences in neurodevelopment between the random-
ization groups became more evident; in boys, delayed CC was
associated with higher scores on several tests: the processing-
speed quotient, the bicycle-trail task, and the ASQ fine-motor
and personal-social domains. However, no differences were
shown in girls. The effect by sex is consistent with previous
results from the same study population at 12 months, which
showed a significant interaction between the intervention
and sex on ASQ outcomes; boys who had delayed CC per-
formed better, but the intervention had the opposite effect on
ASQ in girls.
25
Other studies have shown that boys have lower
iron stores than girls at birth and during infancy.
26,27
In an
analysis involving 6 studies from Ghana, Honduras, Mexico,
and Sweden, Yang et al
28
found a higher risk (adjusted OR,
4.6; 95% CI, 2.5-8.5) for iron deficiency among male infants.
The increased risk for male infants to develop iron deficiency
is a probable explanation for why delayed CC seems to have a
more beneficial effect in boys. Other studies have also shown
that delayed CC in very preterm infants is associated with
improved motor outcomes among boys at follow-up after 7
months.
29
This study has limitations. The initial study was powered
to demonstrate increased infant ferritin levels (which it did)
but not differences in neurodevelopment. The attritionrate was
relatively high (31.2%). We cannot exclude a possible bias in
the overall development of the children whose parents chose
to return for the follow-up, although no major differences in
baseline data were demonstrated, and there were no differ-
ences in baseline data between the randomization groups in
children who participated in the follow-up. The limitationsin
study design and attrition rate must be weighed against the
novelty and originality of the study; this study is the first, to
our knowledge, to assess the effects of delayed vs early CC on
neurodevelopment after 1 year of age.
Conclusions
Delaying CC for 3 minutes after delivery resulted in similar over-
all neurodevelopment and behavior among 4-year-old chil-
dren compared with early CC. However, we did find higher
scores for parent-reported prosocial behavior as well as per-
sonal-social and fine-motor development at 4 years, particu-
larly in boys. The included children constitute a group of low-
risk children born in a high-income country with a low
Figure 2. Proportion of Children With a Neurodevelopmental Score
Below the Normal Range at 48 Months of Age
30
25
20
15
10
5
0
Patients, %
Boys Girls
Delayed CC Early CC
a
WPPSI-III
Processing-Speed
Score <85
Delayed CC Early CC
b
Movement ABC
Bicycling-Trail Task
Score <7
Early CCDelayed CC
c
ASQ Fine-Motor
Score <36.7
Children were assessed using the Wechsler Preschool and Primary Scale of
Intelligence (WPPSI-III), Movement Assessment Battery for Children (ABC),
and Ages and Stages Questionnaire (ASQ). Children were randomized to
delayed umbilical cord clamping (CC) (ⱖ180 seconds after delivery) or early CC
(ⱕ10 seconds after delivery). Pvalues were calculated using logistic regression
analysis and adjusted for the mother’s educational level, father’s educational
level, and child’s age at testing (see also eTable 2 in Supplement 2).
a
P= .06 for boys who received delayed CC vs boys who received early CC.
b
P= .008 for boys who received delayed CC vs boys who received early CC.
c
P= .03 for boys who received delayed CC vs boys who received early CC.
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prevalence of iron deficiency. Still, differences between the
groups were found, indicating that there are positive, and in
no instance harmful, effects from delayed CC. Future re-
search should involve largegroups to sec ureenough power to
draw clear conclusions regarding development. Definite rec-
ommendations for delayed CC have not been issued in full-
term infants,
15,30
with one reason being the alleged increased
risk of hyperbilirubinemia stated in the latest Cochrane report
11
;
however, that report includes unpublished data. When fu-
ture guidelines are developed regarding child birth and tim-
ing of CC, the effect on fine-motor function shown in our study
might be taken into account pending larger studies.
ARTICLE INFORMATION
Accepted for Publication: February 10, 2015.
Published Online: May 26, 2015.
doi:10.1001/jamapediatrics.2015.0358.
Author Contributions: Dr Andersson had full
access to all the data in the study and takes
responsibility for the integrity of the data and the
accuracy of the data analysis.
Study concept and design: All authors.
Acquisition, analysis, or interpretation of data: All
authors.
Drafting of the manuscript: Andersson, Lindquist,
Hellström-Westas.
Critical revision of the manuscript for important
intellectual content: Andersson, Lindgren,
Stjernqvist, Domellöf, Hellström-Westas.
Statistical analysis: Andersson.
Obtained funding: Andersson, Hellström-Westas.
Administrative, technical, or material support:
Andersson, Lindquist, Stjernqvist, Hellström-Westas.
Study supervision: Stjernqvist, Domellöf,
Hellström-Westas.
Conflict of Interest Disclosures: None reported.
Funding/Support: This study was supported by
grants from the Regional Scientific Council of
Halland, the Linnéa and Josef Carlsson Foundation,
the Southern Healthcare Region’s common funds
for development and research, H. R. H. Crown
Princess Lovisa's Society for Child Care, Uppsala
University,the Little Childs foundation, Sweden,
and the Swedish Research Council for Health,
Working Life and Welfare (Dr Andersson).
Role of the Funder/Sponsor:The funding sources
had no role in the design and conduct of the study;
collection, management, analysis, and
interpretation of the data; preparation, review, or
approval of the manuscript; and decision to submit
the manuscript for publication.
Additional Contributions: Eivor Kjellberg, RN, and
Monika Nygren, RN, Department of Pediatrics,
Hospital of Halland, Halmstad, provided assistance
in collecting the data; both received wages for their
work. Per-Erik Isberg, PhD, Department of
Statistics, Lund University,and Maria Lönn, MSc,
Maple Medical Science, provided statistical advice.
Maple Medical Science is a statistical consulting
company that was paid on a time-charge basis.
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