Nigerian Journal of Paediatrics

Congenital anomalies Prospective study of pattern and associated risk factors in infants presenting to a tertiary hospital in Anambra State South east Nigeria

Niger J Paediatr 2017; 44 (2):76 – 80

ORIGINAL

Ekwunife OH

Congenital anomalies: Prospective

Okoli CC

Ugwu JO

study of pattern and associated

Modekwe VI

risk factors in infants presenting to

Ekwesianya AC

a tertiary hospital in Anambra

State, South-east Nigeria

DOI:http://dx.doi.org/10.4314/njp.v44i2.6

Accepted: 2nd April 2017

Abstract : Background: Contem-

mothers took herbal prescriptions

porary understanding of the pat-

in the first trimester of pregnancy.

Ekwunife OH (

)

tern of congenital anomalies is

Risk of anomaly progressively

Okoli CC, Ugwu JO, Modekwe VI

both important in its clinical man-

rises, reaching a peak of 48% in

Ekwesianya AC

agement as well as in improving

the maternal age group of 26-30

Department of Surgery

the overall health of the commu-

years and drops steadily after. Gas-

Nnamdi Azikiwe University

nity.

trointestinal tract anomalies were

Teaching Hospital Nnewi

Methodology: All infants present-

most common (no. =28, 25.9%).

Anambra State Nigeria

ing from January to December

Residences close to dump sites,

Email:

2102 at the centre were prospec-

telecom masts/base stations, elec-

hyginusekwunife@yahoo.com

tively studied.

tricity cables, industries and heavy

Results: A total of 5010 infants

motorised highways contributed to

were screened, of which 108 have

risk factors in 9-12 % of cases.

congenital anomalies giving a

Conclusion: More of younger

prevalence

2.2%.

Major

mothers were affected with gastro

anomalies were noted in 101

intestinal malformations predomi-

(93.5%) infants. Only two (1.9%)

nating. The location of home envi-

were preterm. Consanguineous

ronment is a potential risk factor

relationship was observed in 2

that will require further characteri-

(1.9%) cases. Pre natal Ultrasound

sation.

scan was done in 33(30.8%), but

in only 7 (6.5%) was any anomaly

Key words: Congenital disorder,

detected

Malformations, Birth defects, Risk

Onitsha, a densely populated ur-

factors, Epidemiology, Nigeria,

ban area contributed 45(42%) of

Anambra

the cases. Only 7(6.5%) of the

Introduction

The aetiology of congenital anomalies is unknown in

about 50% cases. Identifiable causes include single

Congenital anomalies also known as birth defects, con-

gene defects(6-7%), chromosomal abnormalities(6-7%),

genital malformations or congenital disorders are struc-

multi-factorial disorders which are the result of interac-

tural or functional anomalies that occur during intrauter-

tion between genetic predisposition and presumed envi-

ine life and can be identified prenatally, at birth or later

ronmental factors(20-25%), and teratogenic factors (6-

7%).

in life. Understanding of the pattern of congenital

Responsible for the high rate of anomalies in

anomalies is both important in the clinical management

low and medium income countries( LMIC’s) is a combi-

of the condition as well as in improving the overall

nation of factors including adverse environmental attrib-

health of the community.

utes like high infective diseases, urbanization with atten-

dant slums, pollution, industrial wastes , living close to

dump sites , and poor nutrition.

The epidemiology of congenital anomalies varies from

period to period and from region to region. In devel-

oped economies, the prevalence varies from 1.07% to

The LMIC’s also bear the greater burden of increasing

4.4%.

2,3

Establishment of congenital anomaly registry

perinatal deaths from congenital anomalies estimated at

or surveillance has enabled better monitoring of epide-

12.7%.

Survivors many times may have livelong dis-

miological trends and institution of preventive mecha-

abilities with impairment of quality of life.

nisms in some of these nations. In Nigeria, available

4,5

reports have prevalence rates ranging from 0.75%-

This article aims to study the contemporary epidemiol-

13.9%.

6-10

ogy and risk factors associated with congenital anoma-

lies in our region, Anambra state, south east Nigeria,

Results

thus enabling data for establishment of better control

measures .

Of the total of 5010 infants screened, 108 have congeni-

tal anomalies giving a prevalence of 2.2%. More males

were affected, 71 (65.7%) than females, 34(31.6%) with

an M: F ratio of 2:1. Three (2.8%) neonates have Disor-

Methodology

ders of Sex Differentiation (DSD). Major anomalies

were noted in 101(93.5%) infants while the rest 7(6.5%)

Every infant that presented for treatment at the outpa-

were minor. Fourteen (13.0%) had multiple anomalies.

tient, inpatient, special baby care and the children emer-

Only two (1.9%) were preterm. Consanguineous rela-

gency departments of the hospital within the study pe-

tionship was observed in another 2(1.9%) cases.

riod was screened for the presence of any structural con-

Prenatal Ultrasound was done in 33(30.8%), but in only

genital anomaly.

7 (6.5%) was any anomaly detected

Once a case was identified, a trained investigator further

Risk of anomaly progressively rises, reaching a peak of

interviewed the parents and examined the infant, obtain-

48% in the maternal age group of 26-30 years and drops

ing required data using a structured close ended inter-

thereafter. Mean peak maternal age was 8.5years (SD

viewer administered questionnaire. Data was collected

=6.05).

Figure 1 shows the trend and compares be-

for one year (January to December, 2012) and covers

tween maternal and paternal age group occurrences.

bio-data, malformation characteristics, parental attrib-

Table 1 shows a summary of identifiable environmental

utes, and environmental conditions at the place of habi-

risk factors. Twelve infants (11.1%) have associated

tation.

identifiable multiple risk factors. Only six(5.6%)mothers

Ethical approval was obtained from the institutions Ethi-

had any form of chronic illness while 23(24.1%) re-

cal Committee. Consent from the child’s parent or

ported abuse of drugs as shown in tables 2 and 3 respec-

guardian was also obtained.

tively.

Congenital cardiac anomalies were excluded from the

study due to unavailability of diagnostic tools.

Table 1: Frequency of identified risk factors

No. of risk factors

frequency

Study place

None

60.2

One risk factor

28.7

Nnamdi Azikiwe University Teaching Hospital is a terti-

Two risk factors

6.5

ary hospital in Anambra State, South East Nigeria. Be-

Three risk factors

ing the only institution in the state with neonatal, paedi-

> 3 risk factors

0.9

atric and paediatric surgical services, it receives such

Total

108

100.0

patients from all parts of the state and some neighbour-

ing states. It thus serves a population of over five mil-

Fig 1: Trend and comparison between maternal and paternal

lion people.

Anambra is one of the most urbanized

age groups, with frequencies

states in Nigeria; over 60% of its population live in ur-

ban areas with most engaging in commercial activities

as occupation.

Distances

For the purposes of the study, living within the under

Maternal age group

mentioned distances is described as living close to the

Paternal age group

site: 100metres circumference from a refuse dump site,

300metres circumference of a telecommunication mast/

base station or a heavily motorised highway and 50me-

tre from high voltage electricity transmission cables.

Distances were estimates obtained by respondents

15-20

21-25

26-30

31-35

36-40

41-45

46-50

>50

guided by trained interviewer.

Data analysis

Table 2: Maternal chronic illness during pregnancy

Data were analyzed using Statistical Package for Social

Illness

frequency

Sciences (IBM SPSS statistics for Windows version

Diabetes Mellitus

0.9

21.0 Armonk, NY: IBM Corp). Results for categorical

Human Immune deficiency virus

0.9

variables were expressed using tables and charts while

Multinodular goitre

0.9

continuous data were expressed using mean and stan-

High Blood Pressure

2.8

dard deviations where appropriate. Associations be-

Total

5.6

tween categorical data were determined using Pearson

Chi square test. Statistical significance was inferred at

p- value of < 0.05.

Fig 2: Number of occurrences according to residence

Fig 3: Potential risk factors at the place of residence

Frequencies of place of residence

Others, 28, 26%

Onitsha, 45, 42%

Onitsha

Nnewi

Awka

Aguata

Nnewi, 23, 21%

Aguata, 6, 6%

Others

Awka, 6, 5%

Table 3: Frequencies of drug abuse

Drug ingestion at 1st Trimester

No (%)

Self medication with orthodox drugs

13 (12.1)

Took herbal preparations

7 (6.5)

Alcohol ingestion

6 (5.6)

Cigarette/marijuana smoking

0 (0)

Discussion

Table 4: Distribution of the anomalies

The prevalence of 2.2% from this study closely resem-

bles rates from other reports from the South Eastern

Type of anomaly

Frequency

region of the country.

It is however lower than rates

Central Nervous System

Spina bifida

7.4

from the northern part of the country (13.9%) where

adequate antenatal care utilization is reportedly low.

Hydrocephalous

5.5

Encephalocoele

1.9

About 90% of the mothers in our study received antena-

Scalp dermoid

0.9

tal care from the second trimester. It may be adduced

Microcephalous

0.9

that an improved education, improved socioeconomic

Total

(18)

(16.7)

state and an increased awareness may have influenced

Gastrointestinal tract

this higher health seeking behaviour and hence a lower

Intestinal atresias

7.4

prevalence.

Omphalocoele

5.5

However, despite this high antenatal care rate, our study

Anorectal malformation

5.5

Hirschsprung’s disease

2.8

showed both low level utilization of prenatal diagnosis

Gastroschisis

1.9

and low capacity of identifying positive cases. Only

Malrotation

1.9

about a third (33%)of the study population with con-

Oesophageal atresia

0.9

genital malformation had prenatal ultrasound. Abnor-

Total

(28)

(25.9)

mality was only detected in 6% of these. Prenatal ultra

Urogenital System

sound has an overall anomaly detection rate of 35%.

Hypospadias

9.3

The low sensitivity may be attributed to the fact that

Posterior Urethral Valve

6.5

more than 90% of these screening were not done in a

Disorders of sex development 3

2.8

tertiary centre. Sensitivity, specificity and positive pre-

Prune belly syndrome

1.9

Bladder extrophy

0.9

dictive value are better when high risk pregnancies are

screened in a tertiary hospital.

Epispadias

0.9

Total

(25)

(23.1)

Musculoskeletal

The pattern of anomalies varies from period to period

Polydactyly

4.6

and from region to region. In our study, anomalies of the

Congenital Talipes EquinoVarus 5

4-6

gastrointestinal tract had the highest occurrence of 28

Syndactyly

1.9

(25.9%), followed in order by the urogenital tract

Aplasia cutis congenita

0.9

(23.1%) and the central nervous system (16.7%) (Table

Total

(13)

(12.0)

4). The predominance of gastrointestinal anomalies was

Face

also documented by several other Nigerian reports.

10, 17

Cleft lip/palate

13.9

Microtia

0.9

However few other centres have central nervous system

Haemangioma

2.8

or musculoskeletal system as the most common affected

Total

(19)

(17.6)

system. Of the individual anomalies; cleft lip/palate

Tumours

(13.9%), hypospadias (9.3%), atresias (7.4%) and Spina

Cervical teratoma

1.9

bifida (7.4%) were the leading anomalies. The high rate

Sacrococcygeal teratoma

0.9

of cleft lip/palate anomalies may be attributed to the

Total

(3)

(2.8)

hospital being recently adopted as a partner for the Smile

Chromosomal

Train (a United State based international children’s

Down’s syndrome

2.8

Total

(3)

(2.8)

charity) free corrective repairs programme and thus was

Grand total

108

100/

receiving referrals from many other regions.

While the maternal age group with the highest number

40% of the aetiology. In our study about 9-14 % of the

of occurrence was 26-30 years, 75% of the mothers were

mothers while pregnant were found to have been ex-

aged 30 years and below (Figure 1). Prevalence was

posed to either one or a combination of pollution from

higher in young mothers and progressively rises, peak-

heavy vehicular traffic, industries, or living near a refuse

ing at 30years and then declines steadily. Twenty eight

dump, high tension electricity transmission cable or tele-

percent of the mothers were primipara. However there

communication mast / base stations (Figure 3). Concerns

was no significant relationship between age of primip

have grown on the effect of these modern conveniences

with the type of the anomaly ( p =0.633 ). The high num-

on the reproductive health. Studies are quite scanty in

ber of young mothers with congenital anomalies can be

this area. Living near telecommunication base stations

explained from the high number of structural, non chro-

or masts, which can transmit 1900-2200MHZ frequency

mosomal anomalies in our study in contrast to chromo-

range, can expose one to high levels of radiofrequency

waves which can affect developing foetus.

somal anomalies which increases with increasing mater-

Living

nal age.

close to a highway predisposes one to pollutants like

carbon monoxide, hydrocarbons and particulate matter

We recorded only 1.9% preterms. This low level may

all of which have adverse reproductive outcomes.

be alluded to the fact that majority of the babies were

High electromagnetic fields from power lines, pollutants

delivered outside the tertiary centre. It may be possible

from industries and emissions from dump sites all have

that some affected neonates may have not survived to

the potential of negatively influencing birth outcome.

reach the tertiary hospital. Also the study did not include

More targeted studies however are still needed to under-

still births and early prenatal deaths. Only two cases of

stand better the roles of these risk factors.

consanguineous relationship were identified. This is

understandable as in our setting consanguinity is not

practised and is viewed as a taboo. The two reported

cases were actually infants from northern Nigerian no-

Conclusion

madic Fulani settlers.

In conclusion, the prevalence of congenital anomalies in

Of the major cities where the patients reside in, Onitsha

Anambra state is low, but with concentrations in urban

contributed almost half (42%) of the burden of congeni-

areas with high population densities. Living close to

tal anomalies prevalence, followed by Nnewi at 21%

dump sites, telecom masts/base stations, high voltage

(Figure 2). These cities, especially Onitsha, are densely

electricity cables and heavy motorised highways are

populated urban cities in Anambra state with high ve-

potential risk factors that will need further specific stud-

hicular traffic, industrial pollutions and their share of

ies for characterisation.

urban slums. The high prevalence may be related to the

dense population, it is also possible that certain environ-

mental factors as stated earlier may be responsible for

Limitations

the increase. Most common anomalies from these areas

were urogenital (no=13, 12.0%) and gastrointestinal (no

Even though the data was collected from the only hospi-

=9, 8.3%). Further studies will be needed to fully under-

tal serving an entire state; being a hospital based study,

stand the specific role of environment on the high rate of

the results may not have been an exact reflection of the

anomalies on children born in these areas.

pattern in the general population. A community based

study will better assess the true pattern.

Worldwide more than half of the aetiology of congenital

anomalies is unknown. Environmental factors either

Conflict of interest: None

alone or in conjunction with genes account for about

Funding: None

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