TERATOLOGY 41:173-176 (1990)
incidence of Anencephaly in Jamaica K. COARD, C. ESCOFFERY, J. GOLDING, AND D. ASHLEY Department of Pathology, University of the West Indies, Mona, Jamaica (K.C., C.E.); Znstitute of Child Health, University of Bristol, Bristol BS2 SBJ, England (J.G.); Maternal and Child Health, Ministry of Health, Kingston, Jamaica (D.A.)
ABSTRACT
Information was collected on 2,197 stillbirths and neonatal deaths on the island of Jamaica during the 12 month period September 1986 to August 1987 as part of the population based nationwide Jamaican Perinatal Morbidity and Mortality Survey. There were 14 cases of anencephalus giving an incidence of 0.26 per 1,000 total births. One of these cases was associated with the amniotic band syndrome; excluding this, the incidence would be even lower (0.24 per 1,000). There was no apparent association with social class, maternal age, or parity. The rate found in Jamaica is considerably lower than found in any other national population study.
During the past 50 years among perinatologists and epidemiologists there has been an increasing interest in neural tube defects, and in anencephaly in particular, due to the possibility of primary prevention with dietary manipulation. Extensive literature from many countries pertains especially to its incidence and epidemiology. In more recent times, the ability to diagnose neural tube defects prenatally, with the consequent potential for reduction in their prevalence at birth, has allowed more meaningful work to be done to identify high risk pregnancies. Many data on the incidence of anencephaly, much like data on many other congenital malformations, have been derived from hospital-based population studies, which have a well recognised inherent bias. Although vital records are population-based, they are often deficient in the identification of perinatal deaths, and even when such deaths are registered, the causes are often inaccurate (Golding, '87). Recently, as more investigators have become aware of these biases, geographical population-based studies have begun to emerge. Such studies are available, for example, for Greece (Lekea et al., '88) and the United Kingdom (Butler and Alberman, ,691, among others. In Jamaica, there have been two previous attempts to estimate the incidence of anencephaly, with varying results. In the first study (Thorburn et al., '691, the incidence was 0.23/1,000 in a total of 68,633 births. Although these data were collected over a 0 1990 WILEY-LISS, INC.
4% year period, they covered two hospital populations, both in the capital, Kingston. The other study, done over a 3 year period, used data from only one of these two hospitals and the rate calculated was three times that of the former study (0.7/1,000)(Wynter and Persaud, '72). In an attempt to more accurately determine the true incidence in Jamaica, we present here the results of the first population-based study. MATERIALS AND METHODS
A nationwide Perinatal Morbidity and Mortality Survey (Ashley et al., '88) was conducted in Jamaica during the period September 1986 to August 1987. Among other things it was devised to determine the true perinatal mortality rate and the pathological causes of the deaths. The study aimed a t collecting data on all neonatal deaths and all stillbirths (SB) of 500 g or more during the 12 month period. It included both hospital and home deliveries; all 14 parishes in Jamaica were included. The deaths were transferred where possible to institutions in Kingston for postmortem examination by three pathologists. For each death, a main questionnaire and an infant death/SB questionnaire were completed by the fieldworkers in the individual parishes, whose responsibility it was to identify all
Received March 31, 1989; accepted August 21, 1989.
174
K. COARD ET AL.
No. Age Parity2 Autopsied infants 1 30 3 2 21 1
3 3 26 4 18 0 5 21 2 6 18 1 7 19 0 Non-autopsied infants 8 29 1 9 18 0
TABLE 1. Characteristics of the anencephalics Maternal Education' Prev. Age 1st pregnancy level SB Sex
Fetal OutGest. come
20 18
T JS
F M
42 37
13
-
S JS P JS JS
F M F F M
30 34 29 40 31
NND SB rnac SB NND NND SB SB
14 17
P JS
F NS
35 35
SB SB
17 15
+
10
28
3
17
JS
F
39
11 12 13 14
22 26 20 14
1 1 1 0
20 21 20
S P JS JS
F M M F
40 38 35 32
-
+
'P = primary; JS = junior secondary; S = secondary; T = tertiaryiother; NND 'No. previous pregnancies resulting in a live or stillbirth.
deliveries and deaths. These questionnaires contained, among other particulars, all relevant aspects of the mother's past obstetric history, her social and environmental background, and history of current pregnancy and delivery. Details of birthweight and sex of the infant together with time of death, details pertaining to the clinical history, and causes of death were recorded. Specific questions asked whether there were any visible congenital malformations. If so, the fieldworkers were asked to describe them in detail. These questionnaires were available on the stillbirths and neonatal deaths, whether or not the infant was subjected to a postmortem examination. In addition to a survey of deaths, all births on the island in September and October 1986 were studied and a main questionnaire was completed. The data from the 10,527 births have been assumed to be representative of the total population of women delivering in the 12 month period. Although these 2 months were those with the highest number of births, there is no evidence that demographic features such as maternal age and parity vary with season on the island. Comparison of the data collected with vital records showed that the survey identified 13 times more stillbirths and 11 times more neonatal deaths than had been registered. The number of surviving births was slightly more than the number registered.
=
rnac SB rnac NND SB NND SB
Wt. 3,3206 1,6548 1,3836 1,380g 1,630g 1,270g 1,650g
61b8oz
51b12oz 41b14oz
-
neonatal death; SB = stillbirth; rnac = macerated.
The overall perinatal mortality rate was 41 per 1,000 total births. RESULTS
In all there were a n estimated 54,200 births during the 12 month study period. Of these, a total of 2,197 fetal and neonatal deaths were identified. Postmortem examination was undertaken on 1,112 of the deaths yielding a n overall postmortem rate of 51%. Of the infants subjected to postmortem, a total of seven infants had anencephaly. Only one of these cases had other congenital anomalies: these comprised bilateral cleft lip and palate together with unusual facial clefting, flexion deformities, and fusion of placental membranes to the cranial defect, features of amnion rupture sequence. This case is reported elsewhere (Escoffrey and Coard, in press). Of the babies who did not come to necropsy, a further seven infants with anencephaly were identified, yielding a total of 14 anencephalics. In all, the incidence of anencephaly in Jamaica was 0.261 1,000 total births with 95% confidence limits 0.12 to 0.40. If the case of amnion rupture sequence were excluded the rate would be 0.24 (95% c.i. 0.11-0.37). Details of the 14 cases of anencephaly are given in Table 1. All were singletons. There were eight females and five males. The sex of one of the non-autopsied infants was not
INCIDENCE OF ANENCEPHALY IN JAMAICA
stated. Eight were delivered preterm (
incidence of Anencephaly in Jamaica K. COARD, C. ESCOFFERY, J. GOLDING, AND D. ASHLEY Department of Pathology, University of the West Indies, Mona, Jamaica (K.C., C.E.); Znstitute of Child Health, University of Bristol, Bristol BS2 SBJ, England (J.G.); Maternal and Child Health, Ministry of Health, Kingston, Jamaica (D.A.)
ABSTRACT
Information was collected on 2,197 stillbirths and neonatal deaths on the island of Jamaica during the 12 month period September 1986 to August 1987 as part of the population based nationwide Jamaican Perinatal Morbidity and Mortality Survey. There were 14 cases of anencephalus giving an incidence of 0.26 per 1,000 total births. One of these cases was associated with the amniotic band syndrome; excluding this, the incidence would be even lower (0.24 per 1,000). There was no apparent association with social class, maternal age, or parity. The rate found in Jamaica is considerably lower than found in any other national population study.
During the past 50 years among perinatologists and epidemiologists there has been an increasing interest in neural tube defects, and in anencephaly in particular, due to the possibility of primary prevention with dietary manipulation. Extensive literature from many countries pertains especially to its incidence and epidemiology. In more recent times, the ability to diagnose neural tube defects prenatally, with the consequent potential for reduction in their prevalence at birth, has allowed more meaningful work to be done to identify high risk pregnancies. Many data on the incidence of anencephaly, much like data on many other congenital malformations, have been derived from hospital-based population studies, which have a well recognised inherent bias. Although vital records are population-based, they are often deficient in the identification of perinatal deaths, and even when such deaths are registered, the causes are often inaccurate (Golding, '87). Recently, as more investigators have become aware of these biases, geographical population-based studies have begun to emerge. Such studies are available, for example, for Greece (Lekea et al., '88) and the United Kingdom (Butler and Alberman, ,691, among others. In Jamaica, there have been two previous attempts to estimate the incidence of anencephaly, with varying results. In the first study (Thorburn et al., '691, the incidence was 0.23/1,000 in a total of 68,633 births. Although these data were collected over a 0 1990 WILEY-LISS, INC.
4% year period, they covered two hospital populations, both in the capital, Kingston. The other study, done over a 3 year period, used data from only one of these two hospitals and the rate calculated was three times that of the former study (0.7/1,000)(Wynter and Persaud, '72). In an attempt to more accurately determine the true incidence in Jamaica, we present here the results of the first population-based study. MATERIALS AND METHODS
A nationwide Perinatal Morbidity and Mortality Survey (Ashley et al., '88) was conducted in Jamaica during the period September 1986 to August 1987. Among other things it was devised to determine the true perinatal mortality rate and the pathological causes of the deaths. The study aimed a t collecting data on all neonatal deaths and all stillbirths (SB) of 500 g or more during the 12 month period. It included both hospital and home deliveries; all 14 parishes in Jamaica were included. The deaths were transferred where possible to institutions in Kingston for postmortem examination by three pathologists. For each death, a main questionnaire and an infant death/SB questionnaire were completed by the fieldworkers in the individual parishes, whose responsibility it was to identify all
Received March 31, 1989; accepted August 21, 1989.
174
K. COARD ET AL.
No. Age Parity2 Autopsied infants 1 30 3 2 21 1
3 3 26 4 18 0 5 21 2 6 18 1 7 19 0 Non-autopsied infants 8 29 1 9 18 0
TABLE 1. Characteristics of the anencephalics Maternal Education' Prev. Age 1st pregnancy level SB Sex
Fetal OutGest. come
20 18
T JS
F M
42 37
13
-
S JS P JS JS
F M F F M
30 34 29 40 31
NND SB rnac SB NND NND SB SB
14 17
P JS
F NS
35 35
SB SB
17 15
+
10
28
3
17
JS
F
39
11 12 13 14
22 26 20 14
1 1 1 0
20 21 20
S P JS JS
F M M F
40 38 35 32
-
+
'P = primary; JS = junior secondary; S = secondary; T = tertiaryiother; NND 'No. previous pregnancies resulting in a live or stillbirth.
deliveries and deaths. These questionnaires contained, among other particulars, all relevant aspects of the mother's past obstetric history, her social and environmental background, and history of current pregnancy and delivery. Details of birthweight and sex of the infant together with time of death, details pertaining to the clinical history, and causes of death were recorded. Specific questions asked whether there were any visible congenital malformations. If so, the fieldworkers were asked to describe them in detail. These questionnaires were available on the stillbirths and neonatal deaths, whether or not the infant was subjected to a postmortem examination. In addition to a survey of deaths, all births on the island in September and October 1986 were studied and a main questionnaire was completed. The data from the 10,527 births have been assumed to be representative of the total population of women delivering in the 12 month period. Although these 2 months were those with the highest number of births, there is no evidence that demographic features such as maternal age and parity vary with season on the island. Comparison of the data collected with vital records showed that the survey identified 13 times more stillbirths and 11 times more neonatal deaths than had been registered. The number of surviving births was slightly more than the number registered.
=
rnac SB rnac NND SB NND SB
Wt. 3,3206 1,6548 1,3836 1,380g 1,630g 1,270g 1,650g
61b8oz
51b12oz 41b14oz
-
neonatal death; SB = stillbirth; rnac = macerated.
The overall perinatal mortality rate was 41 per 1,000 total births. RESULTS
In all there were a n estimated 54,200 births during the 12 month study period. Of these, a total of 2,197 fetal and neonatal deaths were identified. Postmortem examination was undertaken on 1,112 of the deaths yielding a n overall postmortem rate of 51%. Of the infants subjected to postmortem, a total of seven infants had anencephaly. Only one of these cases had other congenital anomalies: these comprised bilateral cleft lip and palate together with unusual facial clefting, flexion deformities, and fusion of placental membranes to the cranial defect, features of amnion rupture sequence. This case is reported elsewhere (Escoffrey and Coard, in press). Of the babies who did not come to necropsy, a further seven infants with anencephaly were identified, yielding a total of 14 anencephalics. In all, the incidence of anencephaly in Jamaica was 0.261 1,000 total births with 95% confidence limits 0.12 to 0.40. If the case of amnion rupture sequence were excluded the rate would be 0.24 (95% c.i. 0.11-0.37). Details of the 14 cases of anencephaly are given in Table 1. All were singletons. There were eight females and five males. The sex of one of the non-autopsied infants was not
INCIDENCE OF ANENCEPHALY IN JAMAICA
stated. Eight were delivered preterm (
