Mehdizadeh A.¹, Akbarian A.¹, Samareh Pahlavan P.², Tavajjohi S.³, MacKay Rossignol A.⁴, Alaghehbandan R.^3,5, Groohi B.^3,5

¹ Department of Obstetrics and Gynaecology, Iran University of Medical Sciences, Tehran, Iran
² Faculty of Medicine, Shahid Beheshtee University of Medical Sciences, Tehran
³ Faculty of Medicine, Iran University of Medical Sciences, Tehran
⁴ Department of Public Health, Oregon State University, Corvallis, Oregon, USA
⁵ Kurdistan University of Medical Sciences, Sanandaj, Kurdistan, Iran

SUMMARY. Objectives: The objectives of the study were to quantify the frequency of burn injuries in pregnant women, to identify risk and predisposing factors, to understand the health consequences of these burns in terms of maternal and foetal mortality, and to compare the results with findings from other published studies. Setting: The study was conducted at the Motahari Burn Centre in Tehran, Iran. Methods: A medical record review was conducted of the 103 pregnant burned women, aged 15-49 yr, admitted over the six-year period beginning 21 March 1994. Data were collected regarding the size and outcome of the burn, and demographic information. These data were supplemented by data from the 1996 population census. Results: The burn incidence rate for pregnant women was estimated as 9.4/100,000 person-years compared with a rate of 15.8 for similarly aged non-pregnant women. The burn rate was higher in women who were illiterate or had only primary school education than in women with a more formal education. Flame burns accounted for 93.2% of all burns. Maternal death occurred in 62.1% of cases; the corresponding percentage for foetuses was 72.8%. The percentage of cases of burns due to suicide attempts was 14.6%. Conclusions: Burn injuries during pregnancy appear to be a larger problem in economically developing countries like Iran where burns are more common in females than in males. As most burns in pregnant females were unintentional, there is clearly an opportunity for prevention, for example by educating pregnant women in the antenatal care clinic as to burn risk factors and prevention efforts.

* This work was completed in the Iran University of Medical Sciences, Theran, Iran.

Introduction

Pregnant women constitute one of the most significant risk groups for burn injuries because of the typically large burn sizes involved and the often severe medical consequences to the woman and her foetus.1-22 In an economically developing country such as Iran, burns in women of reproductive age occur more frequently than they do among similarly aged women residing in economically more developed countries.1-3 Thus, the potential health and societal costs of burns to pregnant women are greater.

To our knowledge, no previous epidemiological report of burn injuries among pregnant patients in Iran has been published. For this reason, and to expand our understanding of the epidemiology of burns in pregnant women in Iran, we conducted a study of all burns in pregnant women treated at a major burn treatment centre in Tehran. The objectives of the study were to quantify the frequency of burns injuries in pregnant women, to identify risk and predisposing factors, to understand the health consequences of these burns in terms of maternal and foetal mortality, and to compare our results with the findings of other published studies.

Materials and methods

We conducted the study at the Motahari Burn Centre in Tehran. This centre is the sole referral centre for all major burns in pregnant women occurring among residents of Tehran province. Thus, both the numbers of burns and the size of the populations giving rise to these burns are known, making the centre a good model for epidemiological research.23 In addition to residents in Tehran province, the centre serves additional burn patients referred from outside Tehran province.

From 21 March 1994 to 20 March 2000, 11,856 patients were admitted to the Motahari Burn Centre. Of these patients, 6685 (56.4%) were women, of whom 3142 (47%) were in their reproductive years (15-49 yr). This study focuses on the 103 patients (3.3% of the 3142 patients) who were pregnant at the time of the burn injury.

Obstetric consultation was sought promptly on admission for each pregnant patient, and the usual antenatal regimen, including supplemental folic acid and ferrous sulphate, was initiated as soon as oral feeding was feasible.

Data including demographic information, province of residence, percentage burned body surface area (BSA), foetal age, and maternal and foetal complications were obtained from each patient’s medical record.

Burn incidence rates for women residing in Tehran province were estimated by relating the number of burns to the number of person-years of observation, as estimated from the 1996 population census.24

All statistical analyses were performed using Epi Info for DOS version 6.04 (CDC, USA and WHO Geneva, Switzerland) on an IBM-compatible microcomputer. Differences between and among various groups were evaluated using Student’s t-test or the chi-square test. The level of significance was set at 0.05.

Results

During the 6-year period, 103 pregnant patients received in-hospital therapy at the Motahari Burn Centre in Tehran, Iran. The annual number of admissions of pregnant patients did not vary substantially over the six years studied (p = 0.8) (Table I). Thirty-nine patients (37.9%) were residents of Tehran province, while the remaining 64 patients (62.1%) were referred from provinces outside Tehran province. The incidence rate of burns among pregnant patients who were residents of Tehran province was calculated as 9.4 per 100,000 person-years (Table II) compared with 15.7/100,000 person-years for all women of reproductive age residing in Tehran province (Table III).

On the basis of the data in Tables II and III, the burn incidence rate for non-pregnant women in Tehran was approximately 15.8 per 100,000 person-years ([2,662 burns - 39 burns)/(17,009,330 P-Y - 415,908 P-Y]).

The distribution of the 103 pregnant patients by age group is shown in Fig. 1. The overall mean and median ages of the patients were 23.5 and 22 yr, ranging from 16-42 yr with a standard deviation for mean age of 5 yr. Seventy per cent (72/103) of the patients were aged between 16-25 yr, and 29% (30/103) were in the age group 26-35 yr.

The literacy levels of the 80 patients for whom this information was available, and the corresponding levels for the general population of women, are shown in Table IV. Of the burned women, 82.5% had no high school qualification, compared with 63.5% of the general population of women aged 15-49 yr. There was a striking association between the level of literacy and the risk of burning during pregnancy, with a risk ratio extending from 1.5 and 1.7 for “illiterate and primary school only” women to about 0.5 for women who had “graduated from high school and/or university”. There also was a significant and direct association between level of literacy (low to high) and mean BSA (p = 0.04), although this association was not uniformly linear (data not shown). No statistically significant correlation was found between level of literacy and cause of burn (p = 0.8).

Burns in pregnant women requiring hospitalization were more common during spring months (28.2%; 29/103), followed by winter (26.2%; 27/103), summer (24.3%; 25/103), and autumn (21.3%; 22/103).

The distribution of the patients by burn type and trimester of pregnancy is shown in Table V. Flame burns involving an accelerant (kerosene, gasoline, or alcohol), burns from gas explosions, and fire-related burns together accounted for 93.2% (96/103) of all burns. Among burns involving flammable liquids, kerosene was the most common flammable liquid agent used (87.1%; 54/62 burns involving a flammable liquid), followed by gasoline (8.1%; 5/62). Burns from gas explosions accounted for 23.3% (24) of all burns. Six pregnant patients were burned by scalds and one patient suffered chemical (acid) burns. Burn type varied little by trimester of pregnancy.

The percentage of burned BSA in the patients ranged from 2 to 100%, with a mean and median of 53.3% and 40%. The extent of the burn was less than 40% BSA in 40% (41) of the patients (Table VI). Sixty pregnant patients (58.3%) had third-degree burns, while the remaining 43 (41.7%) had second-degree burns. The mean BSA in patients with third-degree burns was significantly higher than the mean BSA in second-degree burns (p < 0.00001). There were significant associations of mean BSA (p = 0.001) and burn depth (p = 0.006) with the burn type.

Maternal death occurred in 64 of the 103 cases (62.1%). Foetal death occurred in 75 (72.8%) of the cases. All women with burns larger than 60% BSA (and all except one woman with burns greater than 50% BSA) died from their injuries, as did all the foetuses of women with burns greater than 50% BSA (Table VI).

There was a significant statistical association of maternal death with percentage BSA burned and the degree of burns (p < 0.00001, for each association) but not with maternal age. A statistically significant association was also found between burn type (flame burns involving kerosene plus burns from gas explosions versus other burn types) and maternal death (73.1% versus 20.0% mortality, respectively (p = 0.01), which was mediated in part by burn size.

The most common maternal complication among patients who died was sepsis, while in those who survived it was burn scar (Table VII).

The causes of foetal death were intrauterine foetal death (IUFD), accounting for 39 (52.0%) deaths, and abortion or premature delivery, accounting for the remaining 48% of foetal deaths. The mean percentage of burned BSA among mothers whose foetus respectively died and survived was 66.1% and 33.7% (p < 0.00001).

In 14.6% of cases (15/103), the burns among pregnant patients were due to suicide attempts. The fatality rate in suicidal burn injuries (80.0%; 12/15) was somewhat higher than the 59.1% (52/88) fatality rate observed in unintentional burn injuries (p = 0.5). The largest number of burns from suicide attempts (N = 6) occurred in women aged 16-20 yr, while the largest percentage of suicide burns among all burns in pregnant women (25%) occurred among women aged 31-35 yr (Figs. 1, 2).

Among women admitted during the first trimester of pregnancy, 14.8% (4/27) were admitted because of a suicide attempt. The comparable percentages for the second and third trimesters were respectively 19.0% (8/42) and 9.4% (3/34).

Flame burns involving kerosene were the immediate cause of the injury in 86.6% (13/15) of the suicidal burn patients; this was followed by alcohol (one patient) and chemicals (one patient). The latter burn resulted in a 100% BSA burn.

The foetal death rate among mothers with suicidal burns (12/15; 80%) was somewhat higher among patients with unintentional burns (47/88; 53.4%) (p = 0.3).

Discussion

The possibility of pregnancy must be considered when any woman of reproductive age has sustained a burn injury. Although rare, an extensive burn during pregnancy is a serious complication. In this study, 3.3% of all women of reproductive age admitted with burns were pregnant. Because pregnancy tests are not routinely administered to burned women of reproductive age, the true incidence of pregnancy associated with burn injuries, especially in the first trimester, remains unknown.11,21 The literature suggests that approximately 7% of women of reproductive age treated for large burn injuries are pregnant.14,22,25,26

Table VIII presents a summary review of the literature on burn injuries during pregnancy with respect to both maternal and foetal outcome. While it is difficult to assess how representative these reports are of all burns in pregnant women, these reports nevertheless provide a basis for comparing the results of the current study with outcomes observed in other treatment units. In the current study, the overall maternal fatality rate was 62.1% (64/103), which was unsatisfactory and higher than both overall maternal mortality (27.8%) and maternal mortality during and after 1990 (28.3%), as calculated from the data in Table VIII.

In the current study, flame burns were the most common burn type among the pregnant patients. Flame burns involving kerosene were particularly prevalent. Similar findings have been reported in other studies from both high- and low-income countries.13,14,21,22

Pregnant women with self-inflicted burns were often successful in their attempt: the fatality rate among these women (80.0%) was higher than that among women with unintentional burns (59.1%). This difference in mortality may be attributable in part to the higher percentage of BSA burned (65.7%) in suicidal burn patients compared with the percentage (46%) of women with unintentional burns. Overall, it seems that suicide by burning, especially among pregnant women, is an underestimated mental health problem in our society.

A direct relationship between the percentage of burned BSA and the probability of death is well established.26 In the present study, the fatality rate among patients with a percentage of burned BSA of 40% or more was 5.4 times the fatality rate among women with smaller burns (p = 0.00006). Percentage BSA affected was therefore the best predictor of survival.

Several factors may explain the high fatality rate observed: 1. the absence of effective isolation units for the patients; 2. the high rate of cross-infection and Pseudomonas aeruginosa infection/septicaemia; 3. the high resistance of Pseudomonas aeruginosa to many antimicrobial agents; and 4. the unavailability of preferred antimicrobial agent choices (for example, ceftazidime, azteronam, and imipenem). Similar problems have been reported in other studies from Iran.1-3

The most common complication among patients who died was sepsis. Other studies have reported that infection is one of the most devastating complications of burns, with septicaemia accounting for almost half of all deaths in pregnant burn patients and their foetuses.26

The observed foetal mortality (72.8%) was higher than both the overall foetal mortality (41.7%) and foetal mortality during and after 1990 (44.3%), as shown by a review of the literature (Table VIII). A positive relationship was found between the percentage of maternal body burn and the risk of foetal death.26 In our study, a 40% BSA burn was found to be critical to the finding of foetal death. The most common foetal complication was IUFD, followed by abortion. In addition, there was a significant correlation between foetal complications and the maternal percentage of burned BSA. In this respect, foetal risk has been shown to correspond to maternal well-being. Most foetuses survive when the mother survives and remains free of severe complications such as sepsis, hypotension, hypoxia, and death. 13-15,20,22,25,26

Burn injuries during pregnancy pose two important problems: first, there is spontaneous uterine activity and, second, intrauterine foetal death may occur owing to compromised circulation to the less preferred gravid uterus and foetoplacenta unit. Respiratory injuries add more insult due to the disturbances in respiratory exchange, leading to further hypoxia.9,16,22 Whenever a pregnancy is complicated by thermal injury, a clear management scheme is therefore needed in order to provide optimum care for both the mother and her developing foetus.

A noteworthy feature in the current study is the occurrence of suicide attempts by burning in 14.6% of the pregnant patients. This percentage may be an underestimate, as some victims and their families may have denied that the injury was self-inflicted, owing to social, familial, and/or religious reasons. Furthermore, official statistics are also likely to reflect less than the true rates because of religious and social reasons. Unfortunately, there are no other published statistics about the incidence rate of suicide by burning among pregnant women in Iran that might serve as a comparison for the rates observed in our study.

Conclusion

Burn injuries during pregnancy appear to be a larger problem in economically developing countries like Iran where burns are more common in females. As most burns in pregnant females are unintentional, there is clearly an opportunity for prevention by teaching pregnant women in the antenatal care clinic, for example, to avoid contact with kerosene for cooking and heating and to apply proper first-aid measures, such as prompt cooling of the burn with cold water, to reduce the depth of the injury should a burn occur.

RESUME. Buts: Cette étude s’est proposée de quantifier la fréquence des brûlures dans les femmes enceintes, d’identifier les facteurs de risque et prédisposition, de comprendre les effets médicaux pour ce qui concerne la mortalité maternelle et fœtale et de comparer les résultats avec les résultats publiés par d’autres chercheurs. Lieu: L’étude a été conduite au Centre des Brûlures Motahari à Tehran, Iran. Méthodes: Les données médicales des 103 femmes enceintes brûlées âgées de 15 à 49 ans hospitalisées pendant la période de 6 ans à partir du 21 mars 1994 ont été analysées. Ces données concernaient l’extension des brûlures et le résultat final et comprenaient aussi des informations démographiques, supplémentées par des statistiques provenant du recensement de la population effectué en 1996. Résultats: La fréquence des brûlures dans les femmes enceintes était 9,4/100.000 personne-ans par rapport à une fréquence de 15,8 pour les femmes non enceintes du même âge. La fréquence des brûlures était plus élevée dans les femmes analphabètes ou celles qui avaient fréquenté seulement l’école élémentaire par rapport aux femmes qui avaient reçu une instruction plus formelle. Les brûlures causées par les flammes constituaient 93,2% de toutes les brûlures. Le décès de la mère s’est vérifié dans 62,1% des cas, et du fœtus dans 72,8%. Le pourcentage des cas des brûlures provoquées par des tentatives de suicide était 14,6%. Conclusions: Les brûlures pendant la grossesse semblent être un problème plus grand dans les pays en voie de développement économique comme l’Iran, où les brûlures touchent les femmes plus fréquemment que les hommes. Le fait que la plupart des brûlures dans les femmes enceintes étaient involontaires démontre qu’il existe une bonne occasion pour la prévention, par exemple à travers l’éducation des femmes enceintes dans les cliniques des soins prénataux pour ce qui concerne les facteurs de risque des brûlures et les méthodes de prévention.

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