SNAKEBITE IN PREGNANCY: A PRELIMINARY STUDY

Original paper

SNAKEBITE IN PREGNANCY: A PRELIMINARY STUDY.

P. P. O. PARDAL

, T. MAZZEO , A. C. L. PINHEIRO

1 Associate Professor of Parasital and Contagious Diseases at Federal University of Pará, Belém, Pará, Brazil; 2 Resident at the "João de Barros Barreto" Hospital, Federal University of Pará, Belém, Pará, Brazil; 3 Medical Doctor at the "João de Barros Barreto" Hospital, Federal University of Pará, Belém, Pará, Brazil.

ABSTRACT: Worldwide occurrence of envenomation by snakebite in pregnancy is rare according to the medical literature. The objective of the present study was to evaluate the frequency of snakebite envenomation cases as well as their obstetrical consequences. Thus, we conducted this study based on the medical records of 157 patients, aged from 13 to 54 years old who had been attended at the "João de Barros Barreto" University Hospital from January 1989 to May 1994. These patients presented epidemiological and clinical diagnosis of snakebite envenomation. Of the 157 patients, 8 (5%) were pregnant, 6 of them (75%) were in the first trimester of pregnancy and 2 (25%) in the 2nd trimester. Most of the victims were usually over 18 years old (7 cases, 87.5%). Concerning the severity of the envenomation cases, 5 of them were considered mild accidents. Obstetrical consequences occurred in 3 (37.5%) patients, 2 patients (25%) with moderate manifestations, while 1(12.5%) presented severe manifestations. Patients developed vaginal bleeding in 3 cases (100%), and uterine contraction, threatened abortion, decreased fetal movements, absence of fetal heartbeat and fetal death in one case (33.35%). Snakebite is not common among pregnant women, since in most cases, these women are homebound. However, the obstetrical consequences are severe and related to severity of the envenomation.

KEY WORDS: snakebite envenomation, pregnancy, obstetrical consequences.

INTRODUCTION

Throughout the world there are around 3,000 snake species, of which only 10% are venomous(1). In Brazil, snakes of the genus Bothrops account for most of the envenomation cases. Bothropic venom has a proteolytic, hemorrhagic and coagulating action(5).

According to Parrish and Klan(6), snakebite envenomation is not common in pregnancy. Zugaib et al.(9) reported that the toxin present in the snake venom is a coagulating active agent. This agent when injected in the maternal blood circulation, even in a small amount, soon reaches the placentary circulation. The venom apparently crosses the placenta in amounts that can cause systemic poisoning in the fetus even without evidence of envenomation in the mother(4). The coagulation fraction gradually leads to a consumption coagulopathy by fibrinogen depletion. Finally, the blood reaches the deciduoplacentary cleavage zone and starts its dissociation.

Studies conducted by Dunnihoo et al.(1) indicated a high fetal death rate (43%) associated with a high maternal death rate (10%) due to snakebite envenomation. The scarcity of studies on snakebite in pregnancy in international and Brazilian medical literature, and the severity of such accident in pregnant women justify this study intended to determine the frequency of snakebites in pregnancy, as well as to describe their signs and general and obstetrical symptoms.

PATIENTS AND METHODS

A study was conducted in 8 pregnant women through a retrospective survey of medical records of 157 patients, aged 13 to 54 years old with clinical diagnosis of snakebite envenomation from January 1989 to May 1994. These patients were attended at the" João de Barros Barreto" University Hospital, Federal University of Pará at Belém. The frequency of the envenomation cases in pregnant women, the severity of the envenomation, the gestational age, the clinical manifestations and the obstetrical consequences were considered.

RESULTS AND DISCUSSION

Of the 157 patients studied, only 8 were pregnant, with 5% of occurrence of snakebite envenomation as shown in Table 1.

Source: DAME - HUJBB

TABLE 1. Snakebite in pregnancy related to snakebite in patients in Belém, Pará, Brazil. (January 1989 to May 1994).

Parrish and Klan(6) also reported a few cases (2.98%) of snakebite envenomation among pregnant women in a study conducted in the United States.

Table 2 shows that the prevalent age range for snakebite envenomation among pregnant women was 18 to 32 years old (87.5%). It could also be observed that the accidents were more frequent in the 1 trimester of pregnancy (75% of the cases). There are no reports of envenomation cases in the 3 trimester of pregnancy. These findings agree with those by Malz(3) who studied 14 women in Israel and noticed that snakebites in the 1 trimester of pregnancy were predominant in 64.2% of the cases reported. The scarcity of reported cases of snakebite in pregnancy and their absence in the last trimester seem to be related to the fact that pregnant women are homebound in the final stages of pregnancy, avoiding exposure to outdoors activities. When snakebite occurs, delay in treatment and early gestational age suggest an unfavorable prognosis for pregnancy due to a slight decrease of platelets in the 1 trimester of pregnancy and their gradual increase up to the 3 trimester(7).

Source: DAME - HUJBB

TABLE 2. Snakebite in pregnancy according to age range and gestational age in Belém, Pará, Brazil. (January 1989 to May 1994).

The general clinical manifestations due to snakebite envenomation shown in Table 3 indicated that all the 8 patients presented pain and local edema 8 (100%), (50%) presented ascendant edema, 3 (37.5%) presented gingival bleeding, headache and dizziness. These symptoms/signs were reported in the literature consulted(1,2,3,6,8,9).

Source: DAME - HUJBB

TABLE 3. Clinical systemic and local manifestations due to snakebite in pregnancy in Belém, Pará, Brazil. (January 1989 to May 1994).

The obstetrical consequences shown in Table 4 were present in 8 patients. Concerning the severity of the accident, these were considered moderate in 2 cases (25%), severe in 1 (1=12.5%) and mild in 5 (62.5%) cases, with no obstetrical clinical alterations.

Source: DAME - HUJBB

TABLE 4. Obstetrical consequences related to snakebite severity and time elapsed before medical aid in 8 pregnant women in Belém, Pará, Brazil. (January 1989 to May 1994).

In the 3 (37,5%) cases with obstetrical consequences shown in Table 5, the following complications were reported: 3 (100%) with vaginal bleeding and 1 (33,3%) with uterine contraction, abruptio placentae, decreased fetal movements, absence of fetal heartbeat and fetal death.

Source: DAME - HUJBB

TABLE 5. Obstetrical consequences of snakebite in 3 pregnant women (2 moderate and 1 severe cases) in Belém, Pará, Brazil. (January 1989 to May 1994).

Malz(3) reported a 21.4% abortion rate and one case of severe malformation with subsequent death of the newborn. James(2) reported that his patients complained of decreased fetal movements in the first hours following the accident, leading to absence of fetal heartbeat and fetal movements preceding miscarriage.

In the present study, the reported fetal death occurred on the 20 week of pregnancy following a severe accident. The patient arrived at the hospital 12 hours after the accident and was submitted to a Cesarean section. The placenta presented multiple placentary necrotic grains and extensive vascular congestion detected after a histopathological exam.

09 ZUGAIB BM., BARROS ACD., BITTAR RE., BURDMANN GA., NEME BP. Abruptio placentae following snake bite. J. Obstet. Gynecol. 1985, 151, 754-5.

Received 30 May 1996

Accepted 02 July 1996

• 01 DUNNIHOO DR., RUSH MB., WESE RB., BROOKS GG., OTTERSON WN. Snake bite poisoning in pregnancy. A review of the literature. J. Reprod. Med., 1992, 37, 653-8.
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  02 JAMES RF. Snake bite in pregnancy. Lancet, 1985,2, 731.
• 03 MALZ S. Snake bite in pregnancy.J. Obstet. Gynaecol. Br. Commonw., 1967, 74, 935-7.
• 04 MCNALLY SL., REITZ CJ. Victims of snakebite. A 5 - year study at Shongwe Hospital, Kangwane, 1978-1982.S. Afr. Med. J., 1987, 72, 855-60
• 05 MINISTÉRIO DA SAÚDE. Manual de diagnóstico e tratamento de acidentes ofídicos. Brasília: Centro de Documentação do Ministério da Saúde. 1991: 53p.
• 06 PARRISH H., KLAN MS. Snake bite during pregnancy. Report of four cases. Obstet. Gynecol., 1966,27, 468-71.
• 07 REZENDE J. Obstetrícia. 4.ed. Rio de Janeiro: Guanabara Koogan, 1987: 649-63.
• 08 SUTHERLAND SK., DUCAN AW., TIBBALLS J. Death from a snake bite, associated with the supine hypotensive syndrome of pregnancy. J. Aust. Med. Assoc., 1982,2, 209-56.
• 09 ZUGAIB BM., BARROS ACD., BITTAR RE., BURDMANN GA., NEME BP. Abruptio placentae following snake bite. J. Obstet. Gynecol. 1985, 151, 754-5.  

CORRESPONDENCE TO:

P. P. O. PARDAL - Hospital Universitário João Barros Barreto, Rua dos Mundurucus 4487, CEP 66.073-000, Guamá, Belém, Pará, Brasil.

Publication Dates

• Publication in this collection
  08 Jan 1999
• Date of issue
  1997

History

• Accepted
  02 July 1996
• Received
  30 May 1996