Parasitic infestations in obstetrics and gynaecology 
Intestinal Manifestations 
Hookworm 
Infection by the nematodes, Ankylostoma duode- 
nale and Necator americanus cause hookworm in- 
fection. Human beings are the natural hosts of these 
parasites, which are spread widely in the tropical 
and subtropical areas of the world. 
Infection is through the larvae of the organism 
penetrating the human skin and being spread by 
blood to the lungs. From the lungs the larvae escape 
the blood vessels of the alveoli to the bronchi, tra- 
chea and thence to the gastrointestinal system by 
swallowing. After maturing in the intestine, the 
adults eventually pass eggs which reach the soil 
through faeces, allowing a new cycle to begin. 
A low worm load is usually asymptomatic, espe- 
cially if iron stores are normal. The worm absorbs 
blood from the wall of the intestines. A high worm 
load leads to anaemia, which is hypochromic and 
microcytic. 
When the larvae enter the skin, there may be loc- 
alised irritation or itching which lasts a few days. 
This is commonly felt in the skin of the feet, ankles 
or hands. The pulmonary phase of the life cycle is 
usually silent but rarely cough, bronchitis or even 
blood stained sputum occur. The major symptoms 
are due to the local infestation by a heavy worm load 
and include abdominal discomfort and constipation. 
In very advanced cases there may be nausea, vomit- 
ing and blood stained diarrhoea. By this stage severe 
anaemia and lethargy are apparent. Pregnancy exac- 
erbates the anaemia due to the increased iron de- 
mands. 
The diagnosis is made by identification of the 
parasite eggs in faecal specimens. After treatment, 
the worm may be visible to the naked eye in faeces 
and on microscopic examination. 
Hookworm infestation is treated with mebenda- 
zole, but its use should be limited to the second and 
third trimesters of pregnancy. Bephenium naph- 
thoate can be safely used in the first trimester of 
pregnancy. Other family members should also be 
treated and education regarding hygienic measures 
prevents re-infection and relapses. Adjunct iron 
therapy is also usually required in pregnancy. 
Tapeworm 
Tapeworm infestations are caused by Taenia sagina- 
ta (beef worm) or Taenia solium (pork worm). Hu- 
man beings are the only definitive host of these in- 
fections, which are acquired by eating improperly 
prepared beef or pork. Part of the life cycle in pigs 
and cattle arises when human faecal material con- 
taining eggs of the parasites enters the food chain of 
‘'hese animals. 
Clinical manifestations of these infections are 
very uncommon. Pregnancy does not change the 
course of the disease. The only effect upon pregnan- 
Cy of these infestations is by increasing the demand 
for iron, which may cause mild anaemia. Diagnosis 
is by identification of the eggs in the faeces. Rarely 
vart or all of a tapeworm passes through the anus. 
Treatment is giving niclosamide orally as a sin- 
gle dose, usually followed by a laxative about 2 
hours later. The risk of developing cysticercosis af- 
ter this treatment is now thought to be small. The 
drug is well tolerated in pregnancy. 
Roundworm 
This infestation by the Ascaris lumbricoides nema- 
tode is acquired by ingestion of the larvae of this or- 
ganism from infected soil. The larvae follow a path- 
way similar to that of the hookworm, entering the 
mucosa of the intestine and being carried to the 
heart, lungs, trachae and then swallowed back into 
the gastrointestinal tract. Development to the adult 
stage in the intestine. To complete the cycle, the fe- 
male adult lays eggs after being fertilised and these 
are passed through faeces into the soil. 
The passage of the larvae through the lungs may 
give rise to fleeting symptoms of cough, and an eosi- 
nophilia with raised Ig E serum levels. However, 
most patients only have symptoms with a heavy 
worm load. The worms may ball up and cause intes- 
tinal obstruction. Occasionally they migrate to the 
zommon bile duct, pancreatic duct, larynx or tra- 
chea. If they migrate to the anus or stomach, they 
may be passed in stool, or vomited up, in which case 
che diagnosis is obvious. Pregnancy does not affect 
the course of the disease, and the main effect of the 
infestation on pregnancy is through the development 
of iron deficiency anaemia. 
Treatment should only be given to pregnant 
women with heavy infestation or clinical disease, 
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aurare 22(1999)1- 39-47