Treatment with anthelminthics during pregnancy: what gains and what risks for the mother and child?

Abstract

In 1994 and 2002, respectively, the World Health Organisation proposed that treatment for hookworm and schistosomiasis could be provided during pregnancy. It was hoped that this might have benefits for maternal anaemia, fetal growth and perinatal mortality; a beneficial effect on the infant response to immunisation was also hypothesised. Three trials have now been conducted. Two have examined the effects of benzimidazoles; one (the Entebbe Mother and Baby Study) the effects of albendazole and praziquantel. All three were conducted in settings of high prevalence but low intensity helminth infection. Results suggest that, in such settings and given adequate provision of haematinics, the benefit of routine anthelminthics during pregnancy for maternal anaemia may be small; none of the other expected benefits has yet been demonstrated. The Entebbe Mother and Baby Study found a significant adverse effect of albendazole on the incidence of infantile eczema in the whole study population, and of praziquantel on the incidence of eczema among infants of mothers with Schistosoma mansoni. Further studies are required in settings that differ in helminth species and infection intensities. Further research is required to determine whether increased rates of infantile eczema translate to long-term susceptibility to allergy, and to explore the underlying mechanisms of these effects. The risks and benefits of routine anthelminthic treatment in antenatal clinics may need to be reconsidered.

Fig. 1

Prevalence of the three commonest helminth infections at enrolment and after delivery, according to treatment allocation during pregnancy, among 2507 women participating in the Entebbe Mother and Baby Study. Placebo: double placebo group; alb: single dose albendazole (400 mg) plus placebo for praziquantel; praz: single dose praziquantel (40 mg/kg) plus placebo for albendazole; alb+praz: single dose albendazole (400 mg) plus praziquantel (40 mg/kg). Error bars show the upper 95% confidence interval for the percentage prevalence of infection.

Fig. 2

The effect of treatment with albendazole or praziquantel during pregnancy on the incidence of eczema during infancy in the Entebbe Mother and Baby Study. (A) The effect of albendazole among 2345 live-born infants of all mothers, with or without detected helminth infection. (B) The effect of praziquantel among 421 infants of mothers with detected Schistosoma mansoni infection. Shown are the cumulative hazard functions based on multiple eczema events. Alb, albendazole; praz, praziquantel.