Helicobacter pylori and pregnancy-related disorders

Abstract

Helicobacter pylori (H. pylori) infection is investigated in gastric diseases even during pregnancy. In particular, this Gram-negative bacterium seems to be associated with hyperemesis gravidarum, a severe form of nausea and vomiting during pregnancy. During the last decade, the relationship among H. pylori and several extra-gastric diseases strongly emerged in literature. The correlation among H. pylori infection and pregnancy-related disorders was mainly focused on iron deficiency anemia, thrombocytopenia, fetal malformations, miscarriage, pre-eclampsia and fetal growth restriction. H. pylori infection may have a role in the pathogenesis of various pregnancy-related disorders through different mechanisms: depletion of micronutrients (iron and vitamin B₁₂) in maternal anemia and fetal neural tube defects; local or systemic induction of pro-inflammatory cytokines release and oxidative stress in gastrointestinal disorders and pre-eclampsia; cross-reaction between specific anti-H. pylori antibodies and antigens localized in placental tissue and endothelial cells (pre-eclampsia, fetal growth restriction, miscarriage). Since H. pylori infection is most likely acquired before pregnancy, it is widely believed that hormonal and immunological changes occurring during pregnancy could activate latent H. pylori with a negative impact not only on maternal health (nutritional deficiency, organ injury, death), but also on the fetus (insufficient growth, malformation, death) and sometime consequences can be observed later in life. Another important issue addressed by investigators was to determine whether it is possible to transmit H. pylori infection from mother to child and whether maternal anti-H. pylori antibodies could prevent infant's infection. Studies on novel diagnostic and therapeutic methods for H. pylori are no less important, since these are particularly sensitive topics in pregnancy conditions. It could be interesting to study the possible correlation between H. pylori infection and other pregnancy-related diseases of unknown etiology, such as gestational diabetes mellitus, obstetric cholestasis and spontaneous preterm delivery. Since H. pylori infection is treatable, the demonstration of its causative role in pregnancy-related disorders will have important social-economic implications.

Keywords: Fetal growth restriction; Gastrointestinal disorders; Helicobacter pylori; Hyperemesis gravidarum; Iron deficiency anemia; Pre-eclampsia; Pregnancy.

Figure 1

Helicobacter pylori infection correlation with pregnancy-related disorders. Helicobacter pylori (H. pylori) infection can cause local damage and inflammation, leading to gastrointestinal disorders such as dyspepsia in pregnancy and hyperemesis gravidarum. H. pylori sequesters essential micronutrients from the host organism. In particular, iron depletion may lead to iron deficiency anemia (IDA), while reduction of vitamin B₁₂ and folate may result in fetal neural tube defects. Lack of these micronutrients may also be favored by gastric malabsorption in case of the above mentioned gastrointestinal problems. Furthermore, IDA could indirectly be the consequence of local and systemic inflammation induced by H. pylori infection. Finally, the immune and inflammatory responses caused by this infection lead to endothelial and placental injury, through the cross-reaction of anti-H. pylori and tissue antigens and through the production of pro-inflammatory cytokines. Placental dysfunction characterizes important diseases of pregnancy, such as miscarriage, fetal growth restriction (FGR) and pre-eclampsia that it is also characterized by endothelial damage and it is often associated with FGR. Furthermore, IDA could be a risk factor for FGR.