Experts aren't sure how organophosphates might interfere with fetal brain development, although they do know that in insects the pesticides slow the breakdown of acetylcholine, an important neurotransmitter.

CNN: Pesticide exposure in womb may hurt your child's IQ

They have shown that nerve cells taken from fetal pigs can survive and mature in the brain of a Parkinson's patient much as human grafts do.

ECONOMIST: Something new in mind

Such bleeding may deprive the baby of oxygen - a condition known as fetal hypoxia - and this is turn impacts upon the developing brain, potentially raising the risk of autism.

BBC: Problem pregnancy 'autism risk'