Normal pregnancy is also associated with changes in traditional cardiovascular
risk factors with relative insulin resistance and increase in triglycerides,
total cholesterol (predominately LDL), phospholipids, and
free fatty acids, all of which are thought to benefit foetal growth. In
normal pregnancy, blood pressure begins to decrease as early as 7
weeks of gestation until 32 weeks when it gradually increases back
to normal. The decrease in blood pressure is thought to be secondary
to low resistance flow in the placenta as well as hormonal factors
causing dilation such as oestrogen, progesterone, prostaglandin, prolactin,
prostacyclin, and relaxin, and increased production of nitric oxide.13