Increased maternal blood pressure can attempt to make up for lower cardiac output, ensuring that the fetuss growing brain receives enough oxygen and nutrients. The benefits of being able to walk upright and run on land have outweighed the disadvantages that come from bipedalism, including the placental diseases of pregnancy, such as gestational hypertension. Similarly, the advantages of having a large brain size have outweighed the deleterious effects of having a placenta that does not always convert the spiral arteries effectively, leaving humans vulnerable to contracting gestational hypertension. It is speculated that this was not the case with Neanderthals, and that they died out because their cranial capacity increased too much, and their placentae were not equipped to handle the fetal brain development, leading to widespread pre-eclampsia and maternal and fetal death.Gestational hypertension in the early stages of pregnancy (trimester 1) has been shown to improve the health of the child both in its first year of life, and its later life. However, when the disease develops later in the pregnancy (subsequent trimesters), or turns into pre-eclampsia, there begin to be detrimental health effects for the fetus, including low birth-weight. It has been proposed that fetal genes designed to increase the mothers blood pressure are so beneficial that they outweigh the potential negative effects that can come from pre-eclampsia. It has also been suggested that gestational hypertension and pre-eclampsia have remained active traits due to the cultural capacity of humans, and the tendency for midwives or helpers to aid in delivering babies.
It is a combination of three medical conditions: hemolytic anemia, elevated liver enzymes and low platelet count. Eclampsia
This is when tonic-clonic seizures appear in a pregnant woman with high blood pressure and proteinuria.Pre-eclampsia and eclampsia are sometimes treated as components of a common syndrome. Treatment
There is no specific treatment, but is monitored closely to rapidly identify pre-eclampsia and its life-threatening complications (HELLP syndrome and eclampsia).Drug treatment options are limited, as many antihypertensives may negatively affect the fetus. Methyldopa, hydralazine, and labetalol are most commonly used for severe pregnancy hypertension.The fetus is at increased risk for a variety of life-threatening conditions, including pulmonary hypoplasia (immature lungs). If the dangerous complications appear after the fetus has reached a point of viability, even though still immature, then an early delivery may be warranted to save the lives of both mother and baby. An appropriate plan for labor and delivery includes selection of a hospital with provisions for advanced life support of newborn babies. Evolutionary considerations
Humans
Gestational hypertension is one of the most common disorders seen in human pregnancies. Though relatively benign on its own, in roughly half of the cases of gestational hypertension the disorder progresses into pre-eclampsia, a dangerous condition that can prove fatal to expectant mothers. However, gestational hypertension is a condition that is fairly rare to see in other animals.