Dangers Await Babies with Altitude[理工类、卫生类职称英语教材]
Women who live in the world’s highest communities tend to give birth to underweight babies,a new study suggests.These babies may grow into adults with a high risk of heart disease and strokes. 1
Research has hinted that newborns in mountain communities are lighter than average.But it wasn’t clear whether this is due to reduced oxygen levels at high altitudes or because their mothers are under-nourished many people who live at high altitudes are relatively poor compared with those living lower down.
To find out more,Dino Giussani and his team at Cambridge University studied the records of 400 births in Bolivia during 1997 and 1998.The babies were born in both rich and poor areas of two cities：La Paz and Santa Cruz.La Paz is the highest city in the world,at 3.65 kilometers above sea level, while Santa Cruz is much lower,at 0.44 kilometers.
Sure enough,Giussani found that the average birthweight of babies in La Paz was significantly lower than in Santa Cruz.This was true in both high and low-income families.Even babies born to poor families in Santa Cruz were heavier on average than babies born to wealthy families in lofty La Paz.”We were very surprised by this result,”says Giussani.
The results suggest that babies born at high altitudes are deprived of2 oxygen before birth.“This may trigger the release or suppression of hormones that regulate growth of the unborn child,3”says Giussani.
His team also found that high-altitude babies tended to have relatively larger heads compared with their bodies 4.This is probably because a fetus starved of oxygen will send oxygenated blood to the brain in preference to the rest of the body. 5
Giussani wants to find out if such babies have a higher risk of disease in later life.People born in La Paz might be prone to heart trouble in adulthood,for example.Low birthweight is a risk factor for coronary heart disease.And newborns with a high ratio of head size to body weight
are often predisposed to high blood pressure and strokes in later life.
词汇：
altitude n.纬度,(海拔)高度
birthweight n.出生体重
underweight adj.重量不足的
hormone n.荷尔蒙
stroke n.中风
coronary adj.冠状的
hint vt.暗示
fetus n.胚胎
under-nourished adj.营养不足的
注释：
1.…grow into adults with a high risk of heart disease and strokes：
……长大成人后得心脏病和中风的风险很大
2.…are deprived of…：被剥夺了……,缺乏……
3.This may trigger the release or suppression of hormones that regulate growth of the unborn child:这可能会触发调节未出生儿成长的荷尔蒙的释放或抑制。这里的release是名词。
4.relatively larger heads compared with their bodies:相对身体来说较大的头部
5.…a fetus starved of oxygen will send oxygenated blood to the brain in preference to the rest of the body：……一个缺乏氧的胚胎会首先把充氧的血液输送到脑部, 然后才送到身体的其他部位。starved of是分词短语,修饰fetus,in preference to表示的是第二位的选择,如：I chose to study English in pr
