广播电视英语短句 第 111 课：有关流产-1

A miscarriage is the natural loss of a pregnancy before the twentieth week. 流产是怀孕前二十周的自然流失。

This happens to as many as twenty percent of known pregnancies. 发生率多达已知怀孕比例的20%。

Experts say many pregnancies end before a woman even knows she was pregnant. 专家说很多妊娠在一个女人知道她自己怀孕前就已终止了。

Miscarriages are usually caused by chromosome problems that prevent the baby from developing. 流产通常是因为染色体问题阻止婴儿生长而导致的。

The online medical encyclopedia MedlinePlus says these problems are usually unrelated to the genes of either parent. 在线医学百科全书 MedlinePlus 说这些问题通常和父母双方的基因没有关系。