孕前期和孕早期疾病
Disease during pre-pregnancy and early pregnancy
孕早期产前诊断
First trimester prenatal diagnosis
不同孕期
different gestation periods
Different occasions
第一孕期不适症状
discomforts in the first trimester
父母孕前接触二硫化碳
Parents CS 2 exposure prior to pregnancy
围生期孕妇
Pregnant women in perinatal stage