fetus|fetuses

医生告诉我们胎儿已经发育到第20周了。

The doctor told us the ___fetus has developed to the 20th week.

医生正在监测双胞胎胎儿的健康状况。

The doctor is monitoring the health of the twin ___fetuses.

超声波检查显示双胞胎胎儿发育良好。

The ultrasound shows that both ___fetuses are developing well.