noun
twin pregnancy; twin fetuses
Medical term for a pregnancy with two fetuses, or the twin fetuses themselves. In everyday contexts, 双子 (ふたご) is more common.
超音波検査で双胎と診断された。
She was diagnosed with a twin pregnancy by ultrasound.
双胎妊娠は単胎妊娠よりリスクが高い。
A twin pregnancy carries higher risks than a singleton pregnancy.