胼胝體缺損是連結大腦左右半球胼胝體連接纖維沒有發育或發育不良。活產兒發生胼胝體缺損發生機率為3%~5% 到 1: 4000。此病例報告為一位34 歲婦女結婚5 年因排卵異常而致原發性不孕症並接受3 次卵巢排卵刺激及人工受孕。在第三次卵巢排卵刺激及人工受孕後懷孕，不幸的是在懷孕24 週例行產檢超音波發現胎兒大腦兩側側腦室枕角極度擴大及前角狹窄，即所謂淚滴型腦室，除此之外並無其他異常。當時超音波診斷為單獨胼胝體缺損。病人到其他醫院以核磁共振檢查確認診斷後，選擇終止妊娠。

Failure of development of the callosal commissural fibers connecting the cerebral hemispheres results in complete or partial agenesis of the corpus callosum (ACC). The incidence of ACC ranges 3%~5% to 1:4000 live births. This paper reports a 34-year-old woman married for 5 years with primary infertility due to ovulation dysfunction who received ovulation induction (OI) and intrauterine insemination (IUI) 3 times. She became pregnant after the third OI and IUI procedures. Unfortunately, it was found that the occipital portion of the bilateral lateral ventricles of her fetus were dilated with narrowing of the anterior part, creating the so-called “teardropshaped” ventricles (colpocephaly) at 24 gestational weeks on a routine antenatal ultrasound check. After this discovery, isolated ACC with no associated anomalies was the impression. The diagnosis was confirmed at another hospital by MRI, and then the patient decided to terminate the pregnancy.