Di ethyl stilbesterol causes the following defects except
**Core Concept**
Diethylstilbestrol (DES) is a synthetic estrogen that was previously used to prevent miscarriage and premature birth. However, it has been associated with various adverse effects, particularly in the offspring of women who took DES during pregnancy. The effects of DES exposure in utero can manifest as part of a condition known as DES syndrome.
**Why the Correct Answer is Right**
DES is a potent estrogen that can disrupt normal fetal development. Exposure to DES in utero has been linked to an increased risk of clear cell adenocarcinoma of the vagina and cervix, as well as reproductive tract abnormalities such as vaginal and cervical anomalies, and infertility. The mechanism of DES-induced malformations is thought to involve the disruption of normal estrogen signaling pathways, leading to aberrant development of the reproductive tract.
**Why Each Wrong Option is Incorrect**
**Option A:**
Vaginal clear cell adenocarcinoma is a known consequence of DES exposure in utero. This option is incorrect because it is a recognized effect of DES.
**Option B:**
Infertility is a well-documented consequence of DES exposure in utero. This option is incorrect because it is a known effect of DES.
**Option C:**
Vaginal and cervical anomalies are also known effects of DES exposure in utero. This option is incorrect because it is a recognized effect of DES.
**Clinical Pearl / High-Yield Fact**
DES is a classic example of an iatrogenic cause of reproductive tract abnormalities, highlighting the importance of careful consideration of potential risks and benefits when prescribing medications during pregnancy.
**Correct Answer:** D