This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
[{'content': 'Which of the following statement regarding Clomiphene citrate is true? \nSelect and explain. \nA. Enclomiphene is anti-estrogenic, B. Increases pregnancy rate 3 times as compared to placebo, C. Incidence of twin pregnancy is 5-6%, D. It has been shown to increase feility in oligospermic males in randomized controlled trials', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Clomiphene citrate is a racemic mixture of enclomiphene & zuclomiphene. Clomiphene citrate is a triphenylethylene; its two isomers, zuclomiphene (cis-clomiphene) and enclomiphene (trans-clomiphene), are a weak estrogen agonist and a potent antagonist, respectively. The incidence of multiple pregnancies is approximately 10%. Although clomiphene is effective in inducing ovulation in perhaps 75% of women, successful pregnancy ensues in only 40-50% of those who ovulate. Clomiphene also may be used to evaluate the male reproductive system because testosterone feedback on the hypothalamus and pituitary is mediated to a large degree by estrogens formed from aromatization of the androgen. Enclomiphene is a more potent anti-oestrogenic isomer and the one primarily responsible for the ovulation-inducing actions of clomiphene citrate. Intrauterine insemination and clomiphene citrate increase pregnancy rate 3 times as compared to placebo. Incidence of twin pregnancy following clomiphene citrate ovulation induction is 10%, while that of triplets is 1%. A randomized control study showed that use of clomiphene has improved sperm motility and percent of normal forms but has not established an increased feility. Indications of clomiphene: Ovulation induction To aid invitro feilization when given with gonadotrophins In oligozoospermia: it increases gonadotrophin secretion and promotes spermatogenesis and testosterone secretion Adverse effects of clomiphene: Polycystic ovaries Multiple pregnancy Hot flushes Gastric upset Increased risk of ovarian tumor', 'role': 'assistant'}]