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Subject: TWINS(雙胞胎)的機會是多少?


Author:
t
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Date Posted: 05:15:20 05/11/02 Sat

生雙胞胎的機會是多少?

多胞胎懷孕在臨床上並不少見,一般說來,在80次的懷孕中,就有一次是多胞胎(雙胞胎或更多)。當然,這些多胞胎以雙胞胎最為常見。其實,在早期懷孕時,雙胞胎的比例比實際產下的雙胞胎的比例要高出很多;換句話說,在懷孕初期發現是懷有雙胞胎的,並不代表她一定會生出雙胞胎,因為有2/3的雙胞胎到後來只剩下一胎。通常,這種情況在懷孕第10週就會發生。別為此感到擔憂,因為這是大自然選擇「優良品種」的結果。因為被吸收掉的部份常是不健康,甚至是畸形和異常的胎兒,為了將營養提供給正常發育的寶寶,早些做出這種淘汰是必要的。

雙胞胎的孩子長得完全一樣嗎?

妳可能見過有的雙胞胎長得很像,有的則完全不像,這是怎麼一回事呢?原來,雙胞胎有兩種,一種叫做同卵雙生,另一種叫做異卵雙生。其中同卵雙生的胎兒起源於同一個受精卵,所以他們(或她們)必定是同樣的性別,而且各種特徵和遺傳性質都相同;換句話說,就是兩個寶寶會「一模一樣」﹔而異卵雙生的雙胞胎,則是起源於兩個不同的受精卵,可能性別不同,遺傳特徵也不同,也就是說兩個寶寶長得不一定相像。

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