su·​per·​fe·​ta·​tion ˌsü-pər-fē-ˈtā-shən How to pronounce superfetation (audio)
: a progressive accumulation or accretion reaching an excessive degree

Examples of superfetation in a Sentence

Recent Examples on the Web If superfetation is suspected, a woman's pediatrician can check the maturity of the baby once it's born. Asha C. Gilbert, USA TODAY, 14 Apr. 2021 Her pregnancy was diagnosed as superfetation, a rare condition in which a woman who is already pregnant conceives another baby. Washington Post, 8 Apr. 2021 But fetuses that appear to have different gestational ages aren't necessarily proof of superfetation., 2 Nov. 2017 The rare medical phenomenon is known as superfetation, in which a woman continues to ovulate after becoming pregnant. Char Adams,, 1 Nov. 2017 The difference in their size was obvious in the first trimester of pregnancy and continued, leading the doctor to offer superfetation as a diagnosis. C. Claiborne Ray, New York Times, 27 Feb. 2017

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'superfetation.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


Medieval Latin superfetation-, superfetatio, from Latin superfetare to conceive while already pregnant, from super- + fetare to bear young, from fetus newly delivered — more at fetus

First Known Use

1603, in the meaning defined above

Time Traveler
The first known use of superfetation was in 1603

Dictionary Entries Near superfetation

Cite this Entry

“Superfetation.” Dictionary, Merriam-Webster, Accessed 23 Jun. 2024.

Medical Definition


variants or chiefly British superfoetation
: successive fertilization of two or more ova of different ovulations resulting in the presence of embryos of unlike ages in the same uterus
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