superfetation
noun
su·per·fe·ta·tion ˌsü-pər-fē-ˈtā-shən 
: a progressive accumulation or accretion reaching an excessive degree
Example Sentences
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. Health.com, 2 Nov. 2017 The rare medical phenomenon is known as superfetation, in which a woman continues to ovulate after becoming pregnant. Char Adams, PEOPLE.com, 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
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. Health.com, 2 Nov. 2017 The rare medical phenomenon is known as superfetation, in which a woman continues to ovulate after becoming pregnant. Char Adams, PEOPLE.com, 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 Word History
Etymology
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
Medical Definition
superfetation
noun
su·per·fe·ta·tion
variants or chiefly British superfoetation
ˌsü-pər-fē-ˈtā-shən
: successive fertilization of two or more ova of different ovulations resulting in the presence of embryos of unlike ages in the same uterus