Superfetation
Superfetation , over-fertilization (lat .: Superfetatio ) or Doppelträchtigkeit refers to a phenomenon that different species in reproduction occurs (eg. B. Hare , Cat and Heterandria Formosa ). In the case of the females of the hares, pregnancy is doubled in exceptional cases . H. an already pregnant rabbit can be fertilized again before she has set. Cats have a 10% chance of becoming “over-fertilized”. In contrast, superfetation is the normal case in pygmy carvings giving birth. As a result, the females of this species can give birth to up to 30 young, depending on their age and body size, within a "litter cycle" of approx. 4 weeks, almost as many as the significantly larger (fully grown) females of related species such as metal carrion , guppy or platy at a litter.
In humans, superfetation is usually unlikely, since the hormone level in the body changes within a maximum of 24 hours after ovulation so that no further ovulation is possible. A second ovulation is only possible shortly after the first, which can then lead to dizygotic twins . But since in this case there is no pregnancy (only a fertilized egg is on its way to the uterus), this is not a superfetation, but a superfecundatio .
Even so, a woman in the United States was diagnosed with superfetation in 2009. Two eggs were fertilized independently within one cycle, resulting in two fetuses of different ages. The planned birth dates were December 24th and January 10th, but both babies were born by caesarean section on the same day (December 2nd).
Individual evidence
- ↑ Kathleen Roellig, Frank Goeritz, Joerns Fickel, Robert Hermes, Heribert Hofer, Thomas B. Hildebrandt: Superconception in mammalian pregnancy can be detected and increases reproductive output per breeding season . In: Nature Communications . tape 1 , September 21, 2010, ISSN 2041-1723 , p. 78 , doi : 10.1038 / ncomms1079 , PMID 20865801 .
- ↑ Woman falls pregnant TWICE in a fortnight after scan reveals two fetuses… who aren't twins . dailymail.co.uk
- ↑ Ashley Van Sipma: I got pregnant while I was already pregnant! Woman gives birth to two babies on the same day but they are NOT twins . dailymail.co.uk, July 1, 2011; accessed March 14, 2014.