- Superfetation
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Superfetation (also spelt superfoetation - see fetus) is the simultaneous occurrence of more than one stage of developing embryo in the same animal. In mammals it manifests as the formation of a fetus from a different menstrual cycle while another embryo is already present in the uterus. When there are two separate instances of fertilisation during the same cycle, it is known as superfecundation.
Superfetation is claimed to be common in some species of animals, but is extremely rare in humans. In mammals it can occur only where there are two uteri, or where the menstrual cycle continues through pregnancy. The risk with superfetation is that the second baby is often born prematurely, which can increase its odds of experiencing lung development problems.[1]
Contents
In animals
Animals that have been claimed to be subject to superfetation include rodents (mice and rats), farm animals (horses and sheep), marsupials (kangaroos and sugar gliders), and primates (humans). Superfetation has also been clearly demonstrated in poeciliid fish [2]
In humans
Reports of superfetation occurring long after the first impregnation have often been treated with suspicion, and some have been clearly discredited. Other explanations have been given (and demonstrated) for different levels of development between twins. Artificially induced superfetation has, however, been demonstrated, although only up to a short period after insemination. In 1960, John and Mary Tress of Baltimore MD had what the nurse called twins, she was wrong. Dr Paul C Weinberg of Mt.Sinai hospital delivered the boys Anthony John and Mark Francis and realized that Anthony born five minutes before his brother Mark looked premature. Immediately Dr Weinberg did x-rays of the boys thigh bones and noticed a disparity in bone age. Mark a full term baby born five minutes after his 2 months premature brother Anthony. Anthony was conceived a full 2 months after his brother Mark, {Newsweek Magazine, July 31. 1961} In 1992, Taylor and Evan Barth, conceived 4 weeks apart, were born in Hawaii, USA to Michelle and John Barth. Taylor, the one conceived later was born first.[citation needed]
In 2007 Ame and Lia Herrity, conceived 3 weeks apart, were born in the United Kingdom to Amelia Spence and George Herrity.[3]
In May 2007 Harriet and Thomas Mullineux, also conceived 3 weeks apart, were born in Benfleet, Essex, UK to Charlotte and Matt Mullineux.[4]
In 2009, Todd and Julia Grovenburg of Fort Smith, Arkansas received international media attention for Mrs. Grovenburg's conception of an additional child while already pregnant with a child conceived two and a half weeks earlier. If it were possible to carry both children to term, the birth of the first child would be expected in December 2009, whereas the second child would be due in January 2010.[5][6] Grovenburg's obstetrician reported that cases of superfetation "can only be confirmed after delivery by chromosomal and metabolic studies on the baby."[7] Both healthy babies were delivered through Caesarean section on 2 December 2010.[8]
References
- ^ Jacob, Stephanie (September 2009). "Superfetation Double Pregnancy". AOL Health. http://www.aolhealth.com/condition-center/pregnancy/superfetation-double-pregnancy. Retrieved September 2009.
- ^ FishBase's glossary.
- ^ "Mother Deliveries Babies Minutes Apart but They are Not Twins!", Medindia, 1 October 2007.
- ^ Hale, Beth. "The babies born just a minute apart who AREN'T twins", The Daily Mail, Associated Newspapers, Ltd., 15 January 2008.
- ^ ABC News: Arkansas Pregnant Woman Is Pregnant Again.
- ^ Allen, Nick. "Pregnant woman conceives second child", The Daily Telegraph, 24 September 2009.
- ^ Jacob, Stephanie (September 2009). "Superfetation Double Pregnancy". AOL Health. http://www.aolhealth.com/condition-center/pregnancy/superfetation-double-pregnancy. Retrieved September 2009.
- ^ van Sipma, Ashley (2011-07-01). "I got pregnant while I was already pregnant! Woman gives birth to two babies on the same day but they are NOT twins". MailOnline. MailOnline. Archived from the original on 2011-11-01. http://www.webcitation.org/62sURRryk. Retrieved 2011-11-01.
External links
- Superfetation in Beef Cattle Cattle Doctoral Thesis; Joel Andrew Carter, Louisiana State University, Defended 2002-03-18
- Superfetation in fish
- A case of twins with probable superfetation a report of a case of superfetation demonstrated through different paternity of twins.
Categories:- Reproduction
- Multiple births
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