Superfetation in Humans - Myth or Reality?

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REPRODUCTIONREPRODUCTIONREPRODUCTION
AND SEXUAL HEALTH (JRSH)AND SEXUAL HEALTH (JRSH)AND SEXUAL HEALTH (JRSH)
JournalJournalJournalof
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Official Publication of Delta Reproductive
Health Initiative & Research Centre
JRSH
ISSN:2489-0294
Journal of Reproduction & Sexual Health
Michael Ibobo Enemuwe (Nigeria)
Editor-in-Chief
Lawrence O. Omo-Aghoja (Nigeria)
Deputy Editor-in-Chief
Christopher O Aimakhu (Nigeria)
Scientific Editors
Emmanuel I. Odokuma (Nigeria)
Ikechukwu Awunor (Nigeria)
Vivian Omo-Aghoja (Nigeria)
International Desk Editors
Mudiaga Zini (UK)
Osaretin V Aghedo (Amsterdam)
Friday E. Okonofua
Akinyinka Omigbodun
Rudolp K. Adaegba
Bissallah Ekele
Yao Kwawukume
Thomas Agan
Paul Feyi-Waboso
Anthony Okpani
Silke Dyer
Joseph D. Seffah
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Uchenna I. Nwagha
Michael E. Aziken
King David Terna Yawe
Charles O. Eregie
OUJ Umeora
Josiah Muthir
Innocent A.O. Ujah
EJC Nwanna
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Journal of Reproduction & Sexual Health Vol.1 No. 1 June 2017 ISSN:2489-0294
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Focus and Scope
The Journal of Reproduction and Sexual Health
(JRSH) is an international and multi-disciplinary
journal published on a biannual basis by Delta
Reproductive Health Initiative and Research Centre,
Nigeria. It provides a platform for researchers working
in Nigeria, Africa and other continents of the world to
share and publish their research findings in the field of
human reproduction (including clinical and basic
sciences perspectives) and sexual health. The journal
will publish original research articles, reviews,
editorials, commentaries, short reports, case reports
and letters to the editor. Articles are welcome in areas
directly and remotely related to reproduction and
sexual health including maternal and child health
issues, adolescent reproductive health and andrology.
Social science researchers are also invited to submit
articles that document the backg round and
intermediating sociocultural factors that impact on
reproduction and sexual health globally and
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This journal will be published biannually in the months
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publication should be addressed to:
Lawrence Omo-Aghoja
Editor-in-Chief,
Professor of Obstetrics & Gynecology,
Chair, Infertility & Reproductive
Endocrinology,
Faculty of Clinical Medicine,
College of Health Sciences,
Delta State University, Abraka, Nigeria;
JRSH, Delta Reproductive Health Initiative,
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Chris Aimakhu
Editor,
Department of Obstetrics & Gynecology,
College of Medicine, University of Ibadan,
Ibadan, Nigeria
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General information
Journal of Reproduction & Sexual Health Vol.1 No. 1 June 2017 ISSN:2489-0294
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Ÿ Okonofua FE, Ako-Nai KA, Dighitoghi MD. Lower
genital tract infections in infertile Nigerian women
compared with controls. Genitourin Med 1995;
71:163-168.
Ÿ Moore DE, Cates W. Sexually transmitted disease
and infertility. In: Holmes KK, Mardh PA, Sparling PF,
Wiesner PJ (eds). Sexually Transmitted Diseases. New
York: McGraw-Hill, 1990; 763-771.
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publication remain the property of the journal and can
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Journal of Reproduction & Sexual Health Vol.1 No. 1 June 2017 ISSN:2489-0294
Official Publication of Delta Reproductive
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JRSH

Editorial MessageEditorial MessageEditorial Message
Prof. Lawrence Omo-Aghoja
Executive Director (DERHIREC) & Editor-in-Chief
v
Journal of Reproduction & Sexual Health Vol.1 No. 1 June 2017 ISSN:2489-0294
n behalf of the team of Delta
OReproductive Health Initiative
and Research Centre (DERHI-
REC) Sapele, Nigeria, I proudly unveil and
present the maiden edition of the journal of
Reproduction and Sexual Health (JRSH)
which is in keeping with one of our core
mandate of documentation and publication
in sexual and reproductive health.
The overall goal of the JRSH is to provide a
platform for Researchers working in Nigeria,
Africa and other continents of the world to
share and publish their research findings in
the field of human reproduction (including
clinical and basic sciences perspectives) and
sexual health. Additionally, Researchers
working in areas directly and remotely related
to reproduction and sexual health including
maternal and child health issues, adolescent
reproductive health and andrology, as well as
social science Researchers working on the
background and intermediating sociocultural
factors that impact on reproduction and
sexual health globally and particularly in
developing countries are welcomed to
document their findings through JRSH.
In line with our cardinal objectives of
exhibiting and maintaining excellence at all
material times, DERHIREC team has
painstakingly put together seasoned experts
into the Editorial Board of JRSH and
assembled an array of international
personalities as Editorial Consultants who
shall ensure international best practices in
Journal publication. The journal like our earlier
bestselling textbook of infertility and assisted
conception in the tropics, shall be of extremely high
quality in terms of content and form.
Beyond publishing different types of articles,
a section of the journal shall be devoted to
bringing to the fore newest development and
issues in the field of sexual and reproductive
health, and human reproduction in general. It
is our hope that Researchers particularly
budding academics in Africa and developing
nations will find this aspects stimulating and
rewarding to furthering their research career.
In this maiden issue we have an original
article, and a case report. But significantly, a
huge number of the papers in this edition
have been devoted to review articles in topical
aspects of sexual and reproductive health in
Africa and Nigeria, and will provide clearer
understanding in these areas to the reading
audience.
Finally, I therefore solicit and welcome
submissions to this biannual journal with
expeditious review process in good time.
www.derhirec.org.ng
Official Publication of Delta Reproductive
Health Initiative & Research Centre
JRSH

Editorial
Superfetation in Humans - Myth or Reality?
Superfetation is the simultaneous occurrence of more
than one stage of developing offsprings in the same
animal. In mammals, it manifests as the formation of
an embryo from a different estrous cycle while another
embryo or fetus is already present in the uterus.
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 estrous cycle continues through
[1,2,3]
pregnancy.
Superfetation in humans is an extremely rare situation
in which a woman becomes pregnant a second time
with another (younger) fetus in the face of an ongoing
[1]
pregnancy. It is characterized by the fertilization and
the implantation of a second oocyte in a uterus already
containing the product of a previous conception.
Superfetation is different from the process of twinning
or multiple gestation and involves the conception of an
additional fetus during an established pregnancy. With
superfetation, the two fetuses have different
[4]
gestational ages and due dates. It can occur in some
animals but is so rare in humans that fewer than 10
cases have been reported in the medical literature.
Superfetation should not be confused with situations
in which two separate instances of fertilisation occur
during the same menstrual cycle, and this latter
scenario is known as superfecundation. The risk with
superfetation in humans is that the second baby is
often born prematurely, which can increase its odds of
[5]
experiencing lung development problems.
Animals that have been claimed to be subject to
superfetation include rodents (mice and rats), rabbits,
horse, sheep, marsupials (kangaroos and sugar gliders),
felines, and primates (humans). Superfetation has also
been clearly demonstrated and is normal for some
[1]
species of poeciliid fishes.
In humans, reports of superfetation occurring long
after the first impregnation have often been treated
with suspicion, and some have been clearly discredited.
Ot her ex pl anation s have been give n (and
demonstrated) for different levels of development
between twins. Artificially induced superfetation has,
however, been demonstrated, although only up to a
[6]
short period after insemination.
The arg ume nt t heref ore rem ain s wh eth er
superfetation in humans is a myth or reality? What
makes the situation more challenging is that cases of
superfetation "can only be confirmed after delivery by
[5]
chromosomal and metabolic studies on the baby."
The query therefore is how Well-Documented are
Cases of Superfetation?
While not every story can be considered reliable,
superfetation seems to have occurred in a number of
well-documented cases, and the case scenarios below
are therefore insightful.
Case reports
In 1960, John and Mary Tress of Baltimore MD had
what the nurse mistakenly identified as twins. 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. Anthony was a two-month premature baby
born five minutes before his full-term brother Mark.
Anthony was conceived a full two months after his
[7]
brother Mark.
1 2
Omo-Aghoja LO, Zini M
1Department of Obstetrics and Gynecology, Faculty of Clinical Medicine, College of Health Sciences, Delta State University,
Abraka, Nigeria;
2Epsom and St. Helier NHS Trust, London, UK.
Background
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Superfetation in Humans - Myth or Reality?
Journal of Reproduction & Sexual Health Vol.1 No. 1 June 2017 ISSN:2489-0294

In 2007, Ame and Lia Herrity, conceived three weeks
apart, were born in the United Kingdom to Amelia
[8]
Spence and George Herrity.
In May 2007, Harriet and Thomas Mullineux, also
conceived three weeks apart, were born in Benfleet,
[9]
Essex, to Charlotte and Matt Mullineux. She had been
told she was carrying twins, only to learn that one twin
had been miscarried and was being reabsorbed by her
body (an uncommon but not rare phenomenon known
as vanishing twin syndrome). One of her early
ultrasound examinations had revealed a small blob of
tissue in addition to the twins, but no importance had
been attached to the observation. Ms. Mullineux was
told to undergo another ultrasound a couple of weeks
later, by which time it was clear that the little blob that
had been observed in the previous ultrasound was
growing into a baby!
In 2009, Todd and Julia Grovenburg of Fort Smith,
Arkansas, received international media attention for
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. Both healthy babies were
delivered through Caesarean section on 2 December
[[10,11,12]
2009.
In 2015, Kate and Peter Hill, from Brisbane, Australia,
conceived two baby girls 10 days apart. What makes
this case more rare - the couple had only a single
[13]
intercourse prior to the two conceptions.
Discussion
If you are pregnant, is it possible to become pregnant
again? It sounds impossible, but it can and does
happen, although it may happen only once out of a few
million pregnancies. Superfetation is when an
additional fetus is conceived days or even weeks after
its “elder” sibling. Such babies usually share a birthday,
as it is medically necessary in most cases to induce
labor or to deliver them by C-section, but gestationally,
one baby is “older” than the other.
Superfetation is much more common in the animal
kingdom - among mammals it is well documented in
badgers, buffalo, mink, and panthers - but it is nearly
unheard - of in humans, which leads some to question
[1,14]
whether it can reliably be said ever to happen at all.
The phenomenon of superfetation in animals has long
been speculated as far back as the fourth century B.C
by Aristotle. Aristotle came to this thought when he
observed that hares often gave birth to litters which
comprised sets of healthy and imperfect offsprings.
He deduced that the imperfect offsprings were
younger ones who had spent less time in their mother's
womb - a direct consequence of superfetation. In
effect, Aristotle was supposing that the younger
offsprings were from a litter which was the result of
[15]
the second pregnancy.
To characterize superfetation in humans as “rare”
would be to understate how unusual the phenomenon
truly is. Only about ten cases of superfetation are
documented in the medical literature, and experts are
suspicious of some of these documented cases.
On the other hand, many experts admit that it cannot
be known for certain exactly how often superfetation
occurs (if it occurs), as it is unlikely that every
occurrence is detected and reported; some cases of
superfetation may be mistaken for ordinary twin
pregnancies. The discrepancy in apparent gestational
age (and size) may in some cases be ascribed to a
medical condition such as twin-to-twin transfusion
syndrome, a condition in which one of a pair of twins
who share a placenta (most twins do not) consumes a
larger share of the nourishment provided by the
placenta due to abnormal formation of important
blood-vessel connections. This results in one twin
being larger than the other, although in these cases they
are always identical twins, while in cases of
[16]
superfetation the two babies can never be identical.
This discrepancy in apparent gestational age and size
between twins is known as growth discordance.
Growth discordance is not uncommon; as noted
above, it can be caused by twin-to-twin transfusion
syndrome. Other possible causes of growth
discordance include congenital infection and
chromosomal abnormalities. With fraternal twins, it
can literally just be the “luck of the draw” since
genetically some babies are programmed to be bigger
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Superfetation in Humans - Myth or Reality?
Journal of Reproduction & Sexual Health Vol.1 No. 1 June 2017 ISSN:2489-0294

or smaller at birth than others.
A critical question that must therefore be asked at this
junction, is that “Is Superfetation Medically Possible?”
Some scientists are still sceptical about whether
superfetation occurs at all, and believe there must be
some other explanation for cases in which it appears to
have happened. Ordinarily, physical and hormonal
changes occur after conception that make additional
conceptions impossible while the first pregnancy is
ongoing.
First and most important, once a woman becomes
pregnant, ovulation stops. After conception occurs in a
normal pregnancy, the corpus luteum (and later the
baby's placenta) releases hormones that stop further
ovulation. Also, the lining of the uterus thickens in a
way that should prevent a second embryo from
attaching itself. Finally, the cervix forms a barrier
known as the mucus plug, which is designed to protect
the developing fetus from microbes that might make
their way into the uterus from the outside world. Just as
it prevents microbial infection, the mucus plug is also
[14,16]
an effective barrier to sperm.
To sum up all of the above: superfetation is so unlikely
because three near-impossible things need to happen
in order for it to occur: Ovulation must occur while a
woman is already pregnant, Sperm must somehow
make it past the mucus plug and Implantation must
occur in a uterus that is no longer prepared for it. The
odds of all three of them happening are without doubt
extremely small as reflected by the very occasional
reports of superfetation in humans in the medical
literature. Therefore the debates will certainly persist in
the coming years ahead.
References
1. Roellig KL, Menzies BR, Hildebrandt TB, Goeritz
F. The concept of superfetation: a critical review
on a 'myth' in mammalian reproduction. Biol Rev
Camb Philos Soc. 2011 Feb;86(1):77-95.
2. Ibrahim UN, Dauda M, Khan N, Okon IE.
Superfetation in a double uterus - A case report.
Niger Med J 2009;50:52-3.
3. Singhai S. R., Agarwal U., Sharma D., Sen J.
Superfetation in uterus pseudo didelphys: an
unreported event Arch Gynecol Obstet 2003;
268(3): 243-4.
4. Tuppen, G.D., Fairs, C., de Chazal, R.C. & Konje,
J.C. Spontaneous superfetation diagnosed in the
first trimester with successful outcome.
Ultrasound in Obstetrics and Gynecology 14,
219-221 (1999).
5. Jacob Stephanie (September 2009). “Superfetati
on Double Pregnancy”. AOL Health. Retrieved 1
September 2009.
6. Baijal N, Sahni M, Verma N, KumarA, Parkhe N,
Puliyel JM. Discordant twins with the smaller
baby appropriate for gestational age-unusual
manifestation of superfetation: a case report.
BMC Paeditr 2007-,197: 2.
7. Newsweek Magazine, 31 July. 1961. This rare case
is called *superfetation* http://-en.wiki
pedia.org/wiki/Superfetation.
8. “Mother Deliveries Babies Minutes Apart but
They are Not Twins!", Medindia, 1 October
2007. This rare case is called *superfetation*
http://en.wikipedia.org/wiki-/-Superfeta tion.
9. Hale, Beth. "The babies born just a minute apart
who AREN'T twins", The D aily Mail,
Associated Newspapers, Ltd, 15 January 2008.
This rare case is called *superfetation*
http://en.wikipedia.org/wiki/Superfetation
10. Pape O et al. Pregnant and Pregnant Again:
Superfetation J Gynecol Obstet Biol Reprod
(Paris) 2008; 37(8): 791-95.
11. Rabinerson D et al. Pregnant and Pregnant Again:
Superfetation Harefuah 2008; 147(2): 155-58.
12. Van Sipma, Ashley (1 July 2011). "I got pregnant
while I was already pregnant! Woman gives birth
to two babies on the same day but they are NOT
twins". MailOnline. Archived from the original
on 1 November 2011. Retrieved 1 November
2011.
13. Barns, Sarah "A WOMAN has conceived two
baby girls 10 days apart." The Sun. This rare case
is called *superfetation* http:// en.wikip
edia.org/wiki/Superfetation
14. Roellig, K., Goeritz, F., Fickel, J., Hermes, R.,
Hofer, H. & Hilderbrandt, T.B. Superfetation in
03
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Superfetation in Humans - Myth or Reality?

mammalian pregnancy can be detected and
increases reproductive output per breeding
season. Nature Communications. 2010; 1:78.
15. Cassimally, K. "Superfetation: Pregnant while
already pregnant." Scientific American. Accessed
January 7, 2016. Http://blogs. Scientific-
am erica n. com/g ue st-bl og /superf etation -
pregnant-while-already-pregnant.
16. Harrison, A., Valenzuela, A., Gardner, J., Sargent,
M. & Chessex, P. Superfetation as a cause of
growth discordance in a multiple pregnancy. The
Journal of Pediatrics. 2005 147:2, 254-255.
Citation
This article should be cited as: “Omo-Aghoja
LO, Zini M. Superfetation in humans myth
or reality?. J. Reprod. & Sex. Health 2017; 1
(1): 1-4”.
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Journal of Reproduction & Sexual Health Vol.1 No. 1 June 2017 ISSN:2489-0294
Superfetation in Humans - Myth or Reality?

The Official Publication of Delta Reproductive Health
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