Genetics and Environmental Factors influencing Twinning: Impact on public health and decison-making

1. 1
Genetics and Environmental
Factors Contributing to
Twinning: Impact on Public
Health Practices and Decision
Making
Presentation
by
Sulaimon Olawale
ARAROMI
Sulaimon Araromi B.Sc.

2. OUTLIN
E
• Introduction
• Concept of twinning
• Types of twinning
• Genetic factors contributing to twinning
• Environmental factors contributing to twinning
• Worldwide incidence of twin births
• Incidence of twinning in Nigeria
• Risks and impact of twinning on public health practice
• Public health interventions and decision making
• Challenges and future direction
• Conclusion
• References
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Sulaimon Araromi B.Sc.

3. INTRODUCTIO
N
Twinning, the occurrence of two or more offspring from a
single pregnancy, is influenced by both genetic and
environmental factors.
Twin studies help understand the relative importance of
environmental and genetic influences on individual traits
and behaviors.
This presentation explores the factors that contribute to
twinning and their implications for public health practice
and decision-making.
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Sulaimon Araromi B.Sc.

4. CONCEPT OF
TWINNING
• Twinning is a process whereby their is occurrence of
multiple pregnancies resulting in the birth of two or
more offspring at the same time.
• The phenomenon of two babies born in the same
pregnancy, has long been the subject of curiosity
since time immemorial.
• Scientists have documented the phenomenon of twin
or other multiple births as far back as the 1809s.
• There were two types of twins identified by Scottish
physician J Matthews Duncan in the 19th century.
• In 1875 Sir Francis Galton, cousin of Charles Darwin
has an idea that was based on the assumption that
twins can be used to study heritability of traits and
conditions, including intelligence, personality, mental
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Sulaimon Araromi B.Sc.

5. TYPES OF
TWINNING
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Sulaimon Araromi B.Sc.
(Images source: twinversity.com)

6. TYPES OF
TWINNING
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Sulaimon Araromi B.Sc.
(Images source: twinversity.com)

7. GENETIC FACTORS CONTRIBUTING TO
TWINNING
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• Variations in specific genes, such as the FSH receptor gene and SMAD3
genetic variant rs17293443, have been linked to a higher risk of twinning
(Anifowoshe et al.,2019).
• The FSHR gene codes for the follicle stimulating hormone receptor, which is
important in the control of the menstrual cycle and ovulation.
• Specific changes or polymorphisms in the FSHR gene can impair its activity,
resulting in the release of multiple eggs during ovulation.
• SMAD3 enhance the response of the Ovary to the FSH
• This egg release may enhance the likelihood of having fraternal (dizygotic)
Sulaimon Araromi B.Sc.

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(Image source: Bcm.edu)
Sulaimon Araromi B.Sc.

9. ENVIRONMENTAL FACTORS CONTRIBUTING TO
TWINNING
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Various environmental factors can influence twinning rates. Factors
such as:
• Advanced maternal age
• Parity
• Genetics & Family history
• Race and ethnicity
• Nutrition
• Use of fertility treatments e.g ART(Assisted Reproductive
Technologies) like IVF and IUI- intrauterine insemination, taking
drugs like Clomid and Gonadotrophins which stimulate ovulation.
Most of the factors, both genetic and environmental, mostly result in
Sulaimon Araromi B.Sc.

10. WORLDWIDE INCIDENCE OF TWIN
BIRTHS
• Since the 1980s, the global twinning rate has increased by one-third, from 9.1
to 12.0 twin deliveries per 1000 deliveries, resulting in around 1.6 million twin
pairs per year.
• Natural twinning rates were already known to be low in East Asia and South
America in the 1980s, intermediate in Europe and North America, and high in
several African countries (Christiaan Monden et al., 2021).
• In a study, many countries in Europe, North America, and Asia have seen
significant rises in twinning rates. The rise was above 10 percent in 74 of
the 112 countries studied.
• Africa continues to have the greatest twinning rates, but Europe, North America,
and Oceania are coming up quickly. 10
Sulaimon Araromi B.Sc.

11. INCIDENCE OF TWINNING IN
NIGERIA
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• According to studies, Nigeria has the greatest rate of twinning among
African countries, with the exception of Benin Republic (Anifowoshe et
al., 2019).
• The frequency of twinning in Nigeria was found to be 6,070 out of
189,178 total births, with 32.1 twins born per 1,000 deliveries.
• The Yoruba ethnic group in Southwestern Nigeria has a twinning rate of
68.1/1000 births, 21.1/1000 births from Kano, 26.5/1000 births from
Calabar, and 28/1000 births from Jos (Mosoro, 1996; Adewale et al.,
Sulaimon Araromi B.Sc.

12. INCIDENCE OF TWINNING IN
NIGERIA
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• Igbo-Ora, a town in Oyo state, has been known as the "Twin Capital of the
World" due to an unusually high incidence of twin births.
• The town has an estimated 50 sets of twins per 1,000 live births, which is
approximately ten times the global average of around 5 sets per 1,000 live
births.
• According to research, the many births may be caused by the diets of
the women in the town. It is believed that Yam and Okra leaves soup
consumed by women in Igbo-Ora influence their multiple births.
• There is no scientific justification yet for the eating habit and numerous
Sulaimon Araromi B.Sc.

13. RISKS & IMPACT OF TWINNING ON PUBLIC HEALTH
PRACTICE
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Twin or multiple births have a variety of medical, healthcare, socio-emotional,
psychological, and developmental implications and consequences for families,
healthcare providers, and society as a whole.
Some of these risks and impacts are listed below:
• Intensive prenatal care
• Gestational diabetes (for the mother)
• Risk in labor and delivery
• Neonatal complications such as preterm birth and low birth weight
• Perinatal morbidity and mortality
• Hypertension
• Preeclampsia
• Acute polyhydramnios
(Esteves-Pereira AP et al.,2021; Ionio, C et al.,2019)
Sulaimon Araromi B.Sc

14. PUBLIC HEALTH INTERVENTIONS AND DECISION
MAKING
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By considering the genetic and environmental factors and also considering
the risks associated with twinning, public health policy makers can develop
targeted interventions to support families with twins, enhance maternal
and child health , and promote healthy development.
Here are some key areas where public health can intervene:
• Education and awareness
• Prenatal screening and monitoring
• Access to quality healthcare services
• Evidence based guideline and protocols specific to twin pregnancies
• Health provider training and education
• Support networks and resources
• Data collection and research
Sulaimon Araromi B.Sc.

15. CHALLENGES AND FUTURE
DIRECTIONS
• Despite advances in our understanding of twinning, there are still
problems. Factors such as restricted access to specialized treatment,
socioeconomic inequality, and the possible long-term health effects for
twins all need to be addressed further.
• Future directions should focus on addressing these problems through
interdisciplinary collaboration, promoting equal access to care, and
performing extensive research to study the impacts of twinning.
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Sulaimon Araromi B.Sc.

16. CONCLUSIO
N
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A complex interaction of genetic and environmental factors
influences twinning. Understanding these determinants is essential
for public health practitioners and policymakers who want to
formulate and implement successful policies to promote the health
and well-being of twins and their families. We may improve public
health practice and decision-making in this critical area by
considering the special requirements of twins, implementing
evidence-based interventions, and supporting research and
Sulaimon Araromi B.Sc.

17. REFERENCES
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• Abass, Anifowoshe. (2019). Frequency of Twinning in Nigeria: A Review. 78-88.
• Adewale FB, Ashimi A, Oyewopo OA. Trends of multiple birth at federal medical centre bida, Northcentral Nigeria.
Trop J Obstet Gynaecol [serial online] 2018 [cited 2023 Jul 5];35:68-72. Available from:
https://www.tjogonline.com/text.asp?2018/35/1/68/229864
• Bassey EA, Abastsiattai AM, Udoma EJ, Asuquo EE. Outcome of twin pregnancy in Calabar Nigeria. J Med Sci
2004;3:13–5.
• Burbridge D. Francis Galton on twins, heredity and social class. Br J Hist Sci. 2001 Sep;34(122 Pt 3):323-40. doi:
10.1017/s0007087401004332. PMID: 11700679.
• Eriksson AW, Fellman J. Seasonal variation of livebirths, stillbirths, extramarital births and twin maternities in
Switzerland. Twin Res 2000;3: 189–201.
• Esteves-Pereira AP, da Cunha AJLA, Nakamura-Pereira M, Moreira ME, Domingues RMsm, et al. (2021) Twin pregnancy
and perinatal outcomes: Data from ‘Birth in Brazil Study’. PLOS ONE 16(1): e0245152.
https://doi.org/10.1371/journal.pone.0245152
• Francis G. Inquiries into Human Faculty and its Development. London: Macmilan & Co; 1875. History of Twins; pp.
155–73. [Google Scholar]
• Ionio, C., Mascheroni, E., Colombo, C., & Lista, G. (2019). Prenatal Attachment in Twin Pregnancy. IntechOpen. doi:
10.5772/intechopen.79365
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Sulaimon Araromi B.Sc.