1. What are the twins?
twins are two offspring resulting from the same pregnancy, usually born in close succession.
They can be the same or different sex.

2. Three Types of twins

3. stages of twin formation
As off springs reproduced by fertilization
the fertilized egg, now called a zygote divides one time, resulting in two cells.
By the sixth day after fertilization, the zygote implants itself in the uterine wall and continues to develop for nine months.
after implantation, the developing baby is called an embryo.
Around week nine of development, it is called a fetus
Now we know and twins are formed

4. facts about twins
twins are more common in African American families, and they are least common in the families of Hispanics and Asians.
Male–female twins are the most common result, about 50 percent and the most common grouping of twins.

5. 1)identical twins three main types of twins:
identical twins :occur when a single egg is fertilized to form identical which then divides into two separate embryos.
They have identical genes.
identical twins make up 1/3rd of all twins.

6. Its like looking like in a mirror Identical twins
identical twins, occur when a single egg is fertilized to form one zygote which then divides into two separate embryos.,
The two embryos develop into fetuses sharing the same womb. And two identical cells will result.
If the zygote splits after the first two days after fertilization each cell may develop separately its own placenta and its own sac.

7. Cases of Identical twins
The identical twins can be of separate placentas and separate sacs.
Separate placentas separate sacs

8. Cases of Identical twins
The twins share one placentas, and one amnion sac (rarest combination).

9. fraternal twins
fraternal twins:, usually occur when two fertilized eggs are implanted in the uterine wall at the same time. When two eggs are independently fertilized by two different sperm cells.
The two eggs,, form two zygotes,.
They have same or opposite sex and they don't have to look at all alike.
They have separate placentas

10. Facts about FRATERNAL twins
Africa sees the highest incidence of fraternal twins; Asia, the lowest.
Female fraternal twins have a one in 17 chance of giving birth to their own set of fraternal twins.

11. Risks of female twins
Recently, studies has shown attempt to illustrate when menopause and eating disorders occurs in twins. .
up to 5% of female twins had gone through menopause by age 40
up to 15% of female twins had experienced menopause by age 45
Female Twins have a tendency to share specific eating disorders

12. Conjoined twins
Conjoined twins are joined at some region of their bodies. The many different types of conjoined twins are classified by the area where the attachment is located:

13. How twins become conjoined?
It results when an embryo start to divide but fails to complete the process, and the result is not quite two children
The twins originate from a single fertilized egg, so they are always identical and of the same sex.
It is believed that the first 13th and 15th days after fertilization the malformation occurs

14. Facts about Conjoined twins
Joined twins occur in about one in 100,000 pregnancies

15. cases of Conjoined twins
Pygopagus - back-to-back, joined at the rump (about 19 percent)

16. cases of Conjoined twins
Ischiopagus - joined sacrum to sacrum (about six percent)

17. cases of Conjoined twins
Cephalopagus - connected at the head (about two percent)

18. cases of Conjoined twins
Dipygus - one upper body with two lower bodies (including the abdomen, pelvis and legs)

19. cases of Conjoined twins
Thoracopagus - joined at the chest; may share a single heart or have some cardiac connection; some organs in the abdominal region may be malformed (about 40 percent)

20. cases of Conjoined twins
Omphalopagus - joined at the chest (about 33 percent)

21. cases of Conjoined twins
Rachipagus - back-to-back, joined along the spine above the sacrum

22. Survival rate of conjoined twins
The overall survival rate of conjoined twins is somewhere between 5% and 25%.
If they have separate sets of organs, chances for surgery and survival are greater than if they share the same organs.
Conjoined twins are rare and have a poor survival rate

23. New form of twins discovered
There is another type of twinning that scientists are looking into, called polar body twinning, or "half identical" twinning. This occurs when the mother's egg splits before fertilization and then each half is then fertilized by a sperm. it hasn't been proven that it occurs, or that it would produce viable twins

24. Made by
Saba Nasir
Bahawalpur,Pakistan