Womb Twin Survivors:

A research project about the sole survivors of a

twin or multiple pregnancy

Headed by Althea Hayton

What is a womb twin survivor?

The sole survivor of a

twin or multiple pregnancy

An ultrasound image of a twin pregnancy. The fetus at the top has died. The fetus below will

survive to be born alone.

What is a womb twin?

In a twin or multiple pregnancy one or more of the embryos or fetuses may die during the pregnancy or

around birth.

A womb twin has a very brief life: sometimes lasting only a few days

or weeks.

Some womb twins manage to survive until birth, but are stillborn.

1 in 10 people is a womb twin survivor

How do we know?

• 1 in 100 births is a twin birth• For every twin birth there are 10 womb twin survivors• That is 10% of the population!

Boklage, C. E. (1990). “Survival probability of human conceptions from fertilization to term." International Journal of Fertility 35(2): 75, 79-80, 81-94.

Are YOU a womb twin survivor?

The signs:

1. In your mother’s pregnancy

2. At your birth

3. In your body

Your mother’s pregnancy

Twinning - a brief introduction

Monozygotic twinning

Identical (monozygotic)twins formed from one zygote

Note: zygote = fertilised egg

Dizygotic twinning

Fraternal (dizygotic) twins formed from two zygotes

Note: zygote = fertilised egg

Multiples

Triplets, quadruplets or more, from three or more zygotes

Womb twin survivors can be:

• Monozygotic (MZ)

• Dizygotic (DZ)

• Multiple

The death of a twin before birth

More images like this: www.layyous.com

Uterus extra large in first trimester

One foetal heart stops beating

The “vanishing” twin on the ultrasound scan

The sac on the left is all that remains of the second twin

Bleeding in the first trimester

1 in 5 pregnant women experience first trimester bleeding and the pregnancy proceeds normally.

This can be a sign that one twin has died.

Trimester = 12 weeks

Ovulation stimulating hormones

Clomiphrene citrate is used to assist conception by stimulating the ovaries. This which causes hyperovulation, which often leads to twinning and the birth of twins.

Hyper-ovulation = the production of more than one egg a month by the ovaries

More than one embryo implanted after IVF

After in-vitro fertilization and the re-introduction of several embryos back into the womb, it is not unusual for more than one embryo to implant and begin to grow. In many cases, one or more of these will die after a few

days or weeks.

Embryo = an un-born child less than 12 weeks from conception

Miscarriage, but pregnancy continues normally

When a mother miscarries her baby, and the fetus is completely expelled with a lot of bleeding, it looks as if the pregnancy is over - but sometimes she remains pregnant and a baby is born after all: in that case, she had been carrying twins.

Abortion, but pregnancy continues

A miscarriage is induced but the pregnancy continues, leading to one live birth. This is not a “failed” abortion because the mother had been carrying twins: rather, it is a

partial abortion.

Multi-fetal pregnancy reduction

The number of fetuses in a multiple pregnancy is reduced by selective abortion of one or more of them. The survivor is born alone, along with the shrivelled remains of the others.

Quads or more may be reduced to triplets; triplets to twins, or twins to one baby.

At birth

One twin stillborn

One twin may die in the process of being born, or may have already died in the womb before the time of birth.

The birth of an acardiac twin

One twin may not develop vital organs, such as a heart (acardiac) kidneys or a proper skeleton. The mis-shaped body of the twin will be delivered along with the sole survivor. The body may be attached to the survivor’s placenta or delivered separately. An ultrasound image

of twins, one of them acardiac.

A fetus papyraceousThe fetus papyraceous is the name given to the tiny body of a dead twin, whose body remains in the womb attached to the placenta of the sole survivor. It may be embedded in the placenta and scarcely visible. In this case it is clearly seen, but a fetus papyraceous can be missed if the placenta is not carefully examined after

delivery.

Body of the dead twin

Placenta after delivery

Additional cords or sacs

When the placenta is examined after delivery, an additional umbilical cord, with or without an empty sac, or may be seen. This cord or sac belonged to a twin, who died in the first 10 weeks of life. This was before the skeleton was formed so the body disintegrated and was soon resorbed.

Resorb = to remove cells, a tissue or structure by gradual breakdown into the component materials and disperse into the circulation

In the body of the sole survivor

Parasitic twin

Illustration of an adult man with a parasitic twin from “Monstrorum Historia Memorabilis” by Johann Schenk, 1609

A parasitic twin is formed when a zygote split into a monozygotic twin pair more than 14 days after conception. One twin remains attached to the other. If the parasitic twin is surgically removed, then the individual becomes a half-twin: a womb twin survivor.

The fetus in fetu

If a parasitic twin develops within the body of the other, this is known as a fetus in fetu. At birth, or many years later, the parastic fetus may cause problems, and is surgically removed. After removal, the surviving twin is alone - a womb twin

survivor.

Fetus in fetu = a fetus inside a fetus

TeratomaA teratoma is formed when a parasitic twn begins to develop with the body of the other, but only some tissues form properly. In this example the outer membranes have been removed to reveal, a few teeth, some fatty tissue and a piece

of bone.

Dermoid cyst

Inside the cyst

When a parasitic twin develops inside the other twin, the result is a dermoid cyst. Within it there are no recognisable tissues. In this example there is some hair to be seen. Dermoid cysts can be found anywhere in the body, often on one of the ovaries. In this example the cyst is visible just under the skin, on the jaw.

Signs of the opposite sex

A man

A woman

QuickTime™ and a decompressor

are needed to see this picture.

QuickTime™ and a decompressor

are needed to see this picture.

QuickTime™ and a decompressor

are needed to see this picture.

When a dizygotic, opposite-sex twin dies before birth, an additional dose of hormones passes into the body of the DZ

womb twin survivor.

Cerebral palsy

Pharoah, P. O. and Y. Dundar (2009). "Monozygotic twinning, cerebral palsy and congenital anomalies." Hum Reprod Update 15(6): 639-48.

The incidence of cerebral palsy and some other congenital abnormalities has been strongly associated with the loss of a monozygotic twin in the first few weeks of life.

Left-handedness

Left-handedness has been associated with the loss of a monozygotic “mirror” twin early in life.

“Mirror” twins are monozygotic twins who are like mirror images of each other, one left-handed, one right handed.

If you have none of these signs…

But you feel sure you are a womb twin survivor, you still could be. The loss of

a twin before birth often goes undetected by everyone involved.

There is help available….

Womb Twin Survivors

Find out more

http://www.wombtwinsurvivors.com

http://WombTwinSurvivors.blogspot.com