1. BY:
NURUL HIDAYAH BT MANSOR
HILDA ANAK EMAK
AMIRAH BT SHAARI
AIN NAJWA BT AMRAN
Chapter 3 :
development of
zygote
2. STEP 1 : GROUP SETTING
Our group
consist of 5
members
chosen by
ourself
This is our group’s
member
Ain Najwa Bt AmranHilda anak Emak
Lee Yian Ping
Amirah Bt ShaariNurul Hidayah Bt Mansor
3. HOW TWINS ARE FORM?
Twins are two offspring resulting from
the same pregnancy. The twins can be
the same or different sex which mean
they can either be monozygotic
(identical) or dizygotic or (non-identical).
5. MONOZYGOTIC TWINS
Come from one zygote
Identical twins
DIZYGOTIC TWINS
• Come from two zygotes
• Non-identical @ fraternal twins
6. HALF TWIN
Semi-identical twin
Have the same genes from the mother
but different genes from the father
CONJOINED TWIN
• Many complication resulting of shared
organ
• Occur when the division later than 8
days
7. DEVELOPMENT OF
IDENTICAL TWIN!!
Firstly is the union of 1 sperm 1 ovum.
After the sperm fertilized the ovum, cell division
occur. Then, it undergoes cleavage.
The cell is divided into 2 cell. Each of the 2 cell
then continued divided respectively into
morula.
The morula enter the uterus and develops a
central cavity. This structure known as
blastocyst. The blastocyst attached to the
uterine wall to begin the process of
implantation.
8. Once the cleavage is complete,
gastrulation stage is started.
The primary germ layers are organized
into 3 layers :
~ The external layer is called ectoderm
~ The middle layer is called mesoderm
~ The most internal layer is called
endoderm
The gastrulation followed by
organogenesis.
9. Monozygotic twins develop in 3
ways :
1 placenta and 2 amniotic sac
( mono-chorial and bi-amniotic)
Only 1 placenta and 1 amniotic sacs (
mono-chorial and mono-amniotic)
2 placenta and 2 amniotic sacs
(bi-chorial and bi-amniotic)
10. 1 PLACENTA AND 2 AMNIOTIC SACS
(MONO-CHORIAL AND BI-AMNIOTIC)
The inner cell mass of blastocyte split
completely before the blastocyte has
fully defined the roles of each type of
cells.
Because there are 2 inner cell mass,
hence there are 2 amniotic cell in 1
placenta.
11. ONLY 1 PLACENTA AND 1 AMNIOTIC SACS
( MONO-CHORIAL AND MONO-AMNIOTIC)
After implantation, the inner cell mass
splitted into epiblast and hypoblast.
The fluid-filled space created by the
separation becomes the amniotic
cavity.
The epiblast develop into amniotic
sacs while the hypoblast divide into 2
embryo.
12. 2 PLACENTA AND 2 AMNIOTIC SACS
( BI-CHORIAL AND BI-AMNIOTIC)
The blastocyte splitting at 2-cell stage
form :
The inner cell mass will develop into
embryo itself.
the outer single layer of cells then form
tropoblast. Then tropoblast develop into
placenta.
Because there are 2 blastocyte, they will
be 2 placenta and 2 separate amniotic
sacs.
13. DEVELOPMENT OF NON-
IDENTICAL TWINS
Fertilization of 2 different oocyte by 2
different sperms.
2 separate pregnancy occur at the same
time forming 2 different amniotic sacs
and 2 different placenta.
So, the embryo is non-identical.
14. Aspect Identical twins Non-identical twins
fertilization One sperm and one
ovum
Two separate eggs and
two separate
spermatozoa
Formation of zygote Eggs divide into two
embryo
Each egg divide into one
embryo respectively
Genetic constitution
(chromosomes)
Exactly the same Different
Number of placenta One or two two
Number of amniotic sacs One or two two
sex Same sex Can be same or different
sex
Physical appearance Look alike Doesn’t look alike
WHAT IS THE DIFFERENCE BETWEEN
IDENTICAL AND NON-IDENTICAL TWINS
15. WHAT IS THE COMPLICATION OF
TWINS?
The complication of having multiple are low birth
weight of the baby because twin usually born
premature.
Twin to twin transfusion syndrome which mean
the blood from one twin is being diverted into the
other twin.
Miscarried twin usually occur when a mother
suffering in their early pregnancy yet the
pregnancy still continued.
16. WHAT IS THE MOTHER RISK HAVING
MULTIPLE PREGNANCY?
Mother with gestational diabetes during their pregnancy with
twins or more, probably because the increase in hormones
produced by carrying an additional baby (or babies)
interferes with their body's ability to process insulin.
Placenta problem occur whether there is a single, shared or
multiple placentas, mothers of twins or more are at greater
risk for complications. Problems affecting the placenta can
result in dangerous complications for the mother, including
hemorrhage during pregnancy or after delivery.
Heart problem usually happen to mother with multiple
pregnancy because of each additional fetus raises the level
of cardiac output.
17. Ultrasound scan
The fastest way to know that you are having twins
By producing ultrasound image which shows whether its
more than one fetus.
Elevated HcG Levels
HcG (human chorionic gonadotropin) is a hormone
detectable in pregnant women's blood or urine about 10
days post-conception.
Twins may produce an elevated level of HcG.
HOW DO WE KNOW WE ARE
HAVING TWINS?
18. Doppler heartbeat count
By using Doppler system that amplifier fetal heart sounds
And experienced physician or midwife can hear two heat
beats
The sounds can be misleading
The second heartbeat may be background noise or mother’s
own heartbeat.
Weight Gain
Mothers of twins usually gain about 10 lbs. more than
singleton mothers.
Excessive Morning Sickness
Mother of twins experience double dose of morning sickness
Experience vary greatly depends on individual
19. Early/Frequent Fetal Movement
many mothers of multiples experience more frequent or
earlier fetal movement
considerable disagreement among medical professionals on
the subject
Because some women will recognize feeling of early
movement even if just carrying one baby
Extreme Fatigue
the body is working overtime to nurture more than one baby
History/Hunches
A family history of multiples, or a powerful hunch can be
convincing indicators that they are having twins.
20. HOW TO DELIVERED TWINS??
Usually, twins get birth smoothly, with both born
head down. However, caesarean sections are more
common with twins.
One or both might be breech, coming bottom or feet
first. Which mean one baby lies across the uterus,
in a case like this, caesarean is essential. Twins
can also be smaller and weaker than single babies
and a caesarean might be the easiest, least
stressful way for them to be born.
Twins are more likely to need some time in special
care after the birth. You'll probably be advised to
stay a little longer in hospital yourself, even if your
twins are perfectly healthy (as most are).
21. HOW TO BREASTFEEDING
TWINS?
A mother’s breast can make as much milk
as the babies need - twice the stimulation of
the supply, means twice the amount made.
It's the practical aspects that might be more
tricky - how to hold them so you're all
comfortable, whether to feed them one at a
time or together and so on. The babies may
not have the same appetite and they may be
hungry at different times too.
