multiple pregnancy

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MULTIPLE PREGNANCY

• Dr.Isaac Makanda MD. Mmed

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INTRODUCTION

• Multiple pregnancy is a pregnancy with more than
  ONE foetus, i.e., the development of more than
  one foetus in utero at the same time.
• Simultaneous development of
• Two foetuses - twins (most common)
• Three foetuses - triplets
• Four foetuses - quadruplets
• Five foetuses - quintuplets
• Six foetuses - sextuplets etc.
• Incidence of twin pregnancy
• Among Europeans 180 pregnancies
• The highest is in West Africa (144 pregnancies)
• The lowest is in Asia

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INTRODUCTION

• Due to the rise of infertility treatments and
  ovulation-stimulating drugs the number of
  multiple pregnancies is on the rise.
• Theoretically, according to HEILINS RULE the
  incidence for
• Triplets should be 1802 (1 6,400 pregnancies)
• Quadruplets should be 1803 (1 512,000
  pregnancies)
• Sextuplets should be 1804 etc.

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TYPES OF TWIN PREGNANCY

• Twins will either be monozygotic or dizygotic.
• Monozygotic/Uniovular/Identical twins
• Develop from the fusion of ONE ovum and ONE
  spermatozoon, which after fertilization splits
  into TWO.
• These twins will
• Be of the same sex
• Have the same genes
• Have the same blood group
• Have the same physical features e.g. eye and hair
  colour, ear shapes, palm creases
• However, they may be of different SIZES or have
  different PERSONALITIES

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TYPES OF TWIN PREGNANCY

• Dizygotic/Binovular/Fraternal/Non-identical
  twins
• Develop from TWO ova that are fertilized by TWO
  different spermatozoa during a single ovarian
  cycle
• They are no more alike than any other brother or
  sister and can be of the same or different sex.

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TYPES OF TWIN PREGNANCY

• Note
• Because in any pregnancy there is a 5050 chance
  of a girl or boy, HALF of dizygotic twins will be
  boy-girl pairs.
• 25 of dizygotic twins will be both boys
• 25 of dizygotic twins will be both girls

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SUPERFECUNDATION SUPERFETATION

• Superfecundation
• Is fertilization of TWO different ova in the same
  cycle by separate acts of coitus within a short
  period of time.
• Superfetation
• Is fertilization of TWO ova released in different
  menstrual cycles (this though is thought to be
  very rare)
• The nidation and development of one foetus over
  another is theoretically possible until the
  decidual space is obliterated by 12 weeks of
  pregnancy.

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AETIOLOGY OF MULTIPLE PREGNANCY

• The cause is UNKNOWN.
• The frequency of monozygotic twins remains
  constant globally and is a matter of chance.
• Dizygotic twinning is influenced by several
  factors including
• Race frequency is highest among black race and
  lowest in Mongols
• Heredity more transmitted through the female
  (maternal side). The male factor, familial or
  otherwise does NOT appear to increase the rate of
  twin pregnancy

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AETIOLOGY OF MULTIPLE PREGNANCY

• Maternal age increased incidence with advancing
  age maximum between 30-35 years of the mother.
• Parity increased especially from 5th pregnancy
  onwards.
• Iatrogenic drugs for induction of ovulation
• 20-40 with gonadotrophins
• 5-6 with clomiphene

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IMPORTANCE OF MULTIPLE PREGNANCY

• ALL prenatal, intrapartum and postpartum
  complications are more common than in singleton
  pregnancies.
• A high incidence of prematurity and foetal
  abnormalities is almost six times more in
  perinatal mortality.
• Families expecting a multiple pregnancy birth
  have different health needs requiring extra
  practical support during pregnancy and even after
  delivery.

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PLACENTATION IN TWIN PREGNANCY
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DETERMINATION OF ZYGOSITY

• Means determining whether or not the twins are
  IDENTICAL
• In ? of all twins born, zygosity will be obvious
  as they will be of a DIFFERENT sex
• Of the remaining same-sex twins, the zygosity
  will usually be apparent at about 2 years of age
  from physical features
• Has importance in organ transplantation.

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DETERMINATION OF ZYGOSITY
MONOZYGOTIC DIZYGOTIC
Communicating vessels Present Absent
Sex Identical May differ
Genetic features Same Different
Skin grafting Acceptance Rejection
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Zygosity

• For twins ,this refers to the degree of genetic
  similarity within each pair.
• Dizygotic (DZ,Fraternal ) twins occur when two
  eggs are released at a single ovulation and are
  fertilised by two different sperms .The two
  fertilized eggs then implant independently in the
  uterus
• They share around 50 of their genes which is the
  same type of genetic relationship as non-twin
  siblings
• approx ½ are the same sex and ½
  different sex
• Each has its own placenta which is continous with
  the chorion (outer membrane),with rare
  exceptions
• Each is genetically similar as any same-sex or
  different-sex siblings

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• Monozygotic (MZ,identical ) twins develop when a
  single egg is fertilised by a single sperm and
  during the first two weeks after conception,the
  deloping embryo splits into two each develops
  into a fetus.The two babies are genetically
  identical
• Approx 1/3 of monozygotic twins have separate
  palcentas
• Approx 2/3 of monzygotic twins share a a single
  placenta despitemaintaning their own inner
  sac(amnion),umbilical cord and share the
  placental mass
• All these twins are the same sex with rare
  exceptions
• Are genetically identical ,or almost 100
  identical

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Monozygotic twins

• May actually be discordant for genetic mutations
  because of a postzygotic mutation, or may have
  the same genetic disease but with marked
  variability in expression
• Accordingly, dizygotic or fraternal twins of the
  same sex may appear more nearly identical at
  birth than monozygotic twins.
• The developmental mechanisms underlying
  monozygotic twinning are poorly understood. Minor
  trauma to the blastocyst during assisted
  reproductive technology (ART) may lead to the
  increased incidence of monozygotic twinning
  observed in pregnancies conceived in this manner

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DETERMINATION OF CHORIONICITY

• Chorionicity
• Is clinically important as monochorionic twins
  have 3-5 times higher risk of perinatal mortality
  and morbidity than dichorionic twin pregnancies
• Prenatally, chorionicity is diagnosed by
  ultrasound preferably during the 1st trimester
  whereby the two types of placentation is most
  prominent.
• The information is also important for genetic
  reasons.

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ZYGOSITY AND CHORIONICITY

• In monozygotic twins, twinning may occur at
  different periods after fertilization. Other rare
  cases have the following possibilities
• If the division takes place within 72hrs (prior
  to morula stage), the resulting embryos will have
  two separate placentae, chorions and amnions
  i.e., dichorionic-diamniotic
• If the division takes place between the 4th and
  8th day (after the formation of inner cell mass)
  when chorion has already developed, i.e.
  monochorionic-diamniotic

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ZYGOSITY AND CHORIONICITY

• If the division takes place after the 8th day of
  fertilization (when the amniotic cavity has
  already formed) i.e. monochorionic-monoamniotic
• On extremely rare occasions, division occurs
  after 2 weeks (development of embryonic disc)
  resulting in the formation of conjoined twins.
• Thoracopagus (commonest)
• Pyopagus (posterior fusion)
• Craniopagus (caphalic)
• Ischiopagus (caudal)

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EXAMINATION OF PLACENTA MEMBRANES

• Dizygotic twins
• There are two placentae either completely
  separated or more commonly fused at the margin
  appearing to be one.
• There is no anastomosis between the two foetal
  vessels
• Each foetus is surrounded by a separate amnion
  and chorion
• Monozygotic twins
• The placenta is single
• There is a varying degree of free anastomosis
  between the two foetal vessels.
• Each foetus is surrounded by a separate amniotic
  sac with the chorionic layer common to both
  (monochorionic diamniotic)

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DETERMINATION OF CHORIONICITY
DICHORIONIC MONOCHORIONIC
Two placentae (may be fused) One placenta
Two chorions One chorion
Two amnions Two amnions (one amnion is very rare)
Can be either dizygotic or monozygotic Can only be monozygotic
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DIAGNOSIS OF MULTIPLE PREGNANCY

• History
• Increased nausea and vomiting in early pregnancy
• Cardiorespiratory embarrassment in later months
  (palpitations, shortness of breath)
• Tendency of swelling of legs, varicose veins and
  haemorrhoids is greater
• Excessive foetal movements
• Unusual rate of abdominal enlargement
• History of multiple pregnancy in the family (more
  often present on the maternal side)
• History of infertility treatment/ovulation
  inducing drugs

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DIAGNOSIS OF MULTIPLE PREGNANCY

• General Examination
• Signs of anaemia
• Unusual weight gain
• Evidence of preclampsia

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DIAGNOSIS OF MULTIPLE PREGNANCY

• Abdominal Examination
• Inspection
• Uterus is barrel shaped
• Abdomen is unduly enlarged
• Palpation
• Fundal height is larger than gestational age
• Abdominal girth at level of umbilicus is 100cm
  at term
• Palpation of multiple foetal parts
• Palpation of more than 2 foetal poles
• Auscultation
• Presence of 2 distinct foetal heart sounds
  located at separate spots with a difference of at
  least 10 beats/min
• Note the best diagnosis is by ultrasound

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A. Dichorionic diamnionic twin pregnancy at 6
weeks gestation. Note the thick dividng chorion
(yellow arrow). One of the yolk sacs is indicated
(blue arrow). B. Monochorionic diamnionic twin
pregnancy at 8 weeks gestation. Note the thin
amnion encircling each embryo, resulting in a
thin dividing membrane (blue arrow).
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DIFFERENTIAL DIAGNOSIS OF MULTIPLE PREGNANCY

• Wrong dates
• Wrong examination
• Big foetus
• Polyhydramnios
• Pregnancy with uterine fibroids
• Pregnancy with an ovarian cyst
• Ascites with pregnancy
• Molar pregnancy
• Retention of urine (full bladder)

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MATERNAL COMPLICATIONS OF MULTIPLE PREGNANCY

• Anaemia Iron deficiency and megaloblastic due to
  increased foetal demands
• Preterm labour
• Preeclampsia and eclampsia
• Placenta previa
• Postpartum haemorrhage
• Polyhydramnios
• Prolonged labour
• Premature Rupture of Membranes
• Mechanical distress dyspnea, palpitations

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FOETAL COMPLICATIONS OF MULTIPLE PREGNANCY

• Abortion
• Intrauterine growth restriction
• Preterm birth
• Cord prolapse
• Foetal abnormalities
• Discordant growth
• Vanishing twin

• Intrauterine death of one foetus
• Twin-twin transfusion syndrome
• Locked twins
• Increased perinatal mortality
• Delayed second twin delivery (max 45mins)

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MINOR COMPLICATIONS OF MULTIPLE PREGNANCY

• Increased heartburn
• Varicose veins
• Haemorrhoids
• Pressure effects
• Nutrition
• Care of babies
• Breastfeeding etc.

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OTHER COMPLICATIONS OF MULTIPLE PREGNANCY

• Foetus papyraceous (compressus)
• Occurs when one of the foetus dies early.
• The dead foetus is flattened and compressed
  between the membranes of the living foetus and
  the uterine wall.
• May occur in both varieties of twins but is more
  common in monozygotic twins.
• Is usually discovered at delivery or earlier by
  USS

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OTHER COMPLICATIONS OF MULTIPLE PREGNANCY

• Foetus acardius
• Twin Reversed Arterial Perfusion (TRAP)
• One twin presents without a well defined cardiac
  structure and is kept alive through placental
  anastomoses to the circulatory system of the
  viable foetus
• Occurs only in twins or triplets
• Foetus-in-fetu (endoparasite)
• A foetus may be lodged within another foetus
  (only in monozygotic twins)

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ANTEPARTUM COMPLICATIONS OF MULTIPLE PREGNANCY

• Nausea and vomiting
• Anaemia
• Preeclampsia
• Polyhydramnios
• APH
• Malpresentation
• Preterm labour
• Mechanical distress

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INTRAPARTUM COMPLICATIONS OF MULTIPLE PREGNANCY

• Cord prolapse
• Premature rupture of membranes
• Prolonged labour
• Intrapartum bleeding
• Increased operative interference
• PPH

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PUERPERAL COMPLICATIONS OF MULTIPLE PREGNANCY

• Subinvolution of the uterus
• Infection
• Lactation failure

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MANAGEMENT OF MULTIPLE PREGNANCY

• Before 20 weeks
• Early detection (USS)
• Inform the parent(s)
• Normal ANC
• No need for hospital admission unnecessarily
• A fully balanced diet
• Supplementation of iron and folic acid

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MANAGEMENT OF MULTIPLE PREGNANCY

• After 20 weeks
• As before 20 weeks management
• Early detection and management of possible
  complications e.g. preterm labour, preeclampsia
• Regular foetal growth assessments i.e.
  identification of IUGR

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HIGHER ORDER MULTIPLE PREGNANCIES

• Triplets may develop from fertilization of a
  single ovum, two ova or even three ova
• Similarly with quadruplets and quintuplets
• Female foetuses usually outnumber male ones
• Diagnosis is accidental following USS or during
  birth
• The clinical course and complications are
  intensified compared to twins.

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HIGHER ORDER MULTIPLE PREGNANCIES

• Perinatal loss is markedly increased due to
  prematurity
• Preterm delivery is common (50) in triplets etc.
  and usually delivery occurs by 32-34 weeks
  gestation
• Discordance of foetal growth is more common than
  twins
• Perinatal loss is inversely related to birth
  weight
• To improve the foetal salvage especially in
  quadruplets it is advisable to employ liberal
  Caesarean section

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SELECTIVE REDUCTION (FETOCIDE) IN HIGHER ORDER
MULTIPLE PREGNANCIES

• If there are 4 or more foetuses, selective
  reduction of foetuses leaving behind only two is
  done to improve outcome of the foetuses.
• This can be done by intracardiac injection of
  potassium chloride between 10 and 12 weeks
  gestation under ultrasound guidance.
• It can be done transabdominally, transvaginally
  or transcervically.

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SELECTIVE REDUCTION (FETOCIDE) IN HIGHER ORDER
MULTIPLE PREGNANCIES

• Umbilical cord of the targeted twin is occluded
  to protect the co-twin from adverse drug effects
  by
• Foetocopic ligation or
• Laser or
• Bipolar coagulation

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