Multi Fetal Pregnancy & Complications

MULTIFETAL PREGNANCY AND COMPLICATIONS.

• DEFINITION Multifetal pregnancy is the presence of two or more fetuses in utero INTRODUCTION:Twining has been recogniced for a longtime even in the Bible times. Twining is important socially ,economicaly, traditionaly and in obstetrics.

• Socially ,it is a deviation from the normal more so when it is triplet, quadriplets or quintiplets Economically , multiple pregnancy destabilises the finances of the existing children and parents Traditionally ,Multiple foetuses are abomination in some communities therefore they left in the ant hill to die. • In obstetric practrice,maternal morbidity and mortality is raised.

• Also pregnancy wastage and perinatal morbidity and mortality are increased • INCIDENCE The Incidence of multiple pregnancy varies between races. Hellen’s law of 1895 is usually qouted which states that the frequency of twins is 1/89 births, triplets 1/892 quadruplets 1/893 and so on.

• In Asia the incidence is 1/150 • Cuacasians 1/80-1/90 • Negros 1/50-1/44 There are more dizygotic twins than monozygotic twins. The incidence of monozygotic twins is 1/250 and is the same all over the world.

• The ratio of dizygotic to monozygotic twins is 3 to 1 in general but in West Africa it is 6 to 1. • Nylander reported the incidence of triplets among Yorubas as 1.6 per 1,000 maternities in Lagos while it is 2.15 peer 1,000 in UCH Ibadan. • In UPTH Port Harcourt twining is 29 per 1,000 maternities i.e 1in 34 wile triplets is 1,3 per 1,000. • Generally the incidence of multifetal pregnancies has increased over the last 10 yeas due to wide spread use of ovulation induction and invitro fertilization for infertility

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AETIOLOGY Dizygotic twins are affected by:Race – more in blacks than white or Asians Family history Age > 35 years High parity (related to age) Ovulation drugs Tall and fat women Social class does not affect twins Blood group O and A are prone to twining caucasians • Late ovulation in the late menstrual cycle

• Those who stop COC after long term use (Due to rebound GNRH effect). • MONOZYGOTICS:• Appear to the chance event. • Not affected by above factors • It is uniform all over the world 1:250 • Possibly noxious influences at the time of early cleavage may be responsible.

• PATHOGENESIS • Monozygotic Twin:• Single Ovum and Single Sperm fertilization and division leads to twins of the same sex. • The twins share the same physical characteristics – skin, hair, eye colour, body build. • Genetic features – blood group, M,N, Haptoglobin, serum, histocompatibility genes. • But finger prints defer. • Monozygotic triplets – • It is due to repeated twining also called super twining of a single ovum.

• Trizygotic Triplets • Develops by individual fertilisation of 3 ova. • It could be twining of two ova and elimination of one of the fourth twins. • Dizygotic Twins (Fratanal Twins):• Two ova fertilised by two sperm cells • The ova are released from separate follicles or really from the same at the same time. • Characters:• May be of the same sex. • blood group may be different. • 75% are of the same sex.

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Both male 45% Both female 30% OTHER FORMS OF MULTIPLE Dispermia fertilization of two ova of the same oocyte. Fertilization by one ovum by two sperms. Polar body twining Superfecundation in fertilization of 2 ova released at about the same time, but they are fertilised by sperms from two different intercourse. (Perhaps from two different male partners). • Superfetation is the fertilization of two ova released in two different menstrual cycles. (this is impossible because the corpus lutium formed will suppress ovulation of the ovary 1 month later.

• PATHOLOGIC FACTORS ASSOCIATED WITH TWINNING • Greater demand for iron for the festus leads to Anacus. • Placenta dipnema common because of large placenta • Abruptio • UTI • PET and Eclampsia • Uterine inertia • PPH • PLACENTA AND CORD:• Division prior to morular stage (3 days) after fertilization leads to:• Complete Separation to 2 chorion, 2 amnions or may be fused in 30%. • Division after differentiation of tropholblast, but before formation of amnion 4 – 8 days leads to single placenta,

• Monochroniom placenta prone to disease process due to vascular anastomosis (twin --twin transmission) • Arterioveinous anastomosis is the most serious. • Valenmentous insertion is 7% • Vasa praevia is possible • plolage cord is common FETAL:• Spontaneous Abortion • Twice compare to singleton pregnancy • Vanishing twins • It is estimated that only 50% of altrasound diagnosed. • Congenital Malformation • It is twice as frequent compared to singleton pregnancy • It is more in monozygotic twins

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Conjoint Twins Are describe by site of union By pyopagus – at the sacrum Thoracopagus – chest Craniopagus at the head Omphalopagus at the abdomen Curiously conjoint twins usually are females A fetus acardiacus is a paracytic monodygotic without a heart. Fetus papyraceous is a small blighted and mumified fetus is usually discovered at delivery. Prematurely is the major cause of neonatal death. Abnormal presentation and position is common IUGR

• 2/3 of twins have IUGR • One or both twins may be affected IUGR is due to placenta insufficiency • IUGR is common in monozygotic • Twin – twin transfusion • Perinatal mortality • X5 compare to singleton • More in monodygotic due to prematurity • Chromosomal abnormalities

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CLINNICAL FEATURES MULTIFETAL PREGNANCY Symptoms:Exaggerated early pregnancy symptoms Severe pressure in the pelvis, backache, varicosities, constipation, haemorroid Increased fetal activities Signs:FH > GA by > 2 weeks Excessive maternal weight gain Polyhydramenius Elevated MSAFP Ballotmen of more than two fetal poles and multiple fetal parts. Simultaneous recording of different fetal heart rate and

• DIAGNOSIS • BASED ON HISTORY, CLINICAL FEATURES AND INVESTIGATIONS • INVESTIGATION • HB and blood film to determine anaemia and the type • Urinalysis • FBS – to determine hypoglyceania or hyperglyceania • Ultrasound scan – is the preferred imaging modality for diagnosis as early as 4 weeks using the vaginal probe. • DETERMINATION OF ZYGOSITY AND CHORONICITY • ZYGOSITY • Ultrasound scan will show the same sex. But if the membrane separating the twin is more than 2 cm then dizygotic twin is probable.

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Zygocity can also be determine by DNA from Amniotic fluid sampling Chorionic villa biopsy Fetal blood Chromosomal studies give 100% CHORIONICITY This can be determined by ultrasound which relies on • Fetal gender • Number placenta • And characteristics of the membrane and the two amniotic sacs.

• In dichronic twins the inter twin membrane is composed of a central layer of chronic tissue soundwich between two layers of amnion called the lambda sign. • Whereas in mono zygotic there is no chorion. • DIFFERENTIAL DIAGNOSIS OF MULTIPLE PREGNANCY • Inaccurate date • large fetus • Polyhydraminous • Hydatidiform mole • Abdominal tumous eg uterine fibroid, Ovarian tumour, distended bladder and full rectum.

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COMPLICATIONS Hyperemesis gravidarum, hypertension Pet, eclampsia, HELLP SYNDROME Diabetes APH Thromboembolism Manupulations and Operative Procedures