DR. HAZEM AL-MANDEELOB/GYN ROTATION-COURSE 481

Multiple Pregnancy

Introduction

A pregnancy with two or more embryos/fetuses that exist simultaneously

The perinatal mortality and morbidity are increased disproportionately with number of fetuses

Maternal mortality and morbidity are also increased

Twin gestation is the most common type

Etiology and Classification of Twinning

Occurs as result of the division of one fertilized egg (monozygotic) or fertilization of two eggs (dizygotic). Both processes can occur in other multiple gestation

Dizygotic (Fraternal) twins will always have two amnions and two chorions

In Monozygotic (Identical) twins, the number of membranes depend on the time of cleavage of the fertilized egg

70% of MZ twins are monochorionic (mostly diamniotic) and 30% are diamniotic dichorionic

Incidence of Twin Preganacy

Not constant throughout the world (varies according to race, hereditary factors, maternal age, parity, and the use of fertility agents)

Incidence of MZ twins is ≈ 1 per 250 birthsDZ twins increases with increased family Hx of

twinning, maternal age, and increased parityMultiple gestation occurs in 10%-30% of women

following the use of induction of ovulation agentsSpontaneous triplets is 1 in 8000 pregnancies

and quadruplets I in 800,000. In ART: 1 in 3000 births

Determination of Zygosity

Obstetrical ultrasound can often determine zygosity (esp. if done before 14 weeks)

Determination of number of amnions and chorions are VERY important for management

After delivery, zygosity should be confirmedNo. of membranes, no. of placentas and

gender are essential in determining zygosity

Abnormalities of Twinning Process

Occurs only in monochorionic (MZ) twins

Conjoined Twins

Twin-Twin Transfusion Syndrome (TTTS)

Umbilical Cord Abnormalities

Complications of Multiple Gestation

AnemiaHydramniosPreeclampsiaPreterm labourPostpartum

hemorrhageCesarean delivery

MalpresentationPlacenta previaAbruptio placentaePremature rupture of

the membranesPrematurityUmbilical cord

prolapseIntrauterine growth

restrictionCongenital anomalies

Maternal Fetal

Diagnosis of Multiple gestation

Signs and Symptoms: maternal sensation of larger abdomen, sensation of excessive fetal movement, excessive weight gain, palpation of more fetal parts, ausculation of more than one fetal heart

Ultrasound should be done routinely in all pregnancies (usually between 18-20 weeks)

Failure of early Dx of multiple gestation leads to increased perinatal morbidity and mortality

Antepartum Management

Goal is to minimize perinatal mortality and morbidity and to prevent maternal complications

More frequent visits for antenatal careAssessment of the cervical length

frequently Bed rest for the mother in the late

pregnancy is suggestedFetal surveillance is essential: monthly

obstetrical ultrasound in the late pregnancy period and non stress test in the last month

Intrapartum Management

Prevention and treatment of preterm labourPatient should be delivered in a hospital

with NICU facilityMode of delivery for twins depends on the

fetal presentations (Vx/Vx, Vx/Br, Br/Vx, or Br/Br)

Time interval between twin delivery is controversial (less than 30min)

For other multiple pregnancy, caesarean section is the safest mode of delivery

Causes of Perinatal Morbidity and Mortality

Congenital anomaliesPrematurityBirth hypoxia/AsphyxiaRespiratory Distress SyndromeCerebral hemorrhageBirth TraumaStillbirthsRetained dead fetus Syndrome