RAUL M. QUILLAMOR, MD FPOGS, FPSMFM, FPSUOG UERM College of Medicine MULTIFETAL PREGNANCY RAUL M. QUILLAMOR, MD FPOGS, FPSMFM, FPSUOG UERM College of Medicine

INFERTILITY THERAPY Epidemiology 1980s onwards - increase in number of deliveries: Increasing incidence of twins and higher-order pregnancies

Increasing incidence of multiple births: A public health concern Higher rate of preterm delivery Compromised chances of neonatal survival Increased risk of lifelong disability Increased vulnerability to malformations and twin- to-twin transfusion syndrome Increased incidence of maternal complications: Preeclampsia Postpartum hemorrhage Maternal deaths

Superfetation vs Superfecundation A long interval intervenes between fertilizations Requires ovulation & fertilization during the course of an established pregnancy Unproven to occur in humans Fertilization of 2 ova within the same menstrual cycle but not at the same coitus, nor necessarily by sperm from the same male

Etiology Fraternal Fertilization of two (or more) separate ova - Double-ovum - dizygotic

Dizygotic Twinning Variable incidence Same or different fetal sex Dichorionic, diamnionic Two separate or one fused placenta 2 sperm cells, 2 eggs

Dizygotic Twinning 2 sperm cells, 2 eggs

Etiology Identical Single fertilized ovum Subsequently divides into two (or more) similar structures with a potential to develop into separate individuals - Single-ovum - monozygotic

Monozygotic Twinning 1 sperm cell, 1 egg

Placenta & Membranes

Placenta & Membranes

Monozygotic Twinning: Conjoined twins Anterior - thoracopagus Posterior - pygopagus Cephalic - craniopagus Caudal - ischiopagus

Monozygotic Twinning: Siamese twins CHANG and ENG BUNKER: 1811 - 1874 Conjoined twins: 1:50,000 t0 1:200,000 births Higher incidence in Southwest Asia & Africa Approx 25% survival rate 3:1, females

Monozygotic Twinning: Conjoined twins Conflicting theories: 1. Fission – fertilized egg splits partially 2. Fusion- fertilized egg splits completely but stem cells find like-stem cells on the other twin & fuse the twins together

Monozygotic Twinning Dicephalic parapagus tetrabrachius

Monozygotic Twinning Diprosoic parapagus Twins with one trunk, one head with two faces

Monozygotic Twinning Dicephalic parapagus Twins with one trunk & two heads May be: Dibrachius (2 arms) Tribrachius tetrabrachius ]

Monozygotic Twinning Dicephalic parapagus

Monozygotic Twinning: Conjoined twins Xiphopagus Two bodies fused in xiphoid cartilage (from navel to lower ribs). Twins almost never share any vital organs, except the liver

Monozygotic Twinning: Siamese twins Thoraco-omphalopagus Approx 28% of cases Two bodies fused from the upper chest to the lower chest Twins usually share a heart, liver, & part of the GIT

Monozygotic Twinning Ischiopagus Two bodies fused at the lower half Spines conjoined end- to-end at a 180-degree angle 4 arms; 2,3, or 4 legs Typically one external set of genitalia and anus

Monozygotic Twinning Parasitic twin Asymetrically conjoined twins One twin is small, less formed, dependent on the other twin for survival

Monozygotic Twinning Parasitic twin

Monozygotic Twinning Omphalopagus Two bodies fused at the lower chest Heart is never involved Twins share a liver, digestive system, diaphragm & other organs

Monozygotic Twinning Craniopagus Fused skulls, separate bodies May be conjoined at the back, front, or side of the head, but not on the face & base of the skull

Monozygotic Twinning Parapagus Dithoracic parapagus Fused side-by-side with a shared pelvis Fused at the abdomen & pelvis but not the thorax

Monozygotic Twinning Craniopagus Pyopagus parasiticus Like craniopagus, but with a 2nd bodiless head attached to the dominant head Iliopagus Two bodies joined back-to- back at the buttocks

Monozygotic Twinning Cephalo Synecephalus thoracopagus Fused head & thorax Two faces facing in opposite directions Sometimes a single face and an enlarged skull One head with a single face but four ears & two bodies

Determinants of Twinning Heredity Maternal age & parity Nutritional factors Pituitary gonadotropins: FSH Infertility therapy Assisted reproductive technology . ]

Diagnosis History Physical examination Serial fundal height evaluation Differential diagnoses: Distended bladder Inaccurate menstrual history Polyhydramnios Hydatidiform mole Uterine tumors Adnexal tumors Large baby/ macrosomia

Diagnosis

Diagnosis

Diagnosis

Diagnosis Vanishing Twin One fetus dies or vanishes before the 2nd trimester; the remaining fetus delivers as a singleton

Diagnosis Vanishing Twin May cause elevations in: - maternal serum & amniotic fluid AFP levels - amniotic fluid acetylcholinesterase assay

Determination of Zygosity GENDER Male-Female Male-Male Female-Female Undetermined DIZYGOTIC 2 Placentas 1 Placenta Dichorionic- Diamniotic

Determination of Zygosity SINGLE PLACENTA (+) Chorionic peak (-) Chorionic peak Dichorionic Diamniotic Evaluate inter-twin membrane (-) (+) Thick Thin Mono-mono Mono-di Stuck twin Di-di Mono-di

Pregnancy Outcome Abortion Preterm labor & delivery Low birth weight Congenital malformations from: - Twinning itself - Vascular interchange between monochorionic twins - Fetal crowding

Pregnancy Outcome ACARDIAC TWIN: twin reversed- arterial-perfusion sequence (TRAP) Normal donor twin with heart failure Recipient twin with NO heart (acardius) & other various structures With artery-to-artery & vein-to-vein shunt

Acardiac twin

Pregnancy Outcome ACARDIAC TWIN: Perfusion pressure of donor twin greater than recipient twin Arterial blood from donor twin preferentially goes to the iliac vessels of recipient, perfusing only the lower part of the body ACARDIAC TWIN: Mx: Ligation of umbilical cord of acardiac twin by transabdominal fetoscopy

Pregnancy Outcome Twin-to-Twin Transfusion Syndrome DONOR TWIN RECIPIENT TWIN Anemic Growth-restricted Phletoric Hydrops (circulatory overload) One portion of placenta pale Solitary, deep A-V channels w/in capillary beds of villous tissue

TTTS

Pregnancy Outcome DISCORDANT TWINS: Inequality in size of twin fetuses Mx: Utz monitoring of growth parameters in both twins Inequality in size of twin fetuses Pathological growth restriction in one twin Cause unclear: but may be due to vascular anastomoses resulting in hemodynamic imbalance between the twins

Principles of Management 1. Prevention of preterm delivery 2. Identification and prompt delivery of growth restricted fetuses 3. Avoidance of fetal trauma during labor and delivery 4. Availability of expert neonatal care

Management DIET ANTEPARTUM SURVEILLANCE Additional 300 kcal/day on top of 300 kcal/day required for uncomplicated pregnancy Weight gain of at least 50 lbs 60 – 100 mg/day of iron 1 mg/day of folic acid Non-stress test Biophysical profile Monitoring of fetal growth parameters Doppler velocimetry

Management PREVENTION of PRETERM DELIVERY Bed rest, limited physical activity, early work leave? Tocolytic therapy? Corticosteroids for pulmonary maturation? Prophylactic cervical cerclage ?

Management LABOR Presence of skilled obstetrician & pediatrician, appropriately trained attendant, & experienced anesthesiologist Availability of ultrasound machine & blood transfusion products Establishment of intravenous infusion system

Management DELIVERY : Vaginal or Abdominal? Problems encountered when presenting twin is breech: - Aftercoming head is large for the passageway (big baby) - Delivery of extremities & trunk through an inadequately dilated cervix (small baby, small head) - Risk of umbilical cord prolapse

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