Multiple Pregnancy

Multiple Pregnancy/ Multifetalpregnancy The presence of more than one fetus in the gravid uterus is called multiple pregnancy Two fetuses (twins) Three fetuses (triplets) Four fetuses (quadruplets) Five fetuses (quintuplets) Six fetuses (sextuplets)

INCIDENCE Hellin’s Law: Twins: 1:89 Triplets: 1:892 Quadruplets: 1:893 Quintuplets: 1:894 Conjoined twins: 1 : 60,000 Worldwide incidence of monozygotic - 1 in 250 Incidence of dizygotic varies & increasing

Demography Race: most common in black race Age: Increased maternal age Parity: more common in multipara Heredity - family history of multifetal gestation Nutritional status – well-nourished women ART - ovulation induction with clomiphene citrate, gonadotrophins and IVF Conception after stopping OCP

Twins Varieties: 1. Dizygotic twins: commonest (Two-third) 2. Monozygotic twins (one-third) Genesis of Twins: Dizygotic twins (syn: Fraternal, binovular) - - fertilization of two ova by two sperms.

Differences in zygocity Dizygotic Monozygotic 1 ova + 1 sperm Same sex Identical features Single or double placenta Same genetic features DNA microprobe -same 2 ova + 2 sperm Same or opposite sex Fraternal resemblance Double or s/t fused Different genetic features DNA microprobe - different

Superfecundation Fertilization of two different ova released in the same cycle Superfetation Fertilization of two ova released in different cycles

Up to 3 days - diamniotic-dichorionic Monozygotic twins (syn: Identical, uniovular): Up to 3 days - diamniotic-dichorionic Between 4th & 7th day - diamniotic monochorionic - most common type Between 8th & 12th day- monoamniotic-monochorionic After 13th day - conjoined / Siamese twins.

Conjoined twins Ventral: 1) Omphalopagus 2) Thoracopagus 3) Cephalopagus 4) Caudal/ ischiopagus Lateral: 1) Parapagus Dorsal: 1)Craniopagus 2)Pyopagus

Maternal Complications Increased maternal mortality Increased pregnancy risks Anemia (15%): due to iron deficiency or folic acid deficiency Preeclampsia- eclampsia: GDM Threatened or actual abortion. Polyhydramnios (12%): acute: more in monozygotic than dizygotic twins. OR Chronic: not related to type. Mechanical effects: with the uterus larger than period of amenorrhea; it may be associated with dyspnea, dyspepsia, pressure on ureter with increased UTI, supine hypotension syndrome, increased varicosities and lower limb edema. Rupture of membranes Antepartum hemorrhage: both abruption (due to PIH and folic acid deficiency) and placenta previa (due to large placenta). Psychological: problem of caring, prolonged rest and hospitalization.

Increased labor risks: Preterm labor (50%): which may be spontaneous or induced uterine dystocia. Abnormal fetal presentation. Twins entanglement and locked twins Cord accident Cord prolapse. Vasa Praevia (due to vilamentous insertion of the cord). Two Vessel cord (7% especially monozygotic) N.B; 1% in singelton Postpartum Hemorrhage Puerperal Sepsis

Fetal / Neonatal Complications Increased abortion rate Increased intra-uterine fetal death (IUFD): More in MZ > DZ. Vanishing twin syndrome: (incidence 21%) Early death = Fetus compressus (papyraceous fetus). Later death = macerated fetus. Death during delivery: first fetus: [prolapsed cord], second fetus: [ due to excess sedation, premature seperation of placenta, constriction ring ,dystocia, operative manipulation, hypoxia].

Vanishing twin – before 10 weeks Fetus papyraceous/compressus – 2nd trim IUFD most important in third trimester especially in momochorionic twins due to the risk of meurologic morbidity in the surviving twin

Increased perinatal mortality (10-20%): More in monozygotic twins. It is mainly related to low birth weight. It may be due to preterm delivery IUGR with PIH hypoxia (placental or cord accident) operative manipulation: Birth trauma and CP congenital malformation. Increased low body weight: Neonates are lighter [due to preterm or IUGR], More in monozygotic and with increased fetal number

Single Fetal Demise...?? First trimester Fetal loss of a twin does not appear to impair the development of the surviving twin. Midgestation fetal death occurring after (17 weeks' gestation) Increase the risk of IUGR, preterm labor, preeclampsia and perinatal mortality (17-50% in MC and if TTT) Antenatal necrosis of the cerebral white matter has been associated with the presence of intrauterine fetal death of a co-twin , artery-to-artery, and vein-to-vein anastomosis. Prompt delivery following the death of a co-twin has not been shown to prevent neurological injury Delivery for the purpose of preventing injury should, therefore, be weighed against the risks of premature delivery.

Twin to Twin transfusion Vascular communication between 2 fetuses, mainly in monochorionic placenta (10% of monozygotic twins), Twins are often of different sizes: Donor twin = small, pallied, dehydrated (IUGR), oligohydramnios (due to oliguria), die from anemic heart failure. Recipient twin = plethoric, edematous, hypertensive, ascites, kernicterus (need amniocentesis for bilirubin), enlarged liver, polyhydramnios (due to polyuria), die from congestive heart failure, and jaundice.

TRAP

Instead of normal umbilical artery flow from fetus to the placenta, the umbilical artery flow direction is from the placenta to the recipient (acardiac) twin. Placental anastomosis between the umbilical artery of the donor and recipient twin allows the deoxygenated blood from the donor fetus to enter the arterial circulation of the recipient fetus. The arterial circulation in the recipient preferentially pumps this deoxygenated blood to the lower fetal torso. The recipient umbilical cord contains two vessels, one artery in one vein.

Differentiation of twins Sex: If of different sexes, obviously dizygotic Placenta: If two separated placentae, will be dizygotic If one placenta, may be monozygotic or dizygotic Check septum between sacs by peeling amnions from each other. Blood groups: If doubt in dichorionic types, check the ABO, Rh, Duffy, Kell, MN and Ss. Finger prints: If different, it means dizygotic Typing HLA histocompatibility antigen

Diagnosis 25% of antenatal diagnosis of twin is missed . Twin should be suspected by history and examination It should be confirmed by U/S (as early as 10 wks). To decrease PNM, it should be early diagnosed, properly assessed antenatally and properly managed intranatally.

History… Patient profile: Early pregnancy: Hyperemesis, bleeding. Etiological factors; with positive past history and family history specially maternal. Early pregnancy: Hyperemesis, bleeding. Mid-pregnancy: Greater weight gain than expected, abdominal size > period of amenorrhea, early PIH symptoms, persistent fetal activity. Late pregnancy: Pressure symptoms (dyspnea, dyspepsia, UTI, piles, edema and varicose veins in LL).

Ultrasonography Confirm fetal number [ 2 sacs or 2 fetal heads in 2 perpendicular planes]. Confirm fetal lives Diagnosis of vanishing twin syndrome. Diagnose type: Mono- vs. dizygotic twins. In all dizygotic and in 1/3 of manozygotic twins, the dividing membrane between two sacs in twins comprises a double layer of chorion and amnion from each sac (dichorionic - diamniotic), separated by a triangle-like tongue of decidua extending from the fetal surface of the placenta. This is known as twin peak (or Lambda sign) which is pathognomonic for dichorionic placentation. In monochorionic pregnancy, the dividing thin membrane of the two sacs (made of 2 layers of amnion only) is inserted prependicular to the fetal surface of the placenta. This is known as the T- sign. The width of dividing membrane is a less reliable sign to determine the chorionicity.

ULTRASONOGRAPHY D / D ( fused placenta ) M / D Monozygotic or dizygotic Thick dividing membrane > 2mm Twin peak / lambda sign Monozygotic Thin dividing membrane 2mm or less T sign

Antenatal Follow up… Antenatal visits more often [some advise Twin clinic]: Seen biweekly until 20 weeks, weekly thereafter, even semiweekly if problems arise. Assess maternal condition weight gain, anemia and its type (iron or folic acid deficiency), PIH, Glucose intolerance, UTI] Asses fetal well-being can't rely on fetal movement as reduced one may be obscured by vigorous movement of the other, cautious interpretation of other tests Rest: Advised more rest to decrease pre-term delivery (PTD) and PIH incidence. Reassurance and psychological support: to educate and prepare the expectant mother for raising twins. Diet : Extra-Calories, proteins, essential fatty acids, mineral and vitamins. Prophylactic extra-iron + Folic acid supplementation. Proper delivery timing: Prevent Prematurity and preterm delivery increased bed rest, hospitalization at 32-36 weeks of gestation, monitoring uterine activity and possible use of tocolytic drugs. Prophylactic cerclage ??? The use of steroid to hasten lung maturity in threatened PTD should be considered.

Intranatal assessment and delivery: Managed in well equipped hospital. Admit once patient is in labor, has rupture of membranes or antepartum hemorrhage. Close (continuous and simultaneous) maternal and fetal surveillance to assess labor progress (use 2 machines for CTG).

How are they going to be delivered?

C.S. for Multiple Pregnancy: Indications of C.S. (Chervenak, 1985): More than 2 viable fetuses, if: weight < 2 kg, discordant growth ( i.e.; IUGR or twin-twin transfusion, or disproportionate twins, twin B larger than A (BPD > 2 mm), twin A: is non-vertex. Conjoined Twins Single amniotic cavity. Previous Uterine scar. During Labor: if delayed progress, fetal distress, or if twin B transverse and cervix is thickened (retained second twin). Associated pregnancy complication i.e.; severe PIH, placenta previa. Contracted Pelvis Lack of expertise

Vaginal Delivery for Multiple Pregnancy Team: [Senior obstetrician + scrubbed, gowned gloved assistant – anesthesiologist - neonatologist at least one for each neonate]. Limit the use of ecbolic: only if contractions are insufficient. Analgesia and anesthesia: need skilled anesthesiologist and better conducted via epidural analgesia

Types of Twin Presentations % 2nd twin 1st twin 35 Head 20 Breech 15 10 Transverse or cephalic Cephalic or transverse 5 Transverse or breech Breech or transverse Transverse

Vaginal Delivery for Multiple Pregnancy Always perform an episiotomy. Delivery of twin A (Vertex): with minimal interference (no artificial rupture of membranes, no augmentation, avoid difficult forceps or ventouse), no breech extraction if breech. On delivery of twin A: Clamp and cut cord of twin A immediately, away from vulva and mark it. No ergometrine is given. Assess twin B (abdominally/vaginally) i.e ; presentation, position, exclude mono-amniotic pregnancy or cord prolapse.

Guard against postpartum hemorrhage (massage and I.V ecbolics ) Delivery of twin B: assess second sac: if no sac, immediate delivery. If there is a sac, examine for lie: If longitudinal, wait 10 min (hasten if fetal distress or bleeding). If inertia, give oxytocin. If the presenting part is high, moderate fundal pressure and artificial rupture of membranes, then ventouse or breech extraction. If transverse, bring a leg by abdominovaginal manipulation i.e.; external cephalic version (ECV) or internal podalic version (IPV), then breech extraction. Placental delivery and examination for zygosity: If delayed, then do manual removal. Examine placenta for zygosity. Exploration of genital tract for retained products and lacerations. Guard against postpartum hemorrhage (massage and I.V ecbolics )

Retained Twin B The usual time interval between delivery of twin A and B is 15-20 minutes If there are facilities for proper monitoring this interval may be increased Indications of CS for Twin B Transverse lie Fetal Distress Contracted cervix Prolapsed cord Premature Breech Failed Extraction

Postnatal care Guard against puerperal sepsis. Psychological and possible financial support. Advise for contraception.