OB II 3.01 Multifetal Pregnancy PDF

OBSTETRICS II Multifetal Pregnancy Block 3 Maria Luisa S. Acu, MD | September 30, 2024 OB...

OBSTETRICS II Multifetal Pregnancy Block 3 Maria Luisa S. Acu, MD | September 30, 2024 OB II 3.01 OVERVIEW Distribution of Twin Pregnancies by Zygosity and Chorionicty I. Multifetal Pregnancy B. Conjoined Twins A. Definition and C. Vascular Communication Characteristics VIII. Antepartum Management of B. Twin Pregnancy Twin Pregnancy II. Determination of Zygosity IX. Delivery III. Diagnosis of Multiple Fetuses A. Prevention of Preterm IV. Maternal Adaptations Delivery V. Associated Maternal Risks B. Timing of Delivery VI. Associated Fetal Risks C. Delivery of Twins VII. Special Complications in X. Triplets Monochorionic Twins XI. Informed Consent for A. Monoamnionic Twins Selective Termination ⭐Emphasized / repeatedly discussed by the lecturer ABBREVIATIONS FSH Follicle-Stimulating Hormone Figure 1. Twin Gestation IVF In-Vitro Fertilization ZYGOSITY ONG Ovarian Neoplasm in Gestation How many zygotes were involved in the formation of twins? MCMA Monochorionic-Monoamniotic SFEW Single Fetal Estimated Weight CHORIONICITY ⭐ UMA Umbilical Artery Part of the fetal membrane that surrounds the baby EDF End-Diastolic Flow Part of the placenta TTTS Twin-Twin Transfusion Syndrome IUGR Intrauterine Growth Restriction TG Note: Figures under Table 1 are from Springer Nature to aid in LSCS Lower Segment C-Section visualizing the types of twin pregnancy. LEARNING OBJECTIVES Table 1. Dizygotic Twin vs. Monozygotic Twin List the risk factors for multifetal gestation DIZYGOTIC TWINS Discuss the following: TWO eggs and TWO sperms ○ Embryology of multifetal gestation ○ Each sperm unites with one egg = TWO fertilized eggs ○ Unique maternal and fetal physiologic changes associated ○ ​Each embryo will have her own house (own placenta, own with multifetal pregnancy amniotic membrane) ○ Diagnosis and management of multifetal gestation Total: 2 zygotes → 2 embryos with 2 placentas, 2 amniotic ○ Potential maternal and fetal complications associated with membranes multifetal gestation Accounts for 75% twinning around the world 100% I. MULTIFETAL PREGNANCY Dichorionic TWO placentas A. Definition and Characteristics Diamniotic TWO amniotic membranes Pertains to twins, triplets, quadruplets, etc. Each baby in one amnion Increase number of baby inside, anticipate more preterm MONOZYGOTIC TWINS deliveries and complications Identical twins Comes from one egg and fertilized by one sperm B. Twin Pregnancy Has several variations of twinning TRIVIA: Siamese twins - Chang and Eng Bunker (1811) Only 25% of twinning around the world ○ Each of the twins married and able to bear children TWO placentas ○ Both died of pneumonia 30% TWO amniotic membranes ○ Connected by a piece of skin and muscle Etiology of Twins – increased in the following: Dichorionic Diamniotic 2-4 blastomeres ( < 2 days) 📝 Fission before the formation of the inner cell mass and ○ Race (Africa) (Di-Di) any differentiation will produce two embryos with two ○ Heredity (genotype of mother) separate chorions, amnions and placentas. ○ Maternal age (>35) and parity (>7) ○ Maternal size = large and tall woman ○ Pituitary gonadotropin = ↑ Follicle-Stimulating Hormone Women undergoing infertility treatment (i.e. FSH injections) ○ Infertility treatment = ovulatory drugs (i.e. clomiphene citrate) ○ Assisted reproductive technology = IVF (in-vitro fertilization) Page 1 of 16 | TH: TOLENTINO, F. | MON TG 4 | SACDALAN, SOTTO, TENG, VILLARICO, WU  OB II 3.01 Multifetal Pregnancy Are These Twin Babies? Figure 2. Example of dizygotic twin boys as the consequence of superfecundation ONE placenta 70% TWO amniotic membranes Monochorionic Embryonic bud (3-7 days) 📝 These babies are TWINS ✅ Heteropaternity: seen in a case where the mother was sexually Diamniotic Twinning at the early blastocyst stage, after formation of assaulted on the 10th day of her menstrual cycle and had coitus (Mo-Di) the inner cell mass, will cause the development of two with her husband 1 week later embryos, with one placenta and one chorion but two separate amnions. Table 2. Superfetation and Superfecundation Superfetation Superfecundation An interval as long as or Fertilization of 2 ova within a longer than ovulatory cycle short period of time but not intervenes between at the same coitus nor not fertilization necessarily by sperm from Requires ovulation during the same man the course of established pregnancy TG Note: To differentiate the two:[Cleveland Clinic] Superfetation Superfecundation Superfetation involves two In superfecundation, your body ONE placenta embryos that form during two releases two or more eggs 1% ONE amniotic membrane separate menstrual cycles during the same menstrual Monochorionic Monoamniotic Embryonic disc (8-14 days) 📝 This is when a woman cycle* If separation occurs after the formation of the embryonic becomes pregnant again while This happens when two eggs (Mo-Mo) disc, the amnion has already formed, and will lead to a she’s already pregnant.* are released during the same monoamniotic, monochorionic pregnancy. ovulation period and are fertilized at different times.* Case Study A 36 y/o G1 with 8 weeks amenorrhea came from prenatal care after a (+) pregnancy test 3 days ago She complains of frequency episodes of nausea and vomiting PMH: (+) PCOS and given 2 cycles of Clomiphene Family history: mother has a twin sister BP 120/70; CR 88/min; RR 20/min Speculum: violaceous, smooth cervix with white mucoid discharge Very rare IE: cervix soft, long; uterus uniformity enlarged to 10-12 weeks Conjoined Twins Late (> 14 days) 📝 size Incomplete fission at this stage or later will result in ○ There is discrepancy in uterus size on IE conjoined twins. 📝 2026 Trans — based on Fig. 1 Possible clinical impressions: Wrong dating of pregnancy Doc Acu: If you knew the patient underwent IVF and two fertilized eggs Twin pregnancy were put back in the uterine cavity. You will definitely have this kind of Hydatidiform mole twinning (Dizygotic dichorionic diamniotic). But, if you don’t know their Uterine mass / Ovarian Neoplasm in Gestation (ONG) history and you saw this kind (Dizygotic and Monozygotic dichorionic Hyperemesis gravidarum diamniotic), you won’t know if it is truly identical twinning or non-identical twins. ○ Extreme situation of nausea and vomiting ○ Patient will be dehydrated and have electrolyte imbalance ○ Need admission and IV infusion ○ Consider multifetal pregnancy due to increase size in placenta which produces hormones Page 2 of 16 | TH: TOLENTINO, F. | MON TG 4 | SACDALAN, SOTTO, TENG, VILLARICO, WU  OB II 3.01 Multifetal Pregnancy Transvaginal/Transabdominal UTZ – initial diagnostic exam II. DETERMINATION OF ZYGOSITY Confirm diagnosis of intrauterine pregnancy Examination of placenta Determine accuracy of AOG ○ Usually determined after delivery Establish fetal viability ○ But better to know zygosity even before delivery Determine number of fetuses Infant sex and zygosity ⭐ Establish amnionicity and chorionicity if multifetal pregnancy ○ Twins → check external genitalia → one male, one female = Determine presence of a uterine mass opposite sex → dizygotic automatically[2026} ○ Recall: same sex = monozygotic; same OR opposite sex = Table 3. Monozygotic vs Dizygotic Twins Characteristics ⭐ dizygotic Monozygotic Dizygotic Ultrasound AKA: uniovular, identical AKA: biovular, fraternal ○ More accurate when done in the first half because the dividing amniotic membranes are more easily visualized ⅓ twins ⅔ twins when fetuses are smaller 1 sperm, 1 ovum 2 sperms and 2 ova Identical, monochorionic Dichorionic diamniotic Ultrasound Same gender, blood type, and Same or different gender and Best done in 1st trimester karyotype blood type; different karyotype Easily identify chorionicity → important impact on outcome Type of placenta depends on Presence of chorionic tissue the time of splitting of embryo between 2 amniotic sacs Incidence is dependent of race, Incidence is independent of age, parity, and ovulation race, age, and parity inducing drugs TG Note: See Appendix for table on mechanisms differentiating dizygotic and monozygotic twin pregnancy ⭐[OB Platinum] Figure 4. Gestational Sacs: Dichorionic-diamniotic (L). Monochorionic-diamniotic (M). Monochorionic-Monoamniotic (R) Monozygotic Twinning Monozygotic splits at different days of their early development Table 4. Genesis of Monozygotic Twins ⭐ Time of Division Cleavage of: Outcome Dichorionic / Days 1-3 Morula diamniotic Monochorionic / Days 4-8 Blastocyst diamniotic Monochorionic / Days 8-13 Implanted blastocyst monoamniotic Figure 5. Diamniotic Pregnancy. If you see a separating membrane/intertwin membrane (⬅), it is definitely diamniotic Formed embryonic Days 13-15 Conjoined twins disc Figure 6. Dichorionic-Diamniotic Pregnancy. (P): two placenta located far apart. (⬅): intertwin membrane Twin Peak Sign or Lambda Sign ( 𝝺 ) Twin peak sign: Triangular piece of placenta trying to insinuate between the intertwined membrane ○ Seen by examining the point of origin of the dividing membrane on the placental surface [Williams 25th] Twin peak sign = Dichorionic twins ⭐ Figure 3. Classification of Monozygotic Twinning Page 3 of 16 | TH: TOLENTINO, F. | MON TG 4 | SACDALAN, SOTTO, TENG, VILLARICO, WU  OB II 3.01 Multifetal Pregnancy Figure 7. Twin Peak Sign/Lambda Sign (L, ⬅) seen in Dichorionic Pregnancy. Two amniotic sacs (R). Blue lining = amniotic membrane, opposed to it is the chorionic membrane. Thus, a dichorionic placenta would have the chorionic tissue insinuating between the amniotic sacs Figure 11. Monochorionic-monoamniotic. Twins are separate, but no intervening membrane in between Diagnose: When did splitting occur at images A, B, C? Figure 8. Dichorionic-diamniotic twin placenta. The membrane partition that separated twin fetuses are elevated and consist of chorion (c) between 2 amnions (a) ANSWER: Image A: Days 4-8; Image B: Days 1-3; Image C: Days 8-13 T-sign in Monochorionic Pregnancy The relationship between membranes and placenta without apparent extension of placenta between the dividing III. DIAGNOSIS OF MULTIPLE FETUSES membranes[Williams 25th] History and clinical examination You can see a thin membrane but no intervening tissue at the ○ Family history of twinning insertion of the membrane → inverted letter “T” T-sign = Monochorionic twins ⭐ ○ Intake of ovulatory drugs ○ Fundal height measurement is larger than the AOG ○ Only seen in fetuses less than 20 weeks AOG Ultrasound Puts the fetus at risk for twin-to-twin transfusion syndrome[ 2026] Detection of more than the usual fetal parts upon doing the Leopold’s maneuver during the 3rd trimester Identification of 2 or more fetal heart sounds ○ Heard in different places with a difference of ~10 bpm between each heart sound Biochemical tests: increase in hCG and AFP A radiologic exam is done when ultrasound is not available, would show two heads and two spines ○ NOT useful in cases of: < 18 weeks AOG, maternal obesity, hydramnios Figure 9. T-sign (⬅) in Monochorionic placenta IV. MATERNAL ADAPTATIONS Greater degree of maternal physiologic changes with multiple fetuses Blood volume increases by 50-60% ○ In singletons, it is just 40% ○ Blood loss in NSD is more than 500 ml Cardiac output is increased Uterus and non-fetal contents may have a volume of >10 L and Figure 10. Lambda sign vs T sign weigh in excess of 20 lbs Source: Isuog and Quizlet Acute hydramnios: sudden increase in the amount of amniotic fluid V. ASSOCIATED MATERNAL RISKS Increased symptoms of early pregnancy ○ Due to the increased beta-HCG levels ○ More prone to hyperemesis gravidarum Increase risk of miscarriage Page 4 of 16 | TH: TOLENTINO, F. | MON TG 4 | SACDALAN, SOTTO, TENG, VILLARICO, WU  OB II 3.01 Multifetal Pregnancy Vanishing twin syndrome Vanishing Twin Syndrome More prone to anemia During a transvaginal scan early in pregnancy, there will be a ○ Compensated by iron supplementation documentation of two embryos. Preterm labor and delivery However, in subsequent TVS, the mother will have some form of ⭐ ○ Number one problem in twin pregnancies bleeding. ○ Account for the highest morbidities in the nursery ○ On re-examination, there will only be one baby developing Hypertension (or preeclampsia) normally, while the other baby is being resorbed Antepartum hemorrhage ○ It has a smaller gestational sac compared to the one ○ Due to the enlarged or distended uterus containing a live fetus ○ Also prone to uterine atony As the normally developing fetus increases in size, the other Placental abruption fetus becomes compressed Hydramnios Vanishing twins in the first trimester have a good prognosis. Possible need for prenatal hospitalization Single fetal death in twins Increased risk for operative vaginal delivery and CS Postpartum hemorrhage ○ Due to overstretching of the uterus, wherein it is unable to return to its normal tone ○ Entails administration of uterotonic agents Postnatal problems Maternal mortality Two RARE complications associated with multifetal pregnancy: ○ Postterm pregnancy ○ Macrosomia Figure 14. Vanishing Twin Syndrome. GS2 is a smaller gestational sac and is being resorbed. GS1 contains a normally developing fetus VI. ASSOCIATED FETAL RISKS Stillbirth or neonatal death Hydramnios Single fetal death in twins Twin-to-twin transfusion Preterm labor and delivery syndrome IUGR Risk of asphyxia: Congenital anomalies: occurrence because of three times more likely in operative vaginal birth or multifetal pregnancies CS Twin reversed arterial Operative vaginal birth: perfusion sequence especially the second twin Conjoined twins Twin entrapment Cord accident Cerebral Palsy: due to Figure 12. Mortality rates depending on the twinning classification Monoamniotic twins: higher premature delivery, or Source: 2026 Trans chance of complications asphyxia during delivery Mortality is highest (44%) in Monochorionic-Monoamniotic VII. SPECIAL COMPLICATIONS IN MONOCHORIONIC TWINS pregnancy, since sharing between two fetuses is unequal A. Monoamnionic Twins High fetal death rate Cause: intertwining of umbilical cords Figure 15. Cord entanglement in monoamnionic twins. Twins can move very actively in utero. This happens early on in pregnancy. You have to explain to the mother that she cannot do anything about this. It is one of the dangers of monoamnionic pregnancy. Figure 13. Perinatal Mortality in twins. Solid line: monochorionic. Dashed Line: dichorionic. Monochorionic twins are 7x more likely to die than dichorionic twins Page 5 of 16 | TH: TOLENTINO, F. | MON TG 4 | SACDALAN, SOTTO, TENG, VILLARICO, WU  OB II 3.01 Multifetal Pregnancy B. Conjoined Twins Commonly joined body site: ○ Anterior = Thoracopagus ○ Posterior = Pyopagus ○ Cephalic = Craniopagus ○ Caudal = Ischiopagus Symmetrical: ○ Two babies of equal sizes, separate or joined Asymmetrical: Figure 18. Thoracoomphalagus twins – twins are facing each other and joined at the liver ○ External acardiac (TRAP): one normally grown fetus and one abnormal (“monster”) in utero C. Vascular Communication ○ Attached ecto/hetero parasitis: one of the twins is attached Only in monochorial placenta on the back of the other Most common (75%) artery-to-artery anastomoses on the ○ Internal fetus in fetu: one of the twins developed inside the chorionic surface of the placenta other; can happen as long as there are ovarian tissue ○ Can also be artery-to-venous even in males with ovarian mass; inside a twin, there is a ○ Do not have an equal direction of blood flow mass that is found to be another baby or with elements of ○ Significant vascular placental anastomoses causes endoderm, ectoderm, mesoderm inadequate perfusion of one twin Can potentially cause hemodynamically significant shunts between fetuses Patterns of anastomoses: ○ Acardiac twinning ○ Twin-to-twin transfusion syndrome Twin Reversed Arterial Perfusion (TRAP) or Acardiac Twin One of the twins get adequate blood flow while the other does not This results in missing parts, usually the upper portion of the body, while the lower portion is usually well-formed Acardiac Twin: absent or non-functioning heart Figure 16. Classification of conjoined twins according to symmetry. ○ A parasite, usually a grotesque mask diagnosed on Source: Williams ultrasound Pump Twin: alive and normal, pumps blood to the other twin, thus, at risk of heart failure and preterm birth Figure 17. Types of Conjoined Twins SAMPLE CASE: Conjoined twins attached at the thorax and were successfully separated. Factors contributing to success are Figure 19. Diagram and ultrasound of TRAP attachment sites and race (L) VS conjoined twins attached at almost half of their body. Thus they cannot be separated and suffer teasing from their community as “spiderman kids” (R) Thoracoomphalagus Twins Figure 20. Photos of babies with TRAP or Acardiac Twins. ○ Can be diagnosed sonographically and via MRI to show The lower extremities are more developed, and the upper body is monstrous where they are joined Page 6 of 16 | TH: TOLENTINO, F. | MON TG 4 | SACDALAN, SOTTO, TENG, VILLARICO, WU  OB II 3.01 Multifetal Pregnancy Figure 23. TTTS: AA, AV, VA, VV anastomoses. Figure 21. Placenta injected with a dye to document the anastomoses. One small baby, one big baby that is edematous Fig. 21 Legend ○ Blue & Green: Arteries ○ Red & Yellow: Veins ○ ⭑: Large arterio-arterial anastomoses ○ ⭑: Several arterio-venous anastomoses ○ ⭑: Veno-arterial anastomoses Happens only in monochorionic twins ○ Dichorionic has their own placenta Figure 24. TTTS: 20 wks AOG. Donor - anuric, stuck, and will succumb first (L); Recipient - polyuric due to increased blood flow towards this baby (R) Twin-to-Twin Transfusion Syndrome (TTTS) Donor: anemic, IUGR Table 5. TTTS Summary Recipient: polycythemic, hydrophic (edematous) Donor Twin Recipient Twin Neonatal period may be complicated by circulatory overload Hypovolemic, oliguric Hypervolemic, polyuric with heart failure if hypovolemia & hyperviscosity are not identified Can develop hypertension, Stuck-twin phenomenon – twin Occlusive thrombosis may develop hypertrophic cardiomegaly, in fixed position against uterine Pathophysiology: the anastomoses are deep AV capillary disseminated intravascular wall channels that lead to one-way AV shunts from a donor to a coagulopathy recipient sibling US: cannot see fetal bladder Hyperbilirubinemia after birth Can develop hydrops fetalis due Becomes hydropic because of to anemia and high output hypervolemia failure SAMPLE CASE: Twin-to-Twin Transfusion Syndrome Recipient (L) is more reddish than the pale Donor (R) who is anemic from pumping blood to the other twin. Figure 22. Stuck Twin Syndrome “Stuck Twin Syndrome” ○ One baby: stuck, very little amniotic fluid, cannot move ○ Other baby: lots of amniotic fluid, freely moves around Diagnosis of TTTS ○ Placental vascular connection ○ Hemoglobin difference >5 g/dL ○ Birth Weight difference of > 20% ○ Hydramnios in the larger twin ○ Stuck twin: IUGR with oligohydramnios ○ Monochorionicity: one placenta ○ Same sex fetus Therapy and Outcome: ○ Prognosis is extremely guarded ○ The earlier the AOG at diagnosis, the poorer the outcome ○ Both babies may be lost Page 7 of 16 | TH: TOLENTINO, F. | MON TG 4 | SACDALAN, SOTTO, TENG, VILLARICO, WU  OB II 3.01 Multifetal Pregnancy Table 6. Management of TTTS Diagram Procedure Reduction Amniocentesis Remove fluid from the one with hypervolemia. However, fluid can return after a few weeks Only option available in the PH Laser Ablation of the Anastomoses Only possible for superficial anastomoses Figure 25. Selective intrauterine growth restriction Deep anastomoses cannot be Discordant Twins: 1st trimester ablated ○ Crown Rump Length (CRL): best basis for aging the Selective Cord Coagulation pregnancy ○ You cannot say one is 8 weeks (21.2mm) and the other is 10 weeks (32.6mm) because they were formed at the same Used when laser ablation of the time connecting vessels is not possible ○ Assign one AOG using the CRL of the bigger baby OR one twin is close to death Smaller baby might have a problem early on in the pregnancy that’s why it is not growing well Radiofrequency Ablation Cutting off the blood supply to the acardiac twin Septostomy Puncture a hole between the two babies Figure 26. CRL measurements. (A). GS1, CRL is 21.2mm, Danger: hole can enlarge and cord (B). GS2, CRL is 32.6mm can entrap in that hole → death in utero Death of One Fetus Happens mid-trimester Selective Intrauterine Growth Restriction ○ Recall: first trimester death = vanishing twin Normal sized twin with normal amniotic fluid Fetus papyraceous ○ In the thriving baby ○ Baby is compressed and becomes like parchment or paper “Stuck twin” - oligohydramnios with growth restriction when delivered (dry, white, and compressed) ○ In the non-thriving baby Maternal DIC could be triggered Only 1 fetus is affected ○ From dead baby passing on through placenta to the mother ○ One baby is abnormal but the other is normal Risk of developing serious consumptive coagulopathy in Cause: inadequate placentation sharing & abnormal surviving fetus → death placentation in the smaller twin ○ From dead baby passing on through placenta to the other Unequal size of twin fetuses baby Perinatal mortality is increased as the weight difference within Monochorionic Twins the twin increases ○ If one twin dies after 14 weeks → high risk of neurologic FGR usually in the late 2nd and 3rd trimester damage to the surviving twin due to thromboplastin release Diagnosis: serial ultrasound → thrombotic arterial occlusion of anterior and middle ○ Monitor closely the small twin because delivery timing cerebral anastomosis → Multicystic Encephalomalacia depends on the status of the small twin ○ Either the baby dies or will have brain abnormalities ○ Findings: 1. FGR in 1 fetus: Single Fetal Estimated Weight (SFEW) Impending Death of One Fetus 10 L Recipient: polycythemic, Hydramnios in the larger and weigh in excess of 20 lbs hydrophic (edematous) twin Acute hydramnios: sudden increase in the amount of amniotic “Stuck Twin Syndrome”: Stuck twin: IUGR with fluid ○ One baby: stuck, very oligohydramnios Maternal Risks Fetal Risks little amniotic fluid, Monochorionicity: one Increased symptoms of early Stillbirth or neonatal death cannot move placenta pregnancy Single fetal death in twins ○ Other baby: lots of Same sex fetus Increase risk of miscarriage Preterm labor and delivery amniotic fluid, freely Vanishing twin syndrome IUGR moves around More prone to anemia Congenital anomalies: three Therapy and Outcome Management Preterm labor and delivery times more likely in multifetal pregnancies prognosis is extremely Reduction amniocentesis Hypertension (or preeclampsia) Antepartum hemorrhage Twin reversed arterial perfusion guarded Laser ablation Placental abruption sequence the earlier the AOG at Selective cord coagulation Hydramnios Conjoined twins diagnosis, the poorer the Radiofrequency ablation Possible need for prenatal Cord accident outcome Septostomy hospitalization Monoamniotic twins: higher Both babies may be lost Single fetal death in twins chance of complications Table 5. TTTS Summary Increased risk for operative Hydramnios Donor Twin Recipient Twin vaginal delivery and CS Twin-to-twin transfusion Hypovolemic, oliguric Hypervolemic, polyuric Postpartum hemorrhage syndrome Postnatal problems Risk of asphyxia: occurrence Can develop hypertension, Stuck-twin phenomenon – Maternal mortality because of operative vaginal hypertrophic cardiomegaly, twin in fixed position against Two RARE complications birth or CS disseminated intravascular uterine wall associated with multifetal Operative vaginal birth: coagulopathy pregnancy: especially the second twin US: cannot see fetal bladder Hyperbilirubinemia after birth ○ Postterm pregnancy Twin entrapment Can develop hydrops fetalis ○ Macrosomia Cerebral Palsy: due to Becomes hydropic because of premature delivery, or asphyxia due to anemia and high hypervolemia during delivery output failure Selective Intrauterine Growth Restriction Table 3. Special Complications in Monochorionic Twins Normal sized twin with normal amniotic fluid Complications Description “Stuck twin” - oligohydramnios with growth restriction Monoamnionic High fetal death rate Only 1 fetus is affected Twins Cause: intertwining of umbilical cords Cause: inadequate placentation sharing & abnormal Commonly joined body site: placentation in the smaller twin Anterior = thoracopagus Unequal size of twin fetuses Posterior = pyopagus Perinatal mortality is increased as the weight difference within Cephalic = craniopagus the twin increases Caudal = ischiopagus FGR usually in the late 2nd and 3rd trimester Diagnosis: serial ultrasound Conjoined Twins Discordant Twins: 1st trimester Types: Symmetrical ○ Assign one AOG using the CRL of the bigger baby Asymmetrical: Death of One Fetus ○ TRAP Mid-trimester ○ Attached ecto/hetero parasitis Fetus papyraceous ○ Internal fetus in fetu Maternal DIC risk Most common (75%) artery-to-artery Risk of developing serious consumptive coagulopathy in Vascular anastomoses on the chorionic surface of the surviving fetus → death Communication placenta Risk for Multicystic Encephalomalacia in one of the Can cause shunts Monochorionic Twins Impending Death of One Fetus Table 11. Other Complications If (+) fetal lung maturity, save both the healthy & jeopardized Twin Reversed Arterial Perfusion (TRAP) or Acardiac Twin fetuses One of the twins get adequate blood flow while the other does Abnormal antepartum tests in one twin pose a particular not → missing part, usually upper portion dilemma Acardiac Twin: absent or non-functioning heart Pump Twin: alive and normal, pumps blood to the other twin, Table 5. Antepartum Management of Twin Pregnancy thus, at risk of heart failure and preterm birth General Twin-to-Twin Transfusion Syndrome (TTTS) Diet must be 300 kcal more Pathophysiology Diagnosis Maternal hypertension The anastomoses are deep Placental vascular Antepartum surveillance AV capillary channels that connection Dichorionic Monochorionic lead to one-way AV shunts Hemoglobin difference >5 Lead clinician w/ Lead clinician w/ from a donor to a recipient g/dL multidisciplinary team multidisciplinary team sibling Birth Weight difference of > US at 10-13 wk: viability, US at 10-13 wk: viability, Donor: anemic, IUGR 20% chorionicity, NT, aneuploidy chorionicity, NT, Page 13 of 16 | TH: TOLENTINO, F. | MON TG 4 | SACDALAN, SOTTO, TENG, VILLARICO, WU  OB II 3.01 Multifetal Pregnancy aneuploidy/TTTS Vaginal delivery is advised if the both twins are vertex or first US Surveillance for TTS & twin is vertex Structural anomaly scan at discordant growth at 16 wk and Indications for elective CS 20-22 wk then every 2 weeks More than 2 fetuses Conjoined twins Serial fetal growth scan eg: 24, Structural anomaly scan 20-22 1 twin malpresented FGR in dichorionic twins 28, 32, then 2-4 weekly wk including fetal ECHO Scarred uterus TTTS BP monitoring and urinalysis at Fetal growth scan 2 weekly MCMA 20, 24, 28, and then weekly interval until delivery Discussion of mother’s family BP monitoring and urinalysis at Management of First Stage of Labor needs relating to twins 20, 24, 28 then 2 weekly Determine presentation of 1st twin (lie, wt) 34-36 wk discussion of mode of Discussion of mode and timing Maintain partogram delivery of deliver Establish IV line, blood type, and crossmatch Continuous intrapartum twin CTG monitoring Nutrition Analgesia - epidural anesthesia is advised Calorie recommendation Lithotomy position ○ 300 kcal more than that for singleton; OR Two teams of OB neonatologists, and anesthesiologists ○ 600 kcal more than that of non-pregnant Indications for emergency LSCS: fetal distres, cord prolapse, Folic acid - 1 mg throughout the pregnancy non-progress of labor, 2nd twin is transverse ○ 400 micrograms for singletons Analgesia and Anesthesia problems are imposed by Iron - 30 mg in the first trimester, then 60 mg until delivery prematurity, maternal hypertension, desultory labor, need for intrauterine manipulation, uterine atony and hemorrhage after Table 8. Institute of Medicine Recommendation for Weight Gain delivery BMI (kg/m2) Classification Weight gain Interval delivery (vaginal) between twins: