more than one pregnancy and the likely risks.pptx

Multiple pregnanciea and the risk factors associated with it.

1. MULTIPLE PREGNANCY By MUKISA CHRIS

2. DEFINITION Multiple pregnancy – Occurs when more than one foetus simultaneously develop in the uterus. Twin pregnancy is the simultaneous development of two foetuses. Although rare development of three foetuses(triplets),four (quadruplet), five , six may occur.

3. Zygosity : refers to the genetic makeup of twin pregnancy chorionicity : refers the placenta’s membrane status . Chorionicity is determined by the timing of embryo division.

4. TWIN PREGNANCY Twin pregnancy is the commonest variety of multiple pregnancy and it is of two types; (1) Dizygotic twins —It is most common(80%) and results from the fertilization of two ova by two sperms leading to fraternal twins. (2) Monozygotic twins (20%) results from the fertilization of a single ovum by a single sperm leading to Identical twins.

5. Dizygotic twins : result from fertilization of two ova, most likely ruptured from two distinct Graafian follicles usually of the same or one from each ovary, by two sperms during a single ovarian cycle. There are two placentae either completely separated or more commonly fused at the margin hence dichorionic-diamniotic . Sex of the foetus may differ. Genetic features e.g. blood group, finger prints also differ.

6. Genesis of monozygotic If division takes place within 3 days after fertilization prior to morula stage then the embryos will be diamniotic-dichorionic If division takes place between day 4 and day 8 after formation of inner cell mass when chorion has already developed then the embryos will be diamniotic-monochorionic. If division takes place between day 8 and day 13 then the embryos will be monoamniotic-monochorionic. Division >13days (2 weeks), after development of embryonic disc will result in conjoined twins

7. Determination of Chorionicity in Monozygotic Twin Pregnancy Timing of cleavage Placenta’s membrane status % of monozygotic twins <72 hours Diamniotic– Dichorionic (D/D) 25-30 Days 4-8 Diamniotic– Monochorionic (D/M) 70-75 Days 8-13 Monoamniotic – Monochorionic (M/M) 1-2 Day >13 Conjoined <1

8. RISK FACTORS OF TWIN PREGNANCY Increasing maternal age Increasing parity Family history of twins Infertility induction Race, blacks >> whites

9. Determination of Chorionicity This is done on USD; this is best determined before 14 weeks. Twin peak sign (Lambda sign) ; this signifies DCDA. T-sign; this signifies MCDA

10. Superfecundation is the fertilization of two different ova released in the same cycle. Fetus papyraceous is a state which occurs if one of the fetuses dies early. The dead fetus is flattened, mummified and compressed between the membranes of the living fetus and the uterine wall. It may occur in both varieties of twins. Discordant twin is size inequity in foetuses which may be a sign of pathological growth restriction in one fetus .

11. Fetus acardiacus occurs only in monozygotic twins. one fetus remains amorphous and becomes parasitic fetus Vanishing twin: Serial ultrasound imaging in multiple pregnancy since early gestation has revealed occasional death of one fetus and continuation of pregnancy with the surviving one. The dead fetus (if within 14 weeks) simply ‘vanishes’ by resorption. The rate of disappearance could be to the extent of 40%.

12. diagnosis ( i ) History of ovulation inducing drugs specially gonadotropins, for infertility . (ii)Family history of twinning

13. GENERAL EXAMINATION: ( i ) Prevalence of anemia is more than in singleton pregnancy. (ii) Unusual weight gain, not explained by pre-eclampsia or obesity, is an important feature. (iii) Evidence of pre-eclampsia (25%) is a common association

14. ABDOMINAL EXAMINATION Inspection: The elongated shape of a normal pregnant uterus is changed to a more ‘barrel shape’ and the abdomen is unduly enlarged Palpation: The height of the uterus is more than the period of amenorrhea. This discrepancy may only become evident from mid-pregnancy onward. The girth of the abdomen at the level of umbilicus is more than the normal average at term (100 cm).

15. Fetal bulk seems disproportionately larger in relation to the size of the fetal head. Palpation of too many fetal parts . Finding of two fetal heads or three fetal poles makes the clinical diagnosis almost certain.

16. Auscultation: Simultaneous auscultation of two distinct fetal heart sounds (FHS) located at separate spots with a silent area in between by two observers, gives a certain clue in the diagnosis of twins, provided the difference in heart rates is at least 10 beats per minute.

17. complications MATERNAL—During Pregnancy: Nausea and vomiting Mechanical distress Anemia Hypertension Polyhydramnios Preterm labor PPROM APH PPH Increased risk of C section

18. complications Pre-eclampsia Antepartum haemorrhage Malpresentation Preterm labour Mechanical distress

19. Complications-during labour Early rupture of the membranes and cord prolapse Increased operative interference Bleeding Postpartum hemorrhage

20. Fetal complications Prematurity Abortions Congenital malformations Low birth weight IUGR Discordant growth Cord entngelement

21. Complications specific to Monochorionic twins Twin To Twin Transfusion Syndrome, TTTS Twin Anemia Polycythemia Sequence, TAPS Twin Reversed Arterial Perfusion, TRAP

22. complications ( i ) Twin-twin transfusion syndrome (TTTS)— It is a clinicopathological state, exclusively met within monozygotic twins (10–15%), where one twin appears to bleed into the other through some kind of placental vascular anastomosis. Clinical manifestations of twin transfusion syndrome occur when there is hemodynamic imbalance due to unidirectional deep arteriovenous anastomoses. As a result the recipient twin becomes larger with hydramnios , polycythemic , hypertensive

23. and hypervolemic , at the expense of the donor twin which becomes smaller with oligohydramnios, anemic , hypotensive and hypovolemic. This leads to anemia-polycythemia syndrome. The donor twin may appear ‘stuck’ due to severe oligohydramnios. estimated fetal weight discrepancy is 25% or more

24. Cont.… Donor twin presents with ; Anemia Growth restriction Oligohydramnios Renal failure Cerebral palsy Recipient twin presents with; Polycythemia Plethoric Circulatory overload Heart failure Hydrops Occlusive thrombosis

25. (ii) Dead foetus syndrome —Death of one twin later in gestation is associated with poor outcome of the co-twin especially in monochorionic placenta. The surviving twin runs the risk of cerebral palsy, multicystic encephalomalacia, microcephaly, renal cortical necrosis and DIC. This is due to thromboplastin liberated from the dead twin that crosses via placental anastomosis to the living twin

26. iii) Twin reversed arterial perfusion (TRAP) is characterized by an ‘ acardiac perfused twin’ having blood supply from a normal co-twin via large arterio -arterial or vein to vein anastomosis. In majority the co-twin dies (in the perinatal period) due to high output cardiac failure. The arterial pressure of the donor twin being high, the recipient twin receives the ‘used’ blood from the donor. The perfused twin is often chromosomally abnormal. The anomalous twin may appear as an amorphous mass. Management of TRAP is controversial. Ligation of the umbilical cord (laser or RFA) of the acardiac twin under fetoscopic guidance has been done

27. Twin Anemia Polycythemia Sequence, TAPS This arises due to slow and chronic blood transfusion from twin to the other twin through placental vascular connections. The donor twin has anemia. The recipient twin has polycythemia It can also develop after treatment of TTTS

28. Management of multiple gestation During ANC early confirmation of the pregnancy and determine the chorionicity and amniocity via ultrasound. This is critical for risk stratification. More frequent ANC visits compared to singleton pregnancies in the second trimester and weekly in third trimester. Monitor the weight gain according to the guidelines for multiple gestation. Monitor for complications such as preterm labor, fetal growth, blood pressure since risk of preeclampsia is highest in multiple pregnancies

29. Timing and mode of delivery Dichorionic twins often delivered at 37-38 weeks if uncomplicated and we give corticosteroids such as betamethasone for fetal lung maturity. Monochorionic twins are typically delivered at 36-37 weeks due to higher risks and still give corticosteroids. Triplets or higher order multiples are often delivered a 34-35 weeks.

30. Mode of delivery Vaginal delivery may be possible for twins if the first twin is in vertex presentation and there are no other complications. Cesarean section is often recommended if for triplets or higher order multiples or if the first twin is non vertex.

31. Indications of C-section in multiple pregnancy Previous C-section or uterine surgery Higher order multiples e.g. triplets or more Non vertex presentation of first twin Monochorionic monoamniotic twins Cord prolapse Placenta previa or abruption TTTS