Multiple pregnancy

Question 1

Multiple pregnancy :
- Definition
- Features

Answer 1

Definition:

Pregnancy with two or more fetuses (anomaly with single cavity uterus)

Features:
* Preterm labor rates <28 weeks increase from singleton to twins to triplets
* Monozygotic twins have higher perinatal mortality than dizygotic (due to vascular problems)

• 2/3 of twin pregnancies end in singleton birth (one of the embryos is absorbed or mummified
  also known as fetus papyraceus. Happens usually by 10th week of gestation)
• 30% are monozygotic and 70% are dizygotic

Question 2

Risk factors for multiple pregnancy

Answer 2

1. Familiar factors
2. Parity and maternal age
3. Assisted reproductive technologies (ART) – IVF (decreased since limitation transferred embryos)
   and ovulation inductors (e.g. gonadotropin)

Question 3

Types Multiple pregnancy

Answer 3

Monozygotic
Dizygotic
Tri-zygotic

Question 4

Monozygotic time points

Answer 4

Monozygotic – division of single fertilized ovum.

Diagnosed before 14th week. Zygote divides
after conception as follows:

a. 0-4 days – 2 embryos 2 amnions 2 chorion
i. Before morula stage
ii. Fused or separated placentas
iii. 1/3 of cases

b. 4-8 days – 2 embryos 2 amnions 1 chorion
i. Before formation of amnion
ii. Single placenta
iii. 2/3 of cases

c. 9-12 days – 2 embryos 1 amnion 1 chorion
i. Rarest and highest mortality due to cord enlargement with absence of dividing
membrane.
ii. Single placenta

d. 13-15 days – conjoint twins 1 amnion 1 chorion (seismic twins)
i. Incomplete segmentation or incomplete twinning (postponed cleavage)
ii. Described by site of union (pyopagus, thoracopagus, craniopagus,
omphalopagus)

Question 5

Diagnosis of Multiple pregnancy

Answer 5

1. Ultrasound - determination of the type of twinning in 1st trimester

a. Lambda sign (“twin peak sign”) – dichorionic
b. T sign – monochorionic

2. Large uterus than expected for dates
3. Excessive maternal weight gain (not explained by edema or obesity)
4. History of ART
5. Elevated Maternal serum a-fetoprotein (MSAFP)
6. Recording of different fetal heart rates (asynchronous with mother)
7. Palpation of more than 1 fetus

Question 6

Multiple pregnancy

Complications

Answer 6

1. Nausea and vomiting – higher incidence than singlet.
2. Anemia – due to extra metabolic demands
3. Miscarriage – “vanishing twin syndrome”
4. Antepartum hemorrhage – placenta previa and placental abruption.
5. Pre-eclampsia
6. Intra uterine growth restriction (IUGR) – one fetus is smaller than the other
7. Pre-term labor – due to over distension of uterus (two fetuses and higher amniotic fluid)
8. Twin-to-twin transfusion syndrome (TTTS) – blood shunting; one fetus (donor) transfuses blood
   to the other fetus (recipient) via common vascular channels.

The donor is oligouric, anemic,
oligohydramnionic and growth restricted compared to the recipient which is polyhydramnionic
and polycythemic.

Types of anastomoses are artery to artery, vein to vein or artery to vein (most
dangerous).

9. Monoamniotic and conjoined twinning
10. Undiagnosed twins – oxytocic drugs are administered after delivery leading for entrapment of
    the second twin (irreversible even with using tocolytics drugs)
11. Malpresentation (especially transverse lie)
12. Locked twins – twins lock chin to chin

Question 7

Presentation in twins pregnancy

Answer 7

Question 8

Multiple pregnancy

Management

Answer 8

Management:

1. Antenatal ultrasound to detect anomalies (defect growth, TTTS, IUGR)
2. C-section (same indications for singlet pregnancy but when additional complications exist it is
   chosen – diabetes, pre-eclampsia, subfertility, pervious scar, preterm labor 28-34 weeks)
3. Vaginal delivery
   a. Indication – cephalocephalic or cephalo-breech.

b. Establish IV line
c. Monitor both fetuses
d. Deliver first fetus. For second fetus delivery, lie and presentation are needed to be
verified along with continuous monitoring of heart rate and uterine contractions

i. In case of transverse lie or other abnormal position – internal podalic version or
external cephalic version may be attempted.

i. If contractions are not present – use oxytocin (wait 30 minutes for normal
contraction before administration of oxytocin)

Question 9

TTTS

Answer 9

Amniocenteses – removal of amniotic fluid from the recipient

Selective feticide

Laster ablation of communicating vessels (if one twin dies the other often dies as well due to hemodynamic changes)