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Twin Pregnancy - Double Trouble or Twice the Joy
- Dr. S. Kalaichandran, MBBS, MD, MRCOG,FRCSC
Incidence:
There is a racial variation in the natural incidence of twins - 1 in 50 among Africans, 1 in 80 among Caucasians
and 1 in 150 among Asians and least among the Mongoloid Races. With the proliferation of
Assisted Reproductive Technology, there has been a marked increase (20 %) in the incidence
of twins. The risk is about 5 percent with fertility tablets and 20 percent with fertility
injections (gonadotrophins) and In Vitro-Fertilization and Embryo Transfer (IVF and ET)
when 3 to 4 embryos are transferred to increase the success rate.
Concerns:
“Two for the price of one” and “instant family” may sound like
a good thing, until one realizes that twin pregnancy is associated with an increase in all
Obstetrics complications except post maturity. Hyperemesis,
miscarriage, pre mature labour, pre mature
rupture of membranes, hypertensive disorders (toxemia), ante partum bleeding, fetal growth restriction, fetal death, abnormal
presentation, fetal malformation and post partum
bleeding are all increased. As for the baby, pre-natal mortality is 4 times that of singleton births and cerebral palsy is 6 times
that of singleton births. For optimal outcome, an
early referral and care by an Obstetrician,and delivery
at a well-equipped hospital with anaesthetic and paediatric support are essential.
Types of twins:
Twins may result from the division of
one fertilized egg (mono ovular-identical
twins) or from two fertilized eggs (binovular –fraternal twins).Mono ovular twins may
be present in two sacs (diamniotic-96%) or one sac (mono amniotic- 4%), depending on the
time of separation. Fetal anomalies, growth restriction and death are more common among
mono ovular twins. The risk of cord entanglement and fetal death is very high in mono
amniotic twins.
Diagnosis:
When the
uterus is large for dates and multiple fetal parts are felt, one would suspect a twin
pregnancy. Before the introduction of the Ultrasound Scan, many a twin pregnancy was a
surprise diagnosis after the delivery of twin 1. Routine obstetric ultrasound of all
pregnant women at 18-week gestation with earlier scans for those who are large for dates
will not only detect twins, but also indicate the type and screen for fetal anomalies.
Management:
All pregnant women should have
obstetric ultrasound exam. Twin pregnancy is a high-risk pregnancy and an early referral
to an Obstetrician is advised. The mother will require additional pre-natal vitamins and
iron and more frequent assessment for the early detection of maternal or fetal
complications. Serial Ultrasound will be required to assess the fetal well being. Delivery
should be in a well-equipped hospital as discussed earlier. After delivery, the mother
will require extra time in the hospital to adjust to the demands of the twins and
establish breast-feeding.
8-Week Ultrasound Diamniotic Twins
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