Twin Pregnancy


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Twin pregnancy is the commonest type of multiple pregnancy, accounting for more than 98% of all multiple childbirths.

The other types e.g. triplets (three babies), quadruplets (four babies), quintuplets (five babies), sextuplets (six babies) become less common as the number of babies inside the uterus increases.

Women with a family history of twins or women who have undergone artificial reproductive therapy (ART) for infertility are more likely to have a twin pregnancy.

While most twin pregnancies can have an uncomplicated course and end in a normal delivery, there are certain problems that can occur in this type of pregnancy.

Twin Pregnancy

Different Types of Twin Pregnancies

  • Monozygotic or uniovular twins: Twins are called monozygotic or uniovular when both the babies develop from the same fertilized egg or zygote. A single ovum is fertilized to form a single zygote. But then this single zygote then divides to form two cells with the same number of chromosomes. These cells develop into two babies.

    Since development is from a single egg, the babies are always of the same sex and same blood group. Conjoint twins, where the babies are fused at some part of their bodies are monozygotic and occur due to late division of the zygote.

  • Dizygotic or Biovular twins: Dizygotic or biovular twins occur due to the fertilization of two ovum released in the same menstrual cycle. The babies have the same chromosomal similarities that siblings may have. They may be of different sex and have different blood groups.

  • Polyzygotic: Multiple fetuses produced by two or more zygotes. These are almost always the result of fertility treatment.

Signs and Symptoms of Twin Pregnancy

Most of the problems in multiple pregnancies are due to the large size of the uterus:

  • Size of the uterus: Size of the uterus is larger than normal.

  • Pressure symptoms: The patient may complain of breathlessness and palpitation because of the pressure on the diaphragm by the enlarging uterus, especially in the later weeks of pregnancy.

  • Anemia: Anemia may be present as the need for iron and other nutrients for the growth of the two foetus are more.

  • Edema: There may be swelling of the feet (edema) as the large uterus may cause stagnation of blood and fluids in the feet.

  • Weight gain: Weight gain is more than normal.

  • Pre-eclamptic Toxemia: Symptoms of pre-eclamptic toxemia like edema, high blood pressure and protein in the urine may be present.

  • Hydramnios: Hydramnios or excessive liquor amnii may be present. This is more common in uniovular pregnancy.

  • Malpresentations: Malpresentations or abnormal presentations of the foetus' (like breech or transverse presentation may occur), increasing the incidence of cesarian sections.

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Management/Treatment of a Twin Pregnancy

During the Pregnancy

  • The general health of the patient has to be improved.
  • Repeated and regular visits of the patient to the doctor are a must.
  • Early admission and hospital delivery are advisable.
  • Management of complications like Pre-eclamptic Toxaemia and palpitations.

During labor: Ideally an USG must be done at 36 weeks to determine the relative positions of the fetus to each other, and then determine whether the patient could be allowed to go for normal delivery or should be put up for elective Cesarian Section. Intensive clinical monitoring must be carried out.

Problems during labor

  • Premature onset of labor may occur, usually around the 37th week of pregnancy.

  • The membranes may rupture early causing prolapse of the umbilical cord.

  • Malpresentations can cause difficult and prolonged labour.

  • Progress of labor may be slow due to the failure of the unduly large uterus to contract properly.

  • Perineal tears can occur.

  • Interlocking of twins may occur where a part of the first baby, usually the chin, locks with some part (also usually the chin) of the second baby.

    If USG at 36 weeks makes the doctor suspect that this condition may occur in labour, it is wiser to go for Cesarian Section before the onset of labour.

  • Excessive bleeding can occur after delivery, also called postpartum hemorrhage, it occurs because the flabby uterus fails to contract properly.

  • Excessive bleeding during expulsion of the placenta can occur.

  • There can be retained placenta.

Also Read-

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