Multiple Pregnancies

TWINS

Usually, pregnancies within the human species produce only one child. However, the frequency of multiple pregnancies are:

Twins every 90 births

Triplets every 8,100 births

Quadruplets every 729,000 births

Quintuplets every 65,610,000 births

(no. are subject to further research and changes)

Now there are cases of live sextuplets and septuplets. Multiple births do not tend to repeat themselves in the same women. However, the case of one woman with eleven (11) twin pregnancies has been reported along with another case where the mother had 32 children in 11 pregnancies : two pregnancies of for children each, six of three children, and three of two children. (AMAZING RIGHT!)

Causes and Mechanism

Among the causes of producing twins is the paternal hereditary influence. Today multiple pregnancies are much more common due to the use of ovulation producing drugs (clomiphene, HMG) in the treatment of sterility. They are also more frequent among women who have other children after thirty (30) years of age, the time when diencephalic - hypophyseal maturity of the woman is completed.

1) Mechanism of Fertilization

The mechanism of fertilization, in the case of multiple pregnancy is not always the same. The fertilization of two ova from the same ovary are two possibilities. There is also the possibility of ova from more than two follicles being produced by one or both ovaries.

2) Twins with Different Fathers

It is possible, then , that the twins are children of different fathers, as has been demonstrated by the birth of twins of different races. No more than two twins can come from one ovum in the human species.

3) TYPES OF MULTIPLE PREGNANCIES

The following cases are possible:

* Polyembryonic: formation of Twins from the same ovum

* Polyfecundation: simultaneous fertilization of several ova

* Superfecundation: fertilization of different ova by different fathers

* Superfetation: two fertilization's which are separated in time but which are carried together. These fertilization's will produce two separate child births. Although several cases of superfetation are known, it is extremely rare.

4) Monozygotic Twins

If the twins come from the same ova, they are called monozygotic . They are of the same gender and are physically indistinguishable. Their blood group is the same, their psychological characteristics are similar and even their fingerprints are similar, although they will never be identical beings.

5) Dizygotic Pregnancy

When twins come from separate ova, the pregnancy is called dizygotic. They don not appear any more similar than any other pair of siblings, and they may or may not have the same gender.

DIZYGOTIC TWINS from the Same Ovum

Recently, it has been discovered that dizygotic twins can come from one ovum with two different sperm. This is due to the fertilization of a polar carrier corpuscle of the same chromatic mass of the ovum from which it comes.

6) SPECIAL CHARACTERISTICS

Thanks to ultrasound, multiple pregnancies can be detected very early. From the 5th or 6th week of amenorrhea one can be sure if the pregnancy is single or multiple. In the case of twins, their weight at birth is significantly lower than neonates in a single pregnancy. Multiple pregnancies can be harder on the mothers body. For this reason the doctor establishes special measures of control in such cases and multiple pregnancies are always considered to be high risk. The birth of twins tends to occur on average two (2) weeks before that of single births. The birth tends to be slower since the uterus is over stretched. After expulsion of the fetus, there is a period of latency until contractions begin again and the second child is born.