Genetic predisposition to birth of twins
Prenatal development of two children occurs when fertilization of the two eggs then there are the twins, they can either same-sex or opposite-sex, similar or totally different. Twins can be born with the development of two embryos from a single fertilized egg. In this case, the first stage of division of the ovum, the two cells separate from each other, each zygote gives rise to a new life and are born identical twins.
It has been noticed that if in the family were twins, there is a high probability of their occurrence and the next generations. Interesting fact that the inheritance of this peculiarity is transmitted both through the mother and the father. Therefore, if the family of the woman were not twins or fraternal twins, and a strong desire to become a mother of two children at the same time, it is advisable to choose a husband, in the pedigree which have been similar cases.
Inheritance of predisposition to give birth to twins is transmitted through 2-3 generations. Therefore, when the chosen girls were the grandparents of the twins, and also great-grandmother or great-grandfather had a twin, there is a big chance to get pregnant two kids.
Hormonal changes in the body
Multiple studies have proven that women have a greater chance of getting pregnant with twins after 40 years. This fact is explained by the fact that at this age often there are failures in a hormonal background, which provoke the failure of the menstrual cycle and the simultaneous release of two eggs. Girl is born with 2 million immature follicles and throughout life, only a small part of them turning into an egg, so the body is "in a hurry" before the onset of menopause to release more eggs.
Increases the probability of getting pregnant with twins abrupt withdrawal of hormonal contraceptive. When a woman drinks the pill, her body not formed of ovum, and accumulate the Mature follicles. And if you cancel the drug in the one month immediately released all the prepared egg. This month a woman gets a chance to get pregnant with twins, one egg can be fertilized for a few days before the other.
To be sure to conceive two children, a woman can undergo in vitro fertilization. In this case, the expectant mother is prescribed a course of hormonal therapy that affects her body produce several eggs and fertilize them artificially outside the female body and embedded in the layer of the endometrium. If successful, the result of the uterus begins to develop several embryos.