compared with animals in human multiple pregnancy develops much less.Its frequency varies from 0.4% to 1.6% of all pregnancies.Recently, however, there is a tendency to increase the number of multiple pregnancies.Multiple pregnancy - is not only the joy of the parents, but also a high likelihood of complications during pregnancy and childbirth.Therefore, multiple pregnancy relate to border states, and to a high risk group.A high percentage of multiple births observed in Africa, while in Japan, China multiple pregnancy is less common.
causes and occurrence of multiple pregnancies
say about multiple pregnancy, when the uterus simultaneously develop two or more fruits.Children born as a result of multiple pregnancy are called twins If you have twins, ten Smiles .Most often form a double.There are dizygotic (fraternal) and monozygotic (identical) twins.Dizygotic twins formed by the fertilization of two or more ova and the twins resemble each other no more than brothers or sisters born at
Mechanism of fraternal twins:
main cause of dizygotic multiple pregnancies is a strong hormonal stimulation of the ovaries Ovarian stimulation: if you want to get pregnant .Elevated levels of follicle stimulating hormone (FSH), which is synthesized by the pituitary gland, and acts on the ovaries can lead to:
- maturation of multiple eggs simultaneously in a single menstrual cycle (with further fertilization) in one or both ovaries;
- maturation of multiple eggs in a single follicle and fertilization;
- conceive two or more embryos from several mature eggs, fertilized by sperm of different males.
Mechanism of identical twins:
monozygotic multiple pregnancy rate is 1/3 of all twins.Monozygotic twins can be configured in two ways: either the fertilized egg multicore multiple sperm or in the process of embryo development is its division.The division of the fertilized egg takes place in a period of two to fifteen days after conception.Separation of the zygote in the first three days after fertilization results in the formation of two separate embryos that have two chorionic (future placenta) and two amnion (water bubble).This is called monozygotic twins and bihorionalnoy biamnioticheskoy.The division of the embryo in the period from the 4th to the 8th day after conception leads to the formation of two embryos with separate amniotic cavity (biamnioticheskaya monochorionic twins).In the case of division of the fertilized egg in the 9th - 10th day after conception formed two embryos to a common placenta and membranes (monoamniotic monochorionic twins).At a later division of the embryo (14 -15 days) division is not going to end, and the fruit will be spliced together (as conjoined twins are formed).
Causes of multiple pregnancy:
- late implantation and lack of oxygen;
- metabolic disorder Metabolism: The basis of life of all living environment;
- effects of toxic and other harmful factors;
- widespread use of hormonal contraception Hormonal contraception: birth control pills today ;
- heredity (the presence of twins in the immediate family);
- anomalies of the uterus (the two-horned uterus, intrauterine septum);
- development of technologies of assisted reproduction (IVF and ovarian stimulation with hormones).
course of multiple pregnancy and childbirth
Multiple pregnancy often proceeds with various complications.This is due to the increased loading several times on the woman's body and higher pregnancy hormones.So, the first trimester of pregnancy is associated with severe toxicity and / or uncontrollable vomiting.In the second and third trimester increases the load on the cardiovascular system, and the enlarged uterus is pressing internal organs (heart, lungs, intestines and bladder), which is accompanied by shortness of breath, fatigue, heart palpitations, and urinary, bowel disorders (constipation, diarrhea).Noted earlier onset and severity of the preeclampsia, resulting in enhanced hematopoiesis depleted iron stores in the body that leads to the development of iron deficiency anemia.Most of the placenta or the presence of multiple placentas previa tend to, and therefore bleeding.The risk of premature detachment of the placenta resulting in overstretched uterus.Often there is fetal hypoxia, so fetoplacental complex can not cope with their functions.This leads to the intrauterine development.
Childbirth in multiple pregnancies often start early and / or prenatal outpouring of water.During childbirth is accompanied by weakness of labor (hyperextension of the uterus), the postpartum period is a high risk of bleeding.Often multiple pregnancy rodorazreshayut caesarean section.Prompt delivery is carried out at a breech or transverse position of the first fetal intrauterine hypoxia, and increasing weakness of tribal forces.