Multiple pregnancy – definition and species (twins and twins)
Multiple pregnancy is a pregnancy in which not one, but several (two, three or more) fetuses develop simultaneously in the uterus of a woman. Usually, the name of a multiple pregnancy is given depending on the number of fetuses: for example, if there are two children, then they talk about twins, if there are three, then they are threefold and
Currently, the frequency of multiple pregnancies ranges from 0.7 to 1.5% in various countries of Europe and the USA. The widespread and relatively frequent use of assisted reproductive technology (IVF) has led to an increase in the incidence of multiple pregnancies.
Depending on the mechanism of the appearance of twins, there are dizygotic (dvuyaytsevuyu) and monozygous (identical) multiple pregnancies. Children of twofold twins are called twins, and identical twins are called twins or twins. Among all multiple pregnancies, the frequency of dvuayaytsev twins is about 70%. Twins are always of the same sex and, like two drops of water, resemble each other, since they develop from a single ovum and have exactly the same set of genes. Twins can be of different sexes and are similar only as siblings, since they develop from different eggs, and, therefore, have a different set of genes.
Dual pregnancy develops as a result of the fertilization of two eggs simultaneously, which are implanted in different parts of the uterus. Quite often, the formation of dvuyaytsevny twins occurs as a result of two different sexual acts, held with a small interval between each other – no more than a week. However, dvuayaytsye twins can be conceived during one sexual intercourse, but on condition that there was a simultaneous maturation and release of two eggs from one or different ovaries. With dvuyaytsevoy twins, each fetus necessarily has its own placenta and its own fetal bladder. The position of the fetuses, when each of them has its own placenta and fetal bladder, is called bihorial bamniotic twins. That is, in the uterus there are simultaneously two placentas (bihorial twins), and two fetal bladders (bamniotic twins), in each of which the child grows and develops.
The identical twin develops from a single ovum, which after fertilization is divided into two cells, each of which gives rise to a separate organism. With identical twins, the number of placentas and membranes depends on the period of separation of a single fertilized egg. If separation occurs within the first three days after fertilization, while the ovum is in the fallopian tube and does not attach to the wall of the uterus, two placenta and two separate fetal sacs will form. In this case, in the uterus there will be two fetuses in two separate fetal bladders, each feeding on its own placenta. Such twin twins are called bihorial (two placentas) biamniotic (two fetal bladder).
If the fertilized egg is divided by 3 – 8 days after fertilization, that is, at the stage of attachment to the wall of the uterus, then two fetuses are formed, two fetal bladders, but one for two placenta. In this case, each twin will be in his fetal bladder, but they will eat from one placenta, from which two umbilical cords will move. This variant of twins is called monochorial (one placenta) biamniotic (two fetal bladder).
If the fertilized egg is divided into 8 – 13 days after fertilization, then two fetuses will form, but one placenta and one fetal bladder. In this case, both fetuses will be in the one on two fetal bladder, and be fed from the same placenta. Such twins are called monochorial (one placenta) monoamniotic (one fetal bladder).
If the fertilized egg is divided later than 13 days after fertilization, then as a result of this, Siamese twins develop, which are fused with different parts of the body.
From the point of view of safety and normal development of the fetus, bihorial biamniotic twins, both identical and dual, are the best option. Monochorial bamniotic twins develop worse and the risk of pregnancy complications is higher. And the most unfavorable twins are monochorial monoamniotic.
Probability of multiple pregnancy
However, if the pregnancy occurs under the influence of drugs or assisted reproductive technologies, the probability of twins or triplets is significantly higher than with natural conception. So, when using drugs to stimulate ovulation (for example, Clomiphene, Clostilbegit and
Multiple pregnancy with IVF
If a woman becomes pregnant with IVF (in vitro fertilization), then the probability of a multiple pregnancy is, according to various researchers, from 35% to 55%. In this case, a woman may be twins, triplets or quadruples. The mechanism of multiple pregnancy with IVF is very simple – four embryos are simultaneously planted in the uterus, hoping that at least one of them will take root. However, not only one, but two, three or all four embryos can implant themselves, that is, implant themselves into the wall of the uterus, as a result of which a woman has a multiple pregnancy.
If during the ultrasound after IVF a multiple pregnancy was detected (triplet or quadruple), then a woman is offered "remove" extra embryos, leaving only one or two. If a twin is found, then the embryos are not offered. In this case, the decision is made by the woman herself. If she decides to leave all three or four engrafted embryos, she will have a quadruple or triplet. The further development of multiple pregnancies that have developed as a result of IVF is no different from that which has occurred in a natural way.
Reduction in multiple pregnancies
Deletion "superfluous" An embryo in a multiple pregnancy is called a reduction. This procedure is offered to women who have more than two fetuses in the uterus. Moreover, at present, reduction is offered not only to women who become pregnant with triple or quadruple as a result of IVF, but also conceived in a natural way more than two fruits at the same time. The goal of the reduction is to reduce the risk of obstetric and perinatal complications associated with multiple pregnancies. When reducing, two fruits are usually left, as there is a risk of spontaneous death of one of them in the future.
The reduction procedure for multiple pregnancies is carried out only with the consent of the woman and on the recommendation of the gynecologist. In this case, the woman herself decides how many fruits to reduce and how much to leave. The reduction is not carried out against the background of threatened abortion and with acute inflammatory diseases of any organs and systems, since against such an unfavorable background the procedure can lead to the loss of all fetuses. Reduction can be carried out up to 10 weeks of pregnancy. If you do this in the later stages of pregnancy, the remnants of fetal tissues will irritate the uterus and provoke complications.
Currently, the reduction is performed by the following methods:
- Transcervical. A flexible and soft catheter connected to a vacuum aspirator is inserted into the cervical canal. Under ultrasound, the catheter is advanced to the embryo to be reduced. After the tip of the catheter reaches the fetal membranes of the reduced embryo, a vacuum aspirator is turned on, which separates it from the uterine wall and sucks it into the container. In principle, transcervical reduction is inherently an incomplete vacuum abortion, during which not all fetuses are removed. The method is quite traumatic, so it is rarely used at present;
- Transvaginal. It is produced under anesthesia in the operating room, similar to the process of collecting oocytes for IVF. A biopsy adapter is inserted into the vagina and, under ultrasound guidance, a puncture needle is punctured into the vagina. After which the needle is removed. This method is currently used most often;
- Transabdominal. It is performed in the operating room under general anesthesia in the same way as amniocentesis. A puncture is made on the abdominal wall through which a needle is inserted into the uterus under ultrasound guidance. This needle pierce the embryo to be reduced, and then remove the tool.
Any reduction method is technically difficult and dangerous, since in 23–35% of cases pregnancy is lost as a complication. Therefore, many women prefer to face the severity of carrying several fruits than losing the entire pregnancy. In principle, the modern level of obstetric care allows you to create the conditions for carrying a multiple pregnancy, as a result of which completely healthy children are born.
The Most Multiple Pregnancy
To date, the most multiple pregnancy, which can successfully end with the birth of healthy children without deviations, is the gear. If there are more than six fruits, some of them suffer from developmental delay, which persists throughout their life.
Multiple pregnancy – delivery times
Multiple pregnancy – causes
Signs of a Multiple Pregnancy
Currently, the most informative method for the diagnosis of multiple pregnancy is ultrasound, but the clinical signs on which the doctors of the past were based still play a certain role. These clinical signs of multiple pregnancies allow the doctor or woman to suspect the presence of several fetuses in the uterus and, on the basis of this, to produce a targeted ultrasound study, which with 100% accuracy confirms or refutes the assumption.
So, the following data are signs of a multiple pregnancy:
- The size of the uterus is too large, not up to date;
- Low location of the head or pelvis of the fetus above the entrance to the pelvis in combination with a high standing of the uterus bottom, which does not meet the deadline;
- The discrepancy between the size of the fetal head and the volume of the abdomen;
- Large volume of the abdomen;
- Excessive weight gain;
- Listening to two heartbeats;
- The concentration of hCG and lactogen is twice the normal;
- Rapid fatigue of a pregnant woman;
- Early and severe toxicosis or preeclampsia;
- Persistent constipation;
- Marked swelling of the legs;
- Increased blood pressure.
If you identify a combination of several of these symptoms, the doctor may suspect a multiple pregnancy, however, an ultrasound scan is necessary to confirm this assumption.
How to determine multiple pregnancies – effective diagnostic methods
Ultrasound diagnosis of multiple pregnancy
Ultrasound diagnosis of multiple pregnancy is possible in the early stages of gestation – from 4 to 5 weeks, that is, literally immediately after the delay of menstruation. During the ultrasound, the doctor sees several embryos in the uterus, which is undoubted evidence of multiple pregnancies.
Crucial for the choice of tactics of pregnancy and the calculation of the risk of complications is the number of placentas (chorinity) and fetal bubbles (amniotic), and not dvuyaytsevost or monoaiyatelnost fetus. The most favorable course of pregnancy is with bichorial biamniotic twins, when each fetus has its own placenta and fetal bladder. The least favorable and with the maximum possible number of complications is monochorial monoamniotic pregnancy, when two fetuses are in one fetal bladder and are fed from one placenta. Therefore, during the ultrasound examination, the doctor considers not only the number of fetuses, but also determines how many placentas and saccharides they have.
In case of multiple pregnancies, ultrasound plays a huge role in detecting various malformations or delaying fetal development, since biochemical screening tests (determination of the concentration of hCG, AFP, etc.) are not informative. Therefore, the identification of malformations by ultrasound in multiple pregnancies must be made in the early stages of gestation (from 10 to 12 weeks), while assessing the condition of each fetus separately.
HCG in the diagnosis of multiple pregnancy
Multiple pregnancy development
The development of multiple pregnancies creates a very high load on the mother’s body, since the cardiovascular, respiratory, urinary systems, as well as the liver, spleen, bone marrow and other organs continuously work in a heightened mode for a rather long period of time (40 weeks) to ensure not one and two or more growing organisms with everything necessary. Therefore, the incidence in women carrying multiple pregnancies is increased by 3 – 7 times compared with singleton. Moreover, the more fruits in the uterus of a woman, the higher the risk of complications from various organs and systems of the mother.
If a woman before the onset of multiple pregnancies suffered from any chronic diseases, then they are necessarily exacerbated, because the body is experiencing very strong loads. In addition, with multiple pregnancy, half of the women develop preeclampsia. All pregnant women in the second and third trimesters appear edemas and arterial hypertension, which are the body’s normal response to the needs of the fetuses. A rather common complication of multiple pregnancy is anemia, which must be prevented by taking iron supplements throughout the entire period of gestation.
For normal growth and development of several fruits, a pregnant woman should eat fully and vigorously, since her need for vitamins, microelements, proteins, fats and carbohydrates is very high. The daily caloric intake of a woman who bears twins should be at least 4500 kcal. Moreover, these calories should be gained due to nutrient-rich food, and not chocolate and flour products. If a woman with a multiple pregnancy feeds poorly, then this leads to the depletion of her body, the development of severe chronic pathologies and numerous complications. During a multiple pregnancy, a woman normally gains 20–22 kg in weight, with 10 kg in her first half.
In multiple pregnancies, one fruit is usually larger than the second. If the difference in body weight and height between the fruits does not exceed 20%, then this is considered the norm. But if you exceed the mass and growth of one fetus compared with the second by more than 20%, they speak of a delay in the development of a second, too young child. The delay in the development of one of the fruits in multiple pregnancies is noted 10 times more often than in the case of single pregnancies. Moreover, the likelihood of developmental delay is highest in monochorial pregnancy and minimal in bihorial biamniotic.
Multiple pregnancy usually ends prematurely as the uterus is too stretched. With double birth usually occurs at 36 – 37 weeks, with triple – at 33 – 34 weeks, and at four, at 31 weeks. Due to the development of several fetuses in the uterus, they are born with a smaller weight and body length compared with those born from singleton pregnancy. In all other aspects of the development of multiple pregnancies is exactly the same as the singleton.
Multiple pregnancy – complications
In case of multiple pregnancies, the following complications can develop:
- Miscarriage in early pregnancy;
- Premature labor;
- Fetal death of one or both fetuses;
- Severe preeclampsia;
- Bleeding in the postpartum period;
- Hypoxia of one or both fruits;
- Collision of fruits (coupling of two fruits with heads, as a result of which they simultaneously find themselves at the entrance to the small pelvis);
- Fetofetal blood transfusion syndrome (SPFG);
- Reverse arterial perfusion;
- Congenital malformations of one of the fruits;
- Delayed development of one of the fruits;
- Fusion of fruits with the formation of Siamese twins.
The most severe complication of multiple pregnancy is fetal fetal blood transfusion syndrome (SPFG), occurring in monochorial twins (with one placenta for two). SPFG is a violation of blood flow in the placenta, as a result of which the blood from one fetus is redistributed to another. That is, an insufficient amount of blood flows to one fetus, and an excess amount to another. In case of SFGH, both fetuses suffer from inadequate blood flow.
Another specific complication of multiple pregnancy is the fusion of fetuses. Such accrete children are called conjoined twins. Fusion is formed in those parts of the body with which the fruits are most closely in contact. The most common fusion occurs in the chest cells (thorakopagi), the abdomen in the navel (omphalopagi), the bones of the skull (craniopagi), the coccyx (pygopagi) or the sacrum (isiopagi).
In addition to these, in the case of multiple pregnancies, the same complications can develop as in the case of singleton pregnancies.
Births in multiple pregnancies
If the multiple pregnancy proceeded normally, the fetuses have a longitudinal position, then delivery is possible in a natural way. In multiple pregnancies, complications in childbirth develop more often than in singleton babies, which leads to a higher incidence of emergency cesarean sections. A woman with multiple pregnancies should be hospitalized 3–4 weeks before the expected date of delivery to the maternity hospital rather than waiting for the onset of labor at home. A stay in the maternity hospital is needed to examine and assess the obstetric situation, on the basis of which the doctor will decide on the possibility of natural childbirth or on the need for a planned caesarean section.
The standard delivery tactic for multiple pregnancies is the following: 1. If the pregnancy is complicated, one of the fetuses is in a transverse position or both in pelvic presentation, the woman has a scar on the uterus, then a planned caesarean section is performed. 2. If the woman came to the birth in a satisfactory condition, the fruits are in the longitudinal position, then it is recommended to lead the birth through natural ways. With the development of complications, an emergency caesarean section is performed.
Currently, in multiple pregnancies, a planned cesarean section is usually performed.
Multiple pregnancy: causes, types, diagnosis, childbirth – video
When they give sick leave (maternity leave) for multiple pregnancies
Multiple pregnancy – reviews
Reviews of the course and childbirth in multiple pregnancies are emotionally colored, and in most cases women respond positively to the experience gained, even despite certain difficulties associated with a large belly, great fatigue, edema, and other factors accompanying gestation and the birth of several children at once. Women note that wearing pregnancy, especially after the fifth month, was difficult, since weight gain was about 20 kg, which significantly increased the load on all internal organs and the musculoskeletal system. Also, women say that they should mentally prepare for the fact that physically it will be very difficult. Many indicate in the reviews that they constantly wanted to eat, since the two fruits required a very large amount of energy and nutrients for their growth and development. In this regard, women experienced discomfort and fear associated with a possible strong weight gain after childbirth. In addition, multiple pregnancies almost always lead to stretch marks on the abdomen and a significant change in the usual forms, which should be morally ready.
Regarding childbirth in multiple pregnancies, the overwhelming majority of women respond positively, noting that they had a planned cesarean section in periods of 36 to 38 weeks. Natural childbirth in multiple pregnancies is rarely carried out, but those women who have gone through this indicate that, overall, everything was fine.
The author: Nasedkina