Multiple pregnancies - Management

Patients with multiple pregnancies should visit the antenatal clinic more often than with a single pregnancy: 2 times a month up to 28 weeks (when a certificate of incapacity for work due to pregnancy and childbirth is issued), after 28 weeks - 1 time in 7-10 days. A consultation with a therapist is necessary 3 times during pregnancy.

Given the increased need for caloric food, proteins, minerals, and vitamins during multiple pregnancies, special attention should be paid to educating the pregnant woman on issues of proper balanced nutrition. In contrast to singleton pregnancies, a total weight gain of 20–22 kg is considered optimal during multiple pregnancies.

Pregnant women with multiple pregnancies are prescribed antianemic therapy from the 16th to 20th week (oral administration of iron-containing drugs at a dose of 60–100 mg/day and folic acid at 1 mg/day for 3 months).

To prevent premature birth, pregnant women with multiple pregnancies are recommended to limit physical activity and increase the duration of daytime rest (three times for 1–2 hours). The indications for issuing a sick leave certificate are expanded.

To predict premature birth, it is necessary to examine the condition of the cervix. The method of choice is transvaginal cervicography, which allows, in addition to assessing the length of the cervix, to determine the condition of the internal os, which is impossible with a manual examination. Gestation periods from 22–24 to 25–27 weeks are considered “critical” for pregnant women with multiple pregnancies in terms of the risk of premature birth. With a cervical length of ≤34 mm at 22–24 weeks, the risk of premature birth before 36 weeks is increased; the risk criteria for premature birth at 32–35 weeks is a cervical length of ≤27 mm, and the risk criterion for “early” premature birth (before 32 weeks) is ≤19 mm.

Careful dynamic ultrasound monitoring is necessary for early diagnosis of fetal growth restriction.

In addition to fetometry, in case of multiple pregnancy, as well as in case of singleton pregnancy, the assessment of the fetus condition (cardiotocography, Doppler blood flow in the mother-placenta-fetus system, biophysical profile) is of great importance for developing pregnancy and labor management tactics. Determining the amount of amniotic fluid (polyhydramnios and oligohydramnios) in both amnios is of great importance.

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Treatment of feto-fetal blood transfusion

The method of choice in the treatment of severe feto-fetal hemotransfusion is endoscopic laser coagulation of anastomosing vessels of the placenta under echographic control ("sonoendoscopic" technique). The effectiveness of endoscopic laser coagulation therapy of SFFG (birth of at least one live child) is 70%. This method involves transabdominal introduction of a fetoscope into the amniotic cavity of the recipient fetus. The combination of ultrasound monitoring and direct visual inspection through the fetoscope allows for examination of the chorionic plate along the entire interfetal septum, detection and coagulation of the anastomosing vessels. The surgical intervention ends with drainage of amniotic fluid until its amount is normalized. With the help of endoscopic laser coagulation, it is possible to prolong pregnancy by an average of 14 weeks, which leads to a decrease in intrauterine fetal death from 90 to 29%.

An alternative tactic for managing pregnant women with pronounced SFFH when laser coagulation of anastomosing placental vessels is impossible is amniodrainage of excess amniotic fluid from the amniotic cavity of the recipient fetus. This palliative treatment method, which can be used repeatedly during pregnancy, although it does not eliminate the cause of SFFH, helps reduce intra-amniotic pressure and thus compression, as a rule, of the umbilical cord attached to the membrane and superficial vessels of the placenta, which to a certain extent improves the condition of both the donor fetus and the recipient fetus. The positive effects of amniodrainage include prolongation of pregnancy as a result of a decrease in intrauterine volume.

The effectiveness of amniodrainage performed under ultrasound control is 30–83%. The main and most important difference in perinatal outcomes between endoscopic laser coagulation and repeated amniodrainage is the frequency of neurological disorders in surviving children (5 versus 18–37%, respectively).

Reverse arterial perfusion

Reverse arterial perfusion in twins is a pathology inherent only to monochorionic pregnancy and is considered the most pronounced manifestation of FTD. This pathology is based on impaired vascular perfusion, as a result of which one fetus (recipient) develops at the expense of the donor fetus due to the presence of umbilical arterio-arterial anastomoses. In this case, the donor fetus ("pump"), as a rule, does not have structural anomalies, but signs of hydrocele are detected. The recipient fetus ("parasitic") always has multiple anomalies incompatible with life: the head and heart may be absent, or significant defects of these organs are detected (rudimentary heart). The prognosis for the donor fetus is also unfavorable: in the absence of intrauterine correction, mortality reaches 50%. The only way to save the life of the donor fetus is feticide of the recipient fetus (umbilical cord ligation).

Intrauterine death of one of the fetuses

Intrauterine death of one of the fetuses in multiple pregnancies may occur at any gestational age, resulting in the "death" of one ovum in the first trimester (20% of cases) and the development of the so-called "paper fetus" in the second trimester of pregnancy. The average frequency of death of one or both fetuses in the early stages of gestation is 5% (2% in singleton pregnancies). The frequency of late (in the second and third trimesters of pregnancy) intrauterine death of one of the fetuses is 0.5–6.8% in twins and 11–17% in triplets. The main causes of late intrauterine death include monochorionic placentation of the fetus (FFP), and in bichorionic placentation, growth retardation of the fetus/fetuses and membrane insertion of the umbilical cord. The frequency of intrauterine fetal death in monochorionic twins is 2 times higher than in bichorionic multiple pregnancies.

If one of the fetuses dies in the first trimester of pregnancy, in 24% of cases the second fetus may also die or a miscarriage may occur. However, in most cases there may be no adverse effects on the development of the second fetus.

If one of the fetuses dies in the II-III trimesters of pregnancy, premature termination of pregnancy is possible due to the release of cytokines and prostaglandins by the "dead" placenta. Brain damage also poses a major risk to the surviving fetus, due to severe hypotension due to the redistribution of blood ("bleeding") from the living fetus to the fetoplacental complex of the deceased fetus.

In case of intrauterine death of one of the fetuses in dichorionic twins, the optimal tactic is considered to be prolongation of pregnancy. In case of monochorionic placentation, the only way to save a viable fetus is a cesarean section performed as soon as possible after the death of one of the fetuses, when the brain of the surviving fetus has not yet been damaged. In case of intrauterine death of one of the fetuses in monochorionic twins at an earlier stage (before viability is achieved), the method of choice is considered to be immediate occlusion of the umbilical cord of the dead fetus.

Congenital anomalies of fetal development

The tactics of managing multiple pregnancies discordant with respect to congenital anomalies of fetal development depend on the degree of the defect, the gestational age of the fetus at the time of diagnosis and, most importantly, the type of placentation. In case of bichorionic twins, selective feticide of the affected fetus is possible (intracardiac administration of potassium chloride under ultrasound control), however, given the unsafe nature of the invasive procedure, in case of absolute lethality of the defect (for example, anencephaly), the issue of expectant tactics should be considered in order to reduce the risk of the procedure for the second fetus.

In monochorionic placentation, the presence of interfetal transplacental anastomoses excludes the possibility of selective feticide using potassium chloride due to the risk of it entering the circulation of a sick fetus or bleeding into the vascular bed of a living fetus.

In case of monochorionic twins, other methods of feticide of the sick fetus are used: injection of pure alcohol into the intra-abdominal part of the umbilical artery, ligation of the umbilical cord during fetoscopy, endoscopic laser coagulation, introduction of a thrombogenic coil under echographic control, embolization of the sick fetus. The optimal tactics for managing monochorionic twins with discordance in relation to congenital anomalies of development is considered to be occlusion of the umbilical vessels of the sick fetus.

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Conjoined twins

This pathology is typical for monochorionic monoamniotic pregnancy. Its frequency is 1% of monochorionic twins.

The most common types of fusion include thoracopagus (fusion in the chest area), omphalopagus (fusion in the area of the navel and cartilage of the xiphoid process), craniopagus (fusion of homologous parts of the skull), pygopagus and ischiopagus (fusion of the lateral and lower parts of the coccyx and sacrum), as well as incomplete divergence: bifurcation in only one part of the body.

The prognosis for conjoined twins depends on the location and degree of connection, as well as the presence of concomitant developmental defects. In this regard, in order to more accurately establish the potential for survival of children and their separation, in addition to ultrasound, it is necessary to conduct additional research methods such as echocardiography and magnetic resonance imaging (MRI).

Pregnancy management in case of intrauterinely diagnosed fused twins consists of termination of pregnancy if the diagnosis is established in the early stages of gestation. If surgical separation of the newborns is possible and the mother agrees, expectant tactics are followed until the fetuses reach viability.

Chromosomal pathology in dizygotic multiple pregnancy (in each fetus) is observed with the same frequency as in singleton pregnancy, and thus the possibility of at least one of the fetuses being affected is doubled.

In identical twins, the risk of chromosomal abnormalities is the same as in singleton pregnancies, and in most cases both fetuses are affected.

If the tactics of pregnancy management with twins with diagnosed trisomy of both fetuses is unambiguous - termination of pregnancy, then in case of discordance of fetuses with respect to chromosomal pathology, either selective feticide of the sick fetus or prolongation of pregnancy without any intervention are possible. The tactics are entirely based on the relative risk of selective feticide, which can cause miscarriage, premature birth, and also death of a healthy fetus. The issue of prolongation of pregnancy with bearing of a known sick child should be decided taking into account the wishes of the pregnant woman and her family.

Course and management of labor

The course of labor in multiple pregnancies is characterized by a high frequency of complications: primary and secondary weakness of labor, premature rupture of membranes, prolapse of umbilical cord loops and small parts of the fetus [18]. One of the serious complications of the intranatal period is premature detachment of the placenta of the first or second fetus. The cause of placental abruption after the birth of the first fetus is considered to be a rapid decrease in the volume of the uterus and a decrease in intrauterine pressure, which is especially dangerous in monochorionic twins.

A rare (1 in 800 twin pregnancies), but severe intranatal complication is a collision of fetuses with a breech presentation of the first fetus and a cephalic presentation of the second. In this case, the head of one fetus clings to the head of the second and they simultaneously enter the entrance of the small pelvis. In case of a collision of twins, the method of choice is an emergency cesarean section.

In the postpartum and early postpartum period, due to overstretching of the uterus, hypotonic bleeding may develop.

The method of delivery for twins depends on the presentation of the fetuses. The optimal method of delivery for cephalic presentation of both fetuses is considered to be delivery through the natural birth canal, and for transverse presentation of the first fetus - a cesarean section. Breech presentation of the first fetus in primiparous women is also considered an indication for a cesarean section.

In case of cephalic presentation of the first and breech presentation of the second, the method of choice is delivery through the natural birth canal. During labor, external rotation of the second fetus is possible, with its transfer to cephalic presentation under the control of ultrasound examination.

The transverse position of the second fetus is currently considered by many obstetricians as an indication for a cesarean section on the second fetus, although with sufficient qualification of the doctor, the combined rotation of the second fetus onto the leg with its subsequent extraction does not present any particular difficulties.

Clear knowledge of the type of placentation is of great importance for determining the tactics of labor management, since in monochorionic twins, along with a high frequency of antenatal feto-fetal blood transfusion, there is a high risk of acute intranatal transfusion, which can be fatal for the second fetus (severe acute hypovolemia with subsequent brain damage, anemia, intranatal death), therefore, the possibility of delivering patients with monochorionic twins by cesarean section cannot be ruled out.

The greatest risk of perinatal mortality is associated with the birth of monochorionic monoamniotic twins, which requires particularly careful ultrasound monitoring of the growth and condition of the fetuses, in which, in addition to the specific complications inherent in monochorionic twins, umbilical cord torsion is often observed. The optimal method of delivery for this type of multiple pregnancy is considered to be a cesarean section at 33–34 weeks of pregnancy. Caesarean section is also used for delivery of conjoined twins if this complication is diagnosed late.

In addition, an indication for a planned cesarean section in twins is considered to be a pronounced overstretching of the uterus due to large children (total fetal weight of 6 kg or more) or polyhydramnios. In pregnancy with three or more fetuses, delivery by cesarean section at 34–35 weeks is also indicated.

When conducting labor through the natural birth canal, it is necessary to carefully monitor the patient's condition and constantly monitor the cardiac activity of both fetuses. In case of multiple pregnancy, it is preferable to conduct labor with the mother lying on her side to avoid the development of inferior vena cava compression syndrome.

After the birth of the first child, external obstetric and vaginal examinations are performed to clarify the obstetric situation and the position of the second fetus. It is also advisable to conduct an ultrasound examination.

When the fetus is in a longitudinal position, the amniotic sac is opened, slowly releasing the amniotic fluid; labor then proceeds as usual.

The question of a cesarean section during labor in multiple pregnancies may also arise for other reasons: persistent weakness of labor, prolapse of small parts of the fetus, umbilical cord loops in cephalic presentation, symptoms of acute hypoxia of one of the fetuses, placental abruption, etc.

During multiple births, it is essential to prevent bleeding in the afterbirth and postpartum periods.

Patient education

Every patient with multiple pregnancy should be aware of the importance of a complete, balanced diet (3500 kcal per day), with special attention paid to the need for prophylactic use of iron preparations.

Patients with multiple pregnancies should know that the total weight gain during pregnancy should be at least 18–20 kg, while weight gain in the first half of pregnancy (at least 10 kg) is important to ensure the physiological growth of the fetuses.

All patients with multiple pregnancies should be informed about the main possible complications, primarily miscarriage. It is necessary to explain to the woman the need to follow a protective regimen, including reduced physical activity, mandatory daytime rest (three times for 1-2 hours).

Pregnant women with monochorionic twins should undergo systematic examination, including ultrasound, more frequently than with dichorionic twins, to detect early signs of twin-to-twin transfusion syndrome. These patients should be informed about the possibility of surgical correction of this complication.