Data show that the incidence of twins was only 1% in the 1980s, but by 2005 the incidence of twins had risen to 3%, which is a greater risk than a singleton pregnancy, and a slight error may put both the fetus and the mother’s life at risk.
Causes of twin pregnancies
There are two main reasons for twin pregnancies: on the one hand, it is a family genetic predisposition, which usually inhibits the development of one follicle in a woman’s body, but some women can have two follicles developing at the same time, resulting in two fetuses; on the other hand, it is caused by assisted reproductive techniques, including “ovulation promotion” and “IVF techniques, which are the main reason for the significant increase in twin pregnancies in recent years. Ovulation promotion techniques are generally used for women with ovulation disorders that affect pregnancy, and can cause two or even more follicles to develop at the same time through drug stimulation, but must be monitored by a doctor, otherwise multiple pregnancies may occur. There are other stronger ovulatory drugs used in hospital treatment, such as human chorionic gonadotropin (HCG), which needs to be injected intramuscularly. It is important to note that you should never take ovulation medication such as polypills without permission, as this can easily result in uncontrollable multiple pregnancies, bringing great risk to the mother. When performing IVF, doctors usually implant 2 embryos into the uterus to increase the success rate, but this can also result in the creation of twins or multiples.
Can I get pregnant with twins by taking multiples pills?
It should be said that it is possible. The Duo Pill, also known as Clomiphene, has the effect of promoting ovulation, and if exactly two eggs are conceived at the same time, then there is a possibility of conceiving twins. However, taking clomiphene without permission is very dangerous. Firstly, it does not control the number of follicles, and women who are sensitive to the pills may even ovulate several or even a dozen eggs, and even if they conceive, they will not be able to have children; secondly, abuse of the pills can also lead to ovarian hyperstimulation syndrome, ovarian cysts, ovarian rupture and other problems. Women of childbearing age should not take ovulation-promoting drugs without authorization. If the disease requires it, the drug should be used under the guidance and monitoring of a doctor.
The difference between identical and dizygotic twins
Identical twins are two embryos that develop from the union of an egg and a sperm. They contain the same genetic material, their genotypes are mostly identical, and the fetuses look similar, have the same sex, and develop very similarly. In contrast, dizygotic twins are two eggs that combine with different sperm to develop into two embryos, similar to the relationship between ordinary siblings, and they may not have exactly the same genotype, but the genotypic similarity rate is high, and there are some differences in gender and looks. Heterozygotic twins are more common than identical twins, with the former being roughly three times more likely to occur than the latter, and a dragon and phoenix fetus must be a heterozygotic twin.
The effects of twin pregnancies on pregnant women are risky and not everyone is able to carry a twin pregnancy
Compared to singleton pregnancies, twin pregnancies place a great burden on the pregnant woman’s body in three ways.
(1) In the middle and late stages of pregnancy, the overly enlarged uterus will compress the diaphragm or the heart, causing a decrease in heart and lung function, especially in pregnant women with heart or respiratory diseases, where heart or lung function cannot be tolerated, resulting in heart failure and respiratory distress.
(2) Overstretching of the uterus may be unbearable for some pregnant women, causing frequent contractions, which may lead to miscarriage or premature delivery if this occurs early, and overstretching may cause relaxation of the uterus, which may result in hemorrhage during delivery due to weak contractions of the uterus.
(3) twin pregnancies are more prone to complications such as edema, hypertension, hyperemesis, and even secondary thrombotic disorders that can cause cerebral or pulmonary infarction or even more serious complications.
Effects of twin pregnancy on the fetus
The biggest impact on the baby is the increased chance of miscarriage or premature birth. Premature fetuses may have complications due to immature development of body organs, such as pulmonary dysplasia leading to neonatal pulmonary hyaline membrane disease, hematologic dysplasia leading to disseminated intravascular coagulation (DIC), and digestive dysplasia leading to gastric bleeding. The high incidence of malformations in twin pregnancies is due to the limited space in the uterus and the competition between the two fetuses for growth space and nutrition, which not only leads to smaller size, but also to mutual compression during the competition for space, and some fetuses may develop clubfoot or hand and foot deformities. In this case, one fetus may suffer from severe anemia or even death, and the other fetus may suffer from heart failure due to increased blood volume. In addition, fetal malformations in twin pregnancies are chromosomally and genetically related, such as Down’s syndrome, and we have seen cases of twin pregnancies with either trisomy 21 or trisomy 21 in one fetus, as well as cases of trisomy 18 and trisomy 13.
Can everyone have a twin pregnancy?
In general, women with a body mass index greater than 30, a height of less than 1.5 meters, a scarred uterus, and severe medical conditions (e.g., severe hypertension, poorly controlled diabetes mellitus) should not have a twin pregnancy. This is because the chances of complications increase exponentially with the increased pressure of an overly obese pregnant woman carrying a twin pregnancy, and the chances of extreme preterm delivery are very high in short women who can reach an average gestational age of <30 weeks in labor. Pregnant women with a scarred uterus are not absolutely unable to carry a twin pregnancy, but depending on their last surgical procedure, some uterine incisions are not suitable for excessive stretching, which can easily cause uterine rupture. In addition, pregnant women with cervical insufficiency are also not suitable for carrying twins. Because the cervix cannot bear certain pressure, the pregnant woman may miscarry at 20 or so weeks. Some mothers are very happy to carry twins, but somehow the opening of the uterus opens at 20 or so weeks and they miscarry without feeling pain, such pregnant women should have cervical cerclage if necessary to help them bear the pressure of twins.
Definition of complicated twin pregnancy and principles of avoidance
Complex twins refer to monochorionic twins, which can be divided into two types: monochorionic single amniotic sac and monochorionic double amniotic sac, characterized by both having only one placenta, with interconnected vessels allowing the 2 fetuses to compete for nutrients. Clinically, monochorionic twins usually have 4 dangerous complications: the first is TTTS, Twin-Transfusion Syndrome, which is characterized by too much amniotic fluid in one baby (the recipient) and too little amniotic fluid in the other (the donor), even to the point where the amniotic membrane is attached to the baby’s body, called the “attached baby”. A baby with a lot of amniotic fluid has a lot of blood, urinates a lot and therefore has a lot of amniotic fluid; a baby with too little amniotic fluid is a blood donor and delivers blood to another baby through the placenta, causing anemia, heart failure and weight loss. The second type is sIUGR, which is selective intrauterine growth retardation in twins, manifested as one baby is large and one baby is small, with a big difference in weight, related to vascular traffic or a huge difference in the area of the placenta for blood supply, with very many complications in the smaller baby, such as hypoxic cerebral palsy and mental retardation. The third type is TRAP heartless twin, i.e. twin reverse arterial perfusion syndrome, where one fetus develops normally and one fetus has no heart, and the normal fetus needs to supply blood to the heartless fetus, resulting in a high cardiac burden. The fourth type is TAPS, a twin fetus anemia-erythropoietic sequence syndrome, which is characterized by anemia symptoms in one fetus and an increase in red blood cells in the other baby, which is a relatively good prognosis.
Obstetrical checkups for twin pregnancies
First of all, it is important to check the nature of the chorionic villi at 7-14 weeks, if this golden time is missed, it is difficult to make a reasonable judgment in the subsequent monitoring. We usually determine whether it is monochorionic or bichorionic by ultrasound images. In monochorionic fetuses, there is a diaphragm between the fetuses, which has a sharp angle, while in bichorionic twin fetuses the septum between the two fetuses is very silky. Secondly, the frequency of labor and delivery is not the same. The frequency of checkups for twin fetuses is much more frequent than for single fetuses, with checkups at least once every 4 weeks and ultrasound every 4 weeks, while for monochorionic fetuses, ultrasound every 2 weeks or even once a week from 14 weeks of pregnancy, as complications are likely to occur from 16 to 22 weeks of pregnancy. Thirdly, the number of maternity check-ups has increased. In addition to routine blood tests, ultrasound tests are more frequent in twin pregnancies than in single pregnancies, and attention should also be paid to screening for complications such as gestational hypertension and gestational diabetes, with special attention to the risk of preterm delivery, which can be assessed by ultrasound examination of the length of the cervical canal. Fourth, there is more screening for fetal malformations. For example, Down’s syndrome, a prenatal diagnosis to rule out chromosomal abnormalities is generally considered for pregnant women over the age of 33.
Time to detect twin pregnancies
The presence of twin fetuses can usually be detected between 7 and 14 weeks of pregnancy, and then the nature of the chorionic villi is checked between 7 and 14 weeks of pregnancy. Once a mother knows she is pregnant, the first step is to confirm if the pregnancy is a twin pregnancy as early as possible. Some mothers who have IVF we keep track of and usually confirm if both fetuses are viable at 5-6 weeks. Since the fetus is still small in early pregnancy and the uterus has not yet reached its tolerance limit, most twin pregnancies do not increase pregnancy reactions or physical discomfort, so most twin pregnancies in early pregnancy are not very different from single pregnancies, including nutritional supplements and moderate exercise, which are similar to single pregnancies. To ensure a healthy fetus, it is important to communicate with your doctor, especially when you know you are pregnant with a twin, and to follow your doctor’s instructions for regular maternity checkups, including screening for chorionic villus, various complications, and assessment of whether you can continue the pregnancy.
Treatment of pregnant women who are not suitable for carrying twins
Selective reduction is recommended for pregnant women with severe combined medical conditions, scarred uterus, cervical insufficiency, excessive obesity (body mass index > 30) and excessive short stature (height below 150 CM). If the fetus is a double chorionic twin, potassium chloride can be injected directly into the heart of the target fetus, which is a simple and less invasive method, and is usually done at a relatively early period with fewer complications; however, for a single chorionic twin, because the blood vessels between the two fetuses communicate with each other, if potassium chloride is just administered to one fetus, it will cause the blood to back up after the fetus dies and the other one Therefore, the procedure is more complicated and requires the use of lumpectomy clamping and video ablation to block the umbilical cord blood flow, which is more invasive and has more complications, so this method should be chosen very carefully. For monochorionic twin fetuses, we would choose to reduce the fetus mainly when complications have occurred, meaning that if the fetus is not reduced, complications will occur and the fetus will be on the verge of death and the blood will back up after death causing the other healthy fetus to be affected, so the fetus should be reduced. Nowadays, the technique of reducing a fetus is more mature, and it is usually done in the early stages of pregnancy to assess whether the pregnancy can continue, and then the appropriate method is used to reduce the fetus according to the actual situation.
The main points of care for twin pregnancies in the middle of pregnancy
In fact, there are very few malnourished mothers nowadays, but there are more cases of over-nutrition. The more obvious problems are gestational diabetes, excessive obesity and more cases of thrombophilia.
(1) Diet: do not be picky, diversify nutrients, do not overeat, especially avoid excessive accumulation of carbohydrates, and eat less chocolate and ice-cream, which taste good but have a great impact on blood sugar; must maintain sufficient unsaturated fatty acids, and it is recommended to eat more protein-rich foods such as milk, eggs, red meat and seafood.
(2) Appropriate activities, mainly walking, due to pregnancy in a state of high blood viscosity, if long-term immobility, coupled with the compression of blood circulation in the lower limbs by the enlarged uterus, leading to lower limb edema and thrombophilia. We once had a patient who lay still in bed as soon as she heard she was pregnant, and after a few days she couldn’t move her hands and formed cerebral thrombosis. Although the fetus was finally saved and delivered safely near full term, the mother had a very hard time and was paralyzed and had no strength to hold her child.
(3) The possibility of premature miscarriage in the middle of pregnancy is higher. Pregnant women should monitor themselves and visit hospital outpatient clinics every 2 weeks for consultation and assessment of the risk of premature birth. The doctor will assess the suitability of the pregnant woman to move around according to her condition, because if she is bleeding or her cervix is too short, it is not suitable to move around too much.
Conditions that warrant prompt medical attention in twin pregnancies
When a pregnant woman has symptoms such as lower abdominal cramping, painful cramping, increased vaginal discharge, or abnormal fetal movement (significantly decreased or increased) after a meal, she should seek medical help promptly. It is important to count fetal movements after meals for mothers in the middle and late stages of pregnancy, because the fetus has an awakening cycle, the mother’s blood sugar will increase after eating, and the fetus will respond with increased activity like a feeding reflex. It is generally recommended that the mother count the fetal movements for one hour after the meal, a series of fetal movements is once, stopping for more than a minute, counted as the second, not less than three times an hour is normal, when the fetal movements are significantly reduced or increased, such as several hours or more than ten hours of continuous movement, it is considered too frequent fetal movements, which requires the mother to pay attention. If the mother does not know what is more and what is less, she is advised to go to the hospital as soon as possible to see the doctor, who will be able to determine the health of the baby through some methods.
It is difficult to give birth to a double baby, the safest way to give birth to a baby at 37 weeks of pregnancy is best?
When to give birth is to consider the situation of both the pregnant woman and the fetus. For the fetus, the longer it stays in the womb before reaching the due date, the more mature it is, but it should not exceed the due date for too long, otherwise the placenta function declines and the placenta ages, which can cause intrauterine accidents, and the chance of fetal hypoxia also increases, so it is generally hoped that the fetus will reach 37 weeks before delivery. For pregnant women, the pressure on the pregnant woman increases due to excessive expansion of the uterus, and the risk of bleeding during delivery increases with the increase of the gestational week, and this risk is relatively large. Therefore, it is not desirable for pregnant women to deliver beyond the expected date of delivery to avoid problems such as postpartum shock and removal of the uterus.
At present, the best time for delivery of twins is 37-38 weeks, but it also depends on the nature of the chorionic membrane. For monochorionic twins, as the gestational weeks increase, the chance of sudden intrauterine death of the fetus increases, so it is necessary to advance its termination period, if the fetus has not yet developed complications, it is recommended to deliver at 36-37 weeks, if the fetus has developed complications such as TTTS or SIUGR, as long as the fetus is mature, after If the fetus has developed complications such as TTTS or SIUGR, the pregnancy can be terminated after 34 weeks as long as the fetus is mature; for double chorionic twins, delivery at 37-38 weeks is recommended.
Risks of normal delivery of twins
The risk of normal delivery of twins is determined by the fetal orientation. The fetus that is relatively close to the cervix is called the first fetus, while the second fetus is positioned upwards.
(1) The fetal position of the first fetus is not cephalic, but breech or transverse, which is more risky and may cause fetal asphyxia, difficulty in emergence or the second fetus may be unstable and embedded in the uterus after the first fetus comes out.
(2) The second fetus is in breech position.
(3) The second fetus is larger than the first fetus. In addition, when both fetuses are in cephalic position, there is a risk of interlocking or mutual entrapment of the fetal heads. In general, twin pregnancies require prenatal (near term) assessment of the suitability of the fetal position for normal delivery.
Postpartum care for twin pregnancies
In the first postpartum period, the 24-hour postpartum hemorrhage should be detected because the chances of postpartum hemorrhage in twin pregnancies are exponentially higher than in singleton pregnancies, so the postpartum hemorrhage should be closely monitored, followed by avoidance of thrombophilia, which is now scored comprehensively and is a high-risk factor in twin pregnancies because of the compression of lower limb blood circulation by the enlarged uterus, leading to lower limb edema and thrombophilia , and when combined with factors such as advanced maternal age and bleeding during delivery, all increase the risk of thrombophilia. Therefore, it is recommended that the mother.
(1) Get out of bed as soon as possible after 24 hours to avoid thrombosis.
(2) Use elastic stockings to promote blood circulation in the lower extremities.
(3) Use drugs to inhibit thrombosis, such as low molecular heparin and aspirin. The other thing is to pay attention to the infection and recovery of the postpartum wound, which is generally not much different from that of a singleton. If the pelvic floor is relaxed, we should do some exercises to restore the pelvic floor function to avoid tension incontinence, uterine and vaginal prolapse, etc.