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Multiple pregnancy: risks and complications

by Alivia Nyhan
Published: Last Updated on

It is known as multiple pregnancies or multiple gestations, the simultaneous development of two or more fetuses within the uterus. This condition can result from the fertilization of an ovum that divides, giving rise to identical or monozygotic twins, or by the fertilization of two or more ovules, forming dizygotic or fraternal twins, which can be different in appearance or sex.

This event is rare, representing 1 to 1.2% of births. However, these cases have increased in recent years, mainly caused by fertility treatments. Still, it can also be due to the person’s genetic predisposition, the advanced age of the mother, and previous pregnancies. Multiple pregnancies are considered high risk. The presence of more embryos increases the possibility of abortion and the occurrence of complications, both in the mother and in the fetus. This FastlyHealarticle explains everything about multiple pregnancies: risks and complications.

Remember to go to your doctor, who will monitor the pregnancy, give you care recommendations, and, if necessary, will prescribe a treatment. The risks and complications in multiple pregnancies that we mention here can be controlled if detected in time.

Preeclampsia or high blood pressure

These pregnancies produce a greater possibility of presenting high blood pressure during pregnancy, so the risk of developing preeclampsia in multiple pregnancies is more significant than in a single pregnancy. It increases the risk almost three times in twin pregnancies and up to 9 times in pregnancies triples.

As a more significant effort is placed on each extra fetus in the gestation, the effects of preeclampsia tend to be more severe, causing more complications in both the mother and the fetuses, for example, HELLP syndrome or intrauterine growth retardation. In our article preeclampsia: symptoms, causes, and treatment we provide you with the information you need about this condition.

Primary anemia

The probability of having this condition during multiple gestations is 2 to 3 times higher than in a pregnancy with a fetus, and it occurs in 35 to 40% of multiple pregnancies. The presence of more than one fetus in pregnancy increases the demand for iron and folates, so there is a lack of this mineral in the mother, who is also extremely tired.

In addition, during multiple pregnancies, the mother’s total blood volume and plasma volume increase by up to approximately 50%, causing the level of red blood cells and hemoglobin to decrease. This causes the amount of oxygen that reaches the fetuses to be less, increasing the risk that one or both go into shock even if the mother is not, which leads to premature delivery.

You must go to your doctor to take a blood check and indicate the best treatment for your condition.


Another risk and complication of multiple pregnancies are bleeding after childbirth. This occurs when the uterine contraction, which is responsible for closing the blood vessels of the uterus torn by the beginning, does not happen when the fetuses and the placenta are expelled. Faced with this condition, the uterus is over-distended, and bleeding is triggered, with bruising on the upper lips and severe pain with possible accumulation of internal clots.

Given this condition, some drugs control bleeding, and in severe cases, surgery is used, so medical assistance is essential to evaluate the situation and apply the best treatment. Otherwise, it could be fatal for the mother.

Premature delivery

Preterm birth is a risk that increases in multiple gestations, occurring in 50% of cases. Ideally, delivery happens approximately at week 38 from the fertilization of the ovum, but in multiple pregnancies, it occurs earlier. The anticipation will depend on the number of fetuses that are developing.

On average, twins are born at 36 and a half weeks. In the gestation of three fetuses, it can occur at 33 weeks and quadruples. The birth has been observed at 30 weeks, while quintuplets only reach 26 weeks and a half.

Babies resulting from premature delivery may not have their organs fully developed and may increase the risk of health problems or infections. Even if they pass this stage until their body is mature, there is a possibility that later they will develop complications, so medical monitoring is essential to determine the health status of the children.

Intrauterine fetal death

Fetal death in utero during multiple gestations can be caused by various causes, mainly by the detachment of the placenta or retaining a dead fetus. One of the risks in multiple pregnancies is the death of one fetus, observed in 6.2% of cases.

This risk is up to three times higher in a pregnancy where fetuses share the placenta than in a pregnancy where each fetus has its placenta. When one of the fetuses dies, the probability of death for the other increases. If they are indifferent placentas, the mortality of the other is 14%, and if the fetuses share the placenta, death can occur in 26% of cases.

This can occur because elements are released from the dead fetus that obstructs the other’s arterial blood vessels, causing the blood flow to decrease, affecting their tissues, mainly the kidneys and the cerebral cortex. It is also possible that the loss of vascular resistance, which regulates blood flow, in the lifeless fetus, causes the total loss or a large part of the blood volume of the living twin, causing severe anemia or damage to the organs.

Previous placenta

Of the pregnancies in which placenta previa has occurred, 80% correspond to multiple pregnancies. Placenta previa is the condition in which the placenta establishes itself and develops in the lower part of the uterus. Hence, as there are several placentas or a larger placenta in multiple gestations, it fully or partially covers the orifice of the uterus. Cervix.

Due to this, there may be genital bleeding up to severe bleeding before or during delivery. It also increases the risk of causing premature labor. In these cases, the doctor usually recommends complete rest for a few days or weeks, depending on the topic, which is enough to guarantee the term of the pregnancy.

Premature detachment of the placenta

During pregnancy, there may be a partial or total premature detachment of the placenta, reducing the supply of oxygen and nutrients to the fetus. It occurs in up to 3.5% of pregnancies and increases the risk in multiple fetuses.

Placental abruption in multiple pregnancies can occur after the first baby has left the uterus or rapid amniotic fluid loss. The next baby needs to be delivered to avoid fetal problems, such as hypoxia, anemia, or congenital disabilities. This complication can also bring severe issues for the mother, so immediate medical attention before the first contractions or when water breaks in these pregnancies is essential.

Placental insufficiency

Fetal development in multiple pregnancies and demanding more nutrients from the mother also requires that the placenta be more prominent than in a single pregnancy.

When the placenta is not enlarged enough or abnormally formed, there is an insufficient amount of oxygen, hormones, and nutrients passed to the fetuses. It can cause the death of a fetus by hypoxia or compromise the development and growth of babies.

Intrauterine growth retardation

The restriction of intrauterine growth does occur in 12% of monochorionic multiple pregnancies.

In the pregnancy of identical or monoclonal fetuses, each has its placenta portion. Still, in some cases, these proportions are not the same, which causes the uterine growth of some of them to be restricted.

The restricted growth of the fetus is because the part of its placenta is more minor and does not receive enough nutrients and oxygen. This condition can be very severe, even causing the death of the fetus, which in turn could compromise the health of the other with neurological sequelae or increase the risk of death. If fetuses are still alive, it has been observed that there is a possibility that they will develop brain damage.

Umbilical cord problems

One of the complications that may occur during multiple pregnancies involves the umbilical cord, either due to its malformation or because it could be compromised due to the poor position of a fetus.

The most common abnormality in the umbilical cord is the so-called single umbilical artery, which presents two of the three blood vessels that it usually has, an artery and a vein. The incidence of this condition is 5% in multiple fetuses and can cause premature birth, kidney or heart malformations, or alterations in the baby’s growth.

Another complication is the prolapse of the umbilical cord. During the delivery of multiple gestations, the umbilical cord of the first baby may be ahead of the presentation of the second so that the cable can be trapped and compressed by the body of the baby. Baby. This will cause the infant not to get enough oxygen, leading to brain damage if you don’t act quickly. The most advisable thing in these cases is to practice a cesarean section.

On the other hand, in monochorionic or identical pregnancies that share the amniotic fluid sac, your umbilical cords may become entangled. Tightening or knotting these cords will impede blood flow to the fetus, causing the death of a fetus or the fetuses involved if not detected early.

Twin-twin transfusion syndrome

One of the best-known risks in a monoclonal or identical twin pregnancy is twin-twin or for-fetal transfusion syndrome. In 10 to 15% of these pregnancies, if it is left its natural course, there is mortality for both fetuses of 80 to 100%, and those that survive have a 30% probability of presenting neurological problems.

This syndrome diverts blood from one fetus to the other through the blood vessels that connect to the placenta. The fetus receiving excess blood presents an overload in its cardiovascular system, and there is an increase in amniotic fluid. In contrast, in the donor fetus, its growth is restricted, it does not receive enough blood, and the amount of amniotic fluid decreases. Sometimes it can cause your death.

If there is premature death, the fetus can be completely reabsorbed without leaving evidence of its existence, known as an evanescent twin, or become a compressed mass that adheres to the live fetus, called a compressed fetus.

The importance of adequate prenatal care

As mentioned at the beginning of this article, most of the risks and complications of multiple pregnancies can be prevented with adequate prenatal control, following the medical recommendations, and carrying out the check-ups indicated by the specialist.

Remember that these types of pregnancies are more complex. Therefore you should keep in close contact with your doctor in the event of any symptoms or news.

This article is merely informative. At FastlyHeal .com, we do not have the power to prescribe medical treatments or make any diagnosis. We invite you to see a doctor if you present any type of condition or discomfort.

If you want to read more articles similar to Multiple pregnancies: risks and complications, we recommend that you enter our Pregnancy and baby health category.

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