The umbilical cord is given special diagnostic value during pregnancy. This strong cord reliably connects the fetus and the placenta, providing continuous communication with the source of nutrition, oxygen. How the umbilical cord is arranged, how many vessels it should have, and what deviations from the norm can talk about, we will tell in this article.
Structure and function
The umbilical cord is a long and very strong organ, which at one end connects to the umbilical opening of the fetus, and at the other end to the placenta. The length of the umbilical cord is from 50 to 70 centimeters and even more, it is she who allows the baby to move normally in the uterus, to make coups. A shorter umbilical cord complicates the course of pregnancy and is dangerous in the birth process, since its tension at the time of the birth of a baby can cause a large part of the placenta to come off and detach ahead of time.
The thickness of the umbilical cord is about 2 centimeters, it is strong and can withstand significant loads, resembling strong rubber in its structure.
Normally, the umbilical cord has 3 vessels. They are located inside the cord. There are two umbilical arteries. They come from the internal iliac vessels. Two umbilical arteries perform a transport function - they carry the baby's blood, saturated with carbon dioxide and metabolic products, to the placenta. The placenta helps to remove substances that have become unnecessary into the mother's blood, so that later they leave her body in the traditional way - with urine, then.
The umbilical vein in the structure of the umbilical cord is one. Initially, in the early stages of fetal development, there are also two of them, but one is then obliterated. The task of the umbilical vein is to carry blood to the baby, enriched with oxygen, vitamins, and minerals.
Normally, the blood flow through the vessels of the umbilical cord is balanced - the amount of enriched blood flowing through the vein is equal to the amount of blood flowing through the arteries, removing metabolic products and carbon dioxide. At the 20th week of pregnancy, the blood flow rate through them is almost 35 milliliters per minute. As the gestational age increases, the blood flow becomes more intense, and by the expected day of birth, its rate is already 230-240 ml per minute.
Research methods
The study of the structure of the umbilical cord in the early stages of pregnancy is usually not performed, since it is not possible to study its detailed structure until the second trimester. From the 7th week of pregnancy, theoretically, you can see the umbilical cord itself, more precisely, establish the fact of its presence, determine the place of its attachment, see signs of pulsation in it (usually this rhythm fully corresponds to the rhythm of the baby's heartbeat).
Later, other important details can be established on ultrasound - the length of the umbilical cord, the form of attachment to the placenta, possible entanglement in the neck. To obtain data on the number of vessels and the velocity of blood flow through them, do the so-called Doppler ultrasound (USG). Even if it was not possible to establish an umbilical cord entanglement on a conventional ultrasound scan, dopplerometry will certainly detect it for certain blood flow disorders.
The USDG will determine the exact number of vessels in the umbilical cord, the vascular resistance index and other important mathematical parameters. If there are deviations in the structure of the umbilical cord: it is short - less than 30 centimeters, long - more than a meter, attached not to the central part of the placenta, there are fewer vessels in it, the woman will be recommended to undergo additional examination.
Reasons for deviations
The most common abnormality is a single artery in the umbilical cord. This does not mean that there is only one vessel. It's just that of the two arteries, only one is present. Thus, the diagnosis "a single artery in the umbilical cord" implies that there are still two vessels - a vein and one artery. Blood enriched with nutrients moves through the vein to the baby, and through the artery, blood contaminated with metabolic products leaves the child's body. In principle, one artery copes with the task at hand, but it experiences significant overloads.
The reason for the abnormal structure of the umbilical cord is often the mother's diabetes mellitus, as well as the presence of chronic diseases of the kidneys, heart, and liver. Other unfavorable factors, such as bad habits, infectious diseases, sexually transmitted diseases, influenza or ARVI in early pregnancy, as well as the reasons for an unclear etymology that cannot be determined, can also affect the laying of the structures of the umbilical cord.
This anomaly has no symptoms, it does not affect the course of pregnancy, and in 95% of cases it allows a woman to bring her baby to the due date and give birth to a child quite normally. In the singular, the artery can be initially laid, or it can remain the only one as a result of aplasia of the second artery already during the gestation of the baby.
A single artery may be due to a genetic predisposition (the baby's mom or dad developed with such a pathology during pregnancy), and in some cases, the presence of a single artery can indicate chromosomal abnormalities in the fetus or congenital malformations of the respiratory system, intestines, heart or kidneys ...
That is why, when one artery is found instead of two, which are normal, doctors more closely examine the baby for possible defects and deviations in development and formation - they conduct an expert ultrasound scan, recommend invasive diagnostics or a non-invasive prenatal DNA test, which is capable of fetal blood cells in the bloodstream mothers to determine the baby's DNA and possible chromosomal pathologies.
Women with diagnosed polyhydramnios and multiple pregnancies, with severe early toxicosis, pathologies of the placenta, and obesity are at risk for the development of a single cord artery syndrome. When confirming the presence of a single artery in the umbilical cord, a woman will in no case be recommended to terminate the pregnancy, there is no medical indication for this.
If additional studies show that the child is healthy, then the pregnant woman will be monitored on a regular basis, however, they will have to do ultrasound with Doppler more often to assess blood flow, and at a later date - and CTG to assess the condition of the fetus.
If violations are detected in a single artery (zero diastolic blood flow, retrograde blood flow), a decision will be made to perform an emergency caesarean section in order to save the baby from death as a result of lack of oxygen and nutrients.
What to do?
First of all, pregnant women who at 20 weeks heard the verdict "the only umbilical artery" on an ultrasound scan are advised to calm down and not escalate the situation. Signs of congenital malformations of the fetus or chromosomal abnormalities (Down syndrome, Patau and others), one artery occurs only in 1-1.5% of cases of such a structural abnormality of the umbilical cord. In all other cases, the baby is completely healthy. However, you should not refuse additional diagnostics, you need to go through it in order to know what to do next.
If it is confirmed that the child has defects and chromosomal abnormalities, it is recommended to terminate the pregnancy, but only the woman herself and her relatives should decide this issue. If she wants to leave the baby, the pregnancy will be observed and kept on.
Women with a single umbilical artery and a healthy fetus are advised to visit a doctor more often, as well as to observe certain safety measures that will prevent an unbearable load on a single vessel. The consequences of loading can be quite significant - it is a delay in fetal development, malnutrition, low weight, the threat of premature birth due to the developed placental insufficiency, fetal hypoxia.
First of all, an increase in blood pressure is dangerous for the expectant mother and her baby. A woman needs to closely monitor it, measure it daily, and in case of hypertension, undergo appropriate treatment with drugs approved and recommended by a doctor. To avoid sudden surges in pressure, it is recommended to limit any stress, conflicts, experiences, emotional outbursts.
To maintain normal blood flow, the expectant mother is advised to abandon any hard work, especially associated with lifting weights and standing or sitting for a long time in one position. Sex and walking should be moderate, gentle, not exhausting.
A woman with a single artery in the structure of the umbilical cord cannot smoke, take even small doses of alcohol, and also stay in a stuffy room for a long time - oxygen is extremely necessary for mom and her baby.
It is recommended to take additional oxygen cocktails and drugs that improve uteroplacental blood flow ("Curantil" or "Actovegin") in dosages prescribed by the doctor.
A woman's nutrition must be saturated with vitamins, in addition, it may be necessary to take vitamin complexes so that the baby does not need the nutrients he needs. Otherwise, pregnancy with a single umbilical artery syndrome will be no different from a pregnancy with a normal umbilical cord. Feedback from doctors and patients allows us to safely say that there is nothing wrong with this anomaly.
For more information on what the diagnosis of "Single artery of the umbilical cord" means, see the next video.
