How do multiple births occur? How to reduce pregnancy risks

Since having multiple babies will double the risk of anemia, high blood pressure, prenatal and postpartum hemorrhage, miscarriage, and stillbirth, and the chance of giving birth to premature babies and babies with congenital malformations will also be relatively increased, it is necessary to use some methods to reduce the risk of multiple births.

Fetal reduction to increase fetal survival rate

Many premature babies are born due to early water rupture, which can easily lead to infection and death of newborns. Premature babies are born in the sixth or seventh month of pregnancy, and they are too low in weight and difficult to take care of, which puts the baby's future health and growth at risk.

Whether couples conceive naturally or through artificial insemination and have multiple babies, they can undergo fetal reduction if necessary and work closely with obstetricians.

In the past, due to the immaturity of technology, doctors would implant five or six embryos at a time in order to achieve a successful pregnancy, hoping to increase the pregnancy rate. However, in recent years, IVF technology has gradually matured, and the success rate has steadily grown to 40%. In fact, this is more dangerous.

This is because if too many eggs are obtained during the in vitro fertilization process, resulting in more than four embryos being cultured and all implanted in the uterus, it will not increase the chance of pregnancy. Instead, it will greatly increase the chance of multiple births and increase the chances of miscarriage and premature birth.

The number of embryos implanted should be reduced in older women

According to statistics, the probability of premature birth is significantly higher in pregnant women with multiple babies than in pregnant women with single babies. The average delivery week for triplets is 33 weeks, and for quadruplets it is 25 to 29 weeks. Studies have shown that the survival rate of premature babies born at 29 weeks and weighing about 1,000 grams is only 60%, and 45% will have congenital growth retardation, limb defects and other defects, and the probability of being healthy is only 30%.

The domestic medical community can refer to the recommendations of the American infertility medical community on the number of embryos to be implanted in in vitro fertilization: 5 embryos should be implanted for women over 40 years old, 4 for women aged 35-40, and 3 for women under 35 years old. If the embryos are in good condition, only 2 need to be implanted.

Multiple births are prone to congenital malformations, such as conjoined twins and blood transfusions between fetuses in the womb. In addition, most of them will cause premature births, which often lead to fetal death. The surviving babies often suffer from maldevelopment or lack of oxygen due to inability to breathe normally, which leads to brain damage and even cerebral palsy and mental retardation, becoming a burden to parents and society. Therefore, when pregnant with multiples, it is best to consider fetal reduction in the early stages of pregnancy, which is a measure to protect the mother and the fetus.

How do multiple births occur?

Why do some women give birth to multiple babies? This all starts with the fertilized egg. After a woman's puberty, her sexual organs begin to mature and her ovaries begin to ovulate. Usually, the ovaries only release one egg per month. At this time, if the egg meets the male sperm, a fertilized egg will be formed. After the egg is fertilized, it develops and grows in the mother's uterus. After a 10-month pregnancy period, the fetus will be born. Generally speaking, a pregnant woman only gives birth to one baby at a time.

If the fertilized egg splits into two and each develops and grows separately, two fetuses will be formed. This is called "monozygous twins". The twin fetuses not only have the same gender, blood type and genetic genes, but also have similar appearances.

There is another situation, that is, a woman's ovary releases two eggs at the same time, and they combine with sperm to form two fertilized eggs. In this case, the two fetuses may not look that similar, and the genders may not be the same. They may be one boy and one girl, commonly known as "dragon and phoenix twins." The same principle applies to the formation of triplets and quadruplets.

In the population, twins and multiple births account for a very small proportion, with a pair of twins occurring in approximately 80 fetuses and triplets occurring in only one in 6,400 fetuses.