Am I more likely to have a twin pregnancy with assisted reproduction?
Surely you have noticed that there are more and more cases of multiple pregnancies. What was once something that only happened to some women, usually with a family history, is now seen more frequently at school gates, parks and in the daily environment.
And in recent decades the number of people who resort to assisted reproduction has increased. And this is the reason for the significant increase in twin brothers, fraternal twins or even triplets.
The reasons are several.
Since the incorporation of women into the labor market, they have delayed the decision to become mothers.
Not knowing how they are going to reconcile work and personal life affects many couples when it comes to taking the reins of family planning.
It also adds to the busy pace of life, full of rush and stress. Which also lead us to neglect our diet or acquire bad habits (sedentary lifestyle, smoking, etc.).
All of these are factors that affect fertility, both in women and men.
When conception is achieved naturally, whether or not to have a multiple pregnancy is only a matter of genetics and the woman's hormonal stability: an increase in the FSH hormone favors the maturation and release of more than one egg per cycle.
However, when assisted reproduction is resorted to, whether by artificial insemination or in vitro fertilization, the probability is much higher with assisted reproduction techniques than in natural pregnancy.
In this article we will see in detail what probabilities you have in each case.
Differences between twins and twins
Before going into detail with the data, we are going to differentiate between twins and twins in multiple pregnancy.
Twins or twins?
Twins (identical) They come from the same embryo. That is, a single egg is fertilized by a sperm. But in the first days it divides and gives rise to two (or three...) identical embryos. Since they share DNA with 100%, they will all be the same sex.
These cases occur especially in pregnancies that occur naturally and without medical intervention. The probability is quite low and the causes are inherent to the parents.
Twins or bizygotic twins They come from two different embryos. That is, two eggs and two sperm. They are totally independent, but are conceived in the same cycle. That's why they don't have to be similar in appearance. They don't even have to share the same sex.
When do these cases occur?
- When a woman's ovaries release more than one egg per cycle without medical intervention.
- Assisted reproduction by artificial insemination (AI): ovarian stimulation is used so it is more likely that more than one fertile egg will be generated.
- Reproduction assisted by in vitro fertilization (IVF): in these cases it is easier to control the number of eggs, since you can opt for an embryo transfer of between 1 and 3.
In all the cases mentioned, the pregnancy is called the same: multiple. But let's see the specific figures.
What exactly are the chances of having a multiple pregnancy?
The figures that we offer you in this article are based on the latest publication available on the website of the Spanish Fertility Society.
According to their study, in 2018 the data is as follows:
| Twins due to natural pregnancy | Twins due to natural pregnancy | Multiple birth with AI | Multiple birth with IVF |
| 0,4% | 1,1% | 10,5% | 13,6% |
The relationship between assisted reproduction and increased probability of having twins (or triplets to a lesser extent) is very evident.
In the case of conception naturally, the probability depends only on the parents.
But the good news is that if you need medical help, depending on the treatment, it is easier control the chances of multiple births.
These are your options if you are undergoing fertility treatment
As you have seen, in the case of an unassisted pregnancy, it is human nature that determines whether you will have a multiple birth or not.
But if you are in an assisted reproduction process to conceive, the probability is greater.
In fact, in cases of artificial insemination It is impossible to tell 100% how many follicles are maturing in each cycle.
They are usually 1 or 2, depending on how the woman reacts to the treatment and whether she needs more or less ovarian stimulation to perform artificial insemination.
In fact, in some of these cases it is the doctors themselves who decide to pause the process. If the woman has a high response and is at risk of having a pregnancy of more than 2.
However, with the in vitro fertilization (IVF) or egg donation, the process is more controlled. The number of viable embryos and those transferred in each cycle is known exactly.
In these cases, Spanish law limits the transfer to a maximum of 3 embryos in each transfer attempt after in vitro fertilization.
However, until recently, the usual practice was to transfer two embryos.
In recent times, depending on the medical evaluation of the patient, the analysis of the embryologist and other specialists, a single embryo is transferred to eliminate the risks that a twin pregnancy may entail.
In fact, the final decision to transfer one or two is something agreed between embryologists, gynecologists and the couple or patient:
- The embryologist analyzes and assesses the quality of the viable embryos, the implantation potential of each one.
- With this assessment, the gynecologist assesses the woman's medical condition regarding the possibility of twin pregnancy, if applicable.
- The last word goes to the couple who, with all that information, is the one who makes the decision as to whether they assume that percentage of probability of multiple pregnancy or not.
There is no one decision better than another: each woman is different and in medicine there are no guarantees at 100% neither in artificial insemination nor in vitro fertilization.
What the entire medical community and fertility specialists agree on is that it is always preferable for a pregnancy to be single, since it entails less risk for both the mother and the fetuses.
Be that as it may, if you are going to start an assisted reproduction process, our recommendation is that you look for a center that provides you with security and respects your decisions. Here I link you to a post about How to choose the clinical improvement of assisted reproduction for you 🏥
Multiple pregnancies and health
When a couple with fertility problems receives the news that they are pregnant with twins, they are usually filled with joy. But it is true that a multiple pregnancy at a clinical level is never desirable because it can be a risky pregnancy. Fertility specialists always prefer the transfer of a single embryo or very controlled inseminations to achieve a single pregnancy.
Obviously it is different if the pregnancy is identical twins since in this case it is a spontaneous situation, but even if it is spontaneous, it does not mean that it will not receive more attention than if it were a single pregnancy.
