Similar birth weight between babies born via AR and by natural conception

The World Health Organization (WHO) reports that every year more than 20 million babies are born weighing less than 2,500 grams, many of them coming into the world in developing countries.

For many years it was believed that reproductive treatments were related to low birth weight babies, but a recent study carried out at IVI shows how, for the first time since the arrival of in vitro fertilization more than 40 years ago, children born via assisted reproduction have a similar weight to those conceived spontaneously. 

“We have worked hard to reverse the percentage of low birth weight babies and make it more in line with that obtained in spontaneous pregnancies to term, and today we can state that less than 8% of babies conceived in any of the IVI centres in 2019 presented low birth weight. Taking into account that, according to the latest figures dating back to 2017, the percentage in the case of naturally conceived babies stands at 7.8%, this is a promising figure that allows us to break down some of the stigmas that have marked our field of action. Our goal has been and continues to be to make assisted reproduction more in line with pregnancies achieved by natural methods, and figures like these show us that we are well on our way”, said Dr. Antonio Requena, Medical Director at IVI.

Prematurity and low birth weight do not always go hand in hand. It is estimated that between 3-5% of full-term babies occupy the bottom places of the height and weight tables, however, this does not always lead to abnormal development.

“In just over 15 years, we have seen a threefold reduction in the risk of low birth weight in IVF babies. This reassures patients, as it is clear that today’s IVF is no longer equivalent to premature twins who can spend weeks in the neonatal unit, but to a healthy baby, born with the same weight as a naturally conceived baby”, added Dr. Requena.

This substantial improvement in low birth weight rates in infants coming into the world via our reproductive techniques is linked to the widespread use of single embryo transfer (SET). This practice is the result of our firm commitment to drastically reduce multiple pregnancies – in fact, in just 10 years this type of pregnancy has reduced by 75% – thus increasing the chances of full-term pregnancy and the birth of a healthy baby.

“At IVI, 100% of the transfers we make are from a single embryo, and the twin rate is only 3%, on a par with the national rate of naturally conceived twins, which is 2.4%, according to the Centers for Disease Control and Prevention (CDC)”, said Dr. Requena.

The last 20 years in reproductive medicine have been full of advances, progress that is now joined by this notable decrease in the risk of low birth weight, with the positive implications that this implies for the safety and success of IVF, as well as the continuous improvement in results and optimization of the patients’ experience as they trust us with their greatest wish: to become parents.

“Babies born with our help, and thanks to SET, have a similar weight and similar term pregnancy rates to those of naturally conceived babies. In short, these figures are evidence that the gap is closing between IVF and natural conception, and this is very good news for those fighting against infertility“, concluded the specialist.