The Link Between Assisted Reproduction and Multiple Pregnancies

Naturally, twin pregnancies are relatively rare, occurring in approximately 1 in 80 pregnancies. However, in the realm of assisted reproductive treatments, this rate increases significantly. This is largely due to controlled ovarian stimulation and the transfer of multiple embryos in procedures like in vitro fertilization (IVF).

Is there a choice? Most importantly, how responsible is this practice?

While advancements in reproductive medicine have improved conception rates, the decision to transfer more than one embryo must be carefully weighed from both a medical and ethical perspective. Multiple pregnancies carry higher risks for both the mother and the babies, including preterm birth, low birth weight, and obstetric complications. For this reason, many fertility clinics now prioritize single embryo transfer whenever possible, ensuring a safer pregnancy for both mother and child.

Twins or Fraternal Siblings: What’s the Difference?

Multiple pregnancies fall into two main categories: monozygotic and dizygotic. Monozygotic (identical) twins develop from a single fertilized egg that splits, resulting in two genetically identical individuals. Dizygotic (fraternal) twins, on the other hand, occur when two separate eggs are fertilized by two different sperm cells, making them as genetically similar as any other siblings.

Maternal Age and the Risks of Twin Pregnancies

A woman’s age plays a key role in both the likelihood and risks of a twin pregnancy. Women over 35 tend to have higher levels of follicle-stimulating hormone (FSH), which can lead to the release of multiple eggs during ovulation and increase the chances of a multiple pregnancy. However, advanced maternal age also brings a higher risk of pregnancy complications such as hypertension, gestational diabetes, and preterm labor. These risks are further amplified in twin pregnancies, making specialized prenatal care essential to safeguard both maternal and fetal health.

Prenatal Care for Twin Pregnancies

Multiple pregnancies require more intensive medical monitoring. More frequent prenatal visits are recommended to track fetal growth and detect potential complications early. Additionally, proper rest, a well-balanced diet, and early evaluation of conditions such as twin-to-twin transfusion syndrome (TTTS) in identical twins are critical for a healthy pregnancy.

What is Twin-to-Twin Transfusion Syndrome (TTTS)?

Twin-to-Twin Transfusion Syndrome (TTTS) is a complication that occurs in monochorionic twin pregnancies (where both fetuses share a single placenta). It happens when blood vessels within the placenta create an uneven blood flow between the twins, causing one (the donor) to receive too little blood, leading to restricted growth, while the other (the recipient) gets too much, straining its heart.

TTTS can develop in any monochorionic pregnancy, but the risk increases when vascular connections in the placenta are imbalanced.

Prioritizing the Health of Mother and Baby

While twin pregnancies are more common in assisted reproduction, modern reproductive medicine is increasingly focused on minimizing their occurrence to ensure safer outcomes. The ultimate goal is to achieve a successful pregnancy with the least possible risk, making embryo transfer decisions carefully tailored to each individual case.