Twins in IVF: Chances and Complications of Twin Pregnancy

ICSI is one of the steps of IVF treatment in which a healthy and motile sperm is injected into the egg to fertilize it. This method is mainly used for men with low sperm count (oligospermia) and motility, abnormal sperm morphology, abnormal semen PH, or watery semen. Although ICSI with IVF increases the chance of successful pregnancy, it may lead to multiple births (twins or triplets) and put the mother’s life at risk. In this article, we briefly mention the procedure of ICSI with IVF and discuss the complications of IVF multiple births.

Chances and Complications of Twin Pregnancy

ICSI with IVF Process 

In IVF, multiple healthy sperms are mixed with mature eggs in an IVF dish to make an embryo. However, if there is no strong sperm to penetrate the egg and fertilize it naturally, the fertility specialist uses the ICSI technique to help the fertilization process. In this method, a tiny and narrow needle injects a healthy sperm into the center of the egg. Once fertilization occurs, the embryo is cultured in the laboratory for one to five days, then transferred to the mother’s uterus. As an effective treatment for male infertility, ICSI with IVF improves the chance of fertilization for couples with multiple IVF failures due to sperm problems. 

ICSI in Iran
Read more: ICSI Treatment Procedure and Success Rate

Does IVF Increase the Chance of Twins?

In IVF treatment, fertility specialists usually transfer more than one embryo into the uterus to increase the chance of successful pregnancy. This leads to multiple gestation pregnancies in 30 to 40% of cases. Also, the chance of a single embryo dividing and making identical twins is higher in IVF than in natural pregnancy. Therefore, the best way to prevent twins and triplets in IVF is to transfer only one embryo in each cycle, even if it reduces the chance of pregnancy. 

Complications of IVF Multiple Births

Although being pregnant with two or more babies can be wonderful and exciting for many, it has some risks that may jeopardize the life of both the mother and children. In the following, some of the main complications of IVF multiple births are mentioned:

Complications of IVF Multiple Births

Preterm labor

The chance of preterm labor (giving birth before week 37) in IVF multiple pregnancies is more than 60%. Babies born sooner than expected may suffer from heart and brain problems, gastrointestinal diseases, immune system problems, apnea, respiratory distress, infection, low birth weight, etc. Multiple-birth babies often need additional care in the neonatal intensive care unit (NICU) after birth. Also, mothers who experience early delivery probably face severe bleeding, diabetes, and reproductive tract infections (RTIs) and should be monitored for a couple of weeks after giving birth to their babies. 

Gestational hypertension

Gestational hypertension -or high blood pressure in pregnancy- is a less common complication of IVF multiple births (which happens in only 6% of cases). Usually, high blood pressure begins after 20 weeks of pregnancy or is close to delivery and goes away on its own after delivering the baby. This health condition can cause placenta abruption, poor fetal growth, eclampsia, toxemia, and stroke. Therefore, women with gestational hypertension during their multiple pregnancies should be monitored by their gynecologist throughout the 37 to 42 weeks.


Iron deficiency and anemia are the most common complications of IVF multiple pregnancies, and they may result in a fetus’ heart and brain failure. Anemia usually happens when there is an insufficient red blood cell or hemoglobin in the mother’s blood system. 

Birth defects

Twins and triplets are at a higher risk of developing birth defects such as heart diseases, spinal Bifida, digestive problems, respiratory defects, and cerebral palsy (CP). 


The vanishing twin syndrome -or early miscarriage- is a life-threatening side effect of IVF multiple births, which mostly happens in the first trimester of pregnancy. If one baby is lost due to genetic or chromosomal problems, the other one(s) will perish too. Unfortunately, vanishing twin syndrome cannot be treated or prevented. 

Twin-to-twin transfusion syndrome (TTTS)

Twin-to-twin transfusion syndrome is a rare but prenatal severe disorder in which the fetuses grow at different rates. The reason for TTTS is an imbalance in blood flow in the placenta, which may result in malnourishment and organ failure in one fetus. The other fetus may also develop cardiac complications due to excessive receiving of blood and nutrients in the womb.

Imbalance in amniotic fluid

Amniotic fluid is a clear fluid that surrounds the fetus during pregnancy and protects it from sudden injury and temperature changes. It also helps the fetus to absorb nutrients better and move freely. In multiple pregnancies, there may be an imbalance (polyhydramnios and oligohydramnios) in this fluid which causes preterm labor, congenital anomalies, and miscarriage. 

Increased need for c-section

The risk of fetus mortality in vagina delivery is higher in multiple births than in cesarean sections. Therefore, the doctors usually perform a c-section or mixed birth (also known as combined birth) to deliver the babies. In the mixed method, the first baby is delivered through vaginal delivery, and the other baby(s) are delivered through c-section.

Postpartum hemorrhage (PPH)

Being pregnant with more than one child makes the placenta and uterus larger and heavier than usual. This problem can increase the chance of severe vaginal bleeding after delivery and put the mother’s life at risk. Therefore, special attention should be given to mothers who give birth to more than one fetus to prevent postpartum hemorrhage.

FAQs about Multiple Pregnancies with IVF

FAQs about Multiple Pregnancies with IVF

1) Can my age affect multiple pregnancies with IVF?

Studies have revealed that the lower the maternal age, the higher the chance of multiple IVF births. 

2) What are the chances of having twins in IVF?

According to the American Society for Reproductive Medicine, one-third of IVF pregnancies are multiples.

3) Can you request twins with ICSI?

Yes, legally, you can ask for transferring more than one embryo in ICSI and IVF, but all fertility specialists recommend not doing so. Multiple pregnancies are considered a side effect of fertility drugs and ICSI because they can negatively affect the mother and babies’ health.

IVF Injections Side Effects
Read more: Side Effects of IVF Injections: How to Deal?

4) Does ICSI affect the gender of twins?

 Based on the latest findings, women who conceive with ICSI or IVF are more likely to give birth to twin girls. 

5) Can I have twins with one embryo transfer?

Although there is a small chance of having identical twins with IVF, it is still possible that a single embryo splits and forms two babies.

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