Any mom of twins will tell you the typical questions asked are “Are they identical?” and “Did you go through fertility treatments?”. Of course, such invasive questions, while awkward, come from a place of curiosity. Many people truly believe infertility treatment automatically results in multiples. Although that’s true in some instances, it isn’t always the case, and given the risks involved in a pregnancy with two or more babies, it’s far from encouraged.
Many fertility treatments carry a higher chance of conceiving more than one embryo. The risk is more often associated with the type of medication used in your treatment than the type of procedure you and your doctor choose. Each diagnosis is unique, and the treatments for resolving your infertility depend on what works best for your particular diagnosis. Not all fertility treatments pose the same risk for conceiving twins. Here, we dive into the specific treatments and medications involved as they relate to your chances of having twins.
Naturally Occurring Twins
First, let’s take a look at what impacts the natural occurrence of twins, as they contribute to your chances of having twins, even while undergoing different fertility treatments. There are two ways twins occur naturally. One, when a fertilized egg splits into two separate embryos (identical twins), and two, when two separate sperm fertilize two eggs at the same time (fraternal twins). Factors that increase the odds of having either are:
- Maternal Age: The odds of a woman releasing more than one egg at the same time increase with the hormone fluctuations of perimenopause. Women over the age of 35 have a higher risk of conceiving twins.
- Family History of Multiples: If the mother’s immediate family includes fraternal twins, the odds increase. That’s because there is a genetic predisposition for releasing more than one egg, called hyperovulation.
- Weight: Women with a higher-than-normal BMI are more likely to naturally conceive twins.
- Race: According to a 2019 CDC report, based on a 2018 study, African American women have a higher chance of twins than caucasian women. Asian and Hispanic women have a lower rate of naturally occurring multiples.
Different Fertility Treatments and Your Chances of Twins
Fertility treatments do carry the risk of multiples in pregnancy. The main reason for the increased odds for twins (or more) comes from the medications used to stimulate the ovaries. When these safe medications, an approved component of specific treatment, stimulate your ovaries, it’s common to release more than one mature egg at a time, thus increasing the likelihood for twins.
Injectable Gonadotropins
Injectable gonadotropins are common and essential for IVF. Some doctors use the injectable gonadotropins to stimulate the ovaries in intrauterine insemination (IUI); however, doctors use them less frequently due to the increased risk for multiples. Injectable gonadotropins carry an up to 30% risk for pregnancy with twins, and 3% for more.
Oral Medications
Oral medications such as Clomid or Letrozole stimulate the ovaries but are far less aggressive than their injectable counterpart. When used with IUI, your odds are less than 9%, and when used alone, they may be up to 12% for Clomid and less than that for Letrozole.
Your chances of twins drop depending on your treatment. You and your doctor set out the best course for your success according to several factors, diagnosis, overall health, age, etc. Here are the chances of twins with different fertility treatments.
Intrauterine Insemination (IUI)
With a low-dose medication, or no medication and relying on natural ovulation, your chances of twins with IUI fall to around 1% which is very close to the odds for conceiving twins naturally. As mentioned above, the odds go up with higher-dose meds such as Clomid. Letrozole and injectable gonadotropins.
In Vitro Fertilization (IVF)
In the past, doctors transferred multiple embryos, increasing the odds that at least one would implant and thrive. Today, that’s very rarely the case as more and more clinics recognize the risks involved and the greater odds for success with single embryo transfer IVF.
Moreover, single embryo transfer with preimplantation genetic testing vastly improves the odds for a successful pregnancy and healthy outcome. However, there is always a chance less than 1%) the embryo will split and the pregnancy will result in twins.
Risks Involved with Twins
Whether you have twins or a singleton pregnancy, your doctor monitors you very closely, ensuring a healthy outcome for you and your baby or babies. There are always risks, and those risks increase with multiples for both mother and babies. Here are the most common ones for babies:
- Preterm Birth: Having more than one baby increases your odds for early labor and delivery (before 37 weeks), which may come with complications like an underdeveloped respiratory system, underdeveloped organs, and difficulties in feeding.
- Low Birth Weight: Due to an increase in premature birth, twins more often have a low birth weight.
- Growth Restriction: One or both babies may suffer from slow growth, also called intrauterine growth restriction.
- Twin-to-Twin Transfusion Syndrome: a life-threatening condition that impacts identical twins sharing the same placenta. TTTS results in one twin receiving too much blood and the other twin not receiving enough blood.
- Loss of Pregnancy: The odds for pregnancy loss increase with multiples. You may lose one or both twins through miscarriage or stillbirth.
The risks to the mother are:
- Anemia: Due to the higher nutritional demands of pregnancy, you may not get all you need, which could result in anemia.
- Gestational Diabetes: The surge of hormones in a pregnancy with more than one baby could increase your blood sugar levels.
- Pregnancy Hypertension: High blood pressure is far more common with multiples. This may result in preeclampsia, which may cause organ damage.
- Intrahepatic Cholestasis of Pregnancy: This is a dangerous liver condition that causes a buildup of bile acids in the body. This may result in damage to the liver and fetal meconium ingestion. Severe itching of the feet and hands is the biggest symptom of this condition.
- Postpartum Hemorrhage: In the case of a shared placenta, the placenta is larger than in a singleton birth. That increases the chance for heavy bleeding and even hemorrhage after delivery.
Let Us Put Your Mind At Ease
Conceiving more than one baby, especially if you’ve been trying for a while, may be a blessing. But it comes with risks to the mother and babies. For more information on different fertility treatments and your chances for twins (or more!), please reach out to LA IVF. Our caring and compassionate professionals are here for you.
