Genesis Fertility Clinic Blog
searching: “twins”
April 14, 2011
Multiple births are risky
Today’s Vancouver Sun had an article discussing the risk of multiple births and highlighting that many of the country’s multiple births (twins, triplets, more) are due to IVF.
We sometimes put more than one embryo back in hopes of increasing a couple’s chance of successful pregnancy. The cost of this practice is that multiple births can occur.
So, we shouldn’t put more than one embryo back, right? If it was only that simple! Genesis has always lead the way in putting the fewest embryos back in young women, yet….
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May 4, 2010IVF Pregnancies: As healthy as the rest?
It remains unclear if pregnancies that follow IVF have the same risks for preterm birth, stillbirth, growth restriction, and other pregnancy complications as those conceived without fertility treatment (spontaneously conceived pregnancies). I think it’s reassuring that the answer is unclear. If pregnancies following IVF were significantly more complex or risky, we’d know by now as there have been over 3 million such pregnancies in the world to date.
A Japanese study published in 2010 examining over 53,000 singleton IVF pregnancies found no significant increase in perinatal risk (including stillbirth) to the pregnancy or fetus. In contrast a study published this year of over 20,000 women with singleton pregnancies in Denmark found that risk of stillbirth in women who conceived on their own (spontaneously) was 0.4% compared to 1.6% for those who conceived with IVF. When big studies like this contradict each other, it’s hard to know just what to say to infertile couples.
Twin pregnancies are riskier than singletons whether they are IVF or spontaneously conceived. A recent review suggests that IVF twin pregnancies have a higher risk of premature birth and low birth weight than spontaneously conceived twins.
My belief is that IVF pregnancies may have more risk than spontaneously conceived pregnancies, particularly twin pregnancies, but the increased risk is small. Whether an increased risk is a product of fertility treatment or possible reproductive problems in the couple (i.e. is it the treatment or the couple?) is unknown.
In my opinion and experience, few couples decide not to pursue treatment because of small, unclear pregnancy risks.
Hopefully, in time the picture will be clearer and even more reassuring.
Dr. Beth Taylor, MD, FRCSC
Reproductive Endocrinology & Infertility
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February 18, 2010Home-made twins
Of the 30 people you in Canada one of them is likely to have a twin brother or sister. The lowest chance of meeting a twin is in Asia, where 1 in 70 persons is a twin and the highest chance in Nigeria where 1 in 12 persons is a twin.
There are two types of twins, dizygotic (DZ) and monozygotic (MZ) twins. DZ twinning occurs when two separate eggs are released during the same menstrual cycle and are fertilized by two sperm, creating “fraternal twins.” MZ twinning occurs when a single egg is fertilized by a single sperm and the resulting embryo splits a few days later creating “identical twins.”
DZ twins can occur spontaneously (i.e. home-made!) or as a consequence of fertility treatments. Patients will sometimes ask me about their risk of having twins; “my mother was a twin so am I more likely to have twins?” If you are undergoing fertility treatments the major increase in twin risk is due to the treatment. The minor influence of family history is washed away by the large fertility treatment effect. For example, if a woman’s mother is a DZ twin the woman is about twice as likely to have a DZ twin pregnancy (to about 1:15). If that woman does fertility treatment she has up to a 40% chance of having a DZ twin pregnancy (depending on the type of treatment of course).
It is known that your mother’s family history of twinning effects your chances as does your age (older women have a higher chance of conceiving DZ twins). A study published this month in Fertility & Sterility observed that a woman’s height and body mass index also affected her chances of having DZ twins. Specifically tall women and overweight women have more DZ twins. Current thinking is not that being tall or overweight increase your risk, per se, but are related to a gene that causes multiple ovulations.
Other factors that increase your risk of conceiving DZ twins include increasing female age, conceiving in the summer or autumn, cigarette smoking, recent use of the oral contraceptive pill, and folic acid consumption (controversial).
Understanding factors that influence DZ twinning can help shed light on the mechanism of multiple and single ovulations. The more we know….
Dr. Beth Taylor, MD, FRCSC
Reproductive Endocrinology & Infertility
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December 18, 2009Building Babies - A Cautionary Tale
Surrogacy seems straightforward. A woman (called the intended mother) who cannot carry a pregnancy in her uterus has another woman carry the pregnancy for her. At the end of the pregnancy, the surrogate hands over the baby to the intended parents.
This is how the process works 99% of the time, and it works well. I coordinate the surrogacy program at Genesis, and it is wonderful to see people come together to help each other create their families. The surrogate is supremely generous, and the intended parents are immensely grateful.
Things can go wrong, however, as illustrated in a case reported in the New York Times this week. You can read the New York Times article here. There are five people involved in this complex case: the intended parents, the egg donor, the sperm donor and the surrogate (called a gestational carrier in this context). Briefly, a couple used donor eggs and donor sperm to create embryos. They put two embryos into a gestational carrier who carried the pregnancy and delivered twins. The carrier gave the twins to the intended parents, but a month later learned that the intended mother has schizophrenia. The carrier, fearing the twins will not be well cared for, goes to court and wins custody of the twins. It’s a messy, heart-wrenching story.
Why did things fall apart? In some jurisdictions, surrogacy contracts do not hold up in court. So, although the gestational carrier had a written agreement to give the children to the intended parents, the agreement wasn’t recognized by the courts (in Michigan).
Could this happen in BC? Perhaps, but we go to great lengths to prevent such a disaster. There have been no challenges to surrogacy law in BC to my knowledge. At Genesis, we try to protect all parties as best we can. We require psychological counseling and a report of the appropriateness of all parties before we will embarking on surrogacy (this was not done in the NY Times case). We also require a legal contract, and we interview all parties prior to commencing surrogacy care. This is an expensive and intensive process, but it aims to protect all parties from such problems as the NY Times case highlights.
It’s not easy to engage in surrogacy, but perhaps it shouldn’t be. Clinics should be thoughtful in who they help with surrogacy. After all, we have to protect not just our patients but also their potential children.
Dr. Beth Taylor, MD, FRCSC
Reproductive Endocrinology & Infertility
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November 10, 2009Science of Twins
This weekend (Nov 14-15th) Science World is having a program called “Seeing Double.” It’s about the science of twinning. From what I can gather, it’s about identical twins – and most twins created from assisted reproduction are fraternal (not identical genetically) – but it still might be interesting to attend. Twins get in free!
For more information see Science World Events & Programs.
Dr. Beth Taylor, MD, FRCSC
Reproductive Endocrinology & Infertility
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October 12, 2009NY Times Debate
Today in the NY Times there is a debate on the issue of multiple births, their risks and whether the number of embryos transferred during IVF in the USA should be regulated and how.
It’s interesting as they have infertility doctors (REIs), ethicists, high risk pregnancy specialists and a lawyer weighing in. No patients, though which I consider an mistake.
Otherwise I think it’s excellent. Check it out by clicking here.
Dr. Beth Taylor, MD, FRCSC
Reproductive Endocrinology & Infertility