Why IVF Babies Are More Likely to Be Preemies
Assisted reproductive technology aims at pregnancy — but also affects childbirth.
According to a 2012 report titled Born Too Soon: The Global Action Report on Preterm Birth, by World Health Organization in collaboration with others, 60% of the world’s premature deliveries occur in only 10 countries — one of which is India, which leads the world in sheer number of babies born early. A year later, a different report found premature births in India were rising.
The reasons for the increase varied — increases in maternal age and underlying health problems, such as diabetes and high blood pressure, were cited, along with another major contributing factor: greater use of IVF treatments were contributing to premature birth.
A more recent 2018 study, led by the Indian Council of Medical Research and others, bears this out. Of 113 Mumbai-based women, three out of four who got pregnant using assisted reproductive techniques ended up giving birth birth prematurely.
“The risk of pre-term birth in IVF patients is due to the treatment itself,” reports ran in 2017 following a large-scale study, and is almost double the risk experienced by women who conceived without assistance, concluded researchers behind a different, large-scale study in 2017.
A premature birth is one that occurs before the start of the 37th week of pregnancy in a cycle that should usually last 40 weeks. During the last few weeks of pregnancy, babies’ brains and lungs undergo rapid development. With less time to develop in the womb, premature births can lead to problems related to the heart, breathing, cognition, hearing and vision. Some of these problems, for instance, cerebral palsy, can be serious and lifelong.
Although numbers have established that IVF or other assisted reproductive techniques (ART) increase the chances of preterm births, doctors say the exact mechanism behind the link is unknown yet.
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Gynecologist Dr Arpit Kumar, who specializes in IVF treatments, says preterm birth risk is likely a combination of the IVF procedure itself and factors in the womb. For instance, he suggests, the super-doses of hormones some women require during the IVF process to increase the number of available eggs, may affect the way embryo is implanted in the uterus leading to premature birth.
Other scientists have suggested the harvesting of eggs during fertility treatment could damage the womb’s lining in a way that contributes to preterm birth later on.
Dr Kumar adds that sometimes it’s a human factor. Doctors and patients are often extra cautious when it comes to IVF pregnancies, as many are the culmination of much time, expense and effort. “Because conceiving is hard and the baby is treated as precious, so to avoid any complication, doctors may induce a slightly early delivery,” he says.
It is also common knowledge that often in IVF cycles, there is a multiple embryo transfer that result in twins and triplets. “Normally, multiples are born earlier than singletons. Therefore in IVFs, chances of preterm births are higher given that there are multiple embryos,” Dr Kumar adds.
But he also notes that the risk of premature birth is not a reason to avoid IVF treatments if one requires and desires them, especially since there are things doctors can do to mitigate the risk.
Dr Smriti Parikh, a Mumbai-based gynecologist, says couples should discuss with their fertility specialists the trade-offs between premature birth risk, and a single versus multiple embryo transfer.
“IVFs are expensive and couples don’t want to risk their chances of having a baby. Therefore, they opt for multiple embryo transfers,” she says. “Although it’s not certain that single embryo transfers will reduce the risk of premature babies, it’s best to at least consider a single baby depending on other factors such as your age, your general health, past pregnancies if any, since these factors determine premature and on-time deliveries, too.”
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Some studies suggest a frozen embryo transfer may also be an option to reduce the risk of premature births. It is a cycle where a frozen embryo from a previous fresh IVF cycle is thawed and transferred back into a woman’s uterus. “This means you won’t have to undergo another cycle of hormone stimulation and egg collection, which means less hormone shots, more chances of better embryo implantation and therefore, less chance of premature births,” says Dr Kumar.
And both Drs Kumar and Parikh say they can’t stress enough the importance of keeping mentally and physically fit during an IVF pregnancy. During any pregnancy, whether naturally conceived or assisted, lifestyle factors like obesity, diabetes, high blood pressure, smoking and alcohol consumption are related to premature birth. “Pregnancy and living healthy have to go hand-in-hand, but more when it’s an IVF case,” says Dr Parikh.
Anubhuti Matta is an associate editor with The Swaddle. When not at work, she's busy pursuing kathak, reading books on and by women in the Middle East or making dresses out of Indian prints.