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Low birth weight and premature births on the rise

 

The number of low birth weight babies being born in Canada is on the rise. According to The Canadian Institute for Health Information, since 2001, the percentage of low birth weight babies has risen from 5.7% to 6.2% of live births. Babies who weigh less than two and a half kilograms (5.5 lbs) at birth are considered 'low weight' and are at greater risk for serious and long-term health problems, including mental and developmental health problems, as they grow.

Many, though not all, low birth weight babies are born prematurely, another phenomenon that has been steadily rising in the last two decades. The question is: with better health information for pregnant mothers, better pre-natal care, and maternity leave that can be accessed before birth, why are the numbers of babies born too soon or underweight increasing in Canada?

In vitro fertilization and multiples

What is known, most researchers agree, is that in vitro fertilization (IVF) can account much of the rise in both premature and low-weight births. The logic works like this: IVF pregnancies produce many more multiple births, such as twins and triplets, than natural pregnancies. Multiple births tend to produce lower weight babies who also tend to be born before 37 week's gestation: the measure of prematurity. Therefore, IVF can account for much of the increase in low birth weight and premature babies.

But according to these numbers, IVF does not account for all of the increase. So what else is causing more low weight and premature births?

Some researchers have suggested the missing factor might be because the average woman is having her first baby later in life, which is a risk factor for several types of complication including birth weight and prematurity. Some pundits have even suggested that given the social pressures, many women do not want to gain too much weight, and may go as far as deliberately smoking during the pregnancy, increasing the chance of both low weight and premature birth.

If true, these two factors might account for some of an increase in these rates, but according to some, IVF has an even larger effect than simply increasing the number of multiples.

In vitro fertilization and singletons

"Even when IVF produces single babies, the effect [of low weight and prematurity] is still there," says Dr. Keith Tanswell, Women's Auxiliary Chair in Neonatology and senior scientist at Toronto's SickKids hospital. "I think we've known for a number of years that all these increasing rates can be accounted for almost completely by IVF."

IVF is only one technique under an umbrella called ART or assisted reproductive technologies. Since it is widely known that multiple pregnancies carry more risks, much of the emphasis on new ART techniques has been to artificially produce single births rather than multiples.

When couples begin the often long, expensive, and sometimes unfruitful process of ART, counselling about the possible risks to the baby is a component. The risks are many and varied and go well beyond being born underweight and early.

"No one does IVF for fun. They are invariably a very determined population ready to go through with this in the first place," says Dr. Tanswell. "My interpretation is that they are more willing to take the theoretical risks. Counselling will not deter them - they have already made up their minds."

Dr. Tanswell feels that in many cases there is a disconnect between being told about the risks and really having an understanding of what those risks would mean to the individual. "There is a huge difference between being intellectually aware of the risks and the reality of it happening to you," says Dr. Tanswell. "They really have no concept what it might mean for them or the baby." Dr. Tanswell feels these parents are not alone in their disconnect either. "The ministry of health should understand that subsidizing IVF technology will cost down the road. While the subsidy may make some childless couples happy, I'm not sure the ministry gets the long-term consequence to society in terms of NICU admissions, which is very expensive."

Expensive in every way: emotionally and socially as well as financially. The real question is: if government subsidizes a technology that is more likely to produce babies and children who are in need of long-term care, should they not also increase the funding for services those babies and children require?

6/22/2010

L. A. Schieve, S. F. Meikle, C. Ferre, H. B. Peterson, G. Jeng, and L. S. Wilcox. Low and very low birth weight in infants conceived with use of assisted reproductive technology.New.England.Journal of.Medicine. 346 (10):731-737, 2002.

Giving Birth in Canada: Regional Trends From 2001-2002 to 2005-2006. Published by Canadian Institute for Health Information (2007).

Bellieni C, Buonocore G. Assisted procreation: too little consideration for the babies? Ethics and Medicine.2006 Summer;22(2):93-8.

Hoffman MC, Jeffers S, Carter J, Duthely L, Cotter A, Gonzalez-Quintero VH. Pregnancy at or beyond age 40 years is associated with an increased risk of fetal death and other adverse outcomes. American Journal of Obstetrics and Gynecology. 2007 May;196(5):e11-3.





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