Saturday, 17 August 2013

Where did you get that from?

Many is the patient who, when offered a prescription by me, replies with a, 'Oh no, my friend says....' And then proceeds to tell me why that particular prescription is not a good idea, because of side effects or lack of efficacy etc. But it's not only patients who repeat baseless 'facts'. In the current NHS there is a myriad of guidelines, protocols, proformas which are generally not challenged despite their someimtes flimsy foundations.

One interesting area is the subject of fertility and the associated figures that are banded about. There's a great little article in the August edition of The Atlantic Monthly, entitled,  How long can you wait to have a baby. As a 30 year old and entering a second marriage, Psychology Professor Jean Twenge from San Diego State University,  didn't just have an academic interest in the subject,
My new husband and I seemed to face frightening odds against having children. Most books and Web sites I read said that one in three women ages 35 to 39 would not get pregnant within a year of starting to try. The first page of the ASRM’s 2003 guide for patients noted that women in their late 30s had a 30 percent chance of remaining childless altogether. The guide also included statistics that I’d seen repeated in many other places: a woman’s chance of pregnancy was 20 percent each month at age 30, dwindling to 5 percent by age 40.
Every time I read these statistics, my stomach dropped like a stone, heavy and foreboding. Had I already missed my chance to be a mother?

Unlike most of us who just accept what we hear, Twenge used her professional skills,
As a psychology researcher who’d published articles in scientific journals, some covered in the popular press, I knew that many scientific findings differ significantly from what the public hears about them. Soon after my second wedding, I decided to go to the source: I scoured medical-research databases, and quickly learned that the statistics on women’s age and fertility—used by many to make decisions about relationships, careers, and when to have children—were one of the more spectacular examples of the mainstream media’s failure to correctly report on and interpret scientific research.
The widely cited statistic that one in three women ages 35 to 39 will not be pregnant after a year of trying, for instance, is based on an article published in 2004 in the journal Human Reproduction. Rarely mentioned is the source of the data: French birth records from 1670 to 1830. The chance of remaining childless—30 percent—was also calculated based on historical populations.
In other words, millions of women are being told when to get pregnant based on statistics from a time before electricity, antibiotics, or fertility treatment. Most people assume these numbers are based on large, well-conducted studies of modern women, but they are not. When I mention this to friends and associates, by far the most common reaction is: “No … No way. Really?”
The remainder of the article is a model of lucid and helpful information. Her summary advice, which seems sensible to me, is
No. 1: fertility declines with age. No. 2, and much more relevant: the vast majority of women in their late 30s will be able to get pregnant on their own. The bottom line for women, in my view, is: plan to have your last child by the time you turn 40. 
I guess I should be reading the BMJ or Lancet, but every now and then , a journalist takes the trouble to challenge the status quo and brings clarity and challenge to an oft repeat mantra.
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