If you could choose the best weeks to birth…

One of the first prenatal questions to face a woman, when was the first day of your last menstrual period. This is asked to help estimate the date of birth.

Sigh…I received my own personal gestational wheel in class last week.  The lovely plastic double disks are a gift from Bayer Pharmaceuticals advertising a type of intra-uterine contraception I will no doubt be learning how to administer in a few weeks. Thanks Bayer, because why should I take 20 seconds to do the math in my head (add 7 days, subtract 3 months) when I can spend 10 digging your disk out of my pocket, 20 fiddling to get the dial lined up and another 15 counting the little lines to be sure I have the right date.

OK, so I’m not usually so cynical.  And the markings for specific weeks that include the estimated weight and crown to rump length are actually pretty cool – something fun to share with families that I won’t be able to quickly do math for in my head.  Even hormonal contraception you don’t have to think about every day could be perfect for some families I will work with.  It’s just that arrow pointing to the “Probable Date of Delivery” that makes me roll my eyes (yes, there is an arrow at 40 weeks, but in fairness there is a double ended arrow that sweeps from 38 to 42 weeks).

So why am I so annoyed?  I just read an article about recent research linking birth past 42 weeks with increased rates of cerebral palsy. With so many other reasons (legitimate and otherwise) doctors give for wanting to induce, I hate the idea that they might have one more.

But there is a silver lining here, and that is the risks for cerebral palsy are about the same or higher in weeks 37 and 38 when compared to weeks 42 and after.  Armed with this information, families may feel more confident in their refusal of early induction.

If you are reading the article, please don’t freak out. 40% does not mean that 40% of babies born 42 weeks and after will have cerebral palsy.  40% is the amount of increased risk – in other words the relative risk increases 40% not the total number of cases.