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16 Sep 2008 03:15 pm

Pro-Lifers And Amnio: A Professional OB/GYN's Take

A reader writes:

Interestingly, I started to write you about this very question a few days ago, and figured there were bigger fish to fry. My background: I'm a board-certified OB/GYN, full professor at a major medical school, with an additional degree in epidemiology. Most of my work involves using the tools of decision analysis and cost-effectiveness analysis to address questions in women's health, both at the level of individual decision making and for policy (for example, looking at the cost-effectiveness of vaccination for HPV in combination with cancer screening). Screening for Down syndrome is something I'm very familiar with, from both a personal clinical perspective as well as a classic teaching tool. 

Most pregnant women don't get an amniocentesis.  They are offered a combination of ultrasound and blood tests which quantify the risk of Down syndrome (and a few other chromosomal anomalies, some of which are much more severe). If the risk of an anomaly is greater than the risk of a loss from the amniocentesis (about 1 in 200-1 in 300), then an amniocentesis is offered. As women age, the risk increases--for a 35 year old, it's about 1 in 200, which is why amnio is routinely offered.   For a 44 year old, the risk is about 1 in 50. In order to be optimal, the ultrasound/blood testing needs to be done in the first trimester--it's possible this pregnancy was diagnosed too late to have it done. 

Notice, from a classical decision analysis perspective, this recommendation assumes that the utility of a loss of a healthy infant from the amnio is equivalent to having a child born with Down syndrome. My colleague Miriam Kuppermann has done some very elegant studies which demonstrate that, for most women, this is not the case. 

Most obstetricians don't have the training, or the time, to really go through these probabilities with patients, but most do go through the options with patients. As you suggest, many who would not undergo abortion choose not to have the test. For others, there are some benefits to knowing the diagnosis in advance--emotional and perhaps financial preparation, the chance to become familiar with the challenges of raising a Down syndrome child (including the highly increased risk of certain childhood cancers), etc. It's also possible that some women, while not having an abortion, might decide to be less aggressive in the setting of certain pregnancy complications (like very preterm labor).    

 

In terms of maternal complications, I'm not aware of any specific complications relating to mother of children with Down syndrome, although women in their 40s are clearly at increased risk for a wide range of complications, including hypertension during pregnancy, growth problems in the baby (even normal babies), and the need for c-sections; Down syndrome increases the risk for fetal distress during labor, increasing the need for c-sections. In addition, having had 4 previous children, the risk for a precipitous labor (a very quick labor and delivery) was certainly increased with Gov. Pailn.

As I suspected, the Palin decision remains befuddling and contradicts her resolutely pro-life stance. I also find it bizarre that a woman whose contractions have started and who is at risk for a very precipitous labor and birth would choose to delay seeing a doctor for over 24 hours after her contractions began and take a trans-continental plane trip. But those are questions to be explored in a subsequent post.

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