The National Birth Defects Prevention Study (NBDPS) is a population-based, case-control study and has been collecting data since 1997.
The NBDPS is population-based because it looks at all birth defects that happened in a certain area. That area could be a state or a number of counties. One of the important things to watch is whether the number of birth defects in the study area changes over time.
The NBDPS is a case-control study because information is collected from both mothers who have had a pregnancy affected by a birth defect (these are called case mothers) and mothers of babies who do not have a birth defect (these are called control mothers). The controls might also be called the comparison group. Controls are chosen by random selection. This means they are chosen by chance from the population in the study area. In the NBDPS, controls are chosen by a computer program that picks babies from birth certificates or birth hospitals in a given month in the study area.
After the interview is completed and the cheek cells have been sent in, the work of the participants is done, but that is when the work of the researchers begin.
How is research done?
One of the first steps is coding. During coding, we try to assign values to open-ended questions or responses from the interviews that did not fit the multiple-choice options. For instance, different nursing jobs get combined into one nursing group.
All of the information collected is saved in an anonymous database that investigators can use. Investigators then compare the case group and the control group to see if something happens more or less often in one of the groups. Investigators use a kind of math called statistics to compare the groups. Then, the investigators write papers about what they found. Those papers are reviewed by scientists outside the NBDPS, and the papers are published in medical journals. To read more about recent findings,click here.