SIDS Recurrence in SIDS Siblings

Date: Tue, 19 May 1998
From: Dr. Tom Keens <tkeens@chla.usc.edu>
Subject: SIDS Risk for SIDS Siblings.

The SIDS recurrence risk for siblings of SIDS victims is probably at or very near that of the general population. Thus, we do not believe that the risk that your next baby will die from SIDS is increased. The current SIDS risk for the general population in the U.S. is about 0.8 per 1,000 live births (or 0.08%).

There are nine published studies in the medical literature which address the issue of SIDS risk for siblings of SIDS victims. However, some of these studies are flawed, as they include other diagnoses besides SIDS, some of which may be familial. Thus, they tend to over-estimate the SIDS risk for SIDS siblings. Current evidence suggests that the risk for a sibling of one previous SIDS victim is that of the general population.

There is one additional factor which has not been considered in previous studies, and might make the risk to SIDS siblings lower than the general population. That is, SIDS parents are more likely to be aware of "Back to Sleep" or "Reduce the Risks" recommendations and to follow them. This may make the risk to SIDS siblings even less than that of the general population, who may not be as eager to follow these suggestions.

The question of home apnea-bradycardia monitoring remains unproven. Studies have not been performed to show that home monitoring does or does not reduce the SIDS risk in SIDS siblings. Therefore, it is not recommended on purely scenitific grounds. Some parents find that a home monitor will reduce their (the parents) anxiety, and if this improves their parenting abilities for that child, I could recommend monitoring to them for that purpose. However, the presence of a monitor may increase anxiety or discomfort for some parents. Based on current scientific evidence, SIDS parents should certainly not be forced to use a home monitor if they do not want one. However, neither should those who want one be denied it. In most places around the country, home monitoring for SIDS siblings is left to parent choice after a discussion of what is known about the risks. If home monitoring is used, it is usually used for 6-months, as 95% of SIDS occur before that age. Home monitoring is not a guarantee. A small number of infants have died from SIDS while using home monitors.

Exceptions to the above recommendations are small groups of SIDS siblings for whom home monitoring IS currently recommended.

These include:
1) Siblings of 2 or more SIDS victims.
2) Twin surviviing siblings of SIDS (that is, if one twin dies
from SIDS, the surviving twin may also be at high risk).
3) SIDS siblings who suffer an apparent life-threatening event
(apnea).

SIDS siblings in these three groups should consult a local SIDS and/or infant apnea expert.

I hope this helps. Thank you,
---Tom Keens
Childrens Hospital Los Angeles

9/28/96

In response to the questions about: 1) the SIDS recurrence risk in siblings of SIDS victims? 2) should a SIDS sibling be monitored? 3) Should a SIDS sibling have a pneumogram?

The information about the recurrence risk of SIDS in children born into a family where one or both parents have had a previous baby die from SIDS is based on nine scientific studies published in the medical literature. The studies are not perfect, and some include causes of death other than SIDS. However, taken at face value, these studies suggest that SIDS siblings have a slightly increased chance of dying from SIDS than the general population. However, within the population of SIDS siblings, there are small subgroups who have relatively high risks for SIDS. These include siblings of 2 or more previous SIDS victims and surviving twin siblings of SIDS. When these are removed, the risk for the more common sibling of one previous SIDS victim is probably at or near that of the general population. This currently is about 1 per 1,000 live births in the U.S. Therefore, most researchers do not believe that the SIDS risk for siblings of one previous SIDS victim is increased.

There are no scientific studies which show either: 1) that home monitors prevent SIDS in siblings; or 2) that home monitors do not prevent SIDS in siblings. The scientific information just is not available. Therefore, families need to make the decision about home monitoring based on other considerations. For some families, having their baby on a home monitor provides some reassurance, may decrease their stress, and may permit better parenting because of decreased anxiety. For other families, having their baby connected to an electronic device might increase distress. Thus, in the absence of scientific information, we help families come to the decision which best suits their personalities and values. Proper education of the parents can make home monitoring tolerable, in that "false alarms" are minimized. However, we do reinforce that a home monitor does not guarantee that a baby will not die. Babies have died from SIDS on functioning home monitors when trained and skilled personnel responded, but could not revive the baby.

There is no testing of babies which can be performed which will predict who will die from SIDS and who will not. Therefore, we do not recommend routine testing for siblings of SIDS victims, unless they have an apneic episode or some other clinical problem. Pneumograms or sleep studies do not predict SIDS, death, or apneas. Therefore, we do not recommend them. Families generally decide about monitoring as above.

I hope this helps. Thank you.

Tom Keens
Children's Hospital Los Angeles

In response to questions about whether there is an increase in SIDS in the children of SIDS siblings:

The "party line" is that there is no increased risk of SIDS in cousins, aunts, uncles, nephews, or nieces of SIDS victims compared to the general population. The SIDS rate in the U.S. general population is currently about 1 per 1,000 live births. Therefore, extended family relatives are not thought to have an increased risk.

Having said this, I think it is also fair to say that there are few, if any, good scientific studies to back this up. The above risks are probably true. However, if a family had several SIDS or probable SIDS scattered through various cousins, aunts, uncles, etc., one would want to screen that family for possible inborn errors of metabolism which might have been missed. That is to say, it is more likely that a potentially identifiable disorder caused multiple deaths in a family than true SIDS.

I hope this helps. Thank you.

Tom Keens
Children's Hospital Los Angeles