To the Editor,
In his March 2000 Op-Ed piece, David Grimes repeatedly compares pregnancy to a fire that must be extinguished.1 Surely it follows that women who never become pregnant must have less risk from the worst“fire” : cancer. But childless women have about a 90% higher relative risk of contracting breast cancer than women with a first birth before age 20. 2Nulliparous women also have about double the risk of ovarian cancer compared with parous women. 3However, in the short term (about 21 months), it is presumed that the mortality risk is higher for pregnant women than non pregnant women. In May1985, Dr Grimes and colleagues provided the raw data to disprove the myth that pregnancy has a higher mortality risk.4 This study involved more than 16 million pregnancies in the United States.
The No. 1 killer of young people between the ages of 15 and 24 is car crashes, which should surprise no one. Are pregnant women much less likely to die in car crashes than non-pregnant women ? Yes, more than 80% less likely.Consider the period 1974 to 1978, when about 16,200,000 US women had live births. 4 An extremely low 41 currently or recently pregnant women died in traffic accidents during that period.4 A top 10 killer of young people is suicides. The Grimes article reports a very low 15 suicides for more than 16 million live births.4 So, it is clear :pregnancy saves lives. The reduced car crash death risk saves about 8 to 12lives per 100,000 per year : “Deaths that occurred within one year of the end of pregnancy and were caused or contributed to by pregnancy we reclassified as maternal.”4 From the data on page 607, 4 the mortality rates can be easily computed(table).
Table.
Mortality rates in relation to live births
All numbers are rates per 100,000 live births per year ; the rates are based on dividing by 12 months Instead of 21 months ; that is, the rates are overstated.
| All-cause mortality | Car crash death | Suicide | Neoplasm (cancer) | Homicide |
|---|---|---|---|---|
| 15.3 | 0.25 | 0.09 | 0.15 | 0.05 |
These mortality rates are all lower than those for non pregnant women. Thus, a proper analogy would be that a full-term birth is like a fire-retardant that much reduces the odds of those terrible “fires” : cancer, auto deaths, suicides, etc. As the great epidemiologist Dr Brian MacMahon atHarvard has clearly stated, only full-term births are breast cancer protective. 5
References
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