When did preterm births happen?
The bar graph below describes the proportion of preterm births that happened very early in pregnancy (before 32 weeks), early in pregnancy (between 32-34 weeks), or almost on time (between 34-36 weeks). Pregnancy normally takes at least 37 weeks.
To find out the timing of preterm births in a particular population group, use the filter to select a population group. Scroll down or type key words into the search bar (race-ethnicity, health condition, hospital, housing, insurance, maternal age, maternal birth place, nutrition, prenatal care or zip code).
About 75 percent of babies born too early only needed 1 to 3 more weeks of pregnancy.
Data notes and sources
Data notes and sources
Data source:
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California Department of Public Health (CDPH) Vital Record Business Information System (VRBIS). VRBIS data include one birth certificate record for each and every baby born in California.
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Data were analyzed by the San Francisco (SF) Department of Public Health Maternal Child & Adolescent Health Epidemiology Section.
Data notes:
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We count all live preterm births for each year from January 1 through December 31.
Data limitations:
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Data are not shown if the number of preterm births in the group is less than 20 to protect the privacy of individual people in the group. For small groups, please see the days of pregnancy lost because of preterm birth for the group.
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The total numbers shown here may undercount the true total number of preterm births to San Francisco residents because, because we do not count preterm births that happened outside of California, in another state or country.
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We do not count babies delivered in San Francisco by people who are not San Francisco residents.
Why did preterm births happen?
About half of the preterm births in San Francisco happened because labor contractions started early and were not stopped.
Another third of the preterm births happened because of medical conditions like high blood pressure and infections. Doctors deliver babies early if medical conditions are dangerous for the mother or baby.
The bar graph below shows the percentage of preterm births that happened by reason for early delivery.
To find out the reasons for preterm births in a particular population group, use the filter to select a population group. Scroll down or type key words into the search bar (race-ethnicity, health condition, hospital, housing, insurance, maternal age, maternal birth place, nutrition, prenatal care or zip code).
More than one type of intervention may be needed to reduce preterm birth in San Francisco, because preterm birth is happening for more than one reason.
Data notes and sources
Data notes and sources
Data source:
-
California Department of Public Health (CDPH) Vital Record Business Information System (VRBIS). VRBIS data include one birth certificate record for each and every baby born in California.
-
Data were analyzed by the San Francisco (SF) Department of Public Health Maternal Child & Adolescent Health Epidemiology Section.
Data notes:
-
We count all live preterm births for each year from January 1 through December 31.
Data limitations:
-
Data are not shown if the number of preterm births in the group is less than 20 to protect the privacy of individual people in the group. For small groups, please see the days of pregnancy lost because of preterm birth for the group.
-
The total numbers shown here may undercount the true total number of preterm births to San Francisco residents because, because we do not count preterm births that happened outside of California, in another state or country.
-
We do not count babies delivered in San Francisco by people who are not San Francisco residents.
Did preterm birth happen with low birthweight?
Preterm birth that happens with growth restriction is associated with higher risk of health problems and infant death.
Over the past decade, about 60 percent of the preterm births in San Francisco happened with low birthweight.
To find out how many preterm births happened with low birthweight in a particular population group, use the filter to select a population group. Scroll down or type key words into the search bar (race-ethnicity, health condition, hospital, housing, insurance, maternal age, maternal birth place, nutrition, prenatal care or zip code).
Data notes and sources
Data notes and sources
Data source:
-
California Department of Public Health (CDPH) Vital Record Business Information System (VRBIS). VRBIS data include one birth certificate record for each and every baby born in California.
-
Data were analyzed by the San Francisco (SF) Department of Public Health Maternal Child & Adolescent Health Epidemiology Section.
Data notes:
-
We count all live preterm births for each year from January 1 through December 31.
Data limitations:
-
Data are not shown if the number of preterm births in the group is less than 20 to protect the privacy of individual people in the group. For small groups, please see the days of pregnancy lost because of preterm birth for the group.
-
The total numbers shown here may undercount the true total number of preterm births to San Francisco residents because, because we do not count preterm births that happened outside of California, in another state or country.
-
We do not count babies delivered in San Francisco by people who are not San Francisco residents.
More information
See linked pages about preterm birth in San Francisco