New CDC Reports on Infant Mortality, Pregnancy Rates, Births

By Rachel Walden — November 5, 2009

The Centers for Disease Control and Prevention has released three new reports dealing with pregnancy and birth topics.

Estimated Pregnancy Rates for the United States, 1990–2005: An Update [PDF]

This report provides information on trends in U.S. pregnancy rates from 1976-2005, with an emphasis on the period from 1990 to 2005. Among the findings, it indicates that in 2005 (the most recent year available) the pregnancy rate was 103.2 per 1,000 women, about 11% below the 1990 peak (115.8), but very similar to the rate (102.7) in 1976 when the data collection started.

The report notes that the pregnancy rate for teenagers fell 40% during the 1990–2005 period, to 70.6 pregnancies per 1,000 women ages 15–19, the lowest reported since 1976. The report notes, however, that “Preliminary data on births extending to 2007 show that the long-term decline in the teenage birth rate was halted with increases from 2005 to 2006 and from 2006 to 2007.”

Expanded Health Data From the New Birth Certificate, 2006

In 2003, the CDC began asking providers to provide additional information on birth certificates, with questions on risk factors, obstetric procedures, characteristics of labor and delivery, method of delivery, and congenital anomalies. This report is based on the additional birth data collected from birth certificates in 19 states since 2003.

This report is more of a snapshot of what is happening in pregnancy and birth care, and focuses less on trends. Among the findings:

  • External cephalic version (ECV) to adjust fetal position was performed in 3.2 of every 1,000 births, and was considered successful about 73% of the time;
  • 31.4% of births were by c-section; of the c-sections, about 20% had attempted a trial of labor;
  • 59.9% of women received epidural or spinal analgesia;
  • About 15% of women received antibiotics during labor.

The authors do provide a caveat that studies of the quality of this data are ongoing, and that, for the revised forms, “data quality may suffer initially as hospitals and states become familiar with the new checkboxes and new collection processes” — in other words, it’s possible that some interventions may be under- or over-reported.

They detected racial and ethnic disparities, in that “for all of the interventions featured in this report (cervical cerclage, antibiotics for the infant, epidural or spinal anesthesia, etc.), Hispanic mothers and infants are consistently less likely overall to receive treatment than non-Hispanic white and non-Hispanic black mothers and infants.” The report also notes, however, that Hispanic mothers may need fewer interventions in some cases, for example by being less likely to have gestational diabetes.

Related to the 15% receiving antibiotics, a new retrospective case-control study published in the journal Archives of Pediatrics and Adolescent Medicine (written by some CDC-affiliated authors) compares women whose infants had congenital anomalies with women whose infants did not and surveyed them about antibiotic use during pregnancy.

They found fairly low rates of anomalies among women who took penicillins, erythromycins, and cephalosporins, with somewhat higher odds of anomalies among children of women who took sulfonamides and nitrofurantoins during pregnancy (and a need for additional scrutiny of these drugs). They note, however, that it is not possible for them to tell whether the increased odds of an anomaly with some antibiotic drugs is related to the drug itself, the underlying infection, or some other unexplained factor.

Behind International Rankings of Infant Mortality: How the United States Compares with Europe

Finally, this report compares infant mortality rates in the U.S. with other nations. It includes a handy chart of reporting differences between countries that can help make sense of how the rates compare. Because some countries exclude live births prior to 22 weeks from their data, this CDC report looks only at births and infant deaths at 22 weeks and beyond.

They found that, when births at less than 22 weeks of gestation were excluded, the U.S. infant mortality rate was still higher than for most European countries, at 5.8 per 1,000 live births. The lowest rates were 3.0 for Norway and Sweden, and a number of other nations had better rates between 3.0 and 5.8. The authors note that the infant mortality rate in the U.S. is comparable or favorable to European rates for preterm births, but not for term births.

They explain:

The infant mortality rate for infants born at 24–27 weeks of gestation was lower in the United States than in most European countries (except Norway and Sweden); seven countries had higher rates. For infants born at 28–31 weeks of gestation, the U.S. rate was lower than for all countries shown except Austria, Denmark, and Sweden. For infants born at 32–36 weeks of gestation, the U.S. infant mortality rate was lower than for all countries shown except Austria and Norway. However, for infants born at 37 weeks of gestation or more, the United States’ infant mortality rate was highest among the countries studied.

The U.S. also had higher rates of preterm birth (at 12.4%) than the other countries in the study; Ireland fared best, at 5.5%. The authors attribute the higher rate of infant mortality primarily to preterm births, and estimate that possibly 1/3 of U.S. infant deaths might be avoided if our distribution of births by gestational age looked more like Sweden’s. They don’t, however, offer any possible explanations for the U.S.’s poorer infant mortality rates for term births.

4 responses to “New CDC Reports on Infant Mortality, Pregnancy Rates, Births”

  1. The US has higher infant mortality rates for term babies- I wonder what is the difference in term of care between US and the other countries. Is it that women in other countries are more likely to be cared for by midwives?

  2. In the US, “31.4% of births were by c-section; of the c-sections, [ONLY!?!] about 20% had attempted a trial of labor” — astounding!!

  3. No, the difference between the Scandinavian countries and the US is the Swedes and Fins and in Norway are much more physically active than we are in the US. This might account for the higher term infant mortality rate.

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