Monthly Counts of Coronavirus Disease (COVID-19) During Pregnancy by Selected Characteristics and Outcomes from the Birth Certificate

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Limited information is available on the impact of the COVID-19 pandemic on pregnant women and their newborns. While national data are not available, 14 states vital records offices and the District of Columbia routinely collect information on confirmed or presumed COVID-19 cases among pregnant women who gave birth and report this information to the National Center for Health Statistics (NCHS). The tables below present data for this select area on characteristics of mothers with COVID-19 at any time during pregnancy and their newborns. These data are based on cases of COVID-19 reported to NCHS and linked to the standard birth record, allowing for an analysis of birth-related data by maternal COVID-19 status. While these data are not representative of all births in the United States, they are currently the only multi-state birth certificate-based data available. The information provided is based on 25.6% of all births during the reporting period and the characteristics of the mothers and their newborns reflect the jurisdictions reporting COVID status. States also differed in how information on COVID-19 status was obtained and reported to NCHS. See Table 1 for more information.

Maternal and Infant Characteristics Among Women with Coronavirus Disease (COVID-19) During Pregnancy shows cumulative results for the entire reporting period, that is, from April 2020. Tables shown below include data beginning in July 2020, the first full month for which all reporting areas were providing data.

Births by Month

Technical Notes

A subset of states is providing information to the National Center for Health Statistics (NCHS) on reported cases of COVID-19 occurring during pregnancy for pregnancies ending in a live birth. The number of states reporting increased from eight states and the District of Columbia (DC) in April 2020 to 14 states and DC in June 2020 through September 2022, and 14 states in October 2022 through May 2023 (DC did not report during this period), 13 states in June 2023 (DC and Tennessee did not report during this period), and 12 states in July through December 2023 (DC, Tennessee, and Ohio did not report during this period). Data on this page are presented from July 2020, the first full month in which all states and DC were reporting maternal COVID-19 status to NCHS. The information from the reporting states is not representative of all women giving birth given that the incidence of COVID-19 cases varies by state and by reporting period and that the reporting states are not a random sample of states. It is also important to note that states have varying approaches to capturing information on maternal COVID-19 and different time requirements for reporting birth information (see Table I).

Nature and sources of data

National data on maternal COVID-19 are currently not available. Although a specific reporting item for maternal COVID-19 is not included on the U.S. Standard Certificate of Live Birth, some states are collecting information on maternal COVID-19 as part of the birth registration process and through other methods and are reporting this supplemental information to NCHS. The information presented for July 2020 through September December 2023 represents 25.6% of all births during this period.

Maternal COVID-19 information is sent by the states to NCHS on a recurring basis independently of the standard birth record and of the standard birth record data transmission process. This information is then linked to the standard birth record using a unique identifier, which allows for detailed analysis of information on the birth record (1) by maternal COVID-19 status. The vast majority (99.6%) of cases of maternal COVID-19 reported for July 2020-December 2023 were linked to the corresponding birth record. Unlinked cases are those for which the standard birth record had not been received by NCHS at the time the linkage was performed.

It is important to note that:

  • Since reporting states are not a random sample of states, the statistical information shown in this report reflects the characteristics of the reporting states. For example, California accounts for 44.5% of births in the 15-jurisdiction Maternal COVID-19 reporting area in the current reporting period while only 11.4% of all U.S. births occurred in California during this period. The characteristics of mothers in California will be disproportionately reflected in the data for the reporting area compared to the total U.S. See Table A for the distributions of maternal COVID-19 cases and total births by state for all reporting areas. See Table III for the impact of California on the dataset.
  • Certain jurisdictions (California, Maryland, Ohio, North Dakota, and Tennessee) report only confirmed (and not presumed) cases of COVID-19.
    • In states where only confirmed cases of COVID-19 are reported, there is likely to be an undercount of births to mothers with COVID-19 and an overcount of births to mothers without COVID-19. As a result, differences in maternal characteristics and infant outcomes between the COVID-19 and non-COVID-19 groups may be biased.
  • The information on COVID-19 cases shown may not include all cases of maternal COVID-19 that occurred in the reporting area during the time period indicated, that is, information on cases occurring earlier in the study period may not have been reported due to lack of widespread testing in early 2020 and information on some cases may not have been provided to the state prior to the submission of monthly data to NCHS.
  • States have different methods for collecting maternal COVID-19 information. Some states have modified their state birth certificates to include a COVID-19 data item. Other states are identifying cases through infectious disease surveillance; still others are using a combination of these two methods (see Table I).
  • These data are reported to NCHS outside of the usual process for submission of standard birth certificate data and do not undergo standard NCHS review prior to posting.

Maternal COVID-19 reporting area

Fourteen states and the DC have provided data as of 3/1/24. A total of 14 states and DC for July 2020–September 2022, 14 states reported for October 2022-May 2023, 13 states for June 2023, and 12 states for July-September December 2023 (DC was unable to provided updated cases for October 2022-September December 2022; Tennessee was unable to provide updated cases for June-September December 2023; Ohio was unable to provide updated cases for July-September December 2023). Characteristics of the reporting area are a function of the states participating and the length of time that they have been reporting. Tables includes data for all cases reported by these states by month of birth starting in July 2020 to examine trends over time and compare the characteristics and outcomes of births to women with and without COVID-19 during pregnancy.

Completeness and representativeness of data

Differences in reporting methods used by states to identify cases of maternal COVID-19 may result in varying levels of completeness by state. While most states report both confirmed or presumed COVID-19 during pregnancy, five states — California, Maryland, Ohio, North Dakota, and Tennessee –routinely report only confirmed COVID-19 cases. Limited information is available on the quality of infection data reported on the birth certificate, however, underreporting of specific infections has been observed in some jurisdictions (2); accordingly, maternal COVID-19 may also be underreported and the cases reported to NCHS may not be representative of all maternal COVID-19 cases occurring in that jurisdiction.

The incidence of COVID-19 cases among the general population can vary substantially by state and by time period. Since the reporting states do not represent a random sample of states the results shown for the maternal COVID-19 reporting states are not representative of the total U.S., as is illustrated by comparing maternal characteristics from these states to the total U.S. For births occurring during July 2020- December 2023 the maternal COVID-19 reporting states combined had a larger percentage of Hispanic births than the total U.S. (28.8% compared with 25.3%), and a smaller percentage of non-Hispanic White (47.6% vs. 51.1%) and non-Hispanic Black (11.4% vs. 14.2%) births. The preterm birth rate for the maternal COVID-19 reporting area was lower than that of the entire U.S. (10.02% vs. 10.37%).

State of Occurrence

Maternal COVID-19 cases are reported by state of occurrence, which is the state in which the birth took place. State of occurrence may not be the same as the state of residence. Birth data are typically reported by state of residence.

Source

NCHS, National Vital Statistics System.

Acknowledgement

This analysis was made possible due to the cooperation of 15 vital statistics jurisdictions: Alabama, Alaska, Arkansas, California, District of Columbia, Idaho, Maine, Maryland, New Hampshire, North Dakota, Ohio, Oklahoma, Oregon, Tennessee, and West Virginia.

Suggested Citation

Osterman MJK, Valenzuela CP, Martin JA. Monthly Counts of Coronavirus Disease (COVID-19) During Pregnancy by Selected Characteristics and Outcomes from the Birth Certificate. National Center for Health Statistics. National Vital Statistics System. 2024.

References

  1. National Center for Health Statistics. Vital statistics data available. Natality public use. Hyattsville, MD: National Center for Health Statistics. Published annually.
  2. Gregory ECW, Ely DM. Trends and characteristics of sexually transmitted infections during pregnancy: United States, 2016-2018 [PDF – 253 KB]. National Vital Statistics Report. Vol 69 (3): Hyattsville, Maryland. National Center for Health Statistics. 2020.