Close to 125,000 live births occur in New York City (NYC) each year. Most babies are born healthy, but those born prematurely or with low birth weight are at greater risk of disability or death. This site tracks indicators of fetal growth and development, infant and perinatal mortality, fertility and sex ratio at birth.

Birth Outcomes and the Environment

Because many genetic and lifestyle factors influence growth and development of fetuses and babies, it can be difficult for researchers to study the effects of environmental exposures on birth outcomes. Smoking cigarettes during pregnancy, however, is known to result in exposure to many chemicals that can slow the growth of the fetus. Exposure to second-hand smoke can also be harmful. There is some evidence that  prenatal exposure to air pollution (particulate matter and other pollutants), lead, pesticides and solvents increases the likelihood that a pregnancy results in an adverse outcome.

About the Data and Indicators

We restricted our data to births (and infant deaths) occurring in NYC to mothers whose usual residence is NYC. The mother’s usual residence is recorded on the baby’s birth certificate.

We use the physician’s clinical estimate of gestation to identify preterm births.

We use very low birth weight (< 3 lbs, 5 oz) as an indicator of preterm birth, because most very low birth weight babies are born preterm.

We use low birth weight (< 5 lbs, 8 oz) among pregnancies that reach term (at least 37 weeks) as an indicator of “growth retardation”. Restricting to term pregnancies removes the majority of low birth weight babies who are small because they were born preterm and did not have time to finish growing before birth.

Historically, the ratio of male to female births has been about 1.05. Some have hypothesized that exposure to certain chemicals in the environment can reduce the number of male births, so sex ratio may be a useful environmental public health indicator.

Total (lifetime) fertility rate is the expected number of births to a hypothetical cohort of 1,000 women experiencing the current age-specific birth rates among NYC women. Measures of childbirth are only crude indicators of fertility since the decision to have children is dependent on many behavioral and social customs.

Our tracking indicators differ from those presented by the NYC Bureau of Vital Statistics. For more information, click here. For a definition of terms, click on the glossary link below.

Having a Healthy Pregnancy

The following may increase the likelihood of a healthy pregnancy outcome:

• Pregnant women should seek prenatal care in the first trimester of pregnancy, eat a nutritious and balanced diet and take folic acid beginning before conception, avoid being over or underweight and work with their doctors to control diabetes, high-blood pressure and sexually transmitted infections.
• Health care providers should advise their patients about factors that affect birth outcomes, such as maternal smoking, drug and alcohol abuse, poor nutrition, stress, insufficient prenatal care, chronic illness or other medical problems.
• Damaged lead-containing paint in homes should be safely addressed by properly trained workers, ideally prior to pregnancy.  Pregnant women and small children should stay out of the home until lead-paint projects are completed.
• Employers should provide workplaces free from unsafe chemical exposures and provide protective gear to workers when necessary. To learn more about the chemicals at work, employees can ask their employers for the  Material Safety Data Sheets for the products used.

Key Messages

New York City has made considerable progress in reducing infant deaths. In the early 1990s, the rate was double what it is today, but the rate of decline has slowed in recent years. In lower income neighborhoods, infant mortality rates are almost double the citywide average rate.

The majority of infant deaths occur in the neonatal period (less than 28 days old).

Leading causes of infant death are birth defects, prematurity, low birth weight, cardiovascular disorders, and injury (including sudden infant death syndrome).

Over the past 10 years, about 8% of singleton births to NYC resident mothers have been preterm (less than 37 weeks of pregnancy); about 1.4% of singletons have been very preterm (less than 32 weeks of pregnancy).

Historically, the sex ratio of male to female births has been relatively constant at about 1.05, or 5% more males than females are born each year.

There are many schemes of neighborhood boundaries (or geographies) available for different datasets. These include:

• Citywide
• Borough
• United Hospital Fund 42 (UHF42) and United Hospital Fund 34 (UHF34) neighborhoods
• Community Districts (CD), and, related, Community District Tabulation Areas (CDTA)
• Public Use Microdata Areas (PUMA)
• Neighborhood Tabulation Areas (NTA)

We try to make data available at as fine a geographic resolution as we can. Read more about different geographies at this data story.

It would be convenient if each dataset could be made available at the same geography, but this is not always possible. The neighborhood boundaries available depend on the specifics of the underlying dataset.

When we have multiple years of data, we show the data as trend charts.

Trends for individual neighborhoods tend to be very unstable (or "bouncy"), due to small counts for outcomes in individual neighborhoods. To show clearer trends, we usually aggregate up and show trend data by Borough.

Options on some indicators let you compare this indicator to other similar indicators.

We try to make data available as soon as we can.

Many datasets take a long time to reach us — a "lag" of several years, during which data are gathered from different entities to try to create a complete dataset; data are processed (cleaned, deduplicated, etc), and analyzed. It can take several years to prepare a dataset — so a dataset that is several years old is sometimes the most up-to-date information available. Still, this data continues to show us valuable trends and insights.

We also try to display datasets that have been available for many years. Some datasets (like those that are asked on surveys) are not asked every year of the survey, which means that we cannot provide annual data.

For some datasets, we have to aggregate time periods in order to break down data by borough or neighborhood.

Measures are the numeric ways that a dataset (or indicator) are expressed. Examples of different measures might be: number, percent or rate.

A number tells us how much of an outcome is in a certain area. But a rate (usually expressed as, for example, 40 per 100,000) tells us how much of an outcome there is, relative to the population of the area in question. This lets us compare neighborhoods of different sizes.

On this site, we try to show how environmental factors might be connected to health outcomes. One way we do this is with Correlates. We choose potentially-related datasets and display them on a scatterplot so you can see how these two datasets are correlated.

The Disparities view displays neighborhoods by poverty category to show underlying disparities in the data.

Read more about correlation here.