Number of Births

In 1997, the number of New Jersey resident births was 113,332, a decrease of 1,003 births, or 0.9 percent, from the number of births in 1996 (Martin, R.M., et al., 1999). This was the seventh consecutive year in which the number of births to New Jersey residents declined from the previous year=s level following a long trend of increasing numbers of births which began in the mid-1970s and continued through the 1980s. Between 1996 and 1997, the number of births in the United States decreased 0.3 percent (Table N8). The trend in numbers of births in New Jersey has paralleled the trend in the nation as a whole which experienced a peak in the number of births in 1990 after steady increases beginning in the mid-1970s (Ventura, S.J. et al., 1999).

Birth Rate

The birth rate in New Jersey for 1997 was 14.1 per 1,000 population, a 1.4 percent decrease from the 1996 rate. Like the number of births, the birth rates in New Jersey and the United States had been increasing for approximately fifteen years before peaking in 1990 and then decreasing (Table N8). Birth rates for the United States have been higher than for New Jersey over the past twenty years, but the gap appears to be narrowing (Figure N1).

Birth rates in New Jersey vary considerably by county (Table N9 and Figure N2). In 1997, the county with the highest birth rate per 1,000 county-specific population was Essex County (16.4) and the lowest birth rate was in Salem County (11.6). In addition to Essex County, the following five counties had birth rates higher than the statewide rate in 1997: Passaic (16.3), Hudson (15.8), Somerset (15.4), Atlantic (14.7), and Union (14.6). The following major municipalities had birth rates at least 50 percent higher than the statewide rate: Lakewood (31.2) and Passaic (23.3).

Fertility

The general fertility rate is derived by dividing the number of births by the population of females aged 15 through 44. In 1997 the general fertility rate for New Jersey was 64.1 births per 1,000 females aged 15 through 44 (Table N1). This was 1.2 percent lower than the 1996 rate. The general fertility rate for the United States was 65.0 in 1997, which is slightly above the New Jersey rate (Ventura, S.J., et al., 1999).

Age-specific birth rates have experienced major shifts over the past two and a half decades (Table N1). As in 1996, three age groups had higher fertility rates in 1997 than in 1970: 30 through 34, 35 through 39, and 40 through 44. The fertility rate for women aged 45 through 49 was also slightly higher in 1997 than in 1970. All other age groups had identical or lower fertility rates in 1997 than in 1970 with the greatest decrease occurring in the 20 through 24 group (a 50.5% decline).

Total fertility is an estimate of the number of children a group of women would have over their lifetimes at the age-specific rates in effect at the time total fertility is calculated. The total fertility rate is calculated by multiplying the age-specific birth rate for each five-year age group from ages 10 through 49 by five (the number of years in the age group), and adding the results for each of the groups. In New Jersey in 1997, the total fertility rate was 1,979.9, virtually the same as the 1996 rate. A total fertility rate of 2,110 per 1,000 females aged 10 through 49 is estimated to be the minimum needed for population replacement under current mortality conditions. The minimum population replacement rate assumes no net migration (U.S. Bureau of the Census, 1997). In 1970, the total fertility rate of 2,414.0 was well above the population replacement rate, however in 1980 the rate of 1,609.5 was well below. While the rates during the 1990s have been higher than in 1980, the total fertility rate has remained slightly below the population replacement rate.

Fertility rates differ for black and white females (Table N1A). In 1997, the general fertility rate for black females was 19.7 percent higher than for white females, a larger gap than existed in 1996. While the white rate declined 1.5 percent, the black rate increased 1.1 percent. The fertility patterns continued to differ by age. Through age 24, black age-specific birth rates were considerably higher than white rates. In the age group 25 through 29, the rates were similar and for women in all other age groups through 49 years, white age-specific birth rates exceeded black rates by a substantial margin. The numbers of births to women of racial groups other than white or black were too small to permit calculation of stable rates. Hispanic women of any race had higher fertility rates then black and white women in ages 20 through 29 and rates lower than black women but higher than white women in all other age groups through age 39. At age groups 40 and over, Hispanic women had higher fertility rates than white and black women, although the rates are relatively low.

The total fertility rate for black females exceeded the rate for white females by 19.7 percent. The total fertility rate for black women continued to exceed the population replacement rate (by 3.9 percent), while the total fertility rate for white females remained below the population replacement rate (by 13.2 percent). The Hispanic fertility rate in 1997 was 15.6 percent above the population replacement rate.

Month and Day of Birth

In 1997, the month with the most New Jersey resident births was July (10,354 births or 9.1%) and February had the least (8,744 births or 7.7%). Taking into account the differences in the number of days per month, July had the most births on an average day (334.0) and November had the least per day (292.4). Overall, births occurred with greatest daily frequency in May through July and with the least frequency in March and November through January. This was different from the experience nationally (Ventura, S.J., et al., 1999).

As in the nation as a whole, in New Jersey more births occurred on weekdays than on Saturdays and Sundays (338.1 on an average weekday vs. 244.6 on an average weekend day). This difference has been attributed to cesarean deliveries and induced vaginal deliveries, many of which are scheduled on weekdays (Ventura, S.J., et. al., 1999).

Sex and Plurality

In New Jersey in 1997, as is the usual case, more males were born than females. There were 1,047 males born for every 1,000 females. By race, the male-female ratios were: 1.050 for whites, 1.004 for blacks, and 1.147 for races other than white or black (Table N2). For births to mothers of Hispanic origin (of any race), the ratio was 1.042. Resident births by sex for counties and selected municipalities are given in Table N10.

In 1997, 109,018 or 96.2 percent of births were single deliveries, 3,855 (3.4%) were part of a twin delivery, and 391 (0.3%) were part of a triplet or higher plurality delivery. Plurality was not stated on 68 birth certificates (0.1%) in 1997 (CHS, 2000a).

Attendant at Birth

The majority of New Jersey women had their babies delivered by a Doctor of Medicine (97,266 births or 85.8%), while the remainder used Doctors of Osteopathy (7,036 births or 6.2%), certified nurse midwives (5,662 births or 5.0%), or other midwives (59 births). The remaining babies were delivered by another person or the attendant was not stated on the birth certificate (CHS, 2000a).

Method of Delivery

The revised birth certificate implemented in January, 1989 in New Jersey included an item on method of delivery. This item consisted of a list of six types of delivery, with instructions to "check all that apply". Data tables on method of delivery are presented in Tables N3A and N3B. It should be noted that there were deficiencies found in the quality and completeness of reporting of this item in the early years following implementation of the new certificate. These problems appear to have diminished, with a decline in the number of records with no stated method of delivery and few records with an inconsistent configuration of delivery methods in 1997. These two types of reporting problems were particularly evident in 1989 and 1990 files.

In 1997, 71.6 percent of resident births were vaginal deliveries and 23.9 percent were cesarean sections. The remaining 4.5 percent of deliveries had no method stated (Table N3A). Of the 81,172 vaginal deliveries, 5,225 or 6.4 percent were vaginal deliveries of women who had had a previous cesarean section. Three of every five cesarean sections (62.8%) were first-time cesareans (primary cesareans) and the remaining 37.2 percent were repeat cesarean sections.

No clear trend is evident in the total cesarean delivery rate; this rate has been generally stable over the past six years (Table N3B) and stood at 23.9 percent of total births in 1997. Also, the percent of first-time cesarean deliveries to women who have never had a cesarean (primary cesareans) has fluctuated over the past six years and was at 18.3 per 100 women who had not had a previous cesarean in 1997. More than one in three deliveries in 1997 to women who had had a previous cesarean were vaginal deliveries (34.2 per 100 live births to women with a previous cesarean). This rate had increased steadily from 1989 when it was 15.3 per 100 live births to women with a previous cesarean until 1996 when it peaked at 35.6 percent.

Return to Health Statistics 1997

Continue to next Natality section