NEW JERSEY HEALTH STATISTICS, 2004
For over 30 years, New Jersey ’s birth rate has remained slightly below that of the U.S. as a whole. In 2004, the U.S. birth rate was 14.0 per 1,000 population. Birth rates peaked nationally and in New Jersey in 1990. Since then, New Jersey ’s birth rate has declined 17.1%, while the U.S. rate has declined 16.2% (Table BT1 and Figure BT2).
County birth rates ranged from a low of 8.8 births per 1,000 residents in Cape May County to a high of 15.2 in Passaic County . Eight counties were above the statewide rate of 13.2 births per 1,000 population (Table BC1 and Figure BC1).On average there were 314 births to New Jersey residents each day in 2004. Birth rates were lowest in winter and fall and highest in summer. More births occurred on Tuesdays than on any other day (362, on average). Substantially fewer births occurred on weekends: an average of 238 on Saturdays and 211 on Sundays (Table BS1 and Figure BS1).
Over the past several decades, birth rates have declined among younger women while rising among older women. For example, in 2004, birth rates for women under age 30 were well below those in 1970, while rates for women 30 years and over were far higher in 2004 as compared with 1970. The age pattern of fertility differs by race/ethnicity. Birth rates for Black and Hispanic women under age 25 were substantially higher than those for White and Asian/Pacific Islander women. Hispanic and Asian/Pacific Islander women had the highest birth rates in the 25-29 age range. White and Asian/Pacific Islander women had substantially higher birth rates than Black and Hispanic women aged 30-39 years. For women 40 years and older, birth rates were similar for all races/ethnicities (Table BT2 and Figure BT3).Teen birth rates varied widely across the state. The lowest rates were in the northwestern part of the state: Hunterdon (2.7 births per 1,000 females aged 10-19 years), Morris (3.0), and Sussex (3.1) Counties. The highest rate, 37.3 in Cumberland County , was nearly double the second highest rate, 19.0 in Passaic County (Table BC3 and Figure BC2). When considering the 15-19 year age group, rates in each county were basically double their rates for 10-19 year olds. Hunterdon (5.5 births per 1,000 females age 15-19 years), Morris (6.1), and Sussex (6.3) again had the lowest rates and the highest rate, in Cumberland (75.6), was nearly twice the second highest rate, in Passaic (39.5). Two counties had fewer than 20 births to females aged 15-17 years. Of the other 19 counties, Morris (2.7), Bergen (3.9), and Somerset (4.9) had the lowest rates and Cumberland (42.0) had the highest rate per 1,000 females aged 15-17 years. Morris (11.4), Sussex (14.6), and Bergen (17.1) Counties had the lowest birth rates per 1,000 females aged 18-19 and Cumberland (133.9) and Salem (75.0) had the highest. In every teen age group (10-19, 15-19, 15-17, and 18-19), Cumberland County ’s birth rate was more than three times higher than the rate for New Jersey as a whole. The rates for Hunterdon, Morris, and Sussex Counties were between one-fifth and one-third of the state rate for all teen age groups (Table BC3).
Maternal age distribution
Since 1987, the number of births to women aged 35 years and older has exceeded births to mothers aged less than 20 years (Table BT3 and Figure BT4). The median age of mothers in New Jersey was 30.5 years in 2004 (Table BT4), and the distribution of maternal age was fairly symmetrical around this midpoint of childbearing years. More than half of births (55%) occurred to women aged 25-34 years. The proportion born to women aged 20-24 years and 35-39 years was also quite similar (16% and 18%, respectively). The share of births to those aged less than twenty years (6%) slightly exceeded births to those aged 40 years and older (4%), but the difference was relatively small, reflecting both declines in teen childbearing as well as increases in fertility at older ages (Table BS2 and Figure BS2) .The distribution of maternal age varied geographically, with births to younger women being relatively more common in certain South Jersey counties. In Morris and Hunterdon Counties , births to mothers under the age of 20 comprised less than 2% of births in 2004. In Cumberland County , 18% of births were to mothers under the age of 20. Other counties with high percentages were also in South Jersey : Salem (11%), Camden (10%), Atlantic (10%), and Cape May (9%) (Table BC4 and Figure BC3). As expected, the opposite was true of births to women aged 35 years and over. More than one-quarter of births in Hunterdon (40%), Morris (32%), Somerset (30%), Bergen (29%), Monmouth (28%), and Sussex (28%) Counties were to women aged 35 and over. Less than one-sixth of mothers in Cumberland (8%), Salem (12%), Atlantic (16%), and Cape May (16%) Counties were 35 or older (Table BC4 and Figure BC4).
Median maternal ageThe overall median maternal age increased steadily over the past decade among all race/ethnicity groups, then leveled off between 2003 and 2004. Median maternal age for first births, however, declined slightly among Blacks and Hispanics between 1994 and 2004, while rising slightly for Whites and Asians/Pacific Islanders (Table BT4 and Figures BT5 and BT6).
Race/ethnicity of mother
The share of all births which were to White and Black mothers decreased 16% and 21%, respectively, over the past ten years, while the share to Hispanic and Asian/Pacific Islander mothers increased 56% and 106%, respectively (Table BT5 and Figure BT7). The distribution of births by ancestry among Hispanics and Asians/Pacific Islanders has also changed over time. In 1994, 43% of Hispanic births were to mothers of Puerto Rican descent and 41% were to mothers of Central and South American origin, while Mexicans and Cubans each made up less than 11%. By 2004, the percentage of births to mothers of Central and South American ancestry comprised half of Hispanic births. Births to Puerto Ricans fell to one-quarter of Hispanic births while births to Mexicans increased to 22% of Hispanic births (Table BT6 and Figure BT8). While the number of births to women of Indian, Filipino, Chinese, Korean, Vietnamese, and Japanese descent has increased, the distribution among these groups has changed dramatically as the Indian population has comprised more and more of the Asian and Pacific Islander population in New Jersey . In 1994, births to mothers of Indian and Filipino origin each comprised about 22% of births to mothers of Asian or Pacific Islander ancestry, while 18% of Asian/Pacific Islander births were to mothers of Chinese descent and 15% were of Korean origin. By 2004, nearly half were of Indian ancestry, while Filipinos, Chinese, and Koreans comprised 15%, 15%, and 10%, respectively. Births to mothers of Vietnamese descent increased steadily through 2003 yet made up only 4% of Asian/Pacific Islander births in 2004. Births to mothers of Japanese origin decreased to 2% of Asian/Pacific Islander births (Table BT7 and Figure BT9).
For the first time, less than half of births in New Jersey were to White mothers. In 2004, there were 56,997 births (49.8% of all births) to White mothers, 26,887 (23.5%) to Hispanic mothers, 16,491 (14.4%) to Black mothers, 10,119 (8.8%) to Asian/Pacific Islander mothers , and 450 (0.4%) to mothers of other races (Tables BT5, BS2, and BS3 and Figure BS3). There were more births to mothers of Central and South American ancestry than to women descended from all Asian and Pacific Island countries combined (Table BS3).The highest concentration of births to Hispanics was in Hudson (46.6% of all births) and Passaic (46.2%) Counties. Of those births, more than half were to mothers of Central or South American descent. More than 40% of Essex County births were to Black women. Over one-quarter of births in Middlesex County were to Asians and Pacific Islanders; two-thirds of whom were of Indian descent (Tables BC5 and BC6).
Nativity of mother
The percentage of births to foreign-born mothers increased steadily from 21% in 1994 to 33% in 2004. Foreign-born is defined here as mothers born outside the 50 states, Washington , D.C. , or Puerto Rico . Therefore, under this definition those born in U.S. territories other than Puerto Rico and those born abroad to American parents are considered foreign-born. In both 1994 and 2004, over 89% of Indian, Korean, and Mexican women giving birth were foreign-born. Among Filipinos and Central/South Americans, the percentage decreased slightly from 94% and 91%, respectively, to 86% and 88%, respectively. Large declines occurred among Puerto Rican and Cuban mothers: from 10% to 1% for Puerto Ricans and from 67% to 41% for Cubans. Increases, however, were seen among White and Black mothers and since they comprise a large portion of the births in New Jersey, the increase in the percentage of foreign-born mothers among these two groups caused the overall percentage of foreign-born mothers to increase to 33% of births in 2004 (Table BT8 and Figure BT10).
Maternal and newborn characteristics varied by mother’s nativity. Native-born mothers had higher rates of low birth weight, preterm births, teen births, large families, and no prenatal care than foreign-born mothers. These same rates for those born in Puerto Rico were even higher than for those native-born. In general, native-born mothers had higher levels of educational attainment. Additionally, native-born mothers were more likely than foreign-born and Puerto Rico-born mothers to have received first trimester prenatal care and were less likely to be unmarried. This pattern is somewhat different among Blacks. Native-born Black mothers were nearly twice as likely to be unmarried as compared with foreign-born mothers. Additionally, the percentage of native-born Black mothers who had not completed high school was 1.8 times higher than for foreign-born mothers while the percentage with a college degree was less than half that of foreign-born mothers. Additionally, the first trimester prenatal care rate was lower among native-born Blacks than among those foreign-born (Table BS4).
More than half of births to mothers in Middlesex (53%) and Hudson (52%) Counties were to foreign-born women. The New Jersey State Registrar’s Office does not receive maternal birthplace and other information for many births to residents which occur out of state, so counties with high out-of-state birth rates have higher rates of missing information than others, thereby making it difficult to ascertain which counties truly have the highest and lowest proportions of foreign-born mothers (Table BC7).
Previous pregnancies and family sizeForty percent of women delivering in 2004 had no other living children at the time of delivery. Eight percent already had three or more living children. Nearly 28% had never been pregnant before and 21% had been pregnant three or more times before this birth. Abortions, fetal deaths, and live births who later died account for the differences between the number of previous pregnancies and the number of living children (Table BS5). The first birth rate was 25.5 per 1,000 female population aged 15-44 years. The first birth rate was higher for Hispanics (34.5) and Asians and Pacific Islanders (32.3) than for Blacks (22.6) and Whites (22.5). Overall, women aged 25-29 had the highest first birth rate: 50.3 births per 1,000 females in the age group. Among Blacks and Hispanics, the highest first birth rate was among women aged 18-19 (Table BS6). Forty percent of women who delivered in 2004 gave birth to their first child. This was the second child for one-third and the third child for 16%. Large families varied by race/ethnicity. Over 14% of Black mothers delivering in 2004 had a fourth or higher birth, as compared with 9% of Hispanics, 8% of White mothers, and 3% of Asians and Pacific Islanders (Table BS7).
From 1974 to 2004, the percentage of births which were to unmarried women more than doubled. In 2004, 30% of births were to mothers who were not married at birth, conception, or any time between (Table BT9 and Figure BT11).
Marital status varied considerably by age and race/ethnicity. As expected, the percentage of mothers who were married was positively correlated with age except in the oldest age groups where the percentage declined slightly after 40 years of age. This relationship between maternal age and marital status existed among all races/ethnicities. For all ages, 95% of Asian/Pacific Islander mothers and 86% of White mothers were married. In contrast, only 45% of Hispanic and 35% of Black mothers of any age were married. Thirty percent of Asian and Pacific Islander mothers under the age of 20 were married compared to 15% of Whites, 14% of Hispanics, and 2% of Blacks (Table BS8 and Figures BS4 and BS5).Nearly 60% of mothers in Cumberland County and 47% of mothers in Essex County were unmarried. Other counties in South Jersey and near New York City also had higher than average rates. Only 10% of Hunterdon County mothers were unmarried. All other counties in the northwestern part of the state also had low rates (Table BC8 and Figure BC5).
The percentage of births which were part of a twin pregnancy increased nearly 50% from 1994 (2.8%) to 2004 (4.2%). The percentage which were part of a triplet pregnancy increased 77% and the proportion of births which were quadruplets or higher order increased 87%. There were 4,850 infants born from a twin pregnancy, 331 triplets, and 20 quadruplets in 2004 (Table BT10 and Figure BT12). Numbers given are the number of infants born in each category, not the number of sets of twins, triplets, or quadruplets.
The percentage of births which were part of a twin or higher order delivery was positively correlated with age. In 2004, no one under the age of 15 delivered multiples while more than one-quarter of women aged 45 and over had twins or triplets. However, twins and higher order births were still uncommon among those under age 45, comprising only 4.5% of births among women in that age group. Multiple birth rates also varied by race/ethnicity. Nearly 6% of births to White mothers were twins or higher order, while only 4% of births to Black women, 3.4% to Asians and Pacific Islanders, and 2.5% to Hispanics were multiples (Table BS9 and Figure BS6).The geographical pattern of multiple birth rates reflected patterns in maternal age. Multiple birth rates ranged from 1.5% of births in Cumberland County to 6.3% of births in Somerset County . Other counties with high multiple birth rates were Morris (6.0), Mercer (5.6), Bergen (5.4), Gloucester (5.4), and Warren (5.3) (Table BC9).
Completeness of prenatal care onset reporting improved greatly between 1994 and 2004; therefore trend analysis is based only on those records for which data were available. Throughout the decade, about 80% received first trimester prenatal care; however the proportion receiving early care slowly declined. About 15% of mothers began receiving care in the second trimester and 4% began in the third trimester. These proportions both rose as more mothers delayed the onset of prenatal care and fewer mothers received no care. The percentage receiving no prenatal care remained slightly above one percent (Table BT11 and Figures BT13 and BS7).
In 2004, 87% of White and 85% of Asian/Pacific Islander mothers received first trimester prenatal care compared to 66% of Hispanic mothers and 62% of Black mothers. Less than one percent of Asian/Pacific Islander and White mothers and 1.2% of Hispanic mothers received no prenatal care while 3.7% of Black mothers did not receive prenatal care. Older mothers were much more likely to receive prenatal care in the first trimester than younger mothers. Over 80% of mothers aged 35 years and over received first trimester care compared to 52% of teen mothers (Table BS10 and Figure BS9). Marital status also had an effect on onset of prenatal care. Eighty-six percent of married mothers received first trimester care while only 60% of unmarried mothers did. Additionally, 0.4% of married mothers received no care compared to 2.9% of unmarried women (Table BS11 and Figure BS10). Educational level, which is also correlated with age, had an affect on onset of prenatal care, too. Ninety-one percent of college graduates received first trimester prenatal care compared to 54% of those without a high school diploma. While only 0.2% of those with a college degree received no prenatal care, 3.2% of those who had not completed high school did not receive any care (Table BS12 and Figure BS11). Among women who received prenatal care, the average number of visits was ten. Nearly half of women who began prenatal care in the first trimester had 10-12 visits, while 27% had 13 or more, 20% had 7-9 visits, and 6% had fewer than seven visits. As expected, women who began prenatal care later in pregnancy were more likely to have fewer visits (Table BS13).While 90% of mothers in Sussex County received prenatal care in the first trimester of pregnancy; the same was true of less than two-thirds of Essex and Atlantic County mothers (Table BC10 and Figure BC6). However, Atlantic County had the highest rate of second trimester prenatal care onset (26%). Essex County had the highest rate of no prenatal care (3%) while only 0.1% of mothers in Hunterdon County did not receive prenatal care. The percentage of records with missing prenatal care information ranged from 0.8% in Salem and Atlantic County to 10.3% in Hudson County , thereby making it difficult to draw absolute conclusions about geographic variations (Table BC10).
Substance use during pregnancyThe use of tobacco, alcohol, and drugs during pregnancy declined fairly steadily between 1996 and 2004. Tobacco and drug use each decreased about one-third while the rate of alcohol use in 2004 was less than half of the 1996 rate. In 2004, 7.7% of mothers used tobacco while pregnant, 1.0% used alcohol, and 1.4% used other drugs (Table BT12 and Figure BT14). This analysis does not take into account whether the mother quit or cut down her use of any of these substances while pregnant. Also, use of these substances was self-reported and some under-reporting is likely
Tobacco use was most prevalent among mothers aged 15-24 years (13%). This pattern was true for all races/ethnicities except Blacks. Smoking prevalence was highest among White mothers aged 15-24 (24%), however among mothers of all ages, Blacks had the highest prevalence of tobacco use while pregnant (12%). Only 1% of Asian and Pacific Islander mothers used tobacco during pregnancy (Table BS14 and Figure BS12). The percentage of mothers who used tobacco while pregnant ranged from 3% in Somerset to 18% in Salem and Cape May Counties . However, while as few as 1% of records in some counties had missing tobacco use data, 19% of records in Salem and 10% of records in Hudson County had missing data. Therefore, it is possible that the tobacco use rates for those counties could be much higher than stated (Table BC11).
AlcoholAmong all races/ethnicities combined, mothers aged 15-24 and 35 years and over had the highest prevalence of alcohol use during pregnancy (1.2% and 1.4%, respectively). This was not true in every race/ethnicity group. Among Blacks, alcohol use was positively correlated with age, while it was negatively correlated among Asians and Pacific Islanders. Alcohol use during pregnancy ranged from 0.3% of Asian and Pacific Islander mothers to 1.9% of Black mothers (Table BS15 and Figure BS12). Middlesex County had the lowest rate of alcohol use during pregnancy (0.4%), while the highest rates were in Cumberland and Hunterdon Counties (2.9%). Again, high rates of missing data in other counties such as Salem (19%) and Hudson (10%) could affect results (Table BC12).
DrugsAs in past years, drug use was more prevalent than alcohol use in 2004. Mothers aged 15-19 years were most likely to use drugs while pregnant (3.1%) among age groups with enough cases to calculate a reliable rate. This was true for Whites (4.7%), Hispanics (2.0%), and Asians and Pacific Islanders (1.2%). However, among Black mothers, drug use was most prevalent among older women aged 35 and over (6.8%), followed by mothers aged 20-24 (4.2%). Overall, 4.3% of Black mothers of all ages reported using drugs while pregnant compared to 1.1% of Hispanics, 0.9% of Whites, and 0.1% of Asians and Pacific Islanders (Table BS16 and Figure BS12). Drug use rates ranged from 0.4% of mothers in Morris County to 3.6% in Camden County . Missing data played the same role here as it did for tobacco and alcohol use (Table BC13).
Medical risk factors
For most medical risk factors, there was little change between 1997 and 2004. There was a slight decrease in births to women with cardiac disease (1.4% of births in 2004) or a previous preterm or small-for-gestational-age infant (1.2%). There was a slight increase in births to women with diabetes (5.0%), acute or chronic lung disease (3.6%), and anemia (2.6%) (Table BT13).
In 2004, diabetes was the most commonly reported medical risk factor (5.0% of births). It was followed by acute or chronic lung disease (3.6%), sexually transmitted diseases (3.2%), pregnancy-associated hypertension (2.9%), and anemia (2.6%). The prevalence of diabetes was positively correlated with age and affected 8.8% of mothers over age 40. Acute or chronic lung disease and anemia were negatively correlated with age and affected 5.4% and 4.6% of mothers under age 20, respectively. The most commonly reported medical risk factor among mothers under 20 years of age was sexually transmitted diseases (7.6%). The three most common medical risk factors among White mothers were diabetes (4.3%), pregnancy-associated hypertension (3.2%), and acute or chronic lung disease (3.2%). For Black mothers, the three most common risk factors were sexually transmitted diseases (7.2%), anemia (5.2%), and acute or chronic lung disease (5.1%). The three most commonly reported for Hispanic mothers were diabetes (5.3%), acute or chronic lung disease (4.5%), and anemia (3.7%). Among Asian and Pacific Islander mothers, diabetes was the most commonly reported risk factor (10.1%), followed by anemia (2.1%) and hydramnios/oligohydramnios (2.0%) (Table BS17 and Figure BS13).
LABOR AND DELIVERY
Nearly all mother s in 2004 had electronic fetal monitoring and ultrasound performed. This marks a notable increase from 1997, when only 58% had an ultrasound reported on the birth certificate. Stimulation of labor by use of oxytocin or through artificial rupture of membranes after labor has begun decreased from 32% of births in 1997 to 28% in 2004. Induction of labor, meaning the initiation of uterine contractions before the spontaneous onset of labor by medical and/or surgical means, increased from 16% of births in 1997 to 19% in 2004. The use of amniocentesis decreased from 9% of births in 1997 to 5% in 2004 and tocolysis, the use of medications to inhibit preterm contractions, decreased from 2.5% in 1997 to 1.2% of births in 2004 (Table BT14 and Figure BT15).Obstetric procedures varied little by age except for amniocentesis, which was much more common among older mothers. Rates of electronic fetal monitoring, ultrasound, and stimulation of labor decreased with increasing age, but this may be a data artifact. Older mothers are more likely to give birth out of state and information about obstetric procedures is not provided on out-of-state birth records. Amniocentesis was much more likely among White and Asian/Pacific Islander mothers. Stimulation of labor was most common among Asian/Pacific Islanders while induction of labor was most likely among White mothers (Table BS18 and Figure BS14).
Maternal weight gain
The Institute of Medicine recommends that women with a normal pre-pregnancy body mass index (BMI) gain 25-35 pounds during pregnancy. Mothers who are underweight when they become pregnant are encouraged to gain 28-40 pounds and mothers who start off overweight should gain 15-25 pounds. It is recommended that women carrying twins gain 35-45 pounds. (IOM, 1990.) Pre-pregnancy height and weight necessary for the calculation of BMI are not available on birth certificates, so results are given for women of any BMI. Thirty-nine percent of women who delivered full-term singletons in 2004 gained the recommended 25-35 pounds, while 31% gained less and 30% gained more (Table BS19).
Period of gestation
The share of all births which were preterm increased 26% from 1994 to 2004. More than 10% of infants born in 2004 were delivered prior to 37 weeks of gestation (Table BT15 and Figure BT16). Preterm deliveries were most likely among Black mothers (15.7%). The preterm delivery rate increased with plurality. More than half of twins were born prematurely compared to 8.1% of singletons. As expected, gestational length and birth weight were positively correlated. Seventy-three percent of low birth weight infants (< 2,500 grams) were preterm compared to 5.1% of normal birth weight infants (Table BS20).
The proportion of births which were preterm ranged from 6.1% in Cape May County to 12.9% in Essex County . The clinical estimate of gestation which is used to determine preterm births is not required to be reported on out-of-state birth certificates; therefore some counties have high rates of missing information: Salem (18%) and Hudson (10%) (Table BC14).
Attendant at birth
Between 1994 and 2004, the percentage of births attended by doctors of osteopathy (D.O.s) nearly doubled and the share attended by certified nurse midwives (C.N.M.s) increased 121%. The proportion attended by doctors of medicine (M.D.s) decreased as the other two increased (Table BT16 and Figure BT17).
Attendant at birth varied by age and race/ethnicity with younger mothers more likely to have had a D.O. or C.N.M. attend their child’s birth in 2004. This may, however, be an artifact of geography as D.O.s and C.N.M.s are more prevalent in the southern part of New Jersey which also has higher rates of births among younger mothers (Tables BS21 and BC4). Nearly all births to Hudson (97%), Bergen (94%), Middlesex (94%), and Morris (90%) County mothers were attended by an M.D. D.O.s attended more than one-fifth of births in Cape May (33%), Gloucester (31%), and Burlington (24%) while more than one-fifth of births in Cumberland (41%), Mercer (27%), Atlantic (23%), and Salem (22%) Counties were attended by C.N.M.s. Missing data for Salem (18%) and Gloucester (7%) Counties could affect their rankings among counties with high D.O. or C.N.M. rates (Table BC15). Over 90% of births to Asian and Pacific Islanders were attended by an M.D., while only 80% of White births were. White women were most likely to be attended by a D.O. (11%) and Hispanic women were most likely to be attended by a C.N.M. (11%) compared to women of other races and ethnicities (Table BS21).
Place of delivery
Nearly all births in New Jersey occur in hospitals. In 1994, 133 births occurred in freestanding birth centers but by 2003, all birth centers in New Jersey had closed. Home births decreased by nearly one-quarter over the decade (Table BT17 and Figure BT18).
Method of delivery
A shift in method of delivery occurred around 1995 and 1996. In 1995, 73% of births were delivered vaginally. The percentage began to drop steadily after that and by 2004, only 62% were delivered vaginally. The reason for the decline is twofold. First, the vaginal birth after previous cesarean (VBAC) rate declined from a high of 35.6 births per 100 women with a previous cesarean delivery in 1996 to 11.1% in 2004. Accordingly, the repeat cesarean rate increased from 64.4 births per 100 women with a previous cesarean in 1996 to 88.9% in 2004. Second, the rate of primary cesareans increased from 16.4 births per 100 women who had not had a previous cesarean delivery in 1995 to 26.0% in 2004 (Table BT18 and Figure BT19). The percentage of cesarean deliveries which did not follow a trial of labor also increased 27% since data became available in 1997. Among women without a previous cesarean, the proportion with no trial of labor increased from 35% in 1997 to 45% in 2004 and among women with a previous cesarean delivery, the proportion increased from 75% in 1997 to 92% in 2004 (Table BT19 and Figure BT20).
The cesarean delivery rate was positively correlated with age. Over 56% of mothers aged 45-49 years delivered via cesarean while only 21% of mothers aged 10-14 years did in 2004. Cesarean delivery rates were fairly uniform across races/ethnicities (Table BS23 and Figure BS16). Among counties with low missing data rates, Mercer had the lowest cesarean delivery rate (27.4%) which is to be expected with its high percentage of births attended by C.N.M.s. Passaic County had the highest cesarean delivery rate (38.1%) (Table BC16).
The percentage of mothers who delivered vaginally and received an episiotomy declined steadily from 41% in 1997 to 27% in 2004 (Table BT20 and Figure BT21). Forty-six percent of Asian and Pacific Islanders were given an episiotomy compared to 29% of Whites, 23% of Hispanics, and 15% of Blacks in 2004. Episiotomy did not vary as much by age with the exception of a high rate among mothers aged 10-14 years (43%) and a low rate among mothers aged 45 years and over (21%). All other age groups had rates near the overall rate of 27% (Table BS24 and Figure BS17).
Complications of labor and/or delivery
For most complications of labor and/or delivery, there was little change between 1997 and 2004. The percentage of births with cephalopelvic disproportion decreased from 2.2% of births in 1997 to 1.3% in 2004. Premature rupture of membranes (more than 12 hours before the onset of labor) decreased from 2.0% of births in 1997 to 1.2% in 2004. Excessive bleeding not due to abruptio placenta or placenta previa also decreased, from 2.2% of births in 1997 to 1.7% in 2004. Fetal distress increased from 5.4% of births in 1997 to 6.8% in 2004 (Table BT21).In 2004, the most commonly reported complications of labor and/or delivery were fetal distress (6.8%), moderate or heavy meconium (6.5%), and breech/malpresentation (4.4%). Certain complications were more common among younger mothers. These included febrile (>100°F or 38°C), moderate or heavy meconium, and prolonged labor. Others, such as breech/ malpresentation, abruptio placenta, placenta previa, and other excessive bleeding were more common among older mothers. Above average rates of fetal distress, abruptio placenta, and moderate or heavy meconium were seen among Black mothers, while Hispanic mothers had higher than average rates of prolonged labor and febrile and Asian and Pacific Islander mothers had high rates of febrile, placenta previa, and dysfunctional labor (Table BS25).
The number of births followed by tubal ligation, the tying off of the fallopian tubes to prevent pregnancy, decreased between 1997 and 2004. The proportion decreased among all age groups in which there were enough procedures to calculate a reliable rate (Table BT22 and Figure BT22).
Four percent of mothers had a tubal ligation in 2004. Only tubal ligations performed prior to discharge from the hospital are included in this rate. The procedure is more common among older mothers . Eight percent of mothers aged 35 years and over had their tubes tied compared to 1.3% of mothers under age 25. Tubal ligation was more common among Black (5.5%) and Hispanic (5.5%) mothers than among White (3.6%) and Asian and Pacific Islander (2.3%) mothers (Table BS26 and Figure BS18).
NEWBORN CHARACTERISTICS AND HEALTH
There were 58,422 males and 56,018 females born to New Jersey residents in 2004. The male/female ratio was 1.043. The ratio varied by race/ethnicity. Hispanics had the lowest rate (1.019) and Asians and Pacific Islanders had the highest (1.072) (Table BS27 and Figure BS19). More males than females were born in each county except Cape May , Warren , and Hunterdon. Salem County had the highest male/female ratio (1.198) (Table BC17).
Eight percent of births in 2004 were of low birth weight (less than 2,500 grams or 5 lbs 7.5 oz). The percentage of births which were of low birth weight was 7.8% higher in 2004 than in 1994 (Table BT23). The modal weight group (37%) was 3,000-3,499 grams (6 lb 9 oz - 7 lb 10.49 oz) and 27% of births weighed 3,500-3,999 grams (7 lb 10.5 oz - 8 lb 11.9 oz) (Table BS32). Low birth weight rates ranged from 5.4% in Hunterdon County to 10.3% in Salem County . Missing data rates as high as 10% in Hudson and 7% in Bergen Counties could affect results (Table BC18 and Figure BC7).
Age of mother
Low birth weight was most common among the youngest and oldest mothers. Among mothers aged 40 years and over, where multiple birth rates were high, 12% of births were of low birth weight. Mothers aged 15-19 years also had higher than average low birth weight rates (Table BS28 and Figure BS20).
Race/ethnicity of mother
While the low birth weight rate increased 26% among White mothers and 14% among Asian and Pacific Islanders, it decreased 2% among Blacks and Hispanics from 1994 to 2004. However, throughout the decade, Black mothers had approximately twice the low birth weight rate of mothers of other races/ethnicities (Table BT23 and Figure BT23). In 2004, the low birth weight rate among Black mothers was 1.7 times higher than the overall rate and 1.9 times the rate for Whites. The rate for Black mothers was 13.7% compared to 8.0% for Asian/Pacific Islanders and 7.2% for Hispanics and Whites (Table BS28).
Previous pregnancy losses
Low birth weight was positively correlated with the number of previous pregnancy losses experienced by the mother. Thirteen percent of mothers with three or more previous losses had low birth weight babies compared to less than 8% of those with no prior losses (Table BS29 and Figure BS21).
Multiple birthsAmong singletons, the proportion of births which were low weight decreased slightly between 1994 and 2004, while among multiples this share increased. Therefore, the overall increase in the share of births which are low weight can be attributed to the increase in low weight births among multiples. The proportion of low birth weight infants who were part of a multiple delivery increased from 21% in 1994 to 31% in 2004 (Table BT24 and Figure BT24). While less than 6% of singletons were of low birth weight, 52% of twins, 92% of triplets, and 100% of quadruplets were of low birth weight in 2004 (Table BS30 and Figure BS22).
While the trimester of prenatal care onset does not have a large effect on birth weight, nearly 30% of mothers who did not receive any prenatal care had low birth weight babies. Lack of prenatal care had the greatest affect on the birth weight of newborns of Black (33% low birth weight) and Asian and Pacific Islander (32%) mothers (Table BS31 and Figure BS23).
Apgar score is a summary measure of an infant's clinical condition based on heart rate, respiratory effort, muscle tone, reflex irritability, and color taken at one and five minutes after delivery. A score less than seven is considered an indicator of potential health problems. Less than one percent of births had five-minute Apgar scores below seven. Low Apgar scores were more likely among young mothers under the age of 17 years (1.7%) than among mothers aged 18 years and older. Black mothers had a higher rate of low Apgar scores (1.8%) than mothers of other races/ethnicities. Five percent of births whose mothers did not receive prenatal care had low Apgar scores (Table BS33).
Abnormal conditions of newborn
Rates for all reported abnormal conditions of newborns were low in 1997 (each less than 1%), but all have declined further since then. Rates of meconium aspiration syndrome, assisted ventilation (<30 minutes), and hyaline membrane disease/respiratory distress syndrome halved between 1997 and 2004. The percentage of newborns with anemia and the percentage requiring 30 or more minutes of assisted ventilation decreased by more than one-third from 1997 to 2004. Other abnormal conditions such as fetal alcohol syndrome and seizures also decreased but numbers are too small to produce a reliable trend (Table BT25 and Figure BT25).
Assisted ventilation of 30 or more minutes was the most frequently reported abnormal condition of newborns in 2004. Hyaline membrane disease/respiratory distress syndrome was more common among newborns of younger mothers and Black mothers. Birth injuries were also more common among younger mothers and assisted ventilation was more common among Black mothers than among mothers of other races/ethnicities (Table BS34).
Congenital anomalies are captured on the birth certificate, however some birth defects are not detectable until some time after the infant has been released from the hospital. Therefore, congenital anomaly information from the birth certificate files is not complete. In 2004, rates were virtually the same or lower than in 1997 for all congenital anomalies reported on birth certificates (Table BT26).
Urogenital anomaly was the most commonly reported congenital anomaly on birth certificates in 2004 (0.2%) and it was more common among newborns of White and Hispanic mothers than Black mothers. Polydactyly, syndactyly, and adactyly were four times more commonly reported among births to Black mothers than among White mothers (Table BS35).
The neonatal intensive care unit (NICU) admission rate remained between 7.2% and 8.2% of births from 1997 to 2004 (Table BT27). In 2004, 8.2% of newborns were admitted to the NICU at the hospital of birth or after transfer to another hospital. Multiple births, preterm births, and those of low birth weight were much more likely to be admitted to a NICU than singletons, full-term births, and those of normal birth weight. Twenty-two percent of newborns whose mothers received no prenatal care were admitted to a NICU while the admission rate for births with any prenatal care was about 8% (Table BS36).
The percentage of male newborns who were circumcised decreased 12% from 66% of all male newborns in 1997 to 58% in 2004. Only circumcisions performed prior to discharge from the hospital are counted. Foreign- and Puerto Rico-born mothers were much less likely to have their sons circumcised and while the percentage of circumcisions among newborns of native-born mothers declined 5% from 1997 to 2004, the percentage among foreign-born mothers decreased 21%. However, among mothers born in Puerto Rico , the percentage increased 11% (Table BT28 and Figure BT26). While 78% of Black and 67% of White mothers had their sons circumcised in 2004, only 42% of Asian/Pacific Islander and 38% of Hispanic mothers did. Seventy-two percent of native-born mothers had their sons circumcised compared to 52% of Puerto Rico-born and 38% of foreign-born mothers. Among Blacks, there was little difference based on nativity, but for other races/ethnicities, the mother’s nativity greatly affected circumcision rates. Among native-born mothers, 72% of Whites, 68% of Asian/Pacific Islanders, and 61% of Hispanics had their sons circumcised. However, among foreign-born mothers, the percentages were 44%, 40%, and 26% for Whites, Asian/Pacific Islanders, and Hispanics, respectively (Table BS37 and Figure BS24).
Feeding at discharge
Feeding at discharge refers to the type of feedings given to the newborn in the 24 hours prior to discharge from the hospital. The exclusive breastfeeding rate decreased from 40% in 1997 to 35% in 2004 (Table BT29). In 2004, 31% of newborns were exclusively formula fed and 29% were combination fed (both breast and formula) (Table BS38). Exclusive breastfeeding rates ranged from 15% in Hudson County to 59% in Hunterdon County while exclusive formula feeding rates were lowest in Hunterdon County (18%) and highest in Essex County (44%). Rates of combination feeding ranged from 5% in Gloucester County to 40% in Union County . Missing data for Salem (20%), Hudson (11%), and other counties could affect their rankings (Table BC19).
Age of mother
The percentage of mothers exclusively breastfeeding increased with maternal age up to 30-34 years old where it peaked at 40% before declining again. Exclusive formula feeding was most common among the youngest mothers and the rate decreased with increasing age before leveling off among women aged 30 and over. Combination feeding was most common among mothers aged 15-29 years, though the rate was between 20% and 33% for each age group (Table BS38 and Figure BS25).
Race/ethnicity and nativity of mother
Between 1997 and 2004, the exclusive breastfeeding rate decreased from 49% to 47% among White mothers, 21% to 20% among Black mothers, 30% to 22% among Hispanic mothers, and 47% to 39% among Asian/Pacific Islander mothers (Table BT29 and Figure BT28). In 2004, e xclusive breastfeeding was most common among White mothers (47%), while formula feeding was most common among Blacks (50%) and combination feeding was most common among Hispanics (47%) and Asian/Pacific Islanders (44%) (Table BS39 and Figure BS26 ).
The exclusive breastfeeding rate decreased from 43% to 40% among native-born mothers, from 41% to 30% among foreign-born mothers, and from 22% to 19% among Puerto Rico-born mothers. (Table BT29 and Figure BT27). In 2004, breastfeeding was only slightly more prevalent among native-born mothers than formula feeding (38%), formula feeding was most common among Puerto Rico-born mothers (45%), and combination feeding was most common among the foreign-born (48%) (Table BS39 and Figure BS26).
Among Whites, and Blacks, nativity had little or no effect on breastfeeding rates, but formula feeding was more common among the native-born and combination feeding was more common among the foreign-born in those race/ethnicity groups. The same pattern was seen among native- and foreign-born Hispanics, however feeding choices among those born in Puerto Rico varied from that of both native- and foreign-born Hispanics. Among Asians and Pacific Islanders, nativity had little effect on formula feeding rates, but breastfeeding was more likely among the native-born and combination feeding was more likely among the foreign-born (Table BS39 and Figure BS26).
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