Medical advice on maternal weight gain and actual weight gain. Results from the 1988 National Maternal and Infant Health Survey.

Weight gain advice showed a notable shift for white married mothers during the 1980s, with a large decline in reported advice of less than 22 pounds concomitant with a substantial increase in reported advice of 28 pounds or more. For black married mothers, there was little change in reported advice, except in the proportion of mothers who said they were advised to gain at least 35 pounds, which increased from 2 to 11%. It should be noted that it is not possible to corroborate the information on weight gain advice reported by mothers in 1980 or 1988 because of the lack of similar information from the providers of prenatal care. However, for the 1996 NMIHS, the feasibility of collecting such information from prenatal care providers will be examined. In view of the strong, positive relationship between maternal weight gain and birth weight, optimum weight gain advice for white and black mothers is critical. A recent nationwide survey of practicing dieticians found that 26% of the pregnant mothers they counseled believed that one shouldn't gain more than 20 pounds during pregnancy and that obese women didn't need to gain any weight at all. These beliefs were often culturally transmitted. Although only 12% of white mothers reported advice that did not meet the minimum standard in effect in 1988 and 19% reported advice that did not meet the minimum 1990 IOM guideline for their weight and height, a significantly higher proportion of black mothers reported advice of less than 22 pounds (33%) or the IOM minimum (34%). The far more frequent inappropriate advice reported by black than white mothers cannot be explained by differences in body mass index, age, education, parity, marital status, or site of care. Nevertheless, compliance with advice was almost the same for black and white mothers: More than 70% gained at least 22 pounds when this was the reported weight gain advice. It is thus entirely feasible that more appropriate advice for black women will result in significantly higher weight gains and improvement in infant birth weight and health.

Trends in cesarean section rates for the United States, 1970--78.

With National Hospital Discharge Survey data collected by the National Center for Health Statistics as a basis, rates of cesarean section deliveries were computed for the United States and its regions for 1970 through 1978. For each year and within each region, trends were examined according to variations in the mother's color, age, and marital status and in the hospital size (number of beds), the form of hospital ownership, and the length of the mother's hospital stay. Within each region and for each variable considered, cesarean section deliveries rose fairly uniformly. Nationally, C-sections comprised 5.5 percent of all deliveries in 1970, but rose steadily to comprise 15.2 percent of all deliveries in 1978. Overall, 1978 rates were highest in the Northeast, among whites, among women age 30 and over, among married women, in hospitals with 500 beds or more, and in proprietary hospitals. The mean length of the mother's hospital stay in 1978 was 6.7 days for cesarean section deliveries and 3.2 days for other deliveries, down from the mean hospital stay of 7.8 days for C-sections and 3.9 days for other deliveries observed in 1970.

Childbearing characteristics of U.S.- and foreign-born Hispanic mothers.

This study compares maternal and infant health and sociodemographic characteristics of U.S.-born and foreign- or Puerto Rican-born Hispanic mothers and their babies, using data from the national vital statistics system and the 1980 National Natality Survey. While nearly half of all Hispanic mothers and Mexican and Puerto Rican mothers were born in the United States, less than 10 percent of Cuban and other Hispanic mothers were U.S. born. Compared with foreign- or Puerto Rican-born Hispanic mothers, U.S.-born mothers tended to be younger, to have had fewer high-order births, to be less likely to receive delayed or no prenatal care, to have higher educational attainment, and to be more likely to be unmarried. The incidence of low birth weight among infants born to Hispanic mothers, particularly Mexican and Cuban women, was relatively low. When the proportions of low birth weight were examined by nativity status, infants born to foreign- or Puerto Rican-born women were consistently less likely to be of low birth weight. In an effort to account for these findings, the mother's smoking status before and during pregnancy is examined. Compared with non-Hispanic mothers, Hispanic mothers were much less likely to have smoked before or during pregnancy. These data are examined to see if they account for the better outcome as measured by birth weight for Hispanic births, especially those to foreign- or Puerto Rican-born women.

The frequency of complications in cesarean and noncesarean deliveries, 1970 and 1978.

National Hospital Discharge Survey data, collected by the National Center for Health Statistics, were used to examine complications associated with cesarean and noncesarean deliveries in the years 1970 and 1978. Cesarean deliveries comprised 5.5 percent of all deliveries in 1970 and 15.2 percent in 1978. Two-thirds (68.4 percent) of the 1970 and 82.1 percent of the 1978 cesarean deliveries involved specified complications compared with only 14.6 percent of the 1970 vaginal deliveries and 17.8 percent of the 1978 vaginal deliveries. More than one-fourth of the 1970 and 1978 cesarean deliveries, but less than 1 percent of the vaginal deliveries, were preceded by a cesarean section delivery. From 1970 to 1978, there was both a rise in breech presentations and a shift toward surgical management of them. Also, cesarean deliveries were associated with placenta previa, fetopelvic disproportion, prolonged labor, and premature rupture of membranes. Several competing explanations have been offered for the rise in complication rates and in cesarean delivery rates.

Electronic fetal monitoring in relation to cesarean section delivery, for live births and stillbirths in the U.S., 1980.

In the 1980 National Natality and Fetal Mortality Surveys, information about fetal monitoring and type of delivery was obtained from hospitals for a sample of 9,941 live births and 6,386 fetal deaths of 28 weeks' gestation or more. Data in this analysis are weighted to provide national estimates of live births and late fetal deaths that occurred in U.S. hospitals during 1980. Electronic fetal monitoring (EFM) was used for 47.7 percent of live births; 27.2 percent were monitored by Doppler ultrasound only, 10.2 percent by scalp electrode only, 6.3 percent by Doppler ultrasound and scalp electrode only, and 4.0 percent by other methods and combinations. The distribution by type of EFM used was similar for the 42.7 percent of late fetal deaths (also called stillbirths) that were monitored. Variation in the use of EFM for live births and stillbirths is examined according to maternal age, parity, education, race, marital status, income, previous fetal loss, underlying medical conditions, complications of pregnancy, complications of labor, duration of labor, infant birth weight, and length of gestation. Among live births, 17.1 percent were delivered by cesarean section, as were 16.8 percent of stillbirths. The association between fetal monitoring and the primary cesarean section rate (the probability of cesarean section for women who had never had one) for all birth orders and for first births is examined according to characteristics of the mothers and the infants. Factors involved in the consistent association found between fetal monitoring and the primary cesarean section rate are discussed.

Recent patterns in cesarean delivery in the United States.

The United States cesarean rate has risen from 5.5 per 100 deliveries in 1970 to 24.1 per 100 deliveries in 1986 according to the National Hospital Discharge Survey. Less than 10 per cent of mothers have a vaginal birth after a prior cesarean. Women spend an average of 5.0 days in the hospital for a cesarean delivery, but only 2.6 days for a vaginal delivery. The rise in cesareans is partly responsible for a concurrent increase in postpartum sterilization. If age-specific cesarean rates continue the steady pattern of increase observed since 1970, 40 per cent of births could be by cesarean by the year 2000.

Trends in low birth weight: United States, 1975-85.

National and regional trends in rates of low, moderately low, and very low birth weight are analyzed for the period 1975-85. Also reviewed are 1985 rates of low, moderately low, and very low birth weight in relation to a number of maternal and infant characteristics, as well as changes in low birth weight rates between 1980 and 1985 for many of these characteristics.

Health and demographic characteristics of twin births: United States, 1988.

National trends in twin birth incidence by race of child are analyzed for the period 1950-88. Also reviewed are maternal and infant health and demographic characteristics associated with twin delivery for the year 1988.

Cesarean delivery in the United States, 1990.

Information now available on method of delivery from birth certificates confirms past findings on the groups at highest risk of cesarean delivery and greatly expands our knowledge of the demographic and health characteristics associated with cesarean delivery. Mothers who live in the South, who are in the oldest years of childbearing, having their first birth, married, or who have high educational attainment are all at increased risk of a cesarean delivery. Very short gestations, low or high birthweights, multiple delivery, the presence of certain complications of pregnancy, labor and/or delivery, abnormal conditions of the newborn, and the use of some obstetric procedures are also associated with elevated cesarean rates. Several recent studies (28,29) have concluded that advanced maternal age in and of itself may be an independent risk factor for cesarean delivery, due to physician and patient concern over pregnancy outcome for older women. Many of the characteristics examined in this study are highly related to maternal age (for example, marital status and educational attainment). Therefore, for these variables, mother's age is also taken into account to determine if age itself is the underlying reason for differences in rates of cesarean delivery. The importance of the role of maternal age in the risk of cesarean delivery is clearly demonstrated throughout this report: Older mothers are more likely to deliver by cesarean regardless of race, Hispanic origin, parity, marital status, or educational attainment. The overall rate of cesarean delivery is only slightly lower for black than for white mothers (22.1 percent compared with 23.0 percent), despite the generally lower educational attainment of black mothers and the higher percentage who are unmarried or in their teen years, all factors that tend to substantially lower the risk of cesarean delivery. However, there are many offsetting factors that tend to raise the cesarean rate for black mothers. A relatively high proportion of black births occur in the South, which has the highest cesarean rate of all regions; the incidence of low and very low birthweight is far higher for black births; and premature delivery is twice as frequent for black babies. Also, although rates of cesarean delivery for most medical risk factors, complications of labor and or delivery, and abnormal conditions of the infant are about the same for both races, the incidence of a number of these conditions is substantially higher for black mothers and babies, and that has the effect of increasing the overall cesarean rate for black mothers.(ABSTRACT TRUNCATED AT 400 WORDS)

Vaginal birth after cesarean (VBAC) in the 1980s.

The incidence of vaginal birth after cesarean (VBAC) and characteristics of VBAC births are investigated using 1980-85 National Hospital Discharge Survey Data collected by the National Center for Health Statistics. Only 3.4 per cent of mothers with previous cesarean delivery had VBAC in their subsequent 1980 delivery; this increased to 6.6 per cent in 1985. Because VBAC is a relatively infrequent event, 1980-85 data were combined and indicate that in this period 4.9 per cent of mothers with previous cesarean had a vaginal birth in their subsequent delivery. Combined 1980-85 VBAC rates are under 10 per cent for all age, race, marital status, region, hospital size, hospital ownership, and expected source of payment groups. Between 1980 and 1985, over 1.4 million repeat cesareans were performed for mothers having a live birth. Evidence suggests that potentially over 500,000 of these repeat cesareans could have been VBACs (over and above the 74,000 VBACs which occurred). VBAC mothers' mean length of hospital stay is 3.2 days, which compares closely with 3.0 days for other vaginal deliveries, but both contrast sharply with 5.6 days for repeat cesareans and 6.0 days for primary cesareans. Except for the uterine scar from the previous cesarean, VBAC mothers appear to have about the same history and frequency of complications as mothers with other vaginal deliveries. If the 500,000 repeat cesareans had been VBACs, surgical fees and costs for 1.2 million days of hospital stay would have been averted over the 1980-85 period.

State variation in rates of cesarean and VBAC delivery: 1989 and 1993.

There is wide variation among states in rates of cesarean and vaginal births after cesarean (VBAC) deliveries. In general, states in the South have the highest cesarean rates, states in the West have the lowest, and states in the Northeast and Midwest are intermediate. Louisiana had the highest overall rate in 1993 (27.7 per 100 births) while Alaska had the lowest rate (15.2). The majority of states had declines in their cesarean rate between 1989 and 1993. Patterns in primary cesarean rates are similar to those of the overall rate-states in the South generally have the highest rates while states in the West have the lowest rates. Primary cesarean rates ranged between a high of 19.6 in Louisiana to a low of 10.6 in Wisconsin. In general, states with low cesarean rates have among the highest rates of VBAC delivery. Alaska had the highest VBAC rate (40.0), which was almost quadruple the rate of Louisiana (11.2), the state with the lowest rate. Most states had substantial increases in VBAC rates between 1989 and 1993. When examining cesarean rates by maternal age and birth order, states with the highest overall rates also have among the highest age/birth order-specific rates. Cesarean rates were lowest for mothers under 25 years of age having a second or higher order birth in Alaska, 10.4, and highest for mothers 35 years of age or over having a first birth in Mississippi, 51.3. Standardized cesarean rates which were adjusted for differences between states in maternal age and birth order distributions did not diminish the variation among areas.

Complications in cesarean and non-cesarean deliveries: United States, 1980.

Using 1980 National Hospital Discharge Survey data, complications reported for cesarean and non-cesarean deliveries coded by the Ninth Revision ICD-CM are compared. While over 16 per cent of all deliveries in 1980 were by C-section, 94 per cent of the deliveries where maternal-infant disproportion was noted were by C-section, and this complication was noted in one-fourth of all C-section deliveries. Similarly, where malposition or malpresentation of the fetus was evident, 59 per cent of the mothers were delivered by C-section, and this complication was noted in one-sixth of all C-section deliveries. C-sections were also associated with placenta praevia, pre-eclampsia, infections of the genito-urinary tract, anemia, multiple births, and were almost universal for mothers who had had a previous C-section delivery. Competing explanations for the rise in C-sections from 5.5 per cent of deliveries in 1970 to 16.5 per cent in 1980 are discussed in the context of these findings.

Advice about weight gain during pregnancy and actual weight gain.

In the 1980 National Natality Survey, married mothers were asked whether their doctors had suggested a weight gain limit during pregnancy and, if so, what limit was suggested. Current obstetric recommendations call for 22-27 pound weight gain. Previous research indicates that gaining less than 16 pounds greatly increases the likelihood of a poor pregnancy outcome. Reported advice varied by mother's race, education, parity, and prepregnancy weight. Mothers given no advice or advised to gain less than 22 pounds were far more likely than others to have an inadequate gain. The findings suggest that many more women should be told that it is appropriate to gain at least 22 pounds.

Pregnancy-related weight gain and retention: implications of the 1990 Institute of Medicine guidelines.

OBJECTIVES: Guidelines from the Institute of Medicine's 1990 report call for weight gains during pregnancy that are higher than those previously recommended. This study examines the potential implications of compliance with these guidelines for postpartum weight retention. METHODS: Weight retention 10 to 18 months following delivery was examined for selected women who had live births in the 1988 National Maternal and Infant Health Survey. Women's actual weight gains during pregnancy were retrospectively classified according to the Institute of Medicine's guidelines. RESULTS: Weight retention following delivery increased as weight gain increased, and Black women retained more weight than White women with comparable weight gain. The median retained weight for White women who gained the amount now being recommended was 1.6 lb whereas that for Black women was 7.2 lb. CONCLUSIONS: If pregnant White women gain weight according to the institute's guidelines, they need not be concerned about retaining a substantial amount of weight postpartum. Our findings suggest, however, that Black women are in need of advice about how to lose weight following delivery.

Current and future impact of rising multiple birth ratios on low birthweight.

Before 1980, multiple births with their increased risk of low birthweight comprised too small a proportion of births in the United States to have a significant impact on overall low birthweight levels; the recent steep rise in the multiple birth ratio has heightened their influence, however. Between 1980 and 1992 the white multiple birth ratio rose from 18.5 to 24.0 multiple births per 1,000 births. While the overall level of white low birthweight newborns increased slightly between 1980 and 1992 (from 5.7 percent to 5.8 percent), low birthweight for white singletons actually improved, declining from 4.9 to 4.7 percent. Thus, the increase in overall white low birthweight levels is a reflection of the increase in white multiple births and, to a much lesser extent, of the small increase in low birthweight among these births. Black multiple birth ratios and overall low birthweight also rose in this period. The black multiple birth ratio increased from 24.4 in 1980 to 28.2 per 1,000 births in 1992, and low birthweight rose from 12.7 to 13.3 percent. Although low birthweight for black singletons also increased (from 11.5 percent to 11.8 percent), the increase was at a slower pace than for all pluralities combined. Thus, for both white and black births, overall trends in low birthweight mask the disparate patterns of singleton and multiple births. It is, therefore, essential to examine low birthweight trends by plurality to assess accurately changes in this key indicator of infant health.

Trends in the United States cesarean section rate and reasons for the 1980-85 rise.

The rate of cesarean section delivery in the United States rose from 4.5 per 100 deliveries in 1965 to 22.7 in 1985, and in 1985 an estimated 851,000 live births were cesarean deliveries, according to data from the National Hospital Discharge Survey. This increase has been observed for all ages, and within all regions of the country. The rate for teenagers and mothers aged 20 to 29 was five to six times as high in 1985 as in 1965, and four times as high for mothers aged 30 years and older. Repeat cesareans account for an increasing share of all cesarean deliveries; in 1985 one in three cesareans were repeats. The increase in the cesarean rate of 6.2 percentage points between 1980 and 1985 (from 16.5 to 22.7) was partitioned according to five complications of delivery recorded on hospital discharge records: previous cesarean delivery, breech presentation, dystocia, fetal distress, and all other complications. Nearly half (48 per cent) of the increase was associated with previous cesarean delivery, 29 per cent with dystocia, 16 per cent with fetal distress, 5 per cent with breech presentation, and 2 per cent with all other complications.

Revised U.S. certificate of birth--new opportunities for research on birth outcome.

The 1989 revision of the U.S. Standard Certificate of Live Birth includes a number of new items on medical and life-style risk factors of pregnancy and birth, obstetric procedures performed, method of delivery, abnormal conditions and congenital anomalies of the infant, expanded information on birth attendant and place of birth, and questions on the Hispanic origin of the parents. This major enhancement of medical and health data available on mothers and infants can greatly expand the scope of research on pregnancy outcome in the United States.

Estimates of pregnancies and pregnancy rates for the United States, 1976-85.

After increasing by 9 per cent in the period 1976-80 in the United States, pregnancy rates declined by 4 per cent between 1980 and 1984 (from 111.9 to 107.3 pregnancies per 1,000 women aged 15-44 years). Between 1984 and 1985, the rate rose by less than 1 per cent to 108.2. More detailed data by age and race, available only through 1983, indicate that the decline in the 1980-83 period was not shared by all age groups. For example, pregnancy rates continued to increase for women in their thirties, and teenage pregnancy remained substantially the same. In 1983, 61 per cent of all pregnancies ended in live birth, 26 per cent in induced abortion, and 13 per cent in fetal loss. Pregnancy rates in that year were two-thirds higher for women of races other than White than for White women, and pregnancies of other-than-White women were more likely to terminate as an induced abortion or fetal loss. However, White teenagers and teenagers of other races were about equally likely to have their pregnancy end in induced abortion or fetal loss.

Comparisons of national cesarean-section rates.

Our study of cesarean rates in 19 industrialized countries of Europe, North America, and the Pacific revealed sharp differences in rates, ranging from a low of 5 (Czechoslovakia) to a high of 18 (United States) per 100 hospital deliveries in 1981. Differences in cesarean rates according to maternal age, parity, and complications of pregnancy and childbirth reflected national differences in obstetrical practice. For example, the percentage of mothers who had a vaginal birth after a previous cesarean section was only 5 in the United States as compared with 43 in Norway, where the cesarean rate was half that in the United States. Despite the wide range of cesarean rates, almost all the countries studied have had consistent increases over the past decade, and the annual rate of increase for all countries appears to be converging. The steady pace of increase in developed countries, combined with comparable or even higher rates of cesarean delivery now being reported in less developed countries, underscores the need for the medical community to consider the appropriateness of this continued rise in the number of cesarean deliveries.

Trends and characteristics of births attended by midwives.

In 1994 there were 218,466 births attended by midwives in the United States more than seven times the number in 1975 (29,413). The percent of all births attended by midwives rose from 0.9 percent in 1975 to 5.5 percent in 1994. The vast majority of midwife attended births were by certified nurse-midwives (CNMs) and occurred in hospitals. Births attended by other midwives comprised only 6 percent of all midwife-attended births (down 11 percent since-1989) and are becoming increasingly concentrated in out of hospital settings, particularly residences. Due in large part to population characteristics, the proportions of births attended by midwives varies markedly between states. The percentages range from 19 percent in New Mexico to less than 1 percent in Kansas Louisiana Missouri and Nebraska Mothers with midwife attended births in out of hospital settings generally had demographic and lifestyle characteristics that were lower risk for obstetric complications and poor birth outcomes compared with mothers with physician- or midwife attended births in hospitals. That is these mothers were more likely to be married older more educated having higher order births and were less likely to smoke and gain and adequate amount of weight during pregnancy. However women with midwife attended births regardless of type of midwife or birth setting were more likely to initiate prenatal care later in the pregnancy and have fewer overall visits than were women whose births were attended by physicians. Despite less prenatal care a smaller proportion of babies whose births were attended by midwives were preterm or were of low or very low birth weight.