Umbilical cord length in Down's syndrome.

Fetal motor activity is believed to influence umbilical cord growth. As Down's syndrome is associated with hypotonicity and reduced fetal activity, we hypothesized that newborn infants with this syndrome have short umbilical cords. We identified 21 infants with Down's syndrome and compared each individual cord length to mean standard values derived from the same population and matched for sex, race, and gestational age. Infants with Down's syndrome were found to have significantly shorter umbilical cords (mean of 45.1 cm compared with 57.3 cm for matched standards). It is not clear whether their cords are shorter on the basis of decreased fetal activity, genetics, or both. If it is on the basis of decreased fetal activity, it would be interesting to see if those with the shortest cords (presumed to have been the most hypoactive in utero) could be predicted to have worse neurodevelopmental outcomes.

Are there adverse effects of periconceptional spermicide use?

Recent studies have suggested that spermicide exposure around conception may cause congenital malformations, reduced birth weight, or spontaneous abortion. This large, prospective study examined the risk for multiple malformation, patterns of malformations, low birth weight, preterm delivery, and spontaneous abortion in infants whose mothers used spermicides only before or after their last menstrual period, compared with a control group using other contraceptive methods. The multiple malformation rates in women using spermicides only before or after their last menstrual period were 3.8 and 4.8 per thousand, respectively. For the control groups, the corresponding rates were 5.4 and 6.4 (not significant). No pattern of malformations was found in spermicide-exposed infants. The risk of preterm delivery, the risk for producing a low-birth-weight (less than 2500 gm) infant, and the risk of spontaneous abortion were no higher in women exposed to spermicides than in women using other methods of contraception. This study finds no evidence that spermicide exposure around the time of conception is dangerous to the fetus.

PIP: Recent studies have suggested that spermicide exposure around conception may cause congenital malformations, reduced birthweight, or spontaneous abortion. This large, prospective study examined the risk for multiple malformations, patterns of malformations, low birthweight, preterm delivery, and spontaneous abortion in infants whose mothers used spermicides only before or after their last menstrual period (LMP), compared with a control group using other contraceptive methods. The multiple malformation rates in women using spermicides only before or after their LMP were 3.8 and 4.8/1000, respectively. For the control groups, the corresponding rates were 5.4 and 6.4 (not significant). No pattern of malformations was found in spermicide-exposed infants. The risk of preterm delivery, the risk for producing a low birthweight (2500 gm) infant, and the risk of spontaneous abortion were no higher in women exposed to spermicides than in women using other methods of contraception. This study finds no evidence that spermicide exposure around the time of conception is dangerous to the fetus.

The Pima infant feeding study: breastfeeding and respiratory infections during the first year of life.

Initial episodes of upper respiratory infection, otitis media, and pneumonia identified from medical records in the first year of life were analysed in relation to feeding practices (ascertained by maternal interview in 1978) among 571 infants born 1960-1977 on the Gila River Reservation. The odds ratio of developing a first episode of upper respiratory infection or otitis media during the first year was less than unity for infants exclusively breastfed for four months compared to exclusively bottlefed infants after logistic regression adjustment for seasonality, birthweight, and adverse social conditions (OR = 0.64). This benefit was evident during the first four months of life (OR = 0.61) and during the second four months (OR = 0.48). However, a significant benefit of early exclusive breastfeeding was no longer demonstrable during months 9-12. Exclusive breastfeeding for four months marginally reduced risk of pneumonia after adjustment for covariates. The data suggest that breastfeeding of infants in early life is associated with reduced risk of respiratory infection.

Maternal alcohol consumption and birth weight. How much drinking during pregnancy is safe?

The relationship between maternal alcohol drinking during pregnancy and birth weight was examined using prospectively collected data from 31,604 pregnancies. The percentage of newborns below the tenth percentile of weight for gestational age increased sharply with increasing alcohol intake. After adjustment for other risks, a reduction in mean birth weight was seen in drinkers compared with nondrinkers, ranging from 14 g in those drinking less than one drink each day to 165 g in those drinking three to five drinks each day. The adjusted odds ratio for producing a small-for-dates newborn compared with nondrinkers ranged from 1.11 in those drinking less than one drink daily to 1.96 in those drinking three to five drinks daily. Consuming at least one to two drinks daily was associated with a substantially increased risk of producing a growth-retarded infant. Conversely, consuming less than one drink daily had a minimal effect on intrauterine growth and birth weight.

The Pima Infant Feeding Study: breast feeding and gastroenteritis in the first year of life.

In 1978, a retrospective study of infant feeding was conducted among 257 Pima Indian women of reproductive age, who were residing on the Gila River Reservation, Arizona. With data on infant feeding patterns from 683 infants born 1950-1977 to the Pima Indian women, infants were classified into one of five feeding groups based on the duration breast-fed and time of introduction and duration bottle-fed. History of severe diarrhea/diarrhea with dehydration/diarrhea and vomiting was abstracted from the infant's medical record and classified as a case of gastroenteritis. The risk of developing a first such episode during the first year of life was compared between the exclusively bottle-fed and each of the other four feeding groups. The odds ratio of gastroenteritis during the first year was significantly less than unity for infants exclusively breast-fed for four months before adjustment (odds ratio = 0.49) and after adjustment for adverse social conditions and seasonality (odds ratio = 0.51). Similarly, univariate analysis and multiple logistic regression analysis of gastroenteritis from birth through four months revealed estimates of the odds ratio that were significantly less than unity for infants exclusively breast-fed for four months (odds ratio = 0.33 and 0.30, respectively). Although a trend of decreasing gastroenteritis with increasing breast feeding was noted across all other feeding groups, the rates of first episodes of gastroenteritis did not significantly differ among all other feeding groups and the bottle-fed. Thus, exclusive breast feeding for four months is associated with reduced risk of early first episodes of gastroenteritis among infants in a less developed community in the United States.

Standards for measuring umbilical cord length.

Umbilical cord length was measured in 9620 male and 9068 female infants and related to gestational age in order to construct a growth chart for umbilical cords. In addition to providing a standard for the US white population, these growth charts illustrate that umbilical cord length is widely divergent at the same gestational age, males have longer cords than females (P less than 0.0001), and umbilical cord growth continues throughout the third trimester.

Are spermicides teratogenic?

Recent evidence suggests that spermicides could be teratogenic. In this study, pregnant women provided data at their first prenatal visit on spermicide and other contraceptive exposures in each of the preceding 12 months. Data on malformations in their offspring were obtained by abstracting medical records. Among women practicing contraception before the last menstrual period but not after, the malformation rate in the offspring of spermicide users was no higher than in users of other methods. The same was true of women who continued to practice contraception after the last menstrual period. When malformations were examined by organ system and by individual defect, spermicide exposure again was not associated with an increased risk. Comparing spermicides by active ingredient with other methods of contraception revealed no increased risk of malformations for any compound. Controlling for age, time in pregnancy at which exposure data were collected, concentration of spermicides used, and other possible confounding factors did not alter the results. This study finds no association between maternal spermicide exposure before or after the last menstrual period and congenital malformations.

The Pima infant feeding study: the role of sociodemographic factors in the trend in breast- and bottle-feeding.

In 1978, a retrospective study of the influence of sociodemographic factors on the trend in breast- and bottle-feeding was conducted among a sample of Pima Indian women 15 to 44 yr old residing on the Gila River Reservation. Based on interviews with 257 Pima Indian women about their infant feeding experiences, the proportion of women who breast-fed dropped significantly between 1949 and 1977. The decline in breast-feeding was evident among women aged 35 to 44 in 1978 across three socioeconomic strata, while women aged 30 to 34 experienced an increase in breast-feeding across two socioeconomic strata. Between 1949 and 1963, women of 50 to 100 and 100% Pima Indian descent breast-fed significantly less than those with other tribal affiliations; however, the influence of tribal descent was reduced thereafter. Bottle-feeding was more prevalent in the high birth orders over time. Among women with first births before 1963, those with small families bottle-fed more than those with large families across birth order. Conversely, among women with first births during or after 1963, those with large families bottle-fed more than those with small families across birth order.

Should coitus late in pregnancy be discouraged?

Coitus late in pregnancy has been thought to be a cause of premature rupture of membranes, preterm birth, and amniotic fluid infections. In this study, data on 10 981 singleton, low-risk pregnancies were examined. The mothers were asked at time of delivery if there were any months when they did not have sexual intercourse during pregnancy. Pregnancy outcomes were determined by medical record review. Those having intercourse showed no increased risk of premature rupture of membranes, low birthweight, or perinatal death at any gestational age. Women abstaining from intercourse had more unfavourable outcomes in the seventh and eighth months, but these differences were almost eliminated by adjustment for maternal age. Preterm delivery was no more frequent in those having intercourse than in those abstaining. These findings challenge the view that intercourse late in pregnancy is harmful.

The tendency to repeat gestational age and birth weight in successive births.

PIP: A study was conducted in Norway on all 454,358 single births which occurred during the 1967-73 period. The results confirm and strengthen earlier findings regarding the tendency to repeat low-birth-weight and small- or large-for-gestational age deliveries in later births. Data collected from the Medical Birth Registry included information on birth weight, length of gestation, mothers' health during pregnancy, and complications and interventions during labor and delivery. A contour level graph was prepared to illustrate the joint distribution of gestational age and birth weight. Relative risks were calculated for each type of birth. These risks were correlated with actual outcome of subsequent births. The tendency to repeat birth weight in later births was greatest for mothers of heavy infants. The tendency to repeat gestational age in subsequent births, however, was greatest for mothers with preterm infants. Delivery of prior preterm births carried a lower risk than delivery of prior low-weight births. These tendencies were unaffected by the sex of the offspring or the birth order. The pattern of repeating similar gestational age and birth weight subsequently could not be accounted for by a tendency to repeat medical complications which predispose toward such outcomes. Such environmental factors as smoking or socioeconomic status were not believed to be relevant in the study results. The study demonstrates a cumulative risk for 3rd and later pregnancies.^ieng