Second-trimester serum cotinine levels in nonsmokers in relation to birth weight.

In this study the relationship between birth weight and passive exposure to tobacco smoke is assessed for the first time by serum cotinine measurements. Among 1231 nonsmoking white women whose blood was sampled during the second trimester of pregnancy, 31.4% had serum cotinine levels between 1.

Maternal serum thyroid antibodies in early pregnancy and fetal Down's syndrome.

Thyroid antibodies were measured in mid-trimester antenatal serum samples from 77 pregnancies affected by fetal Down's syndrome and 385 unaffected control pregnancies. Using a haemagglutination technique, thyroglobulin antibodies were detected in 5.2 per cent of cases (4) and 2.

Second-trimester maternal serum alpha-fetoprotein levels in pregnancies associated with gastroschisis and omphalocele.

This population-based study analyzes maternal serum alpha-fetoprotein (MSAFP) distributions for 20 cases of gastroschisis and 13 cases of omphalocele occurring in singleton pregnancies from among 72,782 second-trimester pregnancies in Maine and Rhode Island screened consecutively between January 1, 1979 and February 28, 1987. Median values (and ranges) for the two lesions were 4.1 multiples of the median (0.

Low second trimester maternal serum unconjugated oestriol in pregnancies with Down's syndrome.

Second trimester maternal serum unconjugated oestriol levels were measured in the stored serum samples from 22 pregnancies associated with Down's syndrome and 110 unaffected control pregnancies, matched for maternal age, gestational age, duration of storage of the serum sample, smoking habits and maternal weight. The serum unconjugated oestriol level of each affected pregnancy was expressed as a multiple of the median (MoM) of its five matched controls. The unconjugated oestriol levels were significantly lower in the affected pregnancies than in the unaffected pregnancies; the median MoM was 0.

Maternal serum unconjugated oestriol as an antenatal screening test for Down's syndrome.

The median maternal serum unconjugated oestriol level between 13 and 27 weeks gestation in 77 pregnancies associated with Down's syndrome was lower than the median level in 385 unaffected control pregnancies matched for maternal age, gestational age, and duration of serum sample storage (P less than 0.001). The median level for the affected pregnancies was 73% of that in the controls.

A biomechanical evaluation of sorbothane.

Sorbothane (I.E.M.

Cigarette consumption and serum cotinine in relation to birthweight.

The concentration of serum cotinine (the major metabolite of nicotine) was measured in sera from 4211 women at between 15 and 21 weeks gestation to determine whether a serum cotinine level was a better predictor of low birthweight than the self-reported number of cigarettes smoked per day. Both cotinine levels and smoking history were significantly associated with reduced birthweight, but cotinine correlated significantly better. Smokers of greater than or equal to 25 cigarettes per day, representing the 2.

Very low versus undetectable maternal serum alpha-fetoprotein values and fetal death.

Very low maternal serum alpha-fetoprotein (MSAFP) levels (less than 10 ng/mL) are known to be associated with non-viable pregnancies, including conditions such as fetal death, molar pregnancies, and non-pregnancies. There has not been agreement, however, as to whether very low MSAFP levels indicate already existing fetal deaths or are actually predictive. We analysed 230 pregnancies with MSAFP levels less than 10 ng/mL from among 15,807 women (1.

Can low birth weight after elevated maternal serum alpha-fetoprotein be explained by maternal weight?

Low birth weight infants are delivered with increased frequency in women who have elevated maternal serum alpha-fetoprotein values in the second trimester. Maternal serum alpha-fetoprotein elevations, however, are found more often in lighter-weight women, a group known to have lower-weight infants regardless of maternal serum alpha-fetoprotein levels. To clarify the association between elevated maternal serum alpha-fetoprotein levels and low birth weight independent of maternal weight, we applied a weight correction formula to maternal serum alpha-fetoprotein values from 9507 singleton viable pregnancies without major fetal malformations.

Maternal serum alpha-fetoprotein, age, and Down syndrome risk.

Before the discovery that an association existed between low maternal serum alpha-fetoprotein levels and Down syndrome, the ability to detect Down syndrome pregnancies was limited to women aged greater than or equal to 35, whose individual risks were sufficiently high (greater than or equal to 1:270 in the second trimester) to justify offering amniocentesis. If such women were to opt for that procedure, about 20% of all cases of Down syndrome could be detected. It is now possible to identify an additional 20% of all Down syndrome pregnancies in women under age 35, with the use of a screening process that combines a woman's maternal serum alpha-fetoprotein level and her age.

Determination of nicotine and cotinine in human serum and urine: an interlaboratory study.

An interlaboratory study aimed at determining nicotine and cotinine in human serum and urine was carried out. 11 laboratories from 6 countries, all experienced in performing nicotine and cotinine determinations in biological fluids by radioimmunoassay (RIA) and/or gas chromatography (GC) were involved. Each of them received 18 serum and 18 urine samples.

Alpha-fetoprotein, vaginal bleeding and pregnancy risk.

To assess the interrelation between maternal serum alpha-fetoprotein (MSAFP) levels and vaginal bleeding as a combined pregnancy risk factor, we studied 6829 singleton pregnancies without fetal malformations during the second trimester. The predictive powers of the two risk factors, analysed separately, are consistent with published reports in relation to fetal death and low birthweight. Until now, however, these two risk factors have not been analysed together.