Showing papers on "Pregnancy published in 1992"

Prevention of the First Occurrence of Neural-Tube Defects by Periconceptional Vitamin Supplementation

Abstract: Background. The risk of recurrent neural-tube defects is decreased in women who take folic acid or multivitamins containing folic acid during the periconceptional period. The extent to which such supplementation can reduce the first occurrence of defects is not known. Methods. We conducted a randomized, controlled trial of periconceptional multivitamin supplementation to test the efficacy of this treatment in reducing the incidence of a first occurrence of neural-tube defects. Women planning a pregnancy (in most cases their first) were randomly assigned to receive a single tablet of a vitamin supplement (containing 12 vitamins, including 0.8 mg of folic acid; 4 minerals; and 3 trace elements) or a trace-element supplement (containing copper, manganese, zinc, and a very low dose of vitamin C) daily for at least one month before conception and until the date of the second missed menstrual period or later. Results. Pregnancy was confirmed in 4753 women. The outcome of the pregnancy (whether the fetu...

Characteristics relating to ovarian cancer risk: collaborative analysis of 12 US case-control studies. II. Invasive epithelial ovarian cancers in white women. Collaborative Ovarian Cancer Group.

Abstract: Data collected from 2,197 white ovarian cancer patients and 8,893 white controls in 12 US case-control studies conducted in the period 1956-1986 were used to evaluate the relation of invasive epithelial ovarian cancer to reproductive and menstrual characteristics, exogenous estrogen use, and prior pelvic surgeries. Clear trends of decreasing risk were evident with increasing number of pregnancies (regardless of outcome) and increasing duration of breast feeding and oral contraceptive use. Ovarian dysfunction leading to both infertility and malignancy is an unlikely explanation for these trends for several reasons: 1) The trends were evident even among the highly parous; 2) risk among nulliparous women did not vary by marital status or gravidity; and 3) risk among ever-married women showed little relation to length of longest pregnancy attempt or history of clinically diagnosed infertility. Risk was increased among women who had used fertility drugs and among women with long total duration of premenopausal sexual activity without birth control; these associations were particularly strong among the nulligravid. No consistent trends in risk were seen with age at menarche, age at menopause, or duration of estrogen replacement therapy. A history of tubal ligation or of hysterectomy with ovarian conservation was associated with reduced ovarian cancer risk. These observations suggest that pregnancy, breast feeding, and oral contraceptive use induce biological changes that protect against ovarian malignancy, that, at most, a small fraction of the excess ovarian cancer risk among nulliparous women is due to infertility, and that any increased risk associated with infertility may be due to the use of fertility drugs.

Fetal nuchal translucency: ultrasound screening for chromosomal defects in first trimester of pregnancy.

Abstract: OBJECTIVE--To examine the significance of fetal nuchal translucency at 10-14 weeks' gestation in the prediction of abnormal fetal karyotype. DESIGN--Prospective screening study. SETTING--The Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London. SUBJECTS--827 fetuses undergoing first trimester karyotyping by amniocentesis or chorionic villus sampling. MAIN OUTCOME MEASURE--Incidence of chromosomal defects. RESULTS--The incidence of chromosomal defects was 3% (28 of 827 cases). In the 51 (6%) fetuses with nuchal translucency 3-8 mm thick the incidence of chromosomal defects was 35% (18 cases). In contrast, only 10 of the remaining 776 (1%) fetuses were chromosomally abnormal. CONCLUSION--Fetal nuchal translucency > or = 3 mm is a useful first trimester marker for fetal chromosomal abnormalities.

The outcome of congenital cytomegalovirus infection in relation to maternal antibody status.

Abstract: Background Intrauterine transmission of cytomegalovirus (CMV) can occur whether a mother has prior immunity or acquires CMV for the first time during pregnancy The degree of protection afforded an infected infant by the presence of antibody in the mother before conception is uncertain Methods We compared the outcomes of CMV-infected infants born to mothers who acquired primary CMV infection during pregnancy (primary-infection group) with those of CMV-infected infants born to mothers with immunity (recurrent-infection group) Screening for viruria identified 197 newborns with congenital CMV infection Stored serum samples were used to categorize maternal infection as either primary or recurrent We followed 125 infants from the primary-infection group and 64 from the recurrent-infection group Serial medical, audiologic, psychometric, and eye examinations were used to identify sequelae of CMV infection Results Only infants in the primary-infection group had symptomatic CMV infection at birth

The cumulative embryo score: a predictive embryo scoring technique to select the optimal number of embryos to transfer in an in-vitro fertilization and embryo transfer programme.

Abstract: In order to achieve a clinical pregnancy rate higher than that achieved following initial adoption of in-vitro fertilization embryo transfers, more than one embryo is transferred. This has led to a substantial increase in unwanted multiple pregnancy rates with IVF as compared with natural conception. What is therefore required is a simple, clinically useful embryo scoring system, to reflect embryo developmental potential, which will enable the selection of the optimal number of embryos to transfer in order to achieve the maximum pregnancy rate with a low incidence of high order multiple pregnancies. We believe that the Cumulative Embryo Score (CES) achieves these aims. On the day of embryo transfer the grade of each embryo transferred was multiplied by the number of blastomeres to produce a score for each embryo, and summation of the scores obtained for all the embryos transferred gave the CES. The grouped pregnancy rates obtained rose as the CES increased to maximum of 42. A continued increase in the CES above 42 did not result in any further rise in the pregnancy rate. However, an analysis of all our IVF pregnancies showed that the multiple pregnancy rate continued to rise above a CES of 42. By restricting the CES per embryo transfer to 42, 78% of triplet pregnancies and 100% of the quadruplet IVF pregnancies could have been predicted and potentially avoided.

The effect of maternal smoking during pregnancy on early infant lung function.

Abstract: We studied the effect of prenatal maternal cigarette smoking on the pulmonary function (PF) of 80 healthy infants tested shortly after birth (mean, 4.2 ± 1.9 wk). Mothers' prenatal smoking was measured by: (1) questionnaire reports at each prenatal visit of the number of cigarettes smoked per day, and (2) urine cotinine concentrations (corrected for creatlnine) obtained at each visit. Infant PF was assessed by partial expiratory flow-volume curves and hellum-dilutlon measurement of FRC. Forced expiratory flow rates were significantly lower in infants born to smoking mothers, both when unadjusted and after controlling for infant size, age, sex, and passive exposure to environmental tobacco smoke (ETS) between birth and the time of PF testing. Flow at functional residual capacity (FRC) in infants born to smoking mothers was lower than that found in infants whose mothers did not smoke during pregnancy (74.3 ± 15.9 versus 150.4 ± 8.9 ml/s; p = 0.0007). Differences remained significant when flow was corrected ...

Adaptation of the maternal heart in pregnancy

Abstract: The first haemodynamic change during pregnancy seems to be a rise in heart rate. Starting between two and five weeks this continues well into the third trimester. Stroke volume increases slightly later than the heart rate and continues throughout the second trimester after an augmentation of venous return and a fall of systemic vascular resistance and afterload. Myocardial contractility is probably slightly increased. During the third trimester there is relatively little change in these cardiac indices. After delivery there is a very early and dramatic reduction in volume loading followed by a return towards normal cardiac output. Structural changes within the heart reflect the volume loading of pregnancy and include dilatation of the valve ring and increase in myocardial thickness. Post partum resolution of the ventricular hypertrophy seems to take longer than the rest of the post partum changes. The resemblance to the cardiovascular changes associated with training and exercise are fascinating and worthy of further study.

The Outcome of Congenital Cytomegalovirus Infection in Relation to Maternal Antibody Status

Abstract: Background. Intrauterine transmission of cytomegalovirus (CMV) can occur whether a mother has prior immunity or acquires CMV for the first time during pregnancy. The degree of protection afforded an infected infant by the presence of antibody in the mother before conception is uncertain. Methods. We compared the outcomes of CMV-infected infants born to mothers who acquired primary CMV infection during pregnancy (primary-infection group) with those of CMV-infected infants born to mothers with immunity (recurrent-infection group). Screening for viruria identified 197 newborns with congenital CMV infection. Stored serum samples were used to categorize maternal infection as either primary or recurrent. We followed 125 infants from the primary-infection group and 64 from the recurrent-infection group. Serial medical, audiologic, psychometric, and eye examinations were used to identify sequelae of CMV infection. Results. Only infants in the primary-infection group had symptomatic CMV infection at birth...

Prenatal screening for Down's syndrome with use of maternal serum markers.

Abstract: Background. Approximately 35 percent of all cases of Down's syndrome in fetuses can be detected by measuring maternal serum alpha-fetoprotein during the second trimester in the general population of pregnant women. Recent case–control studies indicate that this detection rate could be approximately doubled by measuring serum levels of unconjugated estriol and chorionic gonadotropin, which are abnormally low and abnormally high, respectively, in women carrying fetuses affected by Down's syndrome. Methods. We prospectively screened 25,207 women and adolescents in the second trimester of pregnancy and assigned each a risk of fetal Down's syndrome with an algorithm that took into account measurements of all three serum markers in combination with maternal age. On this basis, 1661 subjects (6.6 percent) were initially assigned a second-trimester risk of fetal Down's syndrome of at least 1 in 190, and 962 (3.8 percent) were offered amniocentesis for chromosomal analysis after verification of gestationa...

Induction of labor as compared with serial antenatal monitoring in post-term pregnancy. A randomized controlled trial. The Canadian Multicenter Post-term Pregnancy Trial Group.

Abstract: Background The rates of perinatal mortality and neonatal morbidity are higher for post-term pregnancies than for term pregnancies. It is not known, however, whether the induction of labor results in better outcomes than does serial fetal monitoring while awaiting spontaneous labor. Methods We studied 3407 women with uncomplicated pregnancies of 41 or more weeks' duration. The women were randomly assigned to undergo induction of labor or to have serial antenatal monitoring and spontaneous labor unless there was evidence of fetal or maternal compromise, in which case labor was induced or cesarean section was performed. In the induction group, labor was induced by the intracervical application of prostaglandin E2. Serial antenatal monitoring consisted of counts of fetal kicks, nonstress tests, and assessments of amniotic-fluid volume. The outcomes we measured were the rates of perinatal mortality, neonatal morbidity, and delivery by cesarean section. Results Among the 1701 women in the induction gro...

Adaptation of Islets of Langerhans to Pregnancy: Increased Islet Cell Proliferation

Abstract: To elucidate the temporal profile of adaptive changes of the islets of Langerhans to the increased insulin demands of pregnancy, we have studied islet cell proliferation and insulin secretion during gestation in the rat. 5-Bromo-2'- deoxyuridine incorporation into dividing islet cells was signifi- cantly (P < 0.05) increased over age-matched controls by day 10, rose continuously to a peak at day 14, and then returned to control levels by day 18. By day 20, cell division was significantly inhibited (P < 0.05). The pattern of changes in insulin secretory profiles observed with perfused pancreata of pregnant animals was similar to that obtained for islet cell proliferation. Both the threshold of glucose-stimulated insulin secretion and the amount of above threshold insulin secretion began to diverge from con- trols by day 10. By day 12, the glucose-stimulation threshold was significantly decreased from 5.7 mM glucose to 3.3 mM (P < 0.05), remained at this low level through day 15, and returned toward normal by day 20. Concomitant with the increased sen- sitivity of B cells to glucose, the above threshold insulin secretion was significantly increased by day 12 (P < 0.05), peaked at day 15, and returned to control levels by day 20. This insulin secre- tory data demonstrates that the increased sensitivity of B cells to glucose is an important component of the adaptation of islets during pregnancy to the increased demand for insulin at phys- iological concentrations of plasma glucose. To correlate the above changes in islet cell proliferation and insulin secretion with levels of placental iactogen (PL), serum lactogenic hormone activity was measured by Nb2 lymphoma cell replication assays. This analysis revealed the expected bi- phasic pattern: a midpregnancy peak at day 12, followed by a nadir at day 14, and then continuously elevated levels until term. The bioassay data agreed with the known secretory profiles of rat (r) PL-I (midpregnancy) and rPL-II (late pregnancy). Our results provide the first systematic evaluation of changes in islet function during pregnancy in the rat. In addition, they provide evidence that rPL-I may be the critical hormonal signal which triggers the primary adaptive changes in islet function characteristic of pregnancy. The return to normal values of insulin secretion and inhibition of cell division observed at day 20 in the presence of high concentrations of rPL-II suggests that other inhibitory influences become dominant in the later stages of rat pregnancy. These observations suggest that complex in- teractions exist among lactogens and other pregnancy hormones in the regulation of islet function during late pregnancy. (En- docrinology 130: 1459-1466, 1992)

Prenatal maternal stress and prematurity: a prospective study of socioeconomically disadvantaged women.

Abstract: Developed and tested a biopsychosocial model of birthweight and gestational age at delivery using structural equation modeling procedures. The model tested the effects of medical risk and prenatal stress on these indicators of prematurity after controlling for whether a woman had ever given birth (parity). Subjects were 130 women of low socioeconomic status interviewed throughout pregnancy in conjunction with prenatal care visits to a public clinic. The majority of women were Latino or African-American. Half were interviewed in Spanish. Lower birthweight was predicted by earlier delivery and by prenatal stress. Earlier delivery was predicted by medical risk and by prenatal stress. Parity was not related to time of delivery or to birthweight. Implications of results for the development of biopsychosocial research on pregnancy and on stress are discussed.

A framework for analyzing the determinants of maternal mortality.

Abstract: Hundreds of thousands of women in developing countries die each year from complications of pregnancy, attempted abortion, and childbirth. This article presents a comprehensive and integrated framework for analyzing the cultural, social, economic, behavioral, and biological factors that influence maternal mortality. The development of a comprehensive framework was carried out by reviewing the widely accepted frameworks that have been developed for fertility and child survival, and by reviewing the existing literature on maternal mortality, including the results of research studies and accounts of intervention programs. The principal result of this exercise is the framework itself. One of the main conclusions is that all determinants of maternal mortality (and, hence, all efforts to reduce maternal mortality) must operate through a sequence of only three intermediate outcomes. These efforts must either (1) reduce the likelihood that a woman will become pregnant; (2) reduce the likelihood that a pregnant woman will experience a serious complication of pregnancy or childbirth; or (3) improve the outcomes for women with complications. Several types of interventions are most likely to have substantial and immediate effects on maternal mortality, including family planning programs to prevent pregnancies, safe abortion services to reduce the incidence of complications, and improvements in labor and delivery services to increase the survival of women who do experience complications.

Relationship of Sudden Infant Death Syndrome to Maternal Smoking During and After Pregnancy

Abstract: Sudden infant death syndrome (SIDS) is associated with maternal smoking during pregnancy. However, the relationship between tobacco exposure during infancy and SIDS is unknown. The examination of infants whose mothers smoked only after pregnancy will help determine the relationship between passive cigarette exposure during infancy and SIDS risk. This case-control analysis used data on normal birth weight (> or = 2500 g) infants included in the National Maternal and Infant Health Survey, a nationally representative sample of approximately 10,000 births and 6000 infant deaths. Infants were assigned to one of three exposure groups: maternal smoking during both pregnancy and infancy (combined exposure), maternal smoking only during infancy (passive exposure), and no maternal smoking. SIDS death was determined from death certificate coding. Logistic regression was used to adjust for potentially confounding variables. Infants who died of SIDS were more likely to be exposed to maternal cigarette smoke than were surviving infants. Among black infants the odds ratio was 2.4 for passive exposure and 2.9 for combined exposure. Among white infants the odds ratio was 2.2 for passive exposure and 4.1 for combined exposure. After adjustment for demographic risk factors, the odds ratio for SIDS among normal birth weight infants was approximately 2 for passive exposure and 3 for combined exposure for both races. These data suggest that both intrauterine and passive tobacco exposure are associated with an increased risk of SIDS and are further inducement to encourage smoking cessation among pregnant women and families with children.

Delayed Childbearing and Risk of Adverse Perinatal Outcome: A Population-Based Study

Abstract: Objective. —To investigate the effect of advancing maternal age on pregnancy outcome among healthy nulliparous women, after adjustment for demographic characteristics, smoking, history of infertility, and other medical conditions. Design. —A population-based cohort study was conducted with prospectively collected data from the Swedish Medical Birth Register. Patients. —Nulliparous Nordic women (N=173715), aged 20 years and above, who delivered single births at Swedish hospitals from 1983 through 1987. Outcome Measures. —Late fetal and early neonatal death rates; rates of very low birth weight (VLBW, Results. —Compared with women aged 20 to 24 years, women aged 30 to 34 years had significantly higher adjusted odds ratios (ORs) of late fetal deaths (OR=1.4); VLBW (OR=1.2); MLBW (OR=1.4); very preterm birth (OR=1.2); and SGA infants (OR=1.4). Among women aged 35 to 39 years, the adjusted OR was significantly higher for VLBW (OR=1.9); MLBW (OR=1.7); very preterm birth (OR=1.7); moderately preterm birth (OR=1.2); and SGA infants (OR=1.7). Among women 40 years old and older, the adjusted OR was significantly higher for VLBW (OR=1.8); MLBW (OR=2.0); very preterm birth (OR=1.9); moderately preterm birth (OR=1.5); and SGA infants (OR=1.4). Conclusions. —Delayed childbearing is associated with an increased risk of poor pregnancy outcomes after adjustment for maternal complications and other risk factors. (JAMA. 1992;268:886-890)

Maternal smoking and behavior problems of children.

Abstract: Numerous health consequences of children's exposure to maternal smoking have been demonstrated, including increased rates of low birth weight, infant mortality, respiratory infections, asthma, and modest impairments of cognitive development. There is little evidence, however, linking maternal smoking and increased rates of children's behavior problems. Data from the population-based National Longitudinal Survey of Youth were used to investigate the possible association of maternal smoking and behavior problems among 2256 children aged 4 through 11 years. In multiple regression analyses the authors controlled for child's race, age, sex, birth weight, and chronic asthma; family structure, income, and divorce or separation in the prior 2 years; mother's education, intelligence, self-esteem, employment status, chronic disabling health conditions, and use of alcohol during pregnancy; and the quality of the home environment as assessed by the Home Observation for Measurement of the Environment-Short Form to investigate the relationship between maternal smoking and children's behavior problems. The measure of maternal smoking status reflected two levels of smoking intensity (less than a pack per day and a pack or more per day) for each of three different categories of children's exposure: prenatal only (mother smoked only during pregnancy), passive only (mother smoked only after pregnancy), and prenatal plus passive exposure (mother smoked both during and after pregnancy). Measures of children's behavior problems included the overall score on a 32-item parent-reported child Behavior Problem Index (PBI), scores on the BPI's subscales, and rates of extreme scores on the BPI.(ABSTRACT TRUNCATED AT 250 WORDS)