Postterm infants: too big or too small?
Article Abstract:
Considerable confusion exists in the medical literature concerning postterm infants and their characteristics. In many cases, infants considered postterm (based on the expected due date) cannot be said to be postterm on the basis of ultrasonographic evidence. Some researchers maintain postterm infants grow excessively, others maintain that they show signs of weight loss. To learn more about this matter, infants were studied who were born in one medical center during an eight-year period and confirmed as postterm by ultrasonography and date of the mother's last menstrual period. The 7,005 infants were born at or after 39 weeks' gestation; those born at or after 42 weeks' gestation were designated postterm. The infants were weighed and their lengths and head circumferences recorded (these two measurements were made only for 4,020 infants). Other measurements were also made. Results showed increases in average birth weights between 39 and 42 weeks' gestation, with infants born to women with several previous births weighing more than those who were the first infant delivered. No low-birth-weight babies (less than 2,500 grams) were born after 42 weeks' gestation, but more large (more than 4,000 grams) infants were born as pregnancy continued, reaching 30 percent at 42 weeks' gestation. Severe intrauterine growth retardation (reduced birth weight) was not more common in postterm than preterm babies, nor did the ponderal index (a measure of nutritional status) indicate nutritional damage occurred after term. Placental weights also increased as gestation continued. The results do not support earlier beliefs of increased risk of distress or poor nutrition in postterm babies. Confusion has been created by different uses of the concept 'postterm' and by the notoriously unreliable method of predicting the due date from the last menstrual period. Macrosomia (a large baby) is the most important complication associated with postterm pregnancies. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: American Journal of Obstetrics and Gynecology
Subject: Health
ISSN: 0002-9378
Year: 1991
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Is oligohydramnios in postterm pregnancy associated with redistribution of fetal blood flow?
Article Abstract:
Lack of amniotic fluid in postterm pregnancies does not appear to be caused by a redistribution of blood flow within the fetus. Insufficient placental blood flow may cause a compensatory response to protect blood flow to the brain. This results in less blood flow to the kidneys, less urination, and thus, less amniotic fluid. Fifty-seven pregnant women past their due dates had ultrasound imaging and Doppler studies of blood flow in the umbilical, and fetal cerebral and renal arteries. Fifteen women had reduced amniotic fluid volumes. No differences in blood flow patterns were found among women with reduced amounts of amniotic fluid compared with women with normal amounts of fluid. It is still possible that blood flow redistribution may be a factor in more drastic cases of reduced amniotic fluid volume.
Publication Name: American Journal of Obstetrics and Gynecology
Subject: Health
ISSN: 0002-9378
Year: 1995
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Increased maternal age and the risk of fetal death
Article Abstract:
Fetal death is more likely among pregnant women over 35 than among younger women, although the overall incidence of fetal death has decreased since the 1960s. Researchers reviewed data on 94,346 births at a single hospital from 1961 to 1974, and from 1978 to 1993. The overall fetal death rate decreased from 11.5 deaths per 1,000 total births in the 1960s to 3.2 deaths per 1,000 total births in the early 1990s. The average maternal age increased from 27 in the 60s to 30 in the 90s. Between the first and second period, medical problems that increase the risk of fetal death, such as diabetes and hypertension, became more common among pregnant women. But even when these risk factors were statistically adjusted for, women over 35 had twice the risk of fetal death than women under 30.
Publication Name: The New England Journal of Medicine
Subject: Health
ISSN: 0028-4793
Year: 1995
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