Kramer, M. S., McLean, F. H., Boyd, M. E., & Usher, R. H. (1988). The validity of gestational age estimation by menstrual dating in term, preterm, and postterm gestations. JAMA, 260(22), 3306-3308. https://doi.org/10.1001/jama.1988.03410220090034
Kramer MS, McLean FH, Boyd ME, Usher RH. The validity of gestational age estimation by menstrual dating in term, preterm, and postterm gestations. JAMA. 1988;260(22):3306-3308. doi:10.1001/jama.1988.03410220090034
Kramer, Michael S., et al. "The validity of gestational age estimation by menstrual dating in term, preterm, and postterm gestations." JAMA, vol. 260, no. 22, 1988, pp. 3306-3308.
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Department of Pediatrics, McGill University Faculty of Medicine, Montreal, Quebec, Canada.02w6r0892
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Abstract
Despite recognition that estimation of gestational age (GA) based on maternal recollection of the last normal menstrual period (LNMP) is fraught with error, it is not generally appreciated that the magnitude and direction of this error vary as a function of the LNMP estimate. Early second-trimester (16 to 18 weeks) ultrasound determinations of the fetal biparietal diameter were used as the "gold standard" to test the validity of LNMP-based GA estimates in 11,045 women. The large majority of deliveries occurring at or near term showed LNMP estimates that were valid within plus or minus seven days of the ultrasound estimate. As the LNMP GA deviated progressively toward earlier or later GAs, however, the discrepancies became quite marked, especially for postterm dates. The positive predictive values of the LNMP GA estimates decreased dramatically from term (.949) to preterm (.775) to postterm (.119) deliveries. These systematic errors in menstrual GA estimates have profound implications for unnecessary induction, dysfunctional labor and cesarean section, and resultant neonatal and maternal morbidity.
Giménez MC et al., 2023·Biology (Basel)·Free full text on PubMed Central
Modern urban human activities are largely restricted to the indoors, deprived of direct sunlight containing visible and near-infrared (NIR) wavelengths at high irradiance levels. Therapeutic exposure to doses of red and NIR, known as photobiomodulation (PBM), has been effective for a broad range of conditions. In a double-blind, randomized, placebo-controlled study, we aimed to assess the effects of a PBM home set-up on various aspects of well-being, health, sleep, and circadian rhythms in healthy human subjects with mild sleep complaints. The effects of three NIR light (850 nm) doses (1, 4, or 6.5 J·cm(-2)) were examined against the placebo. Exposure was presented five days per week between 9:30 am and 12:30 pm for four consecutive weeks. The study was conducted in both summer and winter to include seasonal variation. The results showed PBM treatment only at 6.5 J·cm(-2) to have consistent positive benefits on well-being and health, specifically improving mood, reducing drowsiness, reducing IFN-γ, and resting heart rate. This was only observed in winter. No significant effects on sleep or circadian rhythms were noted. This study provides further evidence that adequate exposure to NIR, especially during low sunlight conditions, such as in the winter, can be beneficial for human health and wellness.
Early ultrasound scanning estimation of gestational age is known to increase the reported preterm delivery rate (<37 completed weeks) compared with estimation by date of the last normal menstrual period, but it is unclear how this systematic difference arises. This study was a hospital-based study of 44,623 women who delivered a live-born or stillborn infant between January 1, 1978, and March 31, 1996, and who had both last normal menstrual period-based and early (usually at 16-18 weeks) ultrasound scan-based gestational age estimates. Cross-classification of the 2 estimates by completed weeks was used to examine the direction and magnitude of the differences between them and to compare the resulting classifications of preterm birth. The early ultrasound scan-based gestational age distribution was shifted uniformly to the left (ie, lower gestational age) relative to the last normal menstrual period gestational age distribution; the early ultrasound scan-based preterm delivery rate was 9.1%, which was 19.5% (n = 659 births) higher than the 7.6% rate by last normal menstrual period (P <.0001). The last normal menstrual period estimate exceeded the early ultrasound scan estimate far more often than the reverse, up to and including early ultrasound scan estimates of 40 weeks. No concentration of 4-week discrepancies was observed in either direction, as would be expected with random or systematic errors in recall of the last normal menstrual period. The absolute number of births at 37 to 39 weeks of gestation (by last normal menstrual period) that were reclassified as preterm (n = 1206 births) was much higher than the number of preterm births at 34 to 36 weeks of gestation that were reclassified as term (n = 581 births). The net increase of 625 preterm births (from 581 to 1206 births) that resulted from reclassification of births at 37 to 39 last normal menstrual period weeks accounted for 95% of the total 659-birth increase in early ultrasound scan-based preterm births at all last normal menstrual period gestational ages. Early ultrasound scanning reduces the gestational age estimate across the entire gestational age range; early ultrasound scan-based reclassification of gestational age results in a substantial increase in the prevalence of preterm births. Small downward reclassifications exceed upward reclassifications of similar magnitude, which is consistent with previous reports that delayed (>14 days) ovulation is more frequent than early (<14 days) ovulation.
The World Health Organization defines preterm birth as birth at less than 37 completed gestational weeks, but most studies have focused on very preterm infants (birth at <32 weeks) because of their high risk of mortality and serious morbidity. However, infants born at 32 through 36 weeks are more common and their public health impact has not been well studied. To assess the quantitative contribution of mild (birth at 34-36 gestational weeks) and moderate (birth at 32-33 gestational weeks) preterm birth to infant mortality. DESIGN, SETTING, Population-based cohort study using linked singleton live birth-infant death cohort files for US birth cohorts for 1985 and 1995 and Canadian birth cohorts (excluding Ontario) for 1985-1987 and 1992-1994. Relative risks (RRs) and etiologic fractions (EFs) for overall and cause-specific early neonatal (age 0-6 days), late neonatal (age 7-27 days), postneonatal (age 28-364 days), and total infant death among mild and moderate preterm births vs term births (at >/=37 gestational weeks). Relative risks for infant death from all causes among singletons born at 32 through 33 gestational weeks were 6.6 (95% confidence interval [CI], 6.1-7.0) in the United States in 1995 and 15.2 (95% CI, 13.2-17.5) in Canada in 1992-1994; among singletons born at 34 through 36 gestational weeks, the RRs were 2.9 (95% CI, 2.8-3.0) and 4.5 (95% CI, 4.0-5.0), respectively. Corresponding EFs were 3.2% and 4.8%, respectively, at 32 through 33 gestational weeks and 6.3% and 8.0%, respectively, at 34 through 36 gestational weeks; the sum of the EFs for births at 32 through 33 and 34 through 36 gestational weeks exceeded those for births at 28 through 31 gestational weeks. Substantial RRs were observed overall for the neonatal (eg, for early neonatal deaths, 14.6 and 33.0 for US and Canadian infants, respectively, born at 32-33 gestational weeks; EFs, 3.6% and and 6. 2% for US and Canadian infants, respectively) and postneonatal (RRs, 2.1-3.8 and 3.0-7.0 for US and Canadian infants, respectively, born at 32-36 gestational weeks; EFs, 2.7%-5.8% and 3.0%-7.0% for the same groups, respectively) periods and for death due to asphyxia, infection, sudden infant death syndrome, and external causes. Except for a reduction in the RR and EF for neonatal mortality due to infection, the patterns have changed little since 1985 in either country. Mild- and moderate-preterm birth infants are at high RR for death during infancy and are responsible for an important fraction of infant deaths. JAMA. 2000;284:843-849
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To estimate the risk of adverse outcomes in women whose first day of the last menstrual period (LMP) was unreliable. Among 20,244 singleton pregnancies with measurements of biparietal diameter between 12 and 22 weeks' gestation, LMP was registered as unreliable in 3775 (18.6%) and reliable in 16,469 (81.4%). Adverse outcomes were defined as spontaneous or missed abortions after 12 weeks' gestation, stillbirth or postnatal death within 1 year, preterm birth, birth weight less than 2500 g, and low birth weight (LBW) for gestation (lower than 22% below sex-specific expected weight). Logistic regression analysis and Kaplan-Meier survival analysis were used to analyze the risk of adverse outcomes. The risk of death was doubled in pregnant women with unreliable LMPs compared with those with reliable LMPs (odds ratio [OR] 2.0; 95% confidence interval [CI] 1.5, 2.6). This risk was highest with respect to stillbirth (OR 2.7; 95% CI 1.7, 4.3). The risks of preterm birth, LBW, and LBW for gestation were also significantly increased (ORs 1.5, 1.4, and 1.2; 95% CIs 1.3, 1.7; 1.2, 1.6; and 1. 0, 1.4, respectively). An unreliable LMP is associated with increased risk of adverse outcomes, especially fetal death.
Research Methods › Measurement and Statistics › Instrument Development and Validation · Birth and Delivery › Labor and Birth › Induction of Labor
Michael S Kramer, Robert Usher
Mike Kramer, M Kramer, Bob Usher, Rob Usher, Bobby Usher, R Usher
PMID 3054193 3054193 DOI 10.1001/jama.1988.03410220090034 10.1001/jama.1988.03410220090034 Kramer et al. 1988, Kramer 1988
Cite this article
Kramer, M. S., McLean, F. H., Boyd, M. E., & Usher, R. H. (1988). The validity of gestational age estimation by menstrual dating in term, preterm, and postterm gestations. JAMA, 260(22), 3306-3308. https://doi.org/10.1001/jama.1988.03410220090034
Kramer MS, McLean FH, Boyd ME, Usher RH. The validity of gestational age estimation by menstrual dating in term, preterm, and postterm gestations. JAMA. 1988;260(22):3306-3308. doi:10.1001/jama.1988.03410220090034
Kramer, Michael S., et al. "The validity of gestational age estimation by menstrual dating in term, preterm, and postterm gestations." JAMA, vol. 260, no. 22, 1988, pp. 3306-3308.
Keywords
Cohort Studies, Evaluation Studies As Topic, Female, Gestational Age, Humans, Menstruation, Obstetrics/methods, Pregnancy, Time Factors, Ultrasonography
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