gms | German Medical Science

4th International Conference of the German Society of Midwifery Science (DGHWi)

Deutsche Gesellschaft für Hebammenwissenschaft e. V.

16.02.2018, Mainz

Length of gestation: maturity is not calculable

Meeting Abstract

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  • corresponding author Dorothea Zeeb - University of applied sciences Salzburg, Puch bei Hallein, Austria
  • Christine Loytved - Zurich University of Applied Sciences, Institute of Midwifery, School of Health Professions, Winterthur, Switzerland
  • Claudia Berger - Freelance lecturer, Osnabrueck, Germany

German Association of Midwifery Science. 4th International Meeting of the German Association of Midwifery Science (DGHWi). Mainz, 16.-16.02.2018. Düsseldorf: German Medical Science GMS Publishing House; 2018. Doc18dghwiP40

doi: 10.3205/18dghwi46, urn:nbn:de:0183-18dghwi466

This is the English version of the article.
The German version can be found at: http://www.egms.de/de/meetings/dghwi2018/18dghwi46.shtml

Published: February 13, 2018

© 2018 Zeeb et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at http://creativecommons.org/licenses/by/4.0/.


Text

Background: Since more than 200 years attempts are being made to determine the due date, first by arithmetic methods, afterwards using ultrasonic examination. Originally the due date was used to divide the pregnancy in extended stages. Nowadays the due date at 40+0 weeks has become rather a fixed threshold, whose exceeding is considered as a risk.

The calculated due date is used as a fix point for interventions like planned cesareans or inductions of labour. Too little attention is paid to the fact that pregnancies progress at their own pace and experience shows, that the maturity of newborns does not necessarily correlate with their gestational age.

It has to be challenged, whether the due date is indicating the physiological end of pregnancies and how closely the gestational age is correlated with the individual maturation processes of the fetus in utero [1], [2].

Objective: The aim of this study was to assess newborns maturation compared to their gestational age.

Method: 100 newborns at term (calculated weeks 37+4 to 42+6) were examined by the author in the first 72 hours after birth for their maturation, using the New Ballard Score [3], [4]. By reason of the small study as a part of a master thesis there was no calculation of power and sample size in advance.

The sample was investigated for the influence of maternal and fetal parameters on the length of gestation and the maturation state of the newborn at birth. For this purpose the age of the mother, parity, height and weight and also the sex of the offspring have been considered. The correlation between the estimated gestational age and the attained maturation as well as the differences after spontaneous parturition and induced birth were analysed.

The data was evaluated with IBM SPSS 24. Descriptive statistics and univariate analysis, including dependent and independent t-tests and correlations, were applied to compare the means. The Odds Ratio for a distinctive downward deviation of maturity between spontaneous onset of parturition and inductions has been defined.

Results: No influence of the sex of the offspring or the age, parity, height or weight of the mother on the length of gestation and the maturity of the newborn was found in this study. The longer before the calculated due date birth occurred, the higher was the upward deviation of the maturity against the calculated gestational age. The far the calculated due date was exceeded, the higher was the downward deviation of the maturity against the calculated gestational age. Induction of labour was a risk for a distinct downward deviation of maturity against gestational age.

Conclusion: Potentially the calculated gestational age has no diagnostic power for the assessed maturity of the newborn in prolonged or postterm pregnancies. Against this background the medical indication „prolonged pregnancy“ for induction of labour should be critically scrutinised. So an improved research with a large study population is highly desirable.

Ethical criteria and conflict of interests: The research was submitted to an ethics committee. It was financed from own resources. There is no conflict of interest.

The PDF file of the poster submitted for the meeting is available in German as Attachment 1 [Attach. 1].


References

1.
Ahn Y. Assessment of Gestational Age Using an Extended New Ballard Examination in Korean Newborns. J Trop Pediatr. 2008;54(4):278-3.
2.
Alexander GR, de Caunes F, Hulsey TC, Tompkins ME, Allen M. Validity of postnatal assessments of gestational age: a comparison of the method of Ballard et al. and early ultrasonography. Am J Obstet Gynecol. 1992;166(3): 891-4.
3.
Ballard J, Khoury JC, Wedig K, Wang L, Eilers-Walsman BL, Lipp R. New Ballard Score, expanded to include extremely premature infants. J Pediatr. 1991;119(3):417-5.
4.
Ballard J, Novak KK, Driver M. A Simplified Score for Assessment of Fetal Maturation of newly born infants. J Pediatr. 1979;95(5):759-5.