Vellinga, A. (Anita) (2012) 'Does first trimester placental volume and uterine artery resistance index predict development of the placenta inthe second trimester and to term?’. thesis, Medicine.
Full text available on request.Abstract
Objective – The placenta regulates fetal nutrition in-utero, and its function is critical to fetal growth and development. In recent years 3D ultrasound has extended the means of assessing placental development and morphology. It has been shown that a small placental volume in the second trimester of gestation leads to a greater risk of perinatal complications. Moreover, uterine artery Doppler ultrasound studies have shown that an increased impedance of flow in the uterine vessels is associated with an increased risk for pre-eclampsia and IUGR at term. If ultrasound markers of placental dysfunction can be identified early in pregnancy, the possibility of intervening early enough to impact on pregnancy outcomes will arise. The objective of this study was therefore to investigate whether first trimester placental dimensions (placental volume) and uterine artery resistance index are predictive of placental morphological parameters in the second trimester. Methods – Placentae from 23 pregnant women were assessed in-vivo by ultrasound during the first trimester of pregnancy. Assessment of placental volume was done by using a multi-planar technique on 3D ultrasound images at 11- 14 weeks gestation. Uterine artery resistance index was calculated using the mean maximum and minimum blood flow velocity of three subsequent cardiac cycles on a Doppler ultrasound waveform. Means were calculated and used in the following formula: RI= (Vmax-Vmin)/Vmax. These measurements were repeated in the second trimester of pregnancy, between 19 and 22 weeks of gestation. Results – As expected placentas demonstrated significant increase in volume between the first and second trimester. However. the correlation coefficient between the first and second trimester placental volume was 0.14. The correlation coefficient between first and second trimester RI measurements was 0.07 and the longitudinal chance of the resistance index showed a high degree of variation. No significant correlations between first and second trimester placental dimensions were therefore found (n=23). Discussion – Despite using an internally validated technique for measuring placental volume, no significant correlations have been found, but this is likely to reflect the very small sample size of this study. It would be recommended to repeat the statistical analysis after inclusion of more patients. It would also be interesting to relate these first and second trimester measurements to pregnancy outcome and placental parameters at term. Conclusion – Further research is needed to show any correlation between these parameters at first and second trimester of gestation.
| Item Type: | Thesis (Thesis) |
|---|---|
| Supervisor name: | UMC Supervisor: and Erwich, Dr. J.J.H.M |
| Supervisor name: | Host Supervisor: and Macklon, Prof. dr. N.S and Princess Anne Hospital, Department of Obstetrics and Gynaeco |
| Faculty: | Medical Sciences |
| Date Deposited: | 25 Jun 2020 11:06 |
| Last Modified: | 25 Jun 2020 11:06 |
| URI: | https://umcg.studenttheses.ub.rug.nl/id/eprint/2584 |
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