Fetal hemodynamic changes after amniotomy

• Published in: Acta obstetricia et gynecologica Scandinavica Vol. 84; no. 2; pp. 166 - 169
• Main Authors: Fok, Wing Yee, Leung, Tak Yeung, Tsui, Michelle Hy, Leung, Tse Ngong, Lau, Tze Kin
• Format: Journal Article
• Language: English
• Published: Oxford, UK; Malden, USA Munksgaard International Publishers 01.02.2005; Taylor & Francis
• Subjects: Adult; Amnion - surgery; amniotomy; Biological and medical sciences; Blood Flow Velocity; Cohort Studies; Doppler; Female; Fetal Monitoring; Fetus - blood supply; Follow-Up Studies; Gynecology. Andrology. Obstetrics; Heart Rate, Fetal - physiology; Hemodynamics - physiology; Humans; Labor, Induced - methods; Medical sciences; Pregnancy; Pregnancy Trimester, Third; Prenatal Care - methods; Prospective Studies; the ductus venosum; the middle cerebral artery; the renal artery; Ultrasonography, Doppler; Ultrasonography, Prenatal; Sonography; Doppler ultrasound study; Amniotomy; Renal artery; Gynecology; Middle cerebral artery; the renal artery; Obstetrics; Pregnancy; the ductus venosum; the middle cerebral artery; Fetus; Hemodynamics; Doppler
• ISSN: 0001-6349; 1600-0412
• DOI: 10.1111/j.0001-6349.2005.00700.x

Background.  The aim of the study was to assess fetal vascular blood flow after amniotomy. Methods.  This was a prospective observational study. Thirty‐five women with singleton pregnancy beyond 36 weeks of gestation, who underwent amniotomy, were recruited. The pulsatility indices of the fetal middle cerebral artery (MCA), the renal artery, and the ductus venosum were measured before and 30 min following amniotomy. The changes in pulsatility index were compared by means of Wilcoxon signed rank test. Results.  There was a significant reduction in pulsatility indices of the MCA (median reduction: 0.23; interquantile range (IQR): −0.04, 0.4) and the renal artery (median reduction: 0.12; IQR: −0.12, 0.54) after amniotomy. However, there was no obvious change in the ductus venosum (median reduction: 0.00; IQR: −0.06, 0.1). Conclusions.  Amniotomy is associated with significant reduction in the impedance of the fetal MCA and the renal artery. The former may be a result of fetal stress response and the latter could be related to the release of vasoactive substances after amniotomy.