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Originally Posted by Reha  Practicing breathing in utero (making breathing movements) is NOT the same as aspirating mec in utero. If that were the case, all babies with mec stained fluid would aspirate it, as all (healthy, term) babies make breathing movements in utero....but they aren't really breathing.
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I was curious about this so I looked it up... all babies draw amniotic fluid into their lungs in utero through pressure/breathing movements. Those who undergo significant periods of hypoxia have been shown to draw more significant amounts of fluid, thus increasing the risk of MAS. Here are a couple of abstracts if anyone else is interested:
Changes in lung liquid dynamics induced by prolonged fetal hypoxemia.Hooper SB, Harding R.
Department of Physiology, Monash University, Clayton, Victoria, Australia.
Our aim was to determine the effect of prolonged fetal hypoxemia, induced by reduced maternal uterine blood flow (RUBF), on fetal lung liquid secretion, flow, and volume. In chronically catheterized fetal sheep, lung liquid volume (VL) and the secretion rate of lung liquid (Vs) were measured before and after a 24-h period of either RUBF or normoxemia. Tracheal fluid flow and the incidence of fetal breathing movements (FBM) were measured before, during, and after the 24-h period. In normoxic control fetuses Vs was not significantly altered. After 24 h of RUBF, Vs was significantly (P less than 0.005) reduced compared with pre-RUBF values. During 24 h of RUBF the incidence of FBM declined initially but returned to control values after 12-16 h. In seven of eight fetuses, over the 12- to 24-h period of RUBF, large amounts of liquid (22.7-62.6 ml) were drawn into the lungs during FBM, resulting in a net movement of amniotic fluid into the lungs. During the 18- to 24-h period of RUBF, changes in the incidence of FBM were found to be significantly and positively correlated (r = 0.86, P less than 0.005) with the changes in VL that occurred over the 24-h period. Thus, prolonged RUBF can result in the inhalation of large volumes of amniotic fluid by the fetus, which could be a cause of in utero meconium aspiration.
Photogrammetry of fetal breathing movements during the third trimester of pregnancy: observations in normal and abnormal pregnancies.Florido J, Padilla MC, Soto V, Camacho A, Moscoso G, Navarrete L.
Department of Obstetrics & Gynaecology, Granada University, Granada, Spain.
OBJECTIVE: To evaluate parameters of fetal breathing movements-displacement of the fetal abdominal wall during inspiration and expiration, time of inspiration and expiration and speed of inspiration and expiration-between 30 and 36 weeks' gestation in normal pregnancies, and in those complicated by gestational diabetes or maternal hypertension. METHODS: Three categories of pregnancy were investigated: 49 were normal, 16 had pregnancy-induced diabetes and 10 were hypertensive. According to their gestational age, the patients were divided into two groups: Group A between 30 and 32 weeks' gestation and Group B between 33 and 36 weeks. Using photogrammetry and a computer-operated algorithm, six parameters of fetal breathing movements were investigated. RESULTS: There were significant differences in the various fetal parameters measured among the three categories of pregnant women. Up until 32 weeks of gestation, the displacements during inspiration and expiration were larger, the speeds of inspiration and expiration were higher, and the times for inspiration and expiration were shorter in the diabetic and hypertensive groups than in the normal group. In the later period, between 33 and 36 weeks, fetuses of pregnancy-induced diabetic patients showed the lowest inspiration and expiration times and the highest speeds of inspiration and expiration. CONCLUSIONS: Photogrammetry in conjunction with a computer-operated algorithm can be used to assess fetal breathing movements. There are significant differences in fetal breathing movements between normal pregnancies and those that are complicated by gestational diabetes or hypertension. Copyright (c) 2008 ISUOG. Published by John Wiley & Sons, Ltd
: I earned a new brain wrinkle today!
: Sorry to pick on you so much and ask so many questions. I was rather astonished at the lack of info available in my textbook.
