No abstract

The incidence of fetal breathing movements (FBM)*, fetal trunk movements (FTM), and total fetal activity (TFA) was assessed in 100 normal pregnancies between 28 weeks and term. One 30-minute recording was made from each patient between 0900 and 1700 hours. The mean incidences of FBM, FTM and TFA were respectively 37 & 26 (SD) per cent, 18 i 10 per cent, and 53 ' . 24 per cent. The mean breathing rate was 48 k 12 per minute, and the mean number of movements per 30-minute study period was 2 9 i 15. There was a slightly higher incidence of FBM postprandially, but this failed to reach statistical significance. The mean incidence of FBM was lower before 31 weeks and after 40 weeks, compared to that between 31 and 40 weeks, when the values of FBM and FTM were constant. The breathing rate was directly related to gestational age. The mean number of movements per 30-minute study period was inversely related to gestational age, but the duration of movements increased progressively towards term, so that the incidence of FTM was constant throughout the third trimester. There was only one recording of TFA below 10 per cent. STUDIES of activity in normal fetuses have shown large variations in the incidence of fetal breathing movements (FBM) (Patrick et al, 1978), and FBM and fetal trunk movements (FTM) at various times of the day. Roberts et a1 (1979) also found a circadian variation in FBM and FTM, the incidence of FBM being greater during the day and lower in the late evening and early morning, while FTM * In a previous publication we used the expression fetal respiratory movement (FRM) for the parameter, but in the interests of establishing standard nomenclature we have changed to this more generally used term.

Summary The incidence of fetal breathing movements (FBM), fetal trunk movements (FTM), and total fetal activity (TFA) was assessed in 25 pregnancies complicated by maternal diabetes mellitus; 20 mothers had been juvenile insulin dependent diabetics, 4 were diagnosed during pregnancy (one of whom required insulin) and there was one other who was changed from chlorpropamide to insulin during the first trimester of pregnancy. Thirty‐minute records were made postprandial between 32 and 38 weeks making a total of 161 recordings. There were 15 well‐controlled insulin‐dependent diabetic women with uncomplicated pregnancies; and in this group the mean percentage incidence of FBM was 60±25 (SD) per cent, FTM 16±10 (SD) per cent and TFA 73±22 (SD) per cent. The mean breathing rate per minute was 53±12 and the mean number of movements per 30‐minute period 29±18. The incidences of FBM and TFA were significantly higher than those found in postprandial recordings in normal pregnancies. There was only one recording out of 115 where the incidence of TFA fell below 10 per cent. The mean percentage incidences of FBM, FTM and TFA were similar in the four uncomplicated pregnancies in which diabetes was diagnosed during pregnancy. The mean percentage incidence of TFA was significantly lower in the six pregnancies with obstetric complications, and levels of TFA below 10 per cent correlated well with abnormal cardiotocograph traces or fetal distress in labour.

Summary. Calculation of the product of crown‐rump length and trunk area (CRLxTA), as measured by ultrasound between 34 and 36 weeks and combined with accurate assessment of gestational age in early pregnancy, was previously shown to be highly effective in detecting the small‐for‐dates fetus in a largely unselected series of patients. To assess the value of this two‐stage schedule in high‐risk pregnancies, 202 patients with singleton pregnancies at risk of fetal growth retardation were studied. Of the 53 babies that were small‐for‐dates at birth, 49 (92%) were identified in advance by CRLxTA measurement. In contrast to previous findings, measurement of trunk area (TA) alone was similarly effective, identifying in advance 48 (91%) of these small‐for‐dates babies.

Summary The incidence of fetal breathing movements (FBM)*, fetal trunk movements (FTM), and total fetal activity (TFA) was assessed in 100 normal pregnancies between 28 weeks and term. One 30‐minute recording was made from each patient between 0900 and 1700 hours. The mean incidences of FBM, FTM and TFA were respectively 37±26 (SD) per cent, 18±10 per cent, and 53±24 per cent. The mean breathing rate was 48±12 per minute, and the mean number of movements per 30‐minute study period was 29±15. There was a slightly higher incidence of FBM postprandially, but this failed to reach statistical significance. The mean incidence of FBM was lower before 31 weeks and after 40 weeks, compared to that between 31 and 40 weeks, when the values of FBM and FTM were constant. The breathing rate was directly related to gestational age. The mean number of movements per 30‐minute study period was inversely related to gestational age, but the duration of movements increased progressively towards term, so that the incidence of FTM was constant throughout the third trimester. There was only one recording of TFA below 10 per cent.