16 18 20 22 24 26 28 30 32 34 36 38 40 Gestational age (weeks)

Chapter 15 Prenatal Ultrasound Measurements Prenatal Measurements

In general, ultrasound measurements use the longest dimension of a particular structure, whether it is a bone such as the femur or an organ such as the kidney. Ratios help to determine whether there is disproportionate growth, undergrowth, or overgrowth of a structure. When assessing brain growth, ventricular size must be evaluated (Fig. 15.21), and when assessing renal size and function, the amount of amniotic fluid must be evaluated (Fig. 15.23).

Normal Fetal Activity During Gestation

Patterns of fetal activity indicate fetal well-being and help to determine maturation.

Fig. 15.24 Fetal movement during gestation,

Type of movement Normal activity

Movement observed

Embryo movement Limb movement


Hiccoughing Sucking

Swallowing Bladder emptying

From 7 wk

From 10 wk, increases up to 20 wk Decreases from 20-40 wk 12-24 wk 28-40 wk

30 wk onwards

From 12 wk

From 12 wk

From 12 wk

From 12 wk

Mean movement 120/hr Mean movement 60-80/hr Seen 5-17% of time Present 30% of time; episodic and irregular; may go up to 2 hr without breathing movements 20-60 breaths/min Coordinated and synchronized breathing movements Abrupt thoracic and abdominal movement Hands are held around the face; regular thumb sucking in third trimester Amniotic fluid increases if no swallowing occurs Fills over 45 min period, then empties


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Campbell, S., Waldimiroff, J.W., and Dewhyrst, C.J. (1973). The antenatal mesurements of fetal urine production. British Journal of Obstetrics and Gynaecology, 80, 680.

Campbell, S., and Newman, G.B. (1973). Growth of the fetal biparietal diameter during normal pregnancy. British Journal of Obstetrics and Gynaecology, 78, 513.

de Vries, J.I.P., Visser, G.H.A., and van Prechtl, H.F.R., (1982). Behavioural states in the human fetus during labour. Proceedings, 1st Conference, The Society for the Study of Fetal Physiology, Oxford.

Hadlock,F.P., Deter, R.L., Harrist, R.B., and Park, S.K. (1982). Fetal abdominal circumference as a predictor of menstrual age. AJR, American Journal of Roentgenology, 139(2), 367-370.

Hansmann, M. (1985). Ultrasonic diagnosis in obstetrics and gynecology. Springer, Berlin.

Jeanty, P. and Romero, R. (1984). Obstetrical ultrasound. McGraw-Hill, New Yo rk.

Levi, S. (1973). Intra-uterine fetal growth studied by ultrasonic biparietal measurement. The percentiles of biparietal distribution. Acta obstetrica Gynecologica Scandinavica, 52,193.

Mayden, K.L., Tortora, M., Berkowitz, R.L., Braken, M., and Hobbins, J.C. (1982). Orbital diameters. American Journal of Obstetrics and Gynecology, 144,289-297.

Meire, H.B. (1981). Ultrasound assessment of fetal growth patterns. British Medical Bulletin, 37,253-258.

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Sabbagha, R.E., and Hughey, M. (1978). Standardization of sonar cephalom-etry and gestational age. Obstetrics & Gynecology, 52(4): 402-406.

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Pregnancy And Childbirth

Pregnancy And Childbirth

If Pregnancy Is Something That Frightens You, It's Time To Convert Your Fear Into Joy. Ready To Give Birth To A Child? Is The New Status Hitting Your State Of Mind? Are You Still Scared To Undergo All The Pain That Your Best Friend Underwent Just A Few Days Back? Not Convinced With The Answers Given By The Experts?

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