Management of gestational diabetes

Researchers and care providers must recognize that different centers are not automatically comparable in results because the geographic location, the demographic characteristics of the patient population, and the program strategy will alter the rate of patients assigned to insulin therapy and adverse pregnancy outcome. For example, in San Antonio, Texas, with a chronic health problem of obesity and diabetes, the prevalence of GDM is approximately 11%, whereas the general reported rate is 2% to 3%. Despite the disparity in the prevalence of the disease in different demographic areas, pregnancy outcome should be comparable for all centers when a proper management approach has been used. Utilizing our management approach in a large-scale program resulted in an incidence of macrosomia comparable to that in the general population. As a general rule, because constant evaluation of glycemia in pregnancy is the best gauge of the efficacy of the treatment, the use of verified self-monitoring of blood glucose has become a principal component of management. Appropriate assignment of patients to treatment modality utilizing verified blood glucose determinations and targeting mean blood glucose levels throughout pregnancy to 95 mg/dL (5.3 mmol/L) that is similar to normal nondiabetic blood glucose levels will result in pregnancy outcome comparable to the general population.

Is lung maturation related to fetal growth in diabetic or hypertensive pregnancies?

The purpose of this study was to determine whether infants sufficiently affected by maternal diabetes or hypertension to exhibit abnormal growth (macrosomia, growth retardation) would also display significant alteration in timing of pulmonary maturity (delay or acceleration, respectively). We studied 874 consecutive women with fetal pulmonary maturity testing prior to delivery. Patients were stratified by birth weight into fetal size categories (small for gestational age [SGA], appropriate for gestational age [AGA], large for gestational age [LGA]). Cases were compared based on maternal disease, fetal size categories and pulmonary maturity testing results. Pulmonary maturity rates based on both phosphatidylglycerol (PG) and lecithin/sphingomyelin ratio (L/S) did not differ between term LGA infants of diabetic mothers (97%) and term LGA (80%) or AGA (97%) infants of non-diabetic, non-hypertensive mothers. When compared based on PG alone, there was no difference between the rate of positive PG in term AGA infants of non-hypertensive, non-diabetic mothers (75%) and that seen in the other pregnancy groups (33-80%). Breakdown by gestational age revealed no significant differences in maturity rates between the study groups. Macrosomic diabetic infants and growth-retarded hypertensive infants are no different from controls in their timing of fetal pulmonary maturation.

Diabetes in women older than 40 years of age. Social and medical aspects

Prevention of Congenital Anomalies. Because the first few weeks after conception are a critical time in terms of embryopathy, good glycemic control should be established before conception in the pregestational diabetic and stringently maintained throughout the first trimester. Encouraging the diabetic woman to achieve stringent glycemic control before conception would virtually eliminate the excess risk of spontaneous abortion and anomalies. Prenatal Diagnosis. For all mature gravidas with diabetes, early prenatal diagnosis of chromosome abnormalities (mainly trisomies) and congenital anomalies should be determined through detailed ultrasound examination, fetal echocardiography, and alpha-fetoprotein determinations. Glycemic Control. Stringent metabolic control is mandatory throughout pregnancy to prevent the risk for macrosomia and maternal-accompanied medical complications, such as preeclampsia. Fetal Surveillance. Structured fetal surveillance evaluating fetal growth and well-being must be pursued throughout pregnancy.

Glucose tolerance test: degree of glucose abnormality correlates with neonatal outcome

OBJECTIVE

To determine how well the extent of glucose abnormality, as reflected by the number of abnormal values on the 3-hour oral glucose tolerance test (GTT), correlates with the level of carbohydrate intolerance during pregnancy and with the severity of adverse outcome.

METHODS

We followed 764 gestational diabetic women under a once-per-week fasting and 2-hour postprandial serum glucose monitoring system. The subjects were stratified by the number of abnormal values on their GTTs. The level of glucose control and incidence of large for gestational age (LGA) infants were then determined and compared with the findings in 636 gravidas with abnormal screening but all normal GTT values.

RESULTS

Patients with one or more abnormal GTT values had comparable incidences of LGA infants, which were all significantly greater than that in the 0-abnormal group (23-27% versus 13%; P < .01). This difference was due to subjects with poor glucose control. The means of the GTT values for each sampling time were greater and the GTT periodicity (the time for the GTT curve to return to the fasting level) was longer with an increasing number of GTT abnormal values (zero versus one versus two versus three versus four abnormal values, P < .02). The mean fasting, 2-hour postprandial, and overall mean glucose values during the study were positively associated with the number of abnormal GTT values.

CONCLUSIONS

One or more abnormal GTT values were associated with comparably elevated incidences of LGA infants in patients with poor glycemic control. Achievement of recommended glucose control decreased adverse outcomes to near normal levels.

Does maternal diabetes delay fetal pulmonary maturity?

OBJECTIVE

The purpose of our study was to determine whether a relationship exists between diabetic glucose control and the immaturity rate of fetal pulmonary maturity test results.

STUDY DESIGN

One thousand consecutive women who had fetal pulmonary maturity testing before delivery were studied. Diabetic patients were categorized according to whether their diabetes was well controlled or poorly controlled, then compared to the nondiabetic population on the basis of amniocentesis results.

RESULTS

Pregnant women with poorly controlled diabetes had a significantly higher risk of immature fetal lung profiles at amniocentesis than did pregnant women without diabetes. Pregnant women with well-controlled diabetes were not significantly different from the nondiabetic population. There was no difference between gestational and pregestational diabetic pregnancies.

CONCLUSIONS

Timing of fetal pulmonary maturation is linked to the level of maternal glucose control in diabetic pregnancies. Adequate glucose control may lower the risk of fetal pulmonary immaturity to that seen in the nondiabetic population.

Doppler velocimetry in pregnant patients with sickle cell anemia

Women with sickle cell anemia have an increased risk of bearing low-birth-weight (LBW) progeny. To establish prognostic indicators of neonatal outcome, 15 women with sickle cell anemia were followed through their pregnancies with the use of umbilical and uterine Doppler flow velocimetry. The systolic/diastolic ratios obtained were correlated with neonatal birth weight, gestational age, and birth weight percentile. Pregravid hemoglobin levels, reticulocyte counts, dense cell numbers, percentage hemoglobin F, and indirect bilirubin and lactate dehydrogenase levels were also determined, and statistical analysis was performed to assess whether any of these parameters would be useful in conjunction with velocimetry. We report here that, in sickle cell anemia, prenatal umbilical and uterine Doppler velocimetry ratios correlate inversely and significantly with neonatal birth weight (P < 0.005 and P < 0.002, respectively). In addition, prenatal maternal HbF levels also correlate significantly with Doppler velocimetry readings, an independent indicator of LBW progeny. Neither pregravid hemoglobin levels nor dense cell concentration correlates with Doppler umbilical and uterine flow velocimetry ratios determined during pregnancy. Pregravid high levels of HbF and velocimetry readings may serve to delineate a subset of sickle cell patients who may have different requirements for prenatal care. The possible mechanism for the detrimental effects of increased levels of fetal hemoglobin has not been clearly established, but it may involve increased propensity for vasoocclusion due to the unique rheology of the human placenta.

Glucose intolerance as a consequence of oral terbutaline treatment for preterm labor

BACKGROUND

In this case series, glucose regulation is examined prospectively during treatment with terbutaline sulfate for premature labor in women who were (1) previously documented as nondiabetic, (2) found to have gestational diabetes mellitus (GDM), and (3) tested for glucose intolerance while terbutaline was being administered. The glucose profiles of women treated with terbutaline were contrasted with the profiles of nondiabetic women and women known to have GDM who were not in premature labor.

METHODS

Subjects tested capillary blood glucose an average of five times a day during terbutaline treatment and for 1 week after terbutaline treatment was discontinued. They used memory-based reflectometers that stored and transmitted self-monitored blood glucose data to a personal computer.

RESULTS

A significant difference (P = .001) was found between average fasting glucose values (111 +/- 23 mg/dL) for the five nondiabetic subjects treated with terbutaline and values of patients in an historical control group (41 nondiabetic pregnancies [72 +/- 22 mg/dL]) who were not in premature labor. The four diabetic subjects and the one subject who had not been previously tested also experienced higher blood glucose levels during tocolytic therapy. Glucose levels returned to preintervention values with the cessation of terbutaline therapy.

CONCLUSIONS

It has been previously suggested that terbutaline increases hepatic glycogenolysis, which may aggravate glucose intolerance. This phenomenon, combined with normal pregnancy-induced insulin resistance, may explain abnormal ambulatory glucose patterns in women who are euglycemic before introduction of terbutaline therapy.

Fetal surveillance in pregnancies complicated by insulin-dependent diabetes mellitus

OBJECTIVE

Our objective was to determine whether maternal vascular disease and/or glycemic control can be related to tests of fetal condition in diabetic pregnancies.

STUDY DESIGN

A total of 114 women with insulin-dependent diabetes who used a memory-based glucose reflectance meter were prospectively evaluated. Nonstress testing was begun weekly at 28 to 30 weeks and twice weekly at 32 weeks. A nonreactive nonstress test was followed by a biophysical profile in all cases.

RESULTS

A total of 1676 nonstress tests was performed (14.7 +/- 3.2 tests per patient). Eight percent (n = 134) were nonreactive, necessitating a biophysical profile. A comparison of ambulatory glucose profile data, including mean blood glucose level, variation, and excursions from the median, revealed no significant differences in patients with reactive versus nonreactive nonstress tests. Ten patients, including eight with vascular disease, were delivered because of abnormal test results of fetal condition. Nephropathy or hypertension was associated with intervention for fetal well-being in 8 of 20 women (40%) with these risk factors. Only 2 of 94 patients (2%) without nephropathy or hypertension required delivery because of abnormal results of fetal testing (p less than 0.001). One fetal death occurred. No significant differences in the various glycemic parameters were found in women delivered for suspected fetal jeopardy versus the nonintervention group.

CONCLUSION

Pregnancies complicated by vascular disease are at greatest risk for abnormal results of fetal testing that necessitate early delivery. Women without vascular complications and with maintenance of good glycemic control rarely have fetal compromise.

Glucose tolerance test periodicity as a descriptor of glucose tolerance abnormality

The periodicity of the standard 100-g glucose tolerance test (GTT) was examined in a prospective study of 194 pregnant patients to determine how well gestational diabetes could be identified. A simplified formula, the GTT periodicity, was used to estimate the time for the GTT curve to return to the fasting level. One hundred one study subjects had all normal glucose values by the National Diabetes Data Group criteria (0-abnormal group), 47 had one value greater than normal (1-abnormal group), and 46 had more than one value abnormal or gestational diabetes. The 0-abnormal patients had a significantly shorter GTT periodicity than did 1-abnormal or gestational diabetic mothers (3.6 versus 4.8 versus 6.6 hours, respectively; P less than .04). Calculating the periodicity for the corresponding insulin excursions yielded significantly increasing values in a graduated fashion for each group (5.2 versus 6.9 versus 9.6 hours, respectively; P less than .05). Examination of the oscillation of the GTT curve about the fasting level allows a physiologic description of normal and abnormal glucose responses in pregnancy. Furthermore, our findings suggest that glucose and insulin periodicities are useful predictors of gestational diabetes in patients with positive screening.

Use of a more physiologic oral glucose solution during testing for gestational diabetes mellitus

A lower osmolar oral glucose solution (50 g glucose in 450 mL fluid, 0.62 mol/L) was administered in addition to the standard hyperosmolar oral glucose solution (100 g glucose in 300 mL fluid, 1.85 mol/L) for oral glucose tolerance testing 1 week apart to 102 pregnant women. The standard oral glucose solution creates delayed gastric emptying and is associated with frequent nausea and vomiting. Results using the modified, lower osmolar glucose solution, when compared to the standard hyperosmolar glucose solution showed (1) statistically equivalent glucose excursion values 30 minutes after ingestion, (2) statistically significant decreased plasma glucose values greater than or equal to 60 minutes, (3) no statistically significant difference in insulin excursion values 30 minutes after ingestion, (4) equal area under the curve for glucose at 30 minutes using either solution, and (5) a markedly decreased incidence of nausea and vomiting. These data suggest that the modified, lower osmolar glucose solution empties rapidly from the stomach and allows the glucose to be absorbed and enter the peripheral circulation in an expeditious manner.

Rationale for insulin management in gestational diabetes mellitus

A prospective study was undertaken to test the hypothesis that insulin treatment in patients with gestational diabetes mellitus (GDM) with fasting plasma glucose (FPG) greater than 5.3 mM significantly reduces adverse perinatal outcome. Assigned to insulin or diet treatment based on FPG were 471 GDM women. Four factors believed to be associated with infants large for gestational age (LGA) were evaluated: FPG, overall glycemic control, maternal weight, and treatment regimen. We found that when glycemic control was optimized, the key factors related to large infants were FPG and treatment modality. In the low-FPG group (less than 5.3 mM), diet therapy achieved an incidence of 5.3% LGA. When insulin therapy was used to optimize control, an incidence of 3.5% LGA was found. Patients in the mid-FPG group (5.3-5.8 mM) had a higher increased rate of LGA (28.6%) for diet-treated versus insulin-treated women (10.3%). In addition, a fourfold increased risk for LGA was found in the diet-treated obese subjects in the mid-FPG group compared with insulin-treated obese women. Finally, treatment with insulin resulted in similar incidence of LGA within all FPG groups. We concluded that FPG greater than 5.3 mM can be the basis for initiation of insulin treatment in GDM subjects with optimization of glycemic control as the goal. This approach may contribute significantly to reduced neonatal risk and may foster a standardized method for rapid and effective assignment to treatment.

Insignificant transfer of glyburide occurs across the human placenta

No data exist concerning human placental transfer of oral hypoglycemic agents during pregnancy. This study characterizes the transport of glyburide in 10 term human placentas with the single-cotyledon placental model. Serial samples were taken from both the maternal and fetal reservoirs during each 3-hour perfusion, and the percent transport and metabolism of tritiated glyburide was calculated with liquid scintillation spectrometry and high-performance liquid chromatography. Antipyrine labeled with carbon 14 was added to the perfusate solution during these experiments as a control. Virtually no transfer of glyburide occurred, and no appreciable metabolism of the drug was detected. Neither variation in the albumin concentration nor increase in the maternal glyburide levels to 100 times therapeutic concentration materially altered the rate of transport. These data show that insignificant transport of glyburide occurs across the human placenta in vitro and suggest that fetal exposure to maternally administered glyburide likewise may be insignificant.

Shoulder dystocia: should the fetus weighing greater than or equal to 4000 grams be delivered by cesarean section?

A total of 75,979 women who were delivered vaginally in the period 1970 to 1985 were stratified into diabetic and nondiabetic groups. Overall, the incidence of macrosomia (greater than or equal to 4000 gm) was 7.6% (5674/74390) in the nondiabetic group and 20.6% (328/1589) in the diabetic group. Patients were further subdivided by weight categories at 250 gm intervals. Eight percent of shoulder dystocia occurred in the diabetic group when fetal weight was greater than or equal to 4250 gm. In contrast, 20% of shoulder dystocia in the nondiabetic group could have been prevented by elective cesarean section when the fetal weight was greater than or equal to 4500 gm. Furthermore, logistic regression analysis demonstrated that birth weight, diabetes, and labor abnormalities were the principal contributors to shoulder dystocia. Elective cesarean section is strongly recommended for diabetics with fetal weights greater than or equal to 4250 gm, and trial of vaginal delivery for nondiabetic fetuses with weights greater than or equal to 4000 gm is recommended. In all cases the clinician must be watchful for labor abnormalities in macrosomic fetuses.

Abnormal growth patterns in diabetes in pregnancy: a longitudinal study

In this longitudinal study we sought to investigate the presence of different abnormal fetal growth patterns in the pregnant diabetic. At least three serial ultrasound examinations were performed during the third trimester on 522 diabetic and 93 control subjects. Growth curves were established for femur length, abdominal circumference and head circumference. In addition, daily growth rate was calculated for fetal weight and all morphometric measurements. The study revealed: a) in the gestational diabetes group large-for-gestational age infants, two accelerated growth patterns (early mean blood glucose 107 +/- 16 and late mean blood glucose 116 +/- 18) were identified; b) there was a significantly larger abdominal circumference (expressed as an age-related percentile) in the early than in the late pattern (88 +/- 10 vs. 60 +/- 18, P less than 0.05); c) femur length, head circumference and growth rate were similar for large-for-gestational age and appropriate-for-gestational age fetuses; d) in the control macrosomic infants (n = 57), the percentile of femur length, head circumference and abdominal circumference within 4 days of delivery were 91 +/- 11, 89 +/- 10, 60 +/- 26, respectively; e) analysis for small-for-gestational age infants showed a similarity in the morphometric measurements and growth rate of insulin-dependent diabetes mellitus and hypertensive control subjects; and f) in contrast, a significantly larger abdominal circumference was found in the gestational diabetes small-for-gestational age infants than in the previous small-for-gestational age groups. Recognition of the specific dynamics and characteristics of these patterns will allow for early detection of the fetus at risk, which in turn will improve clinical decision-making.

Third-trimester prediction of small-for-gestational-age infants in pregnant women with sickle cell disease. Development of the ultradop index

Twenty-seven women with homozygous sickle cell disease were followed from the third trimester until delivery. All the subjects underwent both Doppler and sonographic assessment at two points in pregnancy, periods I (28-30 weeks) and II (34-36 weeks). Estimated fetal weight (EFW) was calculated. Using a continuous wave Doppler instrument, mean systolic:end diastolic (S:D) ratios were calculated to characterize the umbilical waveforms. S:D ratios greater than or equal to 3 were designated abnormal. An index, the ultra-dop, was developed that combined ultrasound EFW less than or equal to 25th percentile and S:D greater than or equal to 3. Nine of 27 infants (33%) were small for their gestational age, with a mean gestational age of 38 +/- 2 weeks. The sensitivity, specificity and predictive values were calculated for smallness for gestational age utilizing ultrasound, Doppler velocimetry and the ultradop index for periods I and II. For period I, the highest sensitivity was obtained with the ultradop index--88.9% as compared to 77.8% with Doppler scanning and 11.1% with ultrasound. The ultradop also provided the highest positive predictive value, 88.9%; it was followed by Doppler at 77.8% and ultrasound at 50.0%. In period II the ultradop index and Doppler had the same sensitivity, 88.9%, which was much higher than for ultrasound (55.6%). As for period I, the ultradop had the highest positive predictive value, 88.9%. Our data suggest that the ultradop index provides a key assessment of women with sickle cell disease at 28-30 weeks' gestation with reference to the likelihood of their giving birth to small-for-gestational-age infants.

Prevention of macrosomia

In summary, appropriate assignment of patients to treatment modality utilizing verified blood glucose determination and targeting mean blood glucose level throughout pregnancy to 5.3 mmol/l (similar to normal nondiabetic blood glucose levels) will result in neonatal size comparable to the general population. Today, we have the knowledge and the technology not only to strive for the target but also, more importantly, to achieve the goal of pregnancy outcome in the diabetic comparable to the non-diabetic population. To return to our original research question: Is it glucose or insufficient knowledge of the management approach that maintains macrosomia levels? It is evident that glucose is the prime cause of macrosomia, although other nutrients have a secondary role. Proper management of glucose abnormality will result in a significant decrease in the rate of macrosomia.

A longitudinal evaluation of the efficacy of umbilical Doppler velocimetry in the diagnosis of intrauterine growth retardation

In a prospective study of 149 patients, the interrelationship among abnormal umbilical artery systolic/diastolic (S/D) ratios, maternal hypertension and IUGR was examined. Abnormal S/D ratio was defined as a value greater than or equal to 3 in the third trimester. Results suggest that the incidence of abnormal S/D ratios are significantly higher in hypertensive as compared to normotensive pregnancies, as well as in small for gestational age (SGA) compared to appropriate for gestational age (AGA) deliveries. Although umbilical artery velocimetry was more predictive of IUGR in hypertensive than normotensive pregnancies, overall 45% of SGA births were not identified by this technique. Further classification of potential etiologies and mechanisms of IUGR based on maternal factors should improve the positive predictive value of the abnormal S/D ratio in subgroups of pregnant women. In the interim the results strongly suggest that abnormal S/D ratio in a hypertensive pregnancy should alert the obstetrician to the probability of IUGR.

Association between umbilical artery cord pH, five-minute Apgar scores and neonatal outcome

A prospective study was conducted of 270 intrapartum patients admitted in labor to investigate the independent and combined relationships between umbilical arterial cord pH and Apgar scores and neonatal outcome. The results revealed that when assessed independently, a low 5-min Apgar score (less than 7) was associated with both NICU admission and neonatal sepsis. When categorized by both cord pH and 5-min Apgar, the majority of patients (75.9%) had both parameters normal, 20.7% had an abnormal pH (less than 7.20) and normal Apgar (greater than or equal to 7) and few patients had either both normal or an abnormal Apgar given a normal pH. Given a normal 5-min Apgar score, additional information about the cord pH did not enhance the predictability for either NICU admission or neonatal sepsis. Neonates with both an abnormal pH and 5-min Apgar had the highest incidence of NICU admission. For all neonates, the presence of meconium greatly increased the likelihood of being admitted to the NICU.

Relationships between glucose levels and insulin secretion during a glucose challenge test

The relationship between glucose and insulin levels was examined in a prospective study of 153 pregnant patients without diabetes who underwent a standard 50 gm glucose challenge test. One hundred eighteen women had normal screening results (glucose level less than 140 mg/dl) and 35 had abnormal screening values but a normal oral glucose tolerance test. Abnormal responders had greater insulin levels (149 vs 82 pmol/L, p less than 0.0001), and a higher insulin/glucose index (0.96 vs. 0.72, p less than 0.007). Patients with glucose levels less than 100 mg/dl had significantly lower insulin/glucose indices. Overall, obese patients had significantly greater glucose and insulin measurements than did nonobese women, but there was no difference within normal and abnormal groups. Glucose levels accounted for 52% of the insulin output and 29% of the insulin/glucose index variance. Neither age, parity, nor obesity contributed significantly to insulin levels in the multiple regression model. Therefore the accepted threshold for glucose screening reflects abnormal insulin output and this aberration may be indicative of the primary defect in gestational diabetes.

Does fasting interval affect the glucose challenge test?

The relationship between fasting interval and glucose screening was assessed in a prospective study of 153 non-diabetic pregnant patients undergoing a standard 50g glucose challenge test. An interval of less than 3 hours after the last meal was found to be associated with a significantly greater insulin response as opposed to a fasting interval of more than 3 hours (121.3 pmol/l vs. 83.5 pmol/l, p less than .001) and a greater insulin/glucose index (0.92 vs. 0.66, p less than .001), with no difference in plasma glucose. Overall, obese patients had a higher glucose response than non-obese, but only higher insulin levels (107 pmol/l vs. 69 pmol/l, p less than .001) and insulin/glucose index (0.79 vs. 0.59, p less than .02) when the fasting interval was greater than 3 hours. Our data suggest that the fasting interval can influence insulin response during a glucose challenge test and the aberration in insulin secretion may effect screening results, especially in the high-risk gravida with glucose abnormality.

Education does not improve patient perception of preterm uterine contractility

In this prospective study, we sought to compare pregnant women's self-perception of their preterm uterine contractility versus electronically obtained data and to evaluate the impact of intensive patient education on increasing awareness of the presence of uterine contractions. Thirty-eight women each monitored their uterine activity at home for two 60-minute periods daily during a 21-day sequence. An event marker was used to document perceived contractions and after a 3-day baseline interval, an intensive nursing-service educational intervention was initiated for all subjects. Thirty-five percent of women underreported uterine contractions, whereas only 5% overreported their uterine activity during the study. Derived patient scores of underreporting and overreporting of contractions did not vary among seven consecutive 3-day study intervals. Analysis of the data revealed that patients perceived fewer than 10% of all contractions documented electronically. No improvement in the reliability of patient perception of preterm uterine contractility was obtained after the educational intervention.

Uterine contractility patterns after an episode of preterm labor

Uterine contractility patterns were studied in an attempt to identify those women on tocolytic therapy at risk for preterm delivery. One hundred sixteen women treated successfully after an episode of preterm labor were followed with an ambulatory tocodynamometer system. Contractions were monitored twice daily for 1 hour until delivery or until 36 completed weeks of gestation. In this group, 52 women (45%) delivered preterm and 64 (55%) delivered at term. The analysis revealed that 1) from 24-29 weeks' gestation, there was no significant difference in the uterine activity between the two groups; and 2) beginning at 30 weeks' gestation and continuing until the end of the 36th week of gestation, uterine activity was significantly greater in women destined to deliver preterm. These observations suggest that the patterns of daily uterine contractility observed in patients after an episode of preterm labor can identify those at greater risk for a preterm delivery.

Sonographic estimates of fetal weight in the intrauterine growth retardation population

The efficacy of different methods of fetal weight estimation using sonographic measurements of the abdominal circumference (AC), biparietal diameter (BPD), and femur length (FL), either alone or in combination, was evaluated in the fetus with intrauterine growth retardation (IUGR). Eighty-one patients, referred with a clinical suspicion of IUGR, were studied. All patients had sonographic measurements within 7 days of delivery. Four regression equations were used to estimate fetal weight: AC (Hadlock), BPD-AC (Shepard), AC-FL (Hadlock), BPD-AC-FL (Hadlock). For the total study group, as well as for the infants who were found to be IUGR at birth, 75% of the estimates of fetal weight using the BPD-AC-FL method were within 10% of the actual birthweight. Nearly comparable results were obtained using the AC-FL method. In the fetus with IUGR, estimates of fetal weight that incorporated the FL correlated best with the actual birthweight.