The erythrocyte incorporation of absorbed non-haem iron in pregnant women.

Studies of Fe absorption in pregnancy often make unfounded assumptions of erythrocyte incorporation. Therefore, we measured the absorption and utilisation of Fe during early and late pregnancy by the erythrocyte incorporation of two stable isotopes. 8.5 mg 57Fe (oral) and 0.5 mg (58)Fe (intravenous) were given to five non-pregnant women, to five women in early gestation (12 weeks) and five women in late gestation (36 weeks). The stable isotope ratios in whole blood 14 d later were measured by MS. Together with estimation of body Fe mass, this enabled the calculation of Fe absorption and erythrocyte incorporation. In non-pregnant women, Fe absorption averaged 20.3 (range 10.2-34.3) %. It was not significantly different in early pregnancy (11.8 (range, 4.4-24.8) %), but during late pregnancy Fe absorption increased to 59.0 (range 38.2-77.2) %. All non-pregnant and early-pregnancy subjects had normal Fe status, but two women in late pregnancy had evidence of Fe insufficiency. During early and late pregnancy, mean erythrocyte incorporation was 63.4 (SD 12.1) % and 71.0 (SD 10.4) % respectively, significantly reduced compared with non-pregnant subjects (90.1 (SD 6.0) %). Decreased erythrocyte incorporation of absorbed Fe in early pregnancy is compatible with reduced Fe demand and low oral absorption. However, during late pregnancy decreased erythrocyte incorporation associated with high absorption and Fe insufficiency is different from the high erythrocyte incorporation which occurs in non-pregnant Fe-deficient women. This suggests that part of the aetiology of Fe deficiency during pregnancy may be the reduction of Fe utilisation.

Whole body protein kinetics in women: effect of pregnancy and IDDM during anabolic stimulation.

The effects of pregnancy and type 1 diabetes [insulin-dependent diabetes mellitus (IDDM)] on protein metabolism are still uncertain. Therefore, six normal and five IDDM women were studied during and after pregnancy, using [(13)C]leucine and [(2)H(5)]phenylalanine with a hyperinsulinemic-euglycemic clamp and amino acid infusion. Fasting total plasma amino acids were lower in pregnancy in normal but not IDDM women (2,631 +/- 427 vs. 2,057 +/- 471 and 2,523 +/- 430 vs. 2,500 +/- 440 micromol/l, respectively). Whole body protein breakdown (leucine) increased in pregnancy [change in normal (delta N) and IDDM women (delta D) 0.59 +/- 0.40 and 0.48 +/- 0.26 g. kg(-1). day(-1), both P < 0.001], whereas reductions in protein breakdown due to insulin/amino acids (delta N -0.57 +/- 0.19, delta D -0.58 +/- 0.20 g. kg(-1). day(-1), both P < 0.001) were unaffected by pregnancy. Protein breakdown in IDDM women was not higher than normal, and neither pregnancy nor type 1 diabetes altered the insulin sensitivity of amino acid turnover. Nonoxidized leucine disposal (protein synthesis) increased in pregnancy (delta N 0.67 +/- 0.45, delta D 0.64 +/- 0.34 g. kg(-1). day(-1), both P < 0.001). Pregnancy reduced the response of phenylalanine hydroxylation to insulin/amino acids in both groups (delta N -1.14 +/- 0.74, delta D -1. 12 +/- 0.77 g. kg(-1). day(-1), both P < 0.05). These alterations may enable amino acid conservation for protein synthesis and accretion in late pregnancy. Well-controlled type 1 diabetes caused no abnormalities in the regulation of basal or stimulated protein metabolism.

Evaluation of phenylalanine and tyrosine metabolism in late human pregnancy.

The [2H5]-phenylalanine method for measurement of protein metabolism requires the phenylalanine hydroxylation to tyrosine to be calculated from the tyrosine flux. Although this can be estimated, for pregnancy, we made a direct measurement of the molar ratio of the fluxes of tyrosine and phenylalanine from protein breakdown (Pt/Pp) using [2H2]-tyrosine infusion. Six normal pregnant women were studied at 37 weeks' gestation. While fasting, they were administered a 3-hour primed-constant infusion with [13C]-leucine, [2H5]-phenylalanine, and [2H2]-tyrosine. Leucine (alpha-ketoisocaproic acid [KIC]) flux was 136.2+/-15.1 micromol/kg/h (mean +/- SD), phenylalanine flux 41.2+/-5.6, and tyrosine flux 25.0+/-6.0, and phenylalanine hydroxylation was 3.3+/-2.1 micromol/kg/h. The mean tyrosine to phenylalanine molar flux ratio (Pt/Pp) was 0.52+/-0.10, lower than the ratio of 0.65 to 0.85 reported in normal nonpregnant subjects and 0.73 estimated from animal studies. We studied protein metabolism in six additional pregnant women and six nonpregnant women using [13C]-leucine and [2H5]-phenylalanine infusions only and applied the lower Pt/Pp ratio to the former group. Tyrosine flux (42.0+/-7.2 micromol/kg/h) and phenylalanine hydroxylation (9.2+/-4.2 micromol/kg/h) were significantly higher in nonpregnant subjects than in both groups of pregnant subjects. The percent contribution of phenylalanine hydroxylation to total tyrosine flux was reduced from 20% to 14%. When using [2H5]-phenylalanine to study whole-body protein metabolism in pregnancy and tyrosine flux is not measured directly by infusion of [2H2]-tyrosine, the lower Pt/Pp ratio is required. The phenylalanine model shows that tyrosine flux derived from protein breakdown and phenylalanine hydroxylation are both reduced in pregnancy.

Leptin in human pregnancy: the relationship with gestational hormones.

OBJECTIVES: The aims of the study were (1) to examine the relationship between leptin and placental hormones by measuring serial changes in serum levels of leptin during and after pregnancy and (2) to study the effects of several gestational hormones on leptin release from fully differentiated 3T3-L1 adipocyte cell cultures. STUDY DESIGN: Serum levels of leptin were measured throughout pregnancy and at 3 months post partum in 29 healthy women and were also measured in 18 healthy women at delivery by cesarean section and on postpartum day 3. In addition, 3T3-L1 mouse adipocytes were incubated for 24 hours in media containing various reproductive hormones and leptin production was measured. RESULTS: Serum leptin levels increased significantly (8.4 +/- 0.9 vs 13.5 +/- 1.5 ng/mL; P <.001) between the first 2 trimesters of pregnancy but not between the second and third trimesters. These changes in leptin did not correlate significantly with changes in body mass index. Leptin levels dropped significantly during the immediate postpartum period, from 34.1 +/- 4.9 at cesarean delivery to 7.3 +/- 1.4 ng/mL on postpartum day 3 (P <.001). Fasting insulin level did not correlate significantly with leptin level during pregnancy but did so during the postpartum period (r = 0.60; P <.05). Leptin secretion from 3T3-L1 adipocytes was increased significantly when cells were cultured with human chorionic gonadotropin (150%, P <.01) and also when they were cultured with estrogen (120%, P <.03). CONCLUSION: The data suggest that leptin production by adipose tissue is stimulated by several hormones of pregnancy, which may contribute to the increased leptin levels observed during gestation.

Free fatty acids and insulin resistance during pregnancy.

The purpose of this study was to determine whether elevation of plasma free fatty acids (FFA) in early pregnancy would cause alterations in insulin-stimulated glucose disposal similar to those occurring in late gestation. Seven glucose-tolerant women underwent 4-h euglycemic hyperinsulinemic (1 mU/kg.min) clamping during the early second trimester of pregnancy (14-17 weeks) on 2 consecutive days, receiving either lipid (Liposyn II; 1.5 mL/min) and heparin (0.4 U/kg.min; L/H) or saline/glycerol (2.25 g/h; S/G) infusions. Rates of total body glucose disposal (6,6-2H2 glucose) and of carbohydrate and fat oxidation (indirect calorimetry) were determined at hourly intervals. Blood glucose was clamped at about 85 mg/dL. Plasma FFA increased from 290 +/- 50 to 1000 +/- 139 mumol/L during L/H infusion and decreased from 351 +/- 60 to 35 +/- 11 mumol/L during S/G infusion. L/H infusion inhibited insulin stimulation of total body glucose disposal by 28% compared with S/G infusion (from 6.7 +/- 0.7 to 4.9 +/- 0.6 mg/kg.min; P < 0.01). L/H infusion increased fat oxidation from 0.73 +/- 0.04 to 1.26 +/- 0.2 mg/kg.min (P < 0.05) and decreased carbohydrate oxidation from 2.0 +/- 0.2 to 1.6 +/- 0.2 mg/kg.min (P < 0.05). Endogenous glucose production decreased equally by approximately 70% during L/H and S/G infusions. These data showed that elevating plasma FFA levels during early pregnancy inhibits total body glucose uptake and oxidation. We conclude that elevation of plasma FFA can contribute to the peripheral insulin resistance commonly observed during late pregnancy.

Serial hematologic changes and pregnancy outcome.

OBJECTIVE: To reevaluate the concept that poor maternal hematologic changes relate to increased placental protein hormones, increased birth weight, and placenta to birth weight ratio. METHODS: Sixty-nine normal women were studied prospectively. On several occasions, pre-pregnancy, during pregnancy, and post-delivery, plasma volume was measured together with maternal hematologic indices and placental protein hormone levels. Birth weight and placental weight were measured at delivery. RESULTS: The decrements in hemoglobin concentration and hematocrit were apparent by 7 weeks' gestation. By 12 weeks, these progressive changes resulted mostly from the increase in plasma volume, and both hemoglobin concentration and hematocrit continued to decrease until near term. Increments in red cell and hemoglobin mass were maximal at 12-28 weeks of pregnancy. Concentrations of the placental hormones hCG and human placental lactogen at 12 weeks showed a lack of correlation with hemoglobin concentration or any other hematologic index. The correlations of birth weight with hemoglobin concentration and hematocrit at 36 weeks were not significant when we controlled for the effect of plasma volume. Neither hemoglobin mass at 36 weeks nor the change in hemoglobin concentration, hematocrit, and mean cell volume from the pre-pregnancy value to that at 36 weeks were significantly related to birth weight, placental weight, or the placenta to birth weight ratio. CONCLUSION: Low hemoglobin in late pregnancy reflects plasma volume changes, rather than poor maternal nutrition or adaptation, and is not linked to discordant placenta to birth weight ratio.

Comparison of stable isotopes and radioisotopes in the measurement of iron absorption in healthy women.

1. Stable isotope methods are being used to investigate the absorption of dietary iron. In order to be certain that this new methodology is accurate, we have compared results obtained using stable isotopes and inductively coupled plasma mass spectrometry with those determined using a radioisotope and whole body counting. 2. The stable isotope 54Fe (2.8 mg) was given to 10 healthy non-pregnant women. Six women received the isotope in aqueous form, and four took it with a meat meal. The 54Fe served as a carrier for 10 ng of the radioisotope 59Fe. An ampoule (200 micrograms) of the isotope 57Fe or 58Fe was then given intravenously, and in serum samples taken over the next 10 h the ratios of the stable iron isotopes were measured by inductively coupled plasma mass spectrometry and the oral iron absorption was calculated. This was then compared with the results obtained by using a whole body counter to measure (on day 0 and day 14) the gamma-activity emitted by the radioisotope. 3. The mean iron absorption measured by both methods ranged from 8% to 45%. Measurement of the post-absorptive serum enrichment of the stable isotopes provided estimates of absorption from both aqueous and food iron which were similar to that yielded by whole body counting, the mean difference being -1.5% (95% confidence interval -5.2 to 2.1%). Absorption estimated by stable isotopes exhibited the same inverse relationship with the serum ferritin level (body iron stores) to that known to exist with whole body counting.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption of non-haem iron from food during normal pregnancy.

OBJECTIVE: To determine whether the increased iron demands of pregnancy could be met by increased absorption from dietary sources. DESIGN AND SETTING: Longitudinal prospective study in the research unit of a maternity hospital. SUBJECTS: 12 normal pregnant women. INTERVENTIONS: At 12, 24, and 36 weeks' gestation (within one week) and 16-24 weeks after delivery women ate a breakfast of meat, bread, and orange juice (3.2 mg iron), extrinsically labelled with the stable isotope iron-54 (2.8 mg); the stable isotope iron-57 (200 micrograms) was given intravenously. MAIN OUTCOME MEASURES: Serum samples were taken for 10 hours after administration of the isotopes; ratios of the isotopes were measured by inductively coupled plasma mass spectrometry, and the absorption of oral iron was calculated. RESULTS: The geometric mean (95% confidence interval) absorption of iron at 12, 24, and 36 weeks' gestation was 7% (5% to 11%), 36% (28% to 47%), and 66% (57% to 76%) respectively. At 16-24 weeks after delivery the absorption was 11% (6% to 21%). The mean increase in absorption at 36 weeks (compared with that at 12 weeks) was 9.1 times (6.0 to 13.7). One pregnant woman developed iron deficiency anaemia but was otherwise indistinguishable from the others. CONCLUSIONS: An increase in the absorption of iron from food is a physiological consequence of normal pregnancy, not the result of developing anaemia during pregnancy, and such an increase is large enough to meet the increased requirements of pregnancy provided that the dietary intake is adequate.

The intravascular mass of albumin during human pregnancy: a serial study in normal and diabetic women.

OBJECTIVE: To quantify the changes in serum albumin during human pregnancy. DESIGN: Longitudinal prospective study. SETTING: Before conception and antenatal clinic. SUBJECTS: Sixty-nine normal women and 23 women with Type 1 diabetes. INTERVENTIONS: Administration of Evans' blue dye and collection of serum samples. MAIN OUTCOME MEASURES: Albumin concentration, plasma volume and intravascular mass of albumin. RESULTS: In normal subjects serum albumin concentration showed a significant decrease of 1.9 (95% CI 1.0 to 2.9) g/l by 7 weeks gestation with a further 8.2 (95% CI 7.5 to 8.9) g/l decrease by 36 weeks gestation, an overall change of 22%. Plasma volume first increased significantly by 190 (95% CI 105 to 275) ml between 7 and 12 weeks, with a further increase of 1003 (95% CI 871 to 1135) ml between 12 and 36 weeks of pregnancy, a change of 53%. The intravascular mass of albumin showed no change between non-pregnant, 7 and 12 week values but there was a significant rise of 19.5 (95% CI 15.1 to 23.9) g between 12 and 28 weeks of gestation, an overall increase of 19%. Diabetic subjects showed similar changes. CONCLUSIONS: Rather than simply reflecting plasma volume dilution, the changes in serum albumin imply alterations in albumin metabolism during pregnancy.

Absorption of non-haem iron in normal women measured by the incorporation of two stable isotopes into erythrocytes.

1. Iron absorption has been quantitatively measured as the incorporation of physiological doses of stable iron isotopes into erythrocytes. Five milligrams of 57Fe (orally) and 250 micrograms of 58Fe (intravenously) were given to five healthy women on 2 consecutive days. Fourteen days later the changes in the 57Fe/56Fe and 58Fe/56Fe ratios in the erythrocytes of each subject were measured using an inductively coupled plasma mass spectrometer. Isotope ratios were also measured in two subjects who were not given any enriched isotope. Concomitant measurements of plasma volume using a dye-dilution technique enabled the estimation of body iron mass and the calculation of iron absorption. 2. The mean coefficients of variation for the 57Fe/56Fe ratio and the 58Fe/56Fe ratio were 0.22% and 0.47%, respectively. This precision allowed enrichments of basal ratios to be reliably detected in all cases. The mean change in the 57Fe/56Fe ratio was 0.00116 (SD 0.00052, P < 0.001) and the mean change in the 58Fe/56Fe ratio was 0.00035 (SD 0.00004, P < 0.001). Control subjects showed no enrichment. 3. The calculated iron absorption ranged from 10% to 34%, and the amount of absorption was related to the iron stores of the subjects. Percentage iron absorption was identical when estimates of the plasma volume (derived from a body mass equation) were used instead of the plasma volume determined by dye-dilution measurements. Incorporation of intravenous iron into erythrocytes was on average 81% (range 68-93%). 4. The method is especially applicable to the study of iron absorption during pregnancy when incorporation into erythrocytes cannot be predicted.

Albumin metabolism in fasted subjects during late pregnancy.

1. Albumin fractional synthetic rate was determined in five non-pregnant subjects and five normal pregnant subjects in late gestation after an overnight fast by simultaneous prime and intravenous infusion of two precursor amino acids, [15N]glycine and L-[1-13C]leucine, with additional priming of the large but, slowly turning over, urea pool with [15N2]urea. 2. The two tracers yielded similar values of albumin fractional synthetic rate: 6.1 and 6.0%/day in non-pregnant subjects and 7.3 and 7.6%/day in pregnant subjects, for glycine and leucine, respectively. While plasma volume was greater and serum albumin concentration was significantly reduced during pregnancy, the calculated intravascular albumin mass was significantly increased in pregnant subjects. 3. The amount of albumin synthesized in the intravascular compartment was significantly greater at 8.8 and 9.5 g/day in pregnant subjects compared with 6.4 and 6.3 g/day in non-pregnant control subjects (glycine and leucine methods, respectively). Calculated whole-body protein turnover using glycine was not different between the two subject groups, but leucine flux was higher in pregnant subjects. Partitioning of nitrogenous products in urine revealed that pregnant subjects excreted less urea, less ammonia and less creatinine than the non-pregnant control subjects. 4. These findings suggest that whereas the serum albumin concentration decreases during pregnancy secondary to the large increase in plasma volume, there is an increase in albumin synthesis such that total intravascular albumin mass is increased in late pregnancy.

The presence of cation-dependent proteases for insulin-like growth factor binding proteins does not alter the size distribution of insulin-like growth factors in pregnancy.

OBJECTIVE: The aim was to investigate the sera of pregnant women for the presence of specific proteases for insulin-like growth factor binding proteins (IGFBPs) and to determine the effect of these on the distribution of IGFs in the circulation. DESIGN: The method used was the chromatographic and electrophoretic analysis of patients' serum. PATIENTS: Sera were examined from normal women during pregnancy: first trimester (n = 4), second trimester (n = 4) and third trimester (n = 10). Eight women with Type I diabetes in the third trimester were also studied along with sera from ten normal adult volunteers. MEASUREMENTS: Circulating IGF-I and IGF-II levels were measured by RIA and their distribution examined by gel filtration. The pattern and stability of the IGFBPs was investigated by Western ligand blotting. RESULTS: A marked reduction in the serum levels of IGFBP-2, IGFBP-3 and IGFBP-4 on Western ligand blotting, which was associated with the presence of three independent, cation-dependent proteases that were specific for different IGFBPs, was found in late pregnancy. Gel filtration of third trimester serum revealed most of the IGF-I to be present in a complex larger than 130 kDa, with a similar distribution to that found in serum of non-pregnant women. The enzymatic modification of the binding proteins made apparent by the decrease in binding protein bands on Western ligand blotting of preincubated samples had no effect on the distribution of IGF-I following size fractionation. CONCLUSIONS: There appear to be at least three independent enzymes that are induced or activated during pregnancy to modify IGFBP-2, IGFBP-3 and IGFBP-4 sufficiently to prevent their detection by ligand blotting. However, this enzymatic processing does not alter the distribution of IGFs, suggesting that the altered binding proteins are still able to carry IGFs but with reduced affinity. Such an alteration in the carrying mechanism of IGFs may have profound effects upon the bioavailability of the IGFs to the maternal tissues and contribute to the altered metabolic demands of pregnancy.

Iron absorption during normal human pregnancy: a study using stable isotopes.

The absorption of iron has been determined in nine healthy women studied serially during pregnancy and once post delivery. Following the oral administration of 5 mg aqueous 54FeSO4 plus ascorbic acid and the intravenous injection of 200 micrograms 57FeSO4, the isotope ratios of 54Fe: 56Fe and 57Fe: 56Fe in serum were measured by the use of inductively-coupled-plasma mass spectrometry whereby metal ions are vaporized into an argon plasma without previous blood sample preparation. Mean oral Fe absorption was 7.6 (range 1-22)% at 12 weeks gestation, 21.1 (range 9-58)% at 24 weeks, 37.4 (range 18-56)% at 36 weeks and 26.3 (range 8-54)% at 12 weeks post delivery. All the other biochemical and haematological indices were within normal limits for pregnancy. The significant increase (P less than 0.01) in Fe absorption during normal pregnancy suggests that most women would have the potential to meet the Fe demands of pregnancy without the need for supplementation if dietary Fe has similar availability to the aqueous preparation.

Insulin-like growth factor 1 and its binding protein 1 during normal and diabetic pregnancies.

Investigations of circulating insulin-like growth factor 1, hPL, and infant size during pregnancy in normal and insulin-dependent diabetic women have yielded conflicting results and have not been analyzed longitudinally. We studied serial changes in maternal serum insulin-like growth factor 1 levels (measured by radioimmunoassay after acid ethanol extraction) throughout pregnancy in 22 normal women and in 38 with insulin-dependent diabetes. The diabetic women had significantly lower serum insulin-like growth factor 1 concentrations than normal women throughout pregnancy and after delivery, although the rates of change in both groups of women were similar. Within-patient analysis showed a significant decrease in serum insulin-like growth factor 1 between 6-12 weeks' gestation and a significant increase between 24-32 weeks, followed by a significant decrease from 36 weeks' gestation to 12 weeks after delivery. Incremental changes in insulin-like growth factor 1 between 24-32 weeks' gestation correlated significantly with incremental changes in hPL (r = 0.40; P less than .001) and with birth weight (r = 0.37; P less than .01), but not with ultrasound measurements of fetal growth. The correlation of increments in insulin-like growth factor 1 and birth weight became nonsignificant when the association of hPL with both insulin-like growth factor 1 and birth weight was taken into account. Neither insulin-like growth factor binding protein 1 (placental protein 12) nor its ratio to insulin-like growth factor 1 showed any association with infant size. The physiologic changes in maternal serum insulin-like growth factor 1 in pregnant diabetic women do not appear related to the increased birth weight of their infants.

Albumin synthetic rate: a comparison of arginine and alpha-ketoisocaproate precursor methods using stable isotope techniques.

The validity of [15N]glycine and [13C]leucine as tracers for investigating albumin fractional synthetic rate (FSR) has been explored by simultaneous infusion of both amino acids into 5 normal female subjects. Albumin FSR, calculated from the urinary [15N]urea plateau value and the incorporation of arginine into albumin was 0.2250 +/- 0.038 per cent/h (mean +/- s.d.). The infusion of leucine, using alpha-ketoisocaproate enrichment to represent the precursor pool, and with measurement of the direct incorporation of leucine into plasma albumin gave a FSR of 0.2516 +/- 0.044 per cent/h. Calculated absolute albumin synthetic rates (ASR) were 11.29 +/- 1.73 mg/kg/h and 11.13 +/- 2.24 mg/kg/h for the glycine and leucine methods respectively. It is concluded that the latter approach is valid as the two amino acids yielded such similar values. The glycine-arginine protocol used represents an improvement compared with previous methods in that the study is completed within 12 h.

Some endocrinological events associated with early pregnancy failure.

Serial measurements of serum progesterone, oestradiol, human chorionic gonadotrophin (hCG) and human placental lactogen (hPL) have been determined in 33 women experiencing early pregnancy failure and compared with the values of the same hormones in 72 healthy women having uncomplicated pregnancies. Steroid production by the corpus luteum seemed similar in both groups up to 6 weeks gestation but thereafter placental steroidogenesis was not evident in those women in whom spontaneous pregnancy losses occurred. Placental production of the two protein hormones, hCG and hPL, did take place, and whereas the circulating levels were not as high as in normal pregnancies, levels did usually increase before clinical evidence of miscarriage occurred. hCG was not a sensitive discriminator of subsequent failure. In these women there were no significant hormone differences between those with evidence of a fetus and those without.

Inductively coupled plasma mass spectrometric determination of the absorption of iron in normal women.

The determination of iron isotope ratios in blood, without prior sample preparation, using inductively coupled plasma mass spectrometry (ICP-MS) with sample introduction by electrothermal vaporisation (ETV) is described. Following oral administration of 5 mg of enriched 54FeSO4 and intravenous administration of 200 micrograms of 57FeSO4 to non-pregnant women, the 54Fe: 56Fe and 57Fe: 56Fe isotope ratios in serum were measured reliably within 20 min per sample in quintuplicate. Changes in the fractional absorption of iron during human pregnancy could therefore be assessed.

A longitudinal study of circulating progesterone, oestradiol, hCG and hPL during pregnancy in type 1 diabetic mothers.

Serum progesterone, oestradiol, human chorionic gonadotrophin (hCG) and human placental lactogen (hPL) were determined serially throughout 27 pregnancies in insulin-dependent diabetic patients from Newcastle (UK), 15 such patients from Stockholm (Sweden) and in 69 normal women having uncomplicated pregnancies. Mean progesterone, oestradiol and hCG concentrations were somewhat higher in the diabetic women during the third trimester but hPL values were not different from normal. The increased hormone concentrations did not relate to the increased birthweights or placental weights in the diabetic women. It is suggested that the usual physiological endocrine changes during normal pregnancy are relatively undisturbed by insulin-dependent diabetes or the degree of diabetes control achieved.

A prospective study to compare serum human placental lactogen and menstrual dates for determining gestational age.

In a group of 575 healthy pregnant women with certain menstrual dates the estimation of the length of gestation from maternal serum human placental lactogen concentrations has been compared with gestational age calculated from the last menstrual period and ultrasonic measurements of the fetal biparietal diameter. In 412 of these patients labor started spontaneously, and the estimated dates of delivery determined by these three methods were also compared. In the range of 9 to 17 weeks of pregnancy, gestational age can be determined by human placental lactogen measurement to within 7 days (+/- 1 SD) which compares favorably with other methods. Regarding the prediction of the expected date of delivery, 88% were delivered within 2 weeks of the date predicted by last menstrual period, 82% within 2 weeks of the sonar date, and 80% by the date determined by human placental lactogen assessment. Prediction of delivery in a further group of 139 women with uncertain dates gave 73% within 2 weeks by sonar date and 69% within 2 weeks by human placental lactogen determination. We suggest human placental lactogen measurements should become part of routine antenatal care complementing rather than replacing the role of ultrasonic scanning. For those doctors and patients who wish to avoid more exposure to ultrasonic scanning than absolutely necessary, human placental lactogen estimates offer an alternative method for assessing the length of gestation.