Maternal Hb Research Articles

HAEMOGLOBIN AIc PREDICTS THE PERINATAL OUTCOME IN INSULIN‐DEPENDENT DIABETIC PREGNANCIES

Haemoglobin AIc (Hb AIc) was measured in 112 insulin-dependent diabetic pregnancies on an average 4.7 times. Hb AIc was high in early pregnancy in all three patients with severe fetal malformations. There were six pregnancies with a perinatal death. The maximum Hb AIc values were significantly higher in the second trimester (p less than 0.001) in these pregnancies than in the other diabetic pregnancies. When neonatal hypoglycaemia was present, the mean maternal Hb AIc was significantly higher in the second (p less than 0.005) and third (p less than 0.02) trimesters of pregnancy than in the group without neonatal hypoglycaemia. In the group with neonatal hyperbilirubinaemia the mean maternal Hb AIc was significantly higher in the third trimester (p less than 0.02) than in the group with no neonatal hyperbilirubinaemia. The results suggest that poor metabolic control of maternal diabetes during the second trimester is associated with a clearly increased risk of perinatal death and during the second and third trimesters with metabolic derangements in the neonatal period. The results also indicate that Hb AIc could be used to detect the pregnant diabetics at special risk.

Materno-foetal transmission of HB sAg by asymptomatic carrier mothers in Glasgow

Summary Thirty-five infants born to 33 asymptomatic HB s Ag carrier mothers of different ethnic groups in Glasgow were periodically assessed up to age 12 months (mean 6·3 months). Of five (14 per cent) infants who were HB e Ag-positive at three months, only three (9 per cent), whose carrier mothers were also HB e Ag-positive remained HB e Ag-positive at one year. No British mothers were HB e Ag-positive. Of the three HB e Ag-positive mothers, two were Chinese and one Asian. No markers of HBV infection could be found in infants of 22 anti-HB e -positive mothers. We conclude that maternal HB e Ag is an excellent indicator of subsequent HB e Ag carrier status in the infant and the Chinese mothers are more likely to transmit HB e Ag to their offsprings. Continued surveillance of HB e Ag-positive infants is desirable and the value of prophylactic administration of hepatitis B immunoglobulin to selected infants at birth and thereafter should be further evaluated.

1195 GLYCOSYLATION OF HEMOGLOBINS IN THE MOTHER-INFANT DYAD

Since adult hemoglobin (Hb AO) is glycosylated post-translationally, we hypothesized that Hb in the fetus might reflect maternal glucose control. A chemical method (thiobarbituric acid) was used since Hb F co-elutes with glycohemoglobin (Hb AIc) on cation chromatography. Blood was obtained at delivery from 13 normal and 9 insulin-dependent mother-infant pairs. Glycosylation of Hb (G-Hb) was compared to fructose standards and expressed as nM fructose equiv. (FE)/mg Hb. Maternal Hb AIc determined by HPLC correlated significantly with maternal nM FE/mg Hb (p <0.01). Infant G-Hb correlated with maternal G-Hb (r= 0.63, p <.005). Both infant groups were decreased compared to mothers (p <.001). Infant bloods chromatographically separated into “F” pools revealed no differences from whole blood Hb. The decreased glycosylation in fetal blood may relate to decreased fetal red cell survival and/or Hb F structure. Nevertheless, maternal hyperglycemia results in fetal hyperglycemia which glycosylates fetal hemoglobin.

Correlations and cumulative frequency distributions of maternal and newborn hematologic data.

Nonparametric correlation coefficients and cumulative frequency distributions of hematologic data and birth weight obtained from 151 mothers and most of their newborns have been analyzed. Taken overall, the data reaffirm considerable fetal autonomy in maintaining hematologic homeostasis; a dissociation was found between maternal and newborn hemoglobin (Hb) levels, there was no evidence for an effect of maternal iron deficiency on the fetus, nor was birth weight correlated with maternal Hb levels. However, the lack of significance of the latter two correlations was apparent only when three maternal-newborn pairs with alpha-thalassemia were excluded from analysis. An inverse relation was found between birth weight and Hb level in the newborn, and this was present over the entire birth weight range, rather than being restricted to small-for-gestational-age newborns.

'Minor hemoglobins': an alternative approach for evaluating glucose control in pregnancy.

'Minor hemoglobins' (Hb AI) were measured in 178 women during pregnancy and immediately postpartum by a thiobarbituric acid spectrophotometric method. The patients were classified according to an oral glucose tolerance test (GTT) and an assessment of risk factors for diabetes in normal (n = 75), probably normal (n = 72) and chemical diabetics (n = 26). 5 pregnant insulin-dependent diabetics were also studied. Hb AI was unchanged during the second and third trimesters of pregnancy and immediately postpartum (less than 6 days) in women with normal glucose tolerance. Moreover, no difference of Hb AI level was found when compared with a separate group of nonpregnant individuals (n = 15). Chemical diabetics had significantly higher mean third trimester and postpartum Hb AI than normals (p less than 0.001). The highest Hb AI levels during pregnancy were found in the insulin-dependent diabetics, although these were lower compared to a separate group of nonpregnant insulin-dependent diabetics (n = 10; p less than 0.05). During pregnancy, a significant correlation was found between Hb AI and the 2-hour value of the GTT (p less than 0.001). A positive correlation was also found between third trimester maternal Hb AI and infant birth weight (p less than 0.001). Hb AI may complement other parameters in evaluating maternal glucose tolerance during pregnancy.

223 GLYCOHEMOGLOBIN (Hb AIc): CORRELATION WITH MATERIAL BLOOD GLUCOSE CONTROL IN PREGNANCY

Hemoglobin AIc (Hb AIc), the glycosylated form (β-chain) of Hb A, normally comprises <6% of total hemoglobin, but has been found by us previously in third trimester diabetic pregnancy to be elevated (7-10%) and to correlate with infant birth weight. In contrast, non-pregnant uncontrolled diabetics have glycohemoglobin levels which may be 8-15% and may represent the integrated mean blood glucose level over the previous weeks and months. Since fetal size in infants of diabetic mothers has been related to maternal third trimester blood glucose control, we examined the relationship between third trimester maternal Hb AIc and maternal blood glucose control. Twelve diabetic women without evidence of vascular disease and with singleton births had Hb AIc levels determined in their third trimester using Amberlite cation exchange chromatography. Mean random blood glucose values (n=5-32) for each subject were determined for the twelve week period prior to Hb AIc measurement. Hb AIc correlated significantly with mean random blood glucose (r=0.84, p <0.01) as well as birth weight corrected for gestational age (r=0.78, p <0.01). In eight of these same women who required insulin, Hb AIc was determined serially 5-8 months postpartum. Seven of eight had higher Hb AIc levels postpartum (6.0±0.5 vs 8.4±0.6, M±SEM) at a time when glucose management was not accomplished. We speculate that lower levels of Hb AIc later in diabetic pregnancy are due to better blood glucose control during this period.