Estradiol, estriol and human placental lactogen in serum in threatened abortion

In 64 pregnant women admitted to hospital because of threatened abortion the prognostic value of estradiol-17-beta, estriol and human placental lactogen (HPL) in serum was examined. The hormones were determined by radioimmunoassay. Blood samples were taken at regular intervals during admission to hospital and subsequently until delivery. For each hormone a reference range was based on the hormone values obtained from the pregnancies that continued to viability. The study shows that the three hormones examined gave a good indication of the prognosis in threatened abortion, both separately and in combination. The best predictive values were achieved with estradiol and HPL after serial samples. Of these two hormones estradiol is to be preferred because of its fetoplacental origin.     

Dynamics of human placental lactogen

A double antibody radioimmunoassay procedure was set up to measure the human placental lactogen (HPL) in the blood of normal pregnant women. By the use of this technique the dynamics of this protein were studied. It was found that the content of HPL was the same in serum and plasma and that the blood content did not change with time of day, activity of the subject, or blood glucose level. There is a progressive rise in the blood HPL content during normal pregnancy and the level of HPL at term is not related to either the placental weight or the infant birth weight. The HPL does not cross the placental barrier and it is rapidly cleared from the maternal circulation after delivery with a half-life of only 29 minutes.     

Smoking, human placental lactogen and birth weight.

Human placental lactogen (HPL) was measured in 525 serum samples from 144 pregnant women and related to smoking habits and the birth weight of their infants. Women smoking during pregnancy were found to have a level of HPL significantly lower than the non-smokers (p less than 0.05). A significant correlation between HPL and birth weight was found (r=0.38); p less than 0.001) which remained significant when smoking was held constant (r=0.35; p less than 0.001). There was no relationship between birth weight and smoking when HPL was held constant.     

Eutopic and ectopic macromolecular human placental lactogen

Macromolecular forms of human placental lactogen have received little attention because it has been thought that such forms either compose only a small fraction of total immunoactive placental lactogen or are merely laboratory artifacts. We examined serum and placental tissue from women with normal pregnancy (first and third trimesters), serum and tissue from women with eutopic tumors (mole and choriocarcinoma), and serum from men with ectopic placental lactogen production. Samples were chromatographed on dextran gel (Sephadex G-100), and placental lactogen was measured in the fractions by radioimmunoassay. In all specimens examined, immunoactive placental lactogen was found at the void volume of the column (molecular weight greater than 150,000 daltons). This macromolecular placental lactogen comprised less than 4% of total placental lactogen in the third trimester, in mole, and in 16 of 18 first-trimester samples but was significantly higher, up to 19%, in the malignant cases. In two first-trimester placental extracts (but not in their matched sera) macromolecular placental lactogen was the dominant (greater than 45% of the total placental lactogen) immunoactive species. Authentic monomeric placental lactogen was not converted to macromolecular placental lactogen by repeated freezing and thawing. Third-trimester placental macromolecular placental lactogen was unstable; only 13% remained at the void on rechromatography. First-trimester placental macromolecular placental lactogen, on the other hand, was stable to rechromatography. The behavior of immunochemical dilutions of macromolecular placental lactogen from first-trimester placenta was similar to that of monomeric placental lactogen in the same sample. Macromolecular placental lactogen is probably not artifact, and it can comprise a large fraction of the total immunoactive placental lactogen in certain conditions.     

Predictive value of human placental lactogen determinations in pregnancy.

The relation of human placental lactogen (hPL) levels to pregnancy outcome was studied in normal and preeclamptic pregnancies, hPL determinations were performed between 38 and 44 weeks of gestation, and the results were compared with birthweight and Apgar scores in three groups. The results of hPL determinations permitted prediction of intrauterine growth retardation in all except 2 patients. The value of hPL measurement as a screening test in pregnancy is noted.     

Relationship between endometrial Arias-Stella phenomenon and concentrations of urinary chorionic gonadotropin and serum human placental lactogen.

Serum placental lactogen (HPL) and urinary chorionic gonadotrophin (HCG) were measured in 14 patients with the endometrial Arias-Stella phenomenon and in 35 comparable patients without this reaction in order to explore a possible causative relationship between the hormonal levels and the endometrial changes. The concentrations of HPL and HCG were similar in both groups of patients, indicating a lack of correlation between the levels of these two hormones and endometrial changes.     

Absence of human placental lactogen in an otherwise uneventful pregnancy.

Human placental lactogen (hPL) is commonly used in surveying the placental function during normal and pathologic pregnancies. This report describes a pregnancy where hPL could not be found in maternal serum or placental tissue. The pregnancy was in all other respects completely normal, ending with the birth of a normal baby. Some possible reasons and consequences of this unique event are discussed.     

Plasma human placental lactogen, oxytocinase, and placental phosphatase in normal and toxemic pregnancies.

A total of 625 serum samples were drawn from 400 normal and 225 hypertensive toxemic pregnant women. Each sample was simultaneously assayed for its human placental lactogen (HPL), oxytocinase (O), and placental phosphatase (PP) concentration. In addition, accurate placental and infant birth weights were determined in those cases where the serum sample was obtained within 14 days of delivery. The results showed a significant rise and correlation of each of the three proteins with increasing weeks of gestation. Although the infant birth weight was unrelated to the serum level of the three proteins, both the HPL and O concentrations were significantly correlated with the placental weight in the normal pregnancies. In both types of pregnancies, the concentration of O was significantly related to that of PP and this was also true for HPL and O and HPL and PP. In all instances O was more strongly related than PP. In the toxemic pregnancies there was a higher O and lower PP level than in normal gestations. These data suggest that placental enzyme measurements, especially O, could be clinically helpful in monitoring high-risk pregnancies.     

The distribution of placental lactogen in the human term placenta.

Serial frozen sections of human term placentae were examined by quantitative morphology and, after extraction, by a radioimmunoassay for human placental lactogen (HPL). The total quantity of HPL in the placenta was estimated as 720 mg. The amount of HPL was related to the amount of trophoblast in any area, but otherwise did not vary in different parts of the placenta. A semi-logarithmic relationship was observed between the amount of HPL and the percentage trophoblast in a section. It is suggested that the amount of HPL in a given area of the placenta is related to the blood-flow in that area.