Endocrinol. Japon. 1983, 30 (2), 155-162

Unconjugated , and Total Estriol in Maternal Peripheral Vein, Cord Vein, and Cord Artery Serum at Delivery in with Intrauterine Growth Retardation.

CHIKAYUKI, TAYAMA, SHUNZO ICHIMARU, MASAHARU ITO, MICHIO NAKAYANA, MASAO MAEYAMA AND ISAO MIYAKAWA

Department of Obstetrics and Gynecology, Kumamoto University Medical School, Kumamoto 860 and *Department of Obstetricts and Gynecology, Miyazaki Medical College, Miyazaki

Abstract

The levels of unconjugated estradiol(E2), estriol (E3) and total (conjugated plus unconjugated) E3 in maternal vein serum during labor, cord vein serum, and cord artery serum were measured in normal singleton and twin pregnanceis with appropriate for dates babies (AFD) and with light for dates babies (LFD). The mean level of total E3 in the maternal vein serum in singleton was significantlylower in the LFD group than in the AFD group, but no differenceswere seen in the mean levels of unconjugated E2 or E3 between the groups. The concentration of uncon- jugated E2 in the maternal vein serum was significantlyhigher in the twin group with a large placenta than in the singleton group with a small placenta, while the concentration of total E3 in the case of twin pregnancy with LFD was lower than that in singleton pregnancy with AFD but not significantly. No difference in the concentration of total E3 was observed between the cord vein serum and cord artery serum. The present data suggest that the total E3 level in maternal vein serum may be used in evaluating fetal states such as intrauterinegrowth retardation.

In pregnancy complicated by intrauterine conjugated E2 and E3 into the maternal and growth retardationwith or without symptoms fetal circulation and to determine the total of maternal disease,such as toxemia of pre- (conjugated plus unconjugated) E3 in the gnancy or hypertension,not only the urinary maternal and fetal blood. As far aware, no E3 excretion (Aubry et al.,1970; Bell et al., comparative study on pregnancy with in- 1967; Greene et al.,1969) but also the levels trauterine growth retardation between sin- of serum unconjugated E3 (Gorwill and gletons and twins has yet been reported. Sarda, 1977) or total E3 (Klopper et al., 1975) are lower than normal. These obser- Materials and Methods vations indicatethat maternal E3 levels may be used to monitor such high-riskpregnan- Clinicalsubjects. cies,although the issue stillremains con- The patients under study comprised 11 singleton troversial. and 3 twin pregnancies who at clinicalexamination The purpose of the present study was to were thought probably to have fetuses with intra- uterinegrowth retardation. This was confirmed post investigatethe placental secretion of un- partum, when at delivery the neonates were on the weight/gestationalage curve of Gruenwald (Gruen- Received November 4, 1982. wald, 1966) at or lower than the tenth percentile, Endocrinol. Japon. 156 TAYAMA et al. April 1983 i.e. light for dates babies (LFD). Labor occurred fuged. The serum was stored at -20℃ until assay. at or after 37 weeks of gestation. All the patients revealed neither toxemias of pregnancy nor any Radioimmunoassay of serum . other definable medical complication. As a control Serum unconjugated E2 was determined in dupli- group, 11 normal singleton and 8 twin pregnancies cate using an Estradiol RIA kit (tracer: 3H) obtained without definable medical complications were selected. from Commissariat a l'Energie Atomique, Gif-sur- Each patient delivered appropriate for dates babies Yvette, France. Serum unconjugated E3 and total (AFD) at or after 37 weeks of gestation. E3 were determined in duplicate using an Oestriol Maternal peripheral vein blood samples were (unconjugated) RIA kit and an Oestriol RIA kit obtained during labor. Cord artery and vein samples obtained from the Radiochemical Centre, Amersham, were collected from an isolated segment of the cord Buckinghamshire, England (Miyakawa et al., 1978; immediately after fetal delivery. The blood was Ichimaru et al., 1980). allowed to clot at room temperature, and then centri-

Table 1. Clinical data for patients with AFD and LFD in 22 cases of singleton pregnancy.

*: n .s.; **: P<0.005.

Fig. 1. Concentrations of unconjugated estradiol in the maternal peripheral vein, cord vein, and cord artery serum at delivery in normal pregnancies with AFD and LFD. MV: Maternal vein, CV: cord vein, CA: cord artery. Open columns: AFD, hatched columns: LFD. Figures in parentheses indicate the numbers of cases. Vertical lines with bars indicate mean ±SEM. Vol.30, No.2 SERUM IN PREGNANCY WITH IUGR 157

Table 2. Clinical data for patients with AFD and LFD in 11 cases of twin pregnancy.

†: Apgar score at 3min., ††: Total weight, *: n.s., **: P<0.005.

AFD and LFD at birth were 63.9±7.2 and 57.6±6.0nmol/l(mean±SEM), respectively. Result The values for the cord artery serum were 25.3±4.2 and 24.2±4.7nmol/l(mean±SEM), Clinical data for the patients are given respectively, and were significantly lower in Tables 1 and 2. I. Singleton pregnancy. than those in the cord vein (P<0.005 and

P<0.005, respectively). However, no sig- Unconjugated E2 concentrations in maternal nificant differences were seen in the cord peripheral vein serum during labor and in vein and artery among the groups. cord vein and artery serum of the infant at birth (Fig. 1). Unconjugated E3 concentrations in maternal

The 11 women with AFD had serum un- peripheral vein serum during labor and in conjugated E2 concentrations ranging from cord vein and artery serum of the infant at 33.4 to 114.2nmol/l (mean±standard error birth (Fig. 2). of the mean (SEM)=74.9±6.6nmol/l). The The serum unconjugated E3 concentra- serum unconjugated E2 concentrations in 9 tions in the 11 women with AFD during women with LFD ranged from 30.5 to 98.0 labor ranged from 35.0 to 100.6nmol/l

nmol/l (mean±SEM=72.7±7.6nmol/l). (mean±SEM=51.7±7.2nmol/l), and the There was no significant difference between values in the 11 women with LFD ranged the two groups. The unconjugated E2 con- from 1.25 to 104.0nmol/l (mean±SEM= centrations in the cord vein serum of the 47.4±7.5nmol/l). There was no significant Endocrinol. Japon. 158 TAYAMA et al. April 1983

Fig. 3. Concentrations of total (conjugated plus Fig. 2. Concentrations of unconjugated estriol in unconjugated) estriol in the maternal peripheral the maternal peripheral vein, cord vein, and cord vein, cordvein, and cord artery serum at delivery artery serum at delivery in normal pregnancies in normal pregnancies with AFD and LFD. with AFD and LFD. MV: Maternal vein, CV: cord vein, CA: cord MV: Maternal vein, CV: cord vein, CA: cord artery. Open columns: AFD, hatched columns: artery. Open columns: AFD, Hatched columns: LFD. Figures in parentheses indicate the num- LFD. Figures in parentheses indicate the numbers bers of cases. Vertical lines with bars indicate of cases. Vertical lines with bars indicate mean mean±SEM. *: P<0.005. ±SEM. difference between the groups. The un- the values in the cord artery were 7574.2± conjugated E3 concentrations in the cord 718.6nmol/l and 6300.6±602.8nmol/l (mean vein serum of the AFD and LFD at birth ±SEM), respectively. No significant differ- were 651.5±72.4nmol/l and 571.8±67.7 ences were in the cord vein and artery nmol/l (mean±SEM), respectively. The val- among the groups. It is interesting also that ues in the cord artery serum were 327.0± no significant difference in total E3 values 34.8nmol/l and 290.6±37.3nmol/l (mean± was found between the cord vein and artery SEM), respectively, and significantly lower serum. I1. Twin pregnancy. than those in the cord vein (P<0.005 and P<0.005, respectively). However, no sig- nificant differences were seen in the cord and artery among the groups.

Total (conjugated plus unconjugated) E3 con- centrations in maternal peripheral vien serum during labor and in cord vein and artery serum of the infant at birth (Fig. 3). The 11 women with AFD had serum total E3 concentrations ranging from 527.0 to 1338.4nmol/l (mean±SEM=813.1±67.0 nmol/l). The serum E3 concentrations in the 11 waman with LFD ranged from 216.7 to 669.2nmol/l (mean±SEM=406.0±41.3 Fig. 4. Concentrations of unconjugated estradiol in the maternal peripheral vein, cord vein, and cord nmol/l), and were significatly lower those artery serum at delivery in normal twin preg- found in the maternal serum with AFD (P< nancies with AFD and LFD. 0.005). The total E3 concentrations in the MV: Maternal vein, CV: cord vein, CA: cord cord vein serum of the AFD and LFD at artery. Open columns: AFD, hatched columns: LFD. Figures in parentheses indicate the numbers birth were 7245.1±642.1nmol/l and 6158.5± of cases. Vertical lines with bars indicate mean 535.1nmol/l (mean±SEM), respectively, and ±SEM. 159 Vol.30, No.2 SERUM ESTROGEN IN PREGNANCY WITH IUGR

Unconjugated E2 concentrations in maternal peripheral vien serum during labor and in cord vein and artery serum of the infants at birth (Fig. 4). The weights of the placentae in the twin pregnancies with LFD (896.7±27.2g) were significatly larger than those in the singleton pregnancies with AFD (609.1±15.3g) (P <0.005). The unconjugated E2 concen- trations in 6 women with twin AFD and in the 3 women with LFD were 114.2±4.7 nmol/l and 117.5±7.4nmol/l (mean±SEM), Fig. 5. Concentrations of unconjugated estriol in the maternal peripheral vein, cord vein, and cord respectively, and were significatly higher artery serum at delivery in normal twin preg- than those found in singleton pregnancy nanceis with AFD and LFD. women (P<0.005 and P<0.01, respec- MV: Maternal vein, CV: cord vein, CA: cord tively). There was no difference between artery. Open columns: AFD, hatched columns: LFD. Figures in parentheses indicate the numbers the twin groups. The unconjugated E2 of cases. Vertical lines with bars indicate mean concentrations in the cord vein serum of 15 ±SEM. AFD and the 6 LFD were 37.8±1.9nmol/l and 35,2±2.9nmol/l, respectively. The values in the cord artery serum were 13.2 142.2±44.9nmol/l (mean±SEM), respec- ±1.3nmol/l and 20.2±3.8nmol/l, (mean± tively. No significant differences were found SEM), respectively, and were significantly between the cord vein and artery serum lower than those in the cord vein (P<0.005 among the groups.

and P<0.005, respectively). However, no significant differences were seen in the cord Total (conjugated plus unconjugated) E3 vien and artery among the groups. It is concentrations in maternal peripheral vein interesting to note that the concentration of serum during labor and in cord vein and unconjugated E2 in the maternal peripheral artery serum of the infants at birth (Fig. 6.) vein serum was 3times that in the cord vein The 8 women with twin AFD had serum serum. total E3 concentrations ranging from 655.3 to 2211.1nmol/l (mean±SEM=1231.0± Unconjugated E3 concentrationsin maternal 190.3nmol/l), which were significantly higher peripheral vein serum during labor and in than those found in wemen with singleton cord vein and artery serum of the infantsat AFD (F<0.05). The total E3 concentration birth (Fig. 5). in the 3 women with LFD was 686.5± The unconjugated E3 concentrations in 195.0nmol/l (mean±SEM), which was lower the 8 women with AFD and in the 3 women than those found in women with twin AFD with LFD during labor were 83.6±7.7nmol/l but not significantly. The total E3 con- and 66.9±7.Onmol/l (mean±SEM), respec- centrations is the cord vien serum of 15 tively, and there was no significant differ- AFD were 8098.8±357.5nmol/l (mean± ence between the group. The unconjugated SEM), which were significantly higher than E3 concentration in the cord vien of 15 those found in the 6 LFD (mean±SEM AFD and the 6 LFD at birth were 515.3 =6113.7±675.3nmol/l) (P<0.025). The

±43.4nmol/l and 368.2±66.9nmol/l (mean values in the cord artery were 8701.1±362.2 ±SEM), respectively, and the volues in the nmol/l and 5366.2±413.9nmol/l (mean± cord artery serum 184.1±26.1nmol/l and SEM), respectively, and the former was sig- Endocrinol. Japon. 160 TAYAMA et al. April 1983

DHAS on estrogen levels in and serum in late pregnancy with live anencephalic fetuses. In 3 patients between 1 and 12h after i.v. administration of DHAS (100-200 mg), the concentrations of unconjugated , estradial and estriol increased to 13.5, 6.8 and 3.1times the control values, respecitvely. On the other hand, in 2 pati- ents between 1 and 12h or more after the injection of DHAS (200mg) intra-amioti- cally, the concentrations of unconjugated Fig. 6. Concentration of total (conjugated plus un- conjugated) estriol in the maternal peripheral vein, serum estrogens increased progressively, and cord vein, and cord artery serum at delivery in the maximal level of serum estriol was 9.8 normal twin pregnancies with AFD and LFD. times the control values, while those of MV: Maternal vein, CV: cord vein, CA: cord estrone and estradiol were 4-6times the artery. Open columns: AFD, hatched columns: LFD. Figures in parentheses indicate the numbers control values, respectively. We suggested of cases. Vertical lines with bars indicate mean that in late human pregnancy DHAS in the ±SEM. circulation of the mother is converted to *: P<0 .025, **: P<0.05. estriol largely via the phenolic pathway

(DHAS→estrone→estriol), whereas DHAS circulating within the fetoplacental com- nificantly higher than the latter (P<0.05). ponent is converted to estriol via both the However, no significant difference in total phenolic and the neutral intermediates. E3 values was found between the cord vein The present finding that the unconjugated and artery seum. E2 level in maternal vein serum in LFD

pregnancy at delivery did not differ from that in AFD pregnancy (not only singleton but Discussion also twin) appears to be in agreement with the theory that the main precursor of plac- From studieson the formation of estrognes ental E2 is of maternal orgin. The present during normal pregnancy by injecting of observation of no difference in the values tritum-labeledestradiol and 14C-labeleddehy- of unconjugated E2 in cord vein serum droepiandrosteronesulphate (DHAS) into the between AFD and LFD at delivery, sug- maternal circulation,Siiteri and MacDonald gests that the fetus itself does not participate (1966) found that the percentage conversion actively in the E2 production in the feto- of DHAS to E2 was 28%-45% near term . placental unit. Tulchinsky (1973) reported They suggestedthat DHAS from the maternal that the placental secretion of unconjugated side thereforerepresents an important pre- estrone and estradiol into the maternal cir- cursor for the formation of E2, i.e.appro- culation is much higher than into the fetal ximately one-halfof the total amount of E2 circulation. In the present study, the un- produced in the fetoplacentalunit is derived conjugated E2 levels in cord vein serum in from maternal DHAS. Tulchinsy and Koren- both the AFD and LFD of twin pregnancies man (1971) carried out similar studies and at delivery were significantly lower than found that maternal DHAS contributed60% those in the AFD and LFD of singleton pre- to the formation of E2. Previously, we gnancies (P<0.005 and P<0.005, respec- (Maeyama et al., 1976) studied the effect tively), although the unconjugated E2 levels of intravenous or intra-amnioticinjection of in maternal vein serum in both twin groups Vol.30, No.2 SERUM ESTROGEN IN PREGNANCY WITH IUGR 161 were significantly higher than those in the lower only in the most severely growth- singleton groups (P<0.005 and P<0.01, retarded subgroup as compared to the nor- respectively). This may be of benefit in mals. protecting the fetus from exposure to estrone It hat been demonstrated that conjugation and estradiol, which are potent estrogens. of steriodsin the fetus is an extensive and Many investigators (Frandesn and Lund- rapid process. By injecting radiolabeled wall, 1966; Klopper, 1968; Linberg et al., E3 into the fetoplacental circulation at 1974; Mathur et al., 1980; Katagiri et al., laparotomy, Haynes et al.(1964) found that 1976) have shown that E3 is produced in more than 90% of the radioactivematerial increasing amounts during pregnancy, as could be recovered from the fetus in con- much as 10-50mg E2/24hours being ex- jugated form, whereas the unconjugated do- creted in the maternal urine at term in minated the pattern in the placenta. These normal pregnancy. Clinial observations findingswere confirmed by Schwers et al.

(Bashore and Westlake, 1977; Allen and (1965) who perfused previable fetuses with Lachelin, 1978) have revealed that the E2, and by Mikhail et al. (1963) who maternal E3 levels in the urine and plasma administered E3. As for as we are aware, reflect the condition of the fetus in utero and there has been no previous study in which a decreasing E3 concentration of sustained the levels of unconjugated and total E3 low E3 concentration or sustaned low E3 in the maternal vein serum during labor, level is indicative of fetal distress. However, cord vein serum, and cord artery serum the present study demonstrated no difference were measured in normal singletonand twin in unconjugated E3 levels in maternal vein pregnancies related to intrauterinegrowth serum between AFD and LFD pregnancies. retardation. The present data reveled that The reason for this is unknown. However, the mean level of total E3 in the maternal one possible explanation is that the ratio of vein serum of singleton pregnancy was sig- unconjugated E3 to total E3 in the 11 mater- nificantlylower in the LFD group than in nal vein serums with AFD ranged from 1.1 the AFD group (P<0.005) and confirmed to 11.5% (mean±SEM=6.27±0.73%) and the finding of Klopper et al.(1975) that the was significantly lower than that in the 11 plasma E3 concentrationis significantlylower maternal vein serums with LFD ranging in women at 38weeks of gestationwho are from 4.2 to 23.1% (mean±SEM=11.95± carrying a growth retarded fetus. On the 1.7%) (P<0.01). other hand, the levelof total E3 in the cord Siiteriand MacDonald (1963) demon- vein serum was slightlylower in the LFD stratedthat approximately 90% of the E3 group than in the AFD group, but not produced in the fetoplacentalunit was de- significantly.One possible explanation for rived from fetal DHAS and that only 10% this is that the concentration of uncon- originatedfrom maternal DHAS. Contrary jugated E3 secreted into the fetal circu- to our expectations,the serum unconjugated lation,estimated in nmol per literof blood, E3 value in the cord vein serum of LFD does not differbetween AFD and LFD be- did not differfrom that in AFD. Similar cause the circulating volume of blood studies have been undertaken by Gorwill decreases in proportion to the fetal weight. and Sarda (1977), who found that the mean Another possibilityis that secretion into level of unconjugated E3 in maternal vein the fetal circulationof unconjugated E3 is, serum was significatlylower in the intrau- as estimated, only about one tenth of the terine growth retardation group than in amount secreted into the maternal circula- normals (P<0.001), whereas the mean un- tion (Tulchinsky, 1973). conjugated E3 level in cord vein serum was The finding of no differencebetween the Endocrinol. Japon. 162 TAYAMA et al. April 1983

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