The influence of in-vitro culture versus stimulated and untreated oviductal environment on mouse embryo development and implantation

A prospective randomised study was performed to evaluate stimulated versus natural oviductal environment in comparison with in-vitro culture for the developmental capacity of mouse embryos. Therefore, embryos of superovulated F1 hybrid CBAxC57Bl females were collected at 17, 22, 41 and 46 h after human chorionic gonadotrophin treatment and randomly divided into five groups. They were either transferred immediately to untreated pseudopregnant females, cultured in vitro for 5, 24 or 29 h before transfer, or cultured in vitro for 96 h to blastocysts. The transfers resulted in an impaired implantation (P < 0.001) and a lower numbers of living fetuses (P < 0.001) when embryos had been exposed longer to the stimulated oviductal environment. Similar results were obtained after a longer period of in-vitro culture (P < 0.05). However when embryos were flushed earlier from the superovulated mice and cultured longer in-vitro until the transfer was performed, the implantation rate was improved (P < 0.01). Blastocyst development, however, was better (P < 0.001) when embryos were flushed later. In conclusion, the stimulated oviductal environment impairs the developmental capacity of embryos in comparison with untreated pseudopregnant females. In-vitro culture is also suboptimal but better than the stimulated oviductal environment.

Time-related cotyledonary effects of laser coagulation of superficial chorionic vessels in an ovine model

Endoscopic Nd:YAG laser coagulation of superficial chorionic plate vessels has been suggested as a 'causal' therapy for severe twin-to-twin transfusion syndrome (TTS), as it is believed to arrest flow over vascular anastomoses. The therapy remains debated, partly because it is questioned whether coagulation of superficial chorionic vessels can arrest blood flow over deeply located anastomoses. The latter are believed to be responsible for the majority of cases of severe TTs. In this study, the coagulation performance, and the immediate and delayed tissue effects of laser coagulation were evaluated in an in vivo ovine model. Eight pregnant ewes of about 100 days' gestational age (term= 145 days) were studied. In utero coagulation was done through a 1.2 mm fetoscope loaded with a 600 microm laser fibre, connected to an Nd:YAG laser in continuous mode. Superficial cotyledonary vessels were coagulated under visual control at a distance of 1 cm with a mean power of 60 watts. 31 lasered cotyledons were harvested, either immediately (n= 15), 14 days (n = 8) or 42 days (n = 8) after the surgery and evaluated by inspection and histology. Control cotyledons were either neighbouring cotyledons from the same amniotic sac (internal control) or cotyledons from another gestational-age-matched sac (external control). Immediate effects consisted of localized coagulation necrosis at the zone of laser impact with no significant histological effect at more than 2 mm distance, except tissue congestion. Long-term effects consisted of fibrosis without any vascular recanalization or tissue regeneration extending from the impact site over the whole cotyledon. All treated cotyledons underwent complete infarction over time. This study provides experimental evidence supporting that laser coagulation of superficial chorionic vessels entering a cotyledon achieves complete functional elimination of the involved cotyledon.

Pathogenesis of fetal hypomineralization in diabetic rats: evidence for delayed bone maturation

There is some evidence that fetuses of diabetic rats (FDR) are hypomineralized. To explore the pathogenic role of decreased maternal duodenal Ca absorption, fetal hypotrophy, and decreased placental calbindin-D9K, respectively, spontaneously diabetic rats fed a 1.0% Ca diet were compared with diabetic rats treated with 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] (15 ng/ 100 g) during week 3 of pregnancy, which restored duodenal calbindin-D9K concentrations to normal; with nondiabetic rats semistarved during week 3, which resulted in similar fetal hypotrophy; and with nondiabetic rats fed high cation diets (1.5% Ca-1.5% Sr and 1.5% Ca-3.5% Sr) during week 3, the latter of which repressed duodenal and placental calbindin-D9K toward concentrations measured in diabetic rats. In addition, fetal tibiae were studied histologically. Ca content was lower in 21.5-d-old FDR than in control fetuses. FDR had lower plasma osteocalcin (OC) levels and, on histomorphometry, increased hypertrophic cartilage width, indicating retarded bone maturation. Maternal 1,25(OH)2D3 treatment did not change Ca content and hypertrophic cartilage width in FDR. Fetuses of semistarved rats had plasma OC levels and hypertrophic cartilage width comparable to those of control fetuses. Fetuses of rats fed the 1.5% Ca-3.5% Sr diet were more severely hypomineralized than FDR but had higher plasma OC than both FDR and control fetuses, compatible with fetal Ca deficiency. Whereas diabetic placentas showed weak but homogeneous staining of calbindin-D9K in the labyrinth on immunohistology, degenerative zones were present in placentas of rats fed the 1.5% Ca-3.5% Sr diet. Thus, there is no mineralization defect in FDR caused by disturbed maternal duodenal Ca absorption or transplacental Ca transport, but a delay in bone maturation that is unexplained by their lower body weight.

The origin and future of placental bed research

Insights into the structural and functional relationships between maternal and fetal circulations in the human placenta require an understanding of trophoblast invasive behaviour in the uterine wall. The concept of physiologically changed spiral arteries, and the discovery of the restriction of this vascular adaptation in pre-eclamptic pregnancies, are two outstanding contributions of Professor Brosens to this field. His findings inspired different lines of research concerning regulatory mechanisms of trophoblast invasion, which eventually may have wider implications in the fields of cancerology, immunology and reproductive medicine.

Renin-like immunoreactivity in uterus and placenta from normotensive and hypertensive pregnancies

OBJECTIVES

(1) To identify the distribution of renin-like immunoreactivity in placental bed, placenta-free uterine wall, placenta, fetal membranes, and intertwin membranes obtained from normal pregnancies and (2) to compare the findings in normal pregnancies with those in pregnancies complicated by various hypertensive disorders.

STUDY DESIGN

Biopsies were taken from 31 normotensive pregnant women, eight of whom had twin pregnancies, and from 28 women with various hypertensive disorders of pregnancy. The anti-human renal renin monoclonal antibody, F37.1A1, was used for immunostaining. Histological structures were identified with standard H&E and PAS techniques, supplemented with immunostaining using the specific cell markers CD68 and cytokeratin.

RESULTS

Renin-like immunoreactivity was found in cytokeratin immunolabelled placental syncytiotrophoblast, amnionic and glandular epithelium, but most consistently in CD68 immunolabelled maternal and fetal macrophages. The distribution of renin-like immunoreactivity throughout the pregnant uterus roughly parallelled reported renin concentrations in the various tissues, while its localization conforms also with that of cathepsin D. There were no obvious differences in renin-like immunolabelling between normotensive or hypertensive women. Renin-like immunoreactivity was particularly common in the atherotic lesions that are observed more often in pregnancies complicated with hypertensive disorders of pregnancy and/or intra-uterine growth restriction.

CONCLUSIONS

The data complement earlier findings showing that only two of four anti-renal renin monoclonal antibodies, both of which cross-react with cathepsin D, give a positive immunostaining in placental tissue. They question whether classical concepts on renin localisation in uteroplacental tissues all relate to one and the same enzyme. The demonstration of renin-like enzymes in different cell types, including macrophages, may explain the diversity of functions that has been attributed to uterine renin. There were no differences between tissues obtained from normotensive and hypertensive pregnancies, except for the consistent presence of renin-like immunoreactivity in atherotic lesions.

Interaction of interstitial trophoblast with placental bed capillaries and venules of normotensive and pre-eclamptic pregnancies

While endovascular trophoblast invasion of the human placental bed spiral arteries has been studied extensively, no information is available on the interaction between interstitially invading trophoblast and uterine capillaries and venules. Placental bed biopsies of eight normotensive and 15 pre-eclamptic patients were double-immunostained for cytokeratin and the endothelial marker CD31, providing satisfactory staining results in six and 10 biopsies, respectively. Interstitial trophoblast tissue density did not differ between the two series of biopsies, implying that this pathway of invasion is not impaired in pre-eclampsia. Both groups showed a similar incidence of approach of non-arterial vascular structures by perivascular trophoblast. Differences in CD31 staining intensity were noticed in different vascular cross-sections. Lower staining intensity was related to the presence of perivascular trophoblast. Because of the identity of CD31 with the platelet-endothelial cell adhesion molecule (PECAM)-1, the trophoblast-dependent downregulation of CD31 may play a role in the control of leukocytic traffic within the placental bed. The phenomena described in this paper did not show any difference between the normotensive and pre-eclamptic patients, implying that interaction of interstitial trophoblast with venous and capillary structures is not related to the pathogenesis of pre-eclampsia.

Immunolocalization of tumour necrosis factor-alpha (TNF-alpha) in the placental bed of normotensive and hypertensive human pregnancies

To identify tumour necrosis factor (TNF)-alpha immunopositive cells, third trimester human placental bed biopsies were selected from nine normotensive control women, 16 severely pre-eclamptic patients and seven patients with pre-existing hypertension with superimposed pre-eclampsia. In addition, five first and early second trimester specimens were included in the study. Immunostaining was performed with a mouse IgG1 monoclonal antibody (J1D9) reactive specifically with human TNF-alpha (1:300 ascitic fluid), using a biotin-streptavidin-peroxidase technique. Variable staining of stromal cells was noted in all biopsies. Specimens of early pregnancy showed marked immunostaining for TNF-alpha on proliferating tips of anchoring villi, invasive interstitial cytotrophoblast (but not the multinuclear giant cells), and endovascular trophoblast invading the spiral arteries. At term, weak staining was found in trophoblast incorporated within spiral artery walls. In biopsies from pre-eclamptic patients, spiral arteries without physiological change showed very little staining except in atherotic vessels where the infiltrated lipophages often showed intense immunolabelling. The marked presence of TNF-alpha in extravillous cytotrophoblast of young specimens is suggestive of a role in early invasion. Immunostaining of foam cells in non-invaded spiral arteries in pre-eclampsia at or near-term indicates a potential role of this cytokine in the development of atherotic lesions.

Histological study of decidual spiral arteries and the presence of maternal erythrocytes in the intervillous space during the first trimester of normal human pregnancy

During the first trimester in normal human pregnancy, endovascular trophoblast migrate along the decidual spiral arteries and invade their walls to produce physiological change. There is controversy as to whether invading trophoblast plug the arteries and prevent blood flow into the intervillous space. Using light microscopy, placental bed sections from 25 first trimester gravid hysterectomy specimens were examined. From each specimen, one section was divided into equal central and peripheral compartments. Maternal red blood cells were present in the intervillous space in all specimens, in both central and peripheral areas. In total, 232 decidual spiral arteries were found, each of those represented by several cross sections, 136 in the central area and 96 in the periphery. Seventy-nine per cent had undergone physiological change (significantly more in the centre than in the periphery), 63 per cent contained scattered endovascular trophoblast, 20 per cent had plugs of trophoblast partially occluding the vessel and 17 per cent had plugs totally filling the vessel lumen. These data confirm that in the first trimester of normal pregnancy, maternal blood enters the intervillous space, total plugging of the arterial system by trophoblast is not common, and more spiral arteries undergo physiological change in the centre than in the periphery.

Detection of immunoreactive interleukin-11 in human follicular fluid: correlations with ovarian steroid, insulin-like growth factor I levels, and follicular maturity

OBJECTIVE

To prove the presence of interleukin-11 (IL-11) in the follicular fluid (FF), to determine its source and the correlation between IL-11 and fertilization outcome, follicular size, number of follicles per patient, steroids, and insulin-like growth factor-1 (IGF-I) levels.

DESIGN

Interleukin-11 levels were measured in FFs, aspirated during oocyte pickup for IVF.

SETTING

Academic hospital and research environment.

PATIENT(S)

Follicular fluid and serum were obtained with informed consent from 44 patients undergoing IVF-ET. Granulosa cells were isolated from 17 patients.

MAIN OUTCOME MEASURE(S)

We hypothesized that IL-11 might play a role in follicular development, as do other related cytokines present in FF. Interleukin-11 was measured with ELISA.

RESULT(S)

Interleukin-11 was absent in the serum but present in FF and in conditioned medium from granulosa cells. Atretic follicles had higher concentrations of IL-11. No correlation was found between IL-11 and fertilization outcome, follicular size, steroid, IGF-I, and total protein concentrations.

CONCLUSION(S)

We conclude that IL-11 is present in FF. The role of IL-11 in follicular development should be the object of further investigations.

Expression of stromelysin-3 in the human placenta and placental bed

Human placentation is mediated by fetal trophoblastic cells which penetrate into the decidualized uterine endometrium. Trophoblast invasion requires the precisely regulated secretion of specific proteinases able to degrade the endometrial basement membranes and extracellular matrix. To document further the involvement of these proteinases during human placentation, we evaluated in vivo the expression of stromelysin-3, a member of the metalloproteinase family, during the first and third trimesters of pregnancy, by means of immunohistochemistry, in situ hybridization and Northern blot analysis. Human extravillous trophoblasts invading the maternal decidua produced stromelysin-3 during both, the first and third trimesters of pregnancy, but to a lesser extent during the latter. In floating villi, stromelysin-3 expression was restricted to the syncytiotrophoblasts that line intervillous vascular spaces. In conclusion, stromelysin-3 is expressed by differentiated, non-proliferative villous and extravillous trophoblastic cells in early and late placental beds and villi, and its pattern of expression evolves during pregnancy. Our observations suggest that stromelysin-3 could play a role in human placentation.

Quantitative differences in arterial morphometry define the placental bed in preeclampsia

The purpose of this study was to quantitatively analyze normal and preeclamptic uteroplacental vasculature. Myometrial arteries from eight placental bed biopsies from uncomplicated term deliveries and 12 from proteinuric preeclampsia were characterized as uteroplacental, spiral, or basal arteries. Basal lumens within 0.2 mm radius and spiral/uteroplacental lumens within 0.4 mm radius were considered as the same artery. The biopsy area, lumen density, and arterial density (after correction for multiple lumens), lumen area, lumen perimeter, mean wall thickness, inflated diameter, and a slant factor, measuring the obliqueness of arterial transection, and ratios of lumen characteristics to mean wall thickness were analyzed. In preeclamptic cases, there were more basal lumens/mm2 and basal arteries/mm2 (P=.003, P=.03), and more spiral lumens/mm2 and spiral arteries/mm2 (P = .01, P = .03). Basal lumen area (P = .0003) and wall thickness (P = .007), and basal and spiral artery lumen perimeters and inflated diameters (for each, P = .0001, P = .048, respectively) and inflated diameter/wall ratios (P = .04, P = .05) were reduced compared with normal cases. Preeclamptic spiral and basal arteries are more tortuous or densely distributed than normal placental bed arteries, with smaller-caliber lumens and thicker walls. Failure of proper placentation may result in abnormal spatial anatomy in the placental bed. Alternatively, an anatomic variant of spiral and basal arteries may be more susceptible to hemodynamic stresses and endothelial damage and may predispose to preeclampsia.

Evaluation of trophoblast invasion in placental bed biopsies of the baboon, with immunohistochemical localisation of cytokeratin, fibronectin, and laminin

Biopsies of placentas (n = 21), placental bed (n = 17) and decidua (n = 26) of various gestation periods (30 to 140 days) were used to study trophoblast invasion in the baboon. Application of immunohistochemical staining for cytokeratin allowed proper identification of trophoblast. Earlier reports showing restricted trophoblast invasion in this species were confirmed by the finding that endovascular trophoblast was present in only one third of biopsies containing spiral arteries. Moreover, immunostaining for cytokeratin revealed that in several arteries only a few isolated trophoblastic cells were present, while the vessel had not undergone the normal physiological change. Trophoblast invasion could only be detected within decidual, but not in myometrial, segments of spiral arteries. Interstitial trophoblast invasion was very limited and multinuclear giant cells were absent. Immunohistochemical staining suggested a contribution of laminin to the fibrinoid deposition within the physiologically changed spiral arteries, while fibronectin was present intracellularly in the invaded trophoblast. Because of differences in the trophoblast invasion pattern, the baboon cannot be regarded as a satisfactory experimental model to explore results of inadequate endovascular trophoblast invasion which, in the human, leads to pregnancy complications such a preeclampsia.

Attachment and differentiation in vitro of trophoblast from normal and preeclamptic human placentas

OBJECTIVE

Trophoblast from preeclamptic patients shows impairment of various functions, including restricted invasive behavior of extravillous trophoblast. In this light the effect of different matrix components on attachment and differentiation of primary trophoblast cultures derived from normal and preeclamptic pregnancies was investigated.

STUDY DESIGN

Trophoblast was isolated from placentas of normotensive (n = 5) and preeclamptic patients (n = 5) and cultured up to 7 days on LabTek slides precoated with fibronectin, laminin, or vitronectin. Attachment was evaluated 24 hours after plating, the degree of syncytialization was evaluated, and slides were immunocytochemically stained for cytokeratin, vimentin, human chorionic gonadotropin, and human placental lactogen.

RESULTS

Trophoblast from placentas of preeclamptic patients showed a significantly lower attachment on fibronectin and vitronectin compared with controls. Diminished multinuclear cell formation was found on uncoated and laminin-coated slides in preeclamptic cases. No difference was found in the percentage of human chorionic gonadotropin- and human placental lactogen-positive cells between groups.

CONCLUSIONS

Lower trophoblast attachment on fibronectin and vitronectin was observed in preeclamptic pregnancies, which may reflect differences in expression of matrix receptors. Lower syncytialization of trophoblast in this group indicates an intrinsic defect in differentiation, but otherwise no differences were found in differentiation between normotensive and preeclamptic patients.

Renin-like immunoreactivity in human placenta and fetal membranes

Five antibodies that stained renin in the kidney were used to investigate the presence of renin in human placenta and fetal membranes. Despite a large number of experimental approaches to enhance penetration of the immunoglobulins, only two of them showed immunostaining in placenta and fetal membranes. Staining was found in placental syncytiotrophoblast, the amnionic epithelium overlying the placenta, and in glandular epithelial cells present in the decidua adhering to the fetal membranes. It was most consistent, however, in a small infiltrating cell type dispersed through the fetoplacental layers. The two antibodies that revealed immunostaining in all preparations showed high affinity cross-reactivity with cathepsin D. Among other, less plausible, explanations, this raises the possibility that the bulk of 'renin' found in placenta and fetal membranes is not identical to renal renin, but may be cathepsin D or a substance related to both cathepsin D and renin.

Identification of 'renin'-containing cells in the choriodecidua

Chorionic trophoblast, decidual cells, and macrophages have all been named as the site of renin in the placental membranes. To establish more clearly the nature of the renin-containing cells in the placental membranes, double immunostaining techniques were used to stain renin and specific cell markers in the same tissue sections. Cytokeratin was selected as an ectodermal cell marker and CD68 as a cytoplasmic macrophage marker. Cross-binding between antibodies was prevented by blocking species-related binding sites between the first and second sequence of the double-immunostaining procedures and by using highly selective immunostaining techniques in the second sequence. The results clearly show renin immunostaining in CD68-positive macrophages and not in cytokeratin-positive trophoblast. The anti-renal renin monoclonal antibody showed high affinity cross-reactivity with cathepsin D, another aspartic proteinase that can release angiotensin I from angiotensinogen. This should be seen in the context of earlier findings that only two of four anti-renal renin monoclonal antibodies showed staining in uterine and placental tissues and both cross-reacted with cathepsin D. The results indicate that differentiation between renin and cathepsin D and, possibly, other substances with shared properties and epitope homology deserves more attention than it has received thus far.

A study of placental bed spiral arteries and trophoblast invasion in normal and severe pre-eclamptic pregnancies

OBJECTIVE

To investigate trophoblast invasion and vascular changes in placental bed spiral arteries in normal and severe pre-eclamptic pregnancies.

DESIGN

A histological and immunohistochemical study of placental bed biopsies containing spiral arteries.

SETTING

The University Hospital, Leuven, Belgium.

SUBJECTS

Twenty-one placental bed biopsies from 21 normal pregnancies and 24 placental bed biopsies from 24 severe pre-eclamptic pregnancies, taken at caesarean section.

OBSERVATIONS

Histological and immunohistochemical appearance of spiral arteries (stained with haematoxylin and eosin), periodic acid schiff, and a monoclonal antibody to low molecular weight cytokeratin.

RESULTS

One hundred and twenty-seven spiral arteries were studied. In the 21 biopsies from clinically normal pregnancies at term, 100% of the decidual spiral arteries and 76% of the myometrial arteries showed trophoblast invasion. In the 24 biopsies from women with severe pre-eclampsia, trophoblast invasion was seen in 44% and 18% of the decidual and myometrial segments, respectively. Endovascular trophoblast invasion was complete, partial or isolated. A variety of morphological features was present not only in different spiral arteries from the same biopsy but also in different segments of the same artery. The vascular change most commonly associated with normal pregnancies was physiological change and subintimal thickening of both segments of the spiral arteries. In pre-eclampsia medial disorganisation and hyperplasia in the myometrial arteries and acute atherosis in decidual arteries were common.

CONCLUSION

Endovascular trophoblast did not show an all or none invasive phenomenon in normal and pre-eclamptic pregnancies. More decidual than myometrial arteries were invaded in both groups of patients, and there was a gradient in the percentage of decidual and myometrial arteries invaded from normal pregnancy to pre-eclampsia. Morphological features in one spiral artery may not necessarily be representative of all of those in a placental bed.

Immunohistochemical detection of lipoprotein(a) in the wall of placental bed spiral arteries in normal and severe preeclamptic pregnancies

In normal pregnancy trophoblast invades the spiral arteries and produces the physiological fibrinoid degeneration of the vessel wall. In pre-eclampsia, physiological change is restricted and pathological change develops in the non-invaded arteries, including acute atherosis. This study was undertaken to determine if lipoprotein(a) [Lp(a)], which is associated with atherogenesis is present in the wall of spiral arteries that have undergone physiological and pathological change. One hundred and sixteen spiral arteries were examined from 18 normal and 24 severe pre-eclamptic pregnancies. Lp(a) was detected in all atherotic and necrotic lesions, in 57% of spiral arteries with medical disorganization or hyperplasia, and in 45% of those with physiological change. When Lp(a) was detected differences were found in the amount seen: it was most in atherosis, less in necrosis, less still in medical change, and least in physiological change. For the same vascular change generally more Lp(a) was detected in the pre-eclamptic group than in the normal group. The detection of Lp(a) helps to distinguish physiological fibrinoid from atherotic and necrotic fibrinoid. Many atherotic and necrotic areas initially overlooked using standard histology were highlighted using immunohistochemistry. Atherosis can develop in spiral arteries that have been invaded by trophoblast. In those with pre-eclampsia, atherosis was found in 56% of decidual but only in 8% of myometrial spiral arteries. Small areas of necrosis were common in physiologically changed arteries from normal pregnancies.

The age of pronucleate mouse ova influences their development in vitro and survival after freezing

The influence of pronuclear age on embryo development in vitro and on survival and post-thaw development after cryopreservation was investigated. Pronucleate mouse ova were removed from the oviductal environment at three different times: 18 h after human chorionic gonadotrophin (HCG) (just after fertilization), 23 h after HCG (during DNA replication) and 28 h after HCG (just before cleavage). Control ova were either cultured in vitro or transferred in vivo without any treatment or exposed to dimethyl sulphoxide (DMSO) or 1,2-propanediol (PROH) before culture, but without cryopreservation. The effect on survival was evaluated by the development in vitro and in vivo after ultrarapid freezing in 3.5 M DMSO and after slow programmed freezing in 1.5 M PROH. In vitro, the development of control ova to blastocysts was 39, 54 and 77% per treated ovum at 18, 23 and 28 h after HCG, respectively. The survival rate was 78, 92 and 96% after ultrarapid freezing and 69, 90 and 81% after slow freezing, respectively. The subsequent rate of development to blastocysts per survived ovum was 21%, 35% and 62% after ultrarapid freezing and 38, 54 and 63% after slow freezing. In vivo, however, the pronuclear age did not influence the implantation rate or the number of living fetuses per transferred ovum, for neither the control, nor the frozen/thawed ova. The implantation rate and the numbers of living fetuses were not significantly different for frozen/thawed and control ova. In conclusion, early pronucleate mouse ova have a lower developmental capacity in vitro and a lower survival rate after freezing and thawing than pronucleate mouse ova just before cleavage.(ABSTRACT TRUNCATED AT 250 WORDS)

Placental bed spiral arteries in the hypertensive disorders of pregnancy

OBJECTIVE

The investigation of the histology of the placental bed spiral arteries in normal pregnancy and in pregnancies complicated by hypertension, with or without proteinura.

DESIGN

An observational study, based on women having caesarean sections for clinical reasons.

SUBJECTS

17 normal pregnant women, 43 with gestational hypertension, of whom 39 had proteinuria, 17 with chronic hypertension, of whom 6 had proteinuria, and 5 with unclassified hypertension.

INTERVENTIONS

Placental bed biopsies obtained during caesarean section.

MAIN OUTCOME MEASURES

Histological appearance of sections stained with haematoxylin and eosin PAS and Lendrum's MSB.

RESULTS

Biopsies containing spiral arteries were obtained from 6 normotensive and 44 hypertensive women. Trophoblastic invasion was present in 5 of the 6 normotensive biopsies but absent in the majority of those with hypertension. Subintimal proliferation was seen in all the normotensive biopsies but in only 8 of 28 from those with gestational hypertension and proteinuria. Other features seen predominantly or only in the hypertensive biopsies, in order of frequency, were medial hyperplasia, fibrin deposits, acute atherosis, endothelial vacuolation and thrombosis.

CONCLUSION

Absence of physiological changes may not be peculiar to preeclampsia but may be associated or even a result of various forms of hypertension in pregnancy. Spiral arteries show a spectrum of changes in hypertensive pregnancies that do not appear to bear a clear-cut relation to the clinical signs.