Treatment of fetal growth retardation in utero with heparin and dipyridamole

Antithrombotic therapy for improving maternal or infant health outcomes in women considered at risk of placental dysfunction

BACKGROUND

Pregnancy complications such as pre-eclampsia and eclampsia, intrauterine growth restriction and placental abruption are thought to have a common origin related to abnormalities in the development and function of the placenta.

OBJECTIVES

To compare, using the best available evidence, the benefits and harms of antenatal antithrombotic therapy to improve maternal or infant health outcomes in women considered at risk of placental dysfunction, when compared with other treatments, placebo or no treatment.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (17 July 2012).

SELECTION CRITERIA

Randomised controlled trials comparing antenatal antithrombotic therapy (either alone or in combination with other agents) with placebo or no treatment, or any other treatment in the antenatal period to improve maternal or infant health outcomes in women considered at risk of placental dysfunction.

DATA COLLECTION AND ANALYSIS

Two review authors evaluated trials under consideration for appropriateness for inclusion and methodological quality without consideration of their results according to the prestated eligibility criteria. We used a fixed-effect meta-analysis for combining study data if the trials were judged to be sufficiently similar. We investigated heterogeneity by calculating I² statistic, and if this indicated a high level of heterogeneity among the trials included, we used a random-effects model.

MAIN RESULTS

Our search strategy identified 18 reports of 14 studies for consideration. The original review included five studies (484 women) which met the inclusion criteria, with a further five studies included in the updated review, involving an additional 655 women. The overall quality of the included trials was considered fair to good.Nine studies compared heparin (alone or in combination with dipyridamole or low-dose aspirin) with no treatment; and one compared trapidil (triazolopyrimidine).While this review identified the use of heparin to be associated with a statistically significant reduction in risk of perinatal mortality (six studies; 653 women; risk ratio (RR) 0.40; 95% confidence intervals (CI) 0.20 to 0.78), preterm birth before 34 (three studies; 494 women; RR 0.46; 95% CI 0.29 to 0.73) and 37 (five studies; 621 women; RR 0.72; 95% CI 0.58 to 0.90) weeks' gestation, and infant birthweight below the 10th centile for gestational age (seven studies; 710 infants; RR 0.41; 95% CI 0.27 to 0.61), there is a lack of reliable information available related to clinically relevant, serious adverse infant health outcomes, which have not been reported to date.

AUTHORS' CONCLUSIONS

While treatment with heparin for women considered to be at particularly high risk of adverse pregnancy complications secondary to placental insufficiency was associated with a statistically significant reduction in risk of perinatal mortality, preterm birth before 34 and 37 weeks' gestation, and infant birthweight below the 10th centile for gestational age when compared with no treatment for women considered at increased risk of placental dysfunction, to date, important information about serious adverse infant and long-term childhood outcomes is unavailable.

Antithrombotic therapy for improving maternal or infant health outcomes in women considered at risk of placental dysfunction

BACKGROUND

Pregnancy complications such as pre-eclampsia and eclampsia, intrauterine growth restriction and placental abruption are thought to have a common origin related to abnormalities in the development and function of the placenta.

OBJECTIVES

To compare, using the best available evidence, the benefits and harms of antenatal antithrombotic therapy to improve maternal or infant health outcomes in women considered at risk of placental dysfunction, when compared with other treatments, placebo or no treatment.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (March 2010).

SELECTION CRITERIA

Randomised controlled trials comparing antenatal antithrombotic therapy (either alone or in combination with other agents) with placebo or no treatment, or any other treatment in the antenatal period to improve maternal or infant health outcomes in women considered at risk of placental dysfunction.

DATA COLLECTION AND ANALYSIS

Two review authors evaluated trials under consideration for appropriateness for inclusion and methodological quality without consideration of their results according to the prestated eligibility criteria. We used a fixed-effect meta-analysis for combining study data if the trials were judged to be sufficiently similar. We investigated heterogeneity by calculating I(2) statistic, and if this indicated a high level of heterogeneity among the trials included we used a random-effects model.

MAIN RESULTS

Our search strategy identified 14 reports of 10 studies for consideration, of which five met the inclusion criteria, involving 484 women. Four studies compared heparin (alone or in combination with dipyridamole) with no treatment; and one compared trapidil (triazolopyrimidine). While there were no statistically significant differences identified for the primary outcomes following heparin treatment, it was associated with a reduction in the risk of pre-eclampsia, eclampsia, and infant birthweight less than the 10th centile for gestational age.

AUTHORS' CONCLUSIONS

The review identified no significant differences for the primary outcomes perinatal mortality, preterm birth less than 34 weeks' gestation, and childhood neurodevelopmental handicap, although the number of studies and participants was small. While treatment with heparin appears promising with a reduction in pre-eclampsia, eclampsia, and infant birthweight less than the 10th centile for gestational age, the number of studies and participants included was small, and to date important information about serious adverse infant and long-term childhood outcomes is unavailable. Further research is required.

What do we really know about autoantibody abnormalities and reproductive failure: a critical review

CONDENSATION

The diagnosis and treatment of autoantibody-associated forms of reproductive failure is critically reviewed.

OBJECTIVE

To critically evaluate the published literature in reference to autoantibody-associated forms of reproductive failure.

LOCATION

Medical School-affiliated private Infertility Center.

MATERIALS

A review of over 200 published papers reflecting on the topic.

RESULTS

Autoantibody associated reproductive failure, characterized by a decrease in fecundity and an increase in the risk of pregnancy loss, appears established. Autoantibody abnormalities, as routinely detected by standard laboratory assays, are, however, neither immunologically nor biologically specific since cross reactivities between autoantibodies are frequent and a specific autoantibody may cause a biological effect in one but not in another affected individual.

CONCLUSIONS

The evaluation of autoantibody abnormalities in all cases of suspected autoimmune-associated reproductive failure is valuable and will improve clinical care of affected patients. Clinicians need, however, to recognize the limitations of autoantibody testing and have to adjust their clinical management to the degree and quality of autoantibody evaluation available to them in their community.

Acute atherosis. A histopathological hallmark of immune aggression?

Acute atherosis is a maternal vascular lesion observed regularly in cases of pre-eclampsia and idiopathic intrauterine growth retardation. This vasculopathy is characterized by fibrinoid necrosis of the vessel wall, an accumulation of lipid-laden macrophages, and a mononuclear perivascular infiltrate. Similar vascular lesions are seen in the decidual vessels of patients with autoimmune diseases, and in renal, cardiac and hepatic homograft rejection. Immunohistochemical studies often reveal extensive vascular deposition of IgM and complement in acute atherosis-like lesions. Granular deposition of immunoglobulins and complement within the vessel walls and mononuclear perivascular infiltrate may be a histopathological hallmark of a maternal immunological aggression against fetal tissues.

Fibrinoid and trophoblastic necrosis with massive chronic intervillositis: an extreme variant of villitis of unknown etiology

A placental lesion, characterized by fibrinoid and trophoblastic necrosis with massive infiltration of the intervillous space by mononuclear cells (massive chronic intervillositis, MCI), was observed in six cases, five with intrauterine growth retardation (IUGR) and one with sudden intrauterine fetal death. Four out of six had chronic villitis of unknown etiology (CVUE) associated with this lesion, and five had lesions of anchoring villitis. In three cases, acute atherosislike lesions in spiral arteries of parietal and/or basal decidua were observed. Massive deposits of IgM, a smaller amount of C3 and Clq, and slight deposits of IgG and IgA were found in these vessels. Neither mothers nor infants had any clinical or serological evidence of infection. Cases with MCI were compared with those having CVUE without intervillositis. Patients with MCI showed lower values of infant weight, infant length, and ponderal index than controls. However, cases with MCI group showed a higher incidence of IUGR. Placentas from the MCI group had a greater number of acute atherosislike lesions than controls. Massive chronic intervillositis may represent an extreme variant of villitis of unknown etiology. A maternal immunological aggression toward fetal tissues is proposed as pathophysiological mechanism, although a nondetermined placental infection cannot be excluded.

Maternal vascular lesions in placentae of small-for-gestational-age infants

Placentae from 140 term pregnancies were studied. Seventy-four were from uncomplicated pregnancies in which the neonates were within the normal weight range for their gestational age. The remaining 66 placentae were from pregnancies whose infants were small for gestational age (SGA). In eight cases of this latter group a curettage of placental bed was performed during caesarean section. Maternal arterial vessels with absence of trophoblastic migration were observed in basal decidua and basal plate, and acute atherosis in parietal decidua, basal decidua and basal plate, all of them in cases of the SGA group. Furthermore, chronic vasculitis-like lesions were observed in the parietal decidua of three cases from the SGA group and in two others of the control group. No vascular lesions were found in cases of the control group when an infant's birthweight was above the 25th percentile of the normal ponderal range. Atheromatous-like lesions have been described in placental bed arteries in pre-eclampsia, systemic lupus erythematosus and SGA infants: this type of vasculopathy has also been described in rejection of renal transplants. Moreover, lesions similar to those found in chronic vasculitis were also described in the latter pathological entity. It is suggested that these vasculopathies may represent different steps of the same lesion. On the other hand, they may also be the expression of a maternal immunological attack on placental tissues causing a deficit of placentation, low birthweight being the consequence of this deficit.

Decreased prostacyclin production by placental cells in culture from pregnancies complicated by fetal growth retardation

Production of prostacyclin (PGI2) in vitro by human placental cells from pregnancies complicated by fetal growth retardation was significantly reduced compared with that in placental cells from normal pregnancies of either matched gestation or at term. This appeared to be due to a reduction of synthesis of PGI2 rather than to any alteration in the rate of its enzymic metabolism. Addition of oestradiol and progesterone increased PGI2 production by cells from pregnancies with fetal growth retardation in a similar manner to that by cells from first trimester pregnancies, implying that the placental cells are not irreversibly damaged by ischaemia. The decreased PGI2 production by cells of trophoblastic origin may be an aetiological factor in the thrombotic occlusion of the uteroplacental circulation which impairs fetal growth.

Factor VIII complex in normal pregnancy, pre-eclampsia and fetal growth retardation

The levels of the three components of factor VIII complex (VIII R:AG, VIII R:WF, VIII:C) were measured during normal late pregnancy, in pre-eclampsia and in pregnancies complicated by fetal growth retardation. In late normal pregnancy, there was a steady increase in factor VIII complex and the highest level was reached at delivery; in primary fetal growth retardation, the values were similar. In pregnancies complicated by pre-eclampsia, with or without fetal growth retardation, there was a significant increase of VIII R:AG VIII R:WF; the more severe the course of the disease, the greater the increase. The level of VIII R:AG-VIII R:WF appears to be an indicator of vascular pathology and it is suggested that this assessment may be of value in monitoring high risk pregnancies.

Platelet life span in pregnancies resulting in small-for-gestational age infants

Platelet number and life span were determined in the last trimester of pregnancy in 22 women who were delivered of small-for-gestational age (SGA) infants and in 21 women with infants having normal birth weights. Platelet life span was determined by means of a nonradioisotopic method involving the use of acetylsalicylic acid. Mean platelet life span was 7.2 days in women with SGA infants, which is significantly shorter than the 9.2 days found in the control group. The mean platelet count in the SGA group was 235 x 10(9)/L, whereas in the control group it was 208 x 10(9)/L. These data indicate the existence of a compensated thrombocytolytic state in pregnancies with insufficient fetal growth. This could be explained by an increased platelet consumption in the uteroplacental arterial bed.

Whole-blood fibrinolytic activity in normal and hypertensive pregnancies and its relation to the placental concentration of urokinase inhibitor

Whole-blood fibrinolytic activity was measured in 68 pregnant and 29 nonpregnant women with a sensitive, solid-state assay in which 125I-labeled fibrin was bound to polystyrene tubes. Antepartum fibrinolytic activity in 36 normotensive gravid women [234.5 +/- 29.2 (mean +/- standard error of the mean) ng fibrin lysed/30 min] was significantly (p less than 0.001) greater than that found in 28 nonpregnant normotensive women not taking oral contraceptives (63.61 +/- 7.66 ng fibrin lysed/30 min) and not different from the activity observed during the active phase of labor (198.50 +/- 16.5 ng fibrin lysed/30 min.) Normotensive pregnant patients had a significant (p less than 0.001) increase in whole-blood fibrinolytic activity (341.04 +/- 25.7 ng fibrin lysed/30 min) within the first 24 hours after delivery which persisted in measurements taken the second postpartum day. Fibrinolytic activity values before labor, in the active phase of labor, and in the first and second postpartum days in 17 patients with mild to moderate pregnancy-induced or pregd or pregnancy-aggravated hypertension were not different from those found in the normotensive group. However, patients with severe pregnancy-induced or pregnancy-aggravated hypertension had significantly (p less than 0.01) lower levels of fibrinolytic activity than normotensive patients before labor, during the active phase of labor, and on the first and second postpartum days. The placental 800 X g and 110,000 X g fractions of patients with severe hypertension had a significantly (p less than 0.001) greater capacity to inhibit "in vitro" urokinase-induced fibrinolysis than similar fractions obtained from placentas of normotensive women, and there was a significant inverse correlation (r = 0.61; p less than 0.01) between whole-blood fibrinolytic activity and urokinase inhibition by placental fractions. Our findings indicate that contrary to widely held views, fibrinolysis is extremely active in term pregnancies and during labor and that a derangement of this activity is present in cases of severe pregnancy-induced or pregnancy-aggravated hypertension.

Nonspecific decelerations in fetal heart rate during high-risk pregnancy

Solitary nonspecific decelerations in fetal heart rate occurring in three patients during antepartum cardiotocography are described. The decelerations were nonspecific in that they were neither variable nor late nor associated with maternal hypotension. All occurred in pregnancies complicated by hypertension and placental insufficiency. In the three patients described, the fetus lived for at least three days after the first nonspecific deceleration was observed. Although solitary nonspecific decelerations may indicate may indicate danger to the fetus from placental insufficiency, these decelerations should not be considered as an indication for immediate delivery.

Fetal growth retardation and the arteries of the placental bed

The morphology of the placental bed spiral arteries was studied in 68 pregnancies complicated by fetal growth retardation and in 40 pregnancies with a normally grown fetus. When the birth weight was normal the extent and depth of physiological vascular changes were normal except in those pregnancies complicated by pre-eclampsia. When the birth weight was low and the mothers were normotensive the extent and depth of physiological vascular changes were either normal or restricted, and in all patients with hypertension and a baby with low birth weight the physiological changes were restricted to the decidual segments of the spiral (uteroplacental) arteries. Acute atherosis was only found in pregnancies complicated by hypertension, particularly if there was proteinuria. We do not believe that there exists an arteriopathy which is common to hypertensive and normotensive pregnancies complicated by fetal growth retardation.

Ultrasound measurement of the fetal head to abdomen circumference ratio in the assessment of growth retardation

Fetal head and abdomen circumference measurements have been made using pulsed ultrasound techniques. The mean head to abdomen (H/A) circumference ratio with 95% confidence limits was determined in 568 normal pregnancies from 17 to 41 weeks menstrual age. The mean ratio was 1-18 at 17 weeks, but decreased slowly until 29 weeks when the ratio was 1-11; thereafter there was a sharp fall in the mean ratio to 1-01 at 36 weeks and 0-96 at 40 weeks. The H/A circumference ratio was also determined in 31 small-for-dates fetuses within one week of delivery. In all cases the fetal weight as predicted from the fetal abdomen circumference measurement was below the 5th centile weight for gestation. The ratio was above the 95th centile limit in 22 (71%) of these fetuses and evidence is presented to suggest that the H/A circumference ratio can be used to distinguish between symmetrical and asymmetrical growth retardation.

Uteroplacental vasculature

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