The interval between pregnancies and the risk of preeclampsia

The paternal role in pre-eclampsia and giving birth to a small for gestational age infant; a population-based cohort study

OBJECTIVE

To estimate the effect of partner change on risks of pre-eclampsia and giving birth to a small for gestational age infant.

DESIGN

Prospective population study.

SETTING

Sweden.

PARTICIPANTS

Women with their first and second successive singleton births in Sweden between 1990 and 2006 without pregestational diabetes and/or hypertension (n=446 459).

OUTCOME MEASURES

Preterm (<37 weeks) and term (≥37 weeks) pre-eclampsia, and giving birth to a small for gestational age (SGA) infant. Risks were adjusted for interpregnancy interval, maternal age, body mass index, height and smoking habits in second pregnancy, years of involuntary childlessness before second pregnancy, mother's country of birth, years of formal education and year of birth. Further, when we calculated risks of SGA we restricted the study population to women with non-pre-eclamptic pregnancies.

RESULTS

In women who had a preterm pre-eclampsia in first pregnancy, partner change was associated with a strong protective effect for preterm pre-eclampsia recurrence (OR 0.24; 95% CI 0.07 to 0.88). Similarly, partner change was also associated with a protective effect of recurrence of SGA birth (OR 0.75; 95% CI 0.67 to 0.84). In contrast, among women without SGA in first birth, partner change was associated with an increased risk of SGA in second pregnancy. Risks of term pre-eclampsia were not affected by partner change.

CONCLUSIONS

There is a paternal effect on risks of preterm pre-eclampsia and giving birth to an SGA infant.

Hypertension in pregnancy

Hypertension is a common complication of pregnancy. Preeclampsia, in particular, is associated with substantial risk to both the mother and the fetus. Several risk factors have been recognized to predict risk for preeclampsia. However, at present no biomarkers have sufficient discriminatory ability to be useful in clinical practice, and no effective preventive strategies have yet been identified. Commonly used medications for the treatment of hypertension in pregnancy include methyldopa and labetalol. Blood pressure thresholds for initiating antihypertensive therapy are higher than outside of pregnancy. Women with prior preeclampsia are at increased risk of hypertension, cardiovascular disease, and renal disease.

Selenium and preeclampsia: A global perspective

Preeclampsia is a complex multisystem disorder of pregnancy where oxidative stress plays an important aetiological role. The role of selenium in the synthesis of endogenous antioxidants is well documented, and a significant reduction in selenium has been reported in preeclamptic women. The objective of this study was to map global selenium status and preeclampsia incidence. This study identified peer reviewed journal articles reporting national preeclampsia incidence (%) and matched these with reported values of selenium intake and plasma/serum selenium concentrations (μg/L). Matched data were obtained for 45 regions, reporting 6456,570 births, spanning Europe, Asia, Australasia, Africa, North and South America. Increasing plasma selenium concentration was found to be correlated with a reduction in preeclampsia incidence (Pearson's r=-0.604, P<0.0001). Countries with a reported serum/plasma selenium level of ⩾95μg/L were considered selenium sufficient and a significant reduction in preeclampsia incidence for countries above this value (P=0.0007) was noted. Significant reductions in preeclampsia incidence were found to coincide with increases in plasma/serum selenium concentration in the New Zealand (P=0.0003) and Finland (0.0028) populations following Government intervention. This study supports the hypothesis that selenium supplementation may be beneficial in reducing oxidative stress in women at risk of preeclampsia.

Cardiovascular risk in women after metabolic complications in pregnancy

Hypertensive pregnancy disorders complicate 10% of all pregnancies. In this article we discuss the spectrum of hypertensive conditions that may occur during pregnancy. Recent studies have consistently shown that hypertensive disorders in pregnancy implicate a two-fold higher risk for the development of hypertension and cardiovascular disease later in life. To optimise preventive management of cardiovascular disease in women with previous complicated pregnancies, we therefore recommend monitoring of hypertension and other cardiac risk factors at an early stage in life. Furthermore, the obstetric history should be routinely incorporated in cardiovascular risk assessment in women who seek medical attention for hypertension and/or cardiac symptoms. (Neth Heart J 2007;15:415-7.).

How does variability of immune system genes affect placentation?

Formation of the placenta is a crucial step in mammalian pregnancy. Apart from its function in ensuring an optimal supply of nutrients and oxygen to the fetus, the placenta is also the interface at which allo-recognition of invading trophoblast cells by the maternal immune system can potentially occur. We summarise here the “state of the art” on how variability of immune system genes that code for major histocompatibility complex (MHC) molecules and natural killer receptors (NKR) may impact on human placentation. MHC and NKR are the most polymorphic human genes. Our recent reports point out that specific combinations of fetal MHC and maternal NKR genes in humans correlate with the risk of pre-eclampsia, recurrent miscarriage (RM) and fetal growth restriction (FGR). Research in this field is still at an early stage and future studies in mouse and humans will be needed before the results can be translated to clinical applications. We discuss our recent work, as well as the opportunities offered by mouse genetics, to understand the cellular and molecular mechanisms underlying immune interactions at the maternal-fetal interface.

Population-based trends in pregnancy hypertension and pre-eclampsia: an international comparative study

OBJECTIVE

The objective of this study was to compare international trends in pre-eclampsia rates and in overall pregnancy hypertension rates (including gestational hypertension, pre-eclampsia and eclampsia).

DESIGN

Population data (from birth and/or hospital records) on all women giving birth were available from Australia (two states), Canada (Alberta), Denmark, Norway, Scotland, Sweden and the USA (Massachusetts) for a minimum of 6 years from 1997 to 2007. All countries used the 10th revision of the International Classification of Diseases, except Massachusetts which used the 9th revision. There were no major changes to the diagnostic criteria or methods of data collection in any country during the study period. Population characteristics as well as rates of pregnancy hypertension and pre-eclampsia were compared.

RESULTS

Absolute rates varied across the populations as follows: pregnancy hypertension (3.6% to 9.1%), pre-eclampsia (1.4% to 4.0%) and early-onset pre-eclampsia (0.3% to 0.7%). Pregnancy hypertension and/or pre-eclampsia rates declined over time in most populations. This was unexpected given that factors associated with pregnancy hypertension such as pre-pregnancy obesity and maternal age are generally increasing. However, there was also a downward shift in gestational age with fewer pregnancies reaching 40 weeks.

CONCLUSION

The rate of pregnancy hypertension and pre-eclampsia decreased in northern Europe and Australia from 1997 to 2007, but increased in Massachusetts. The use of a different International Classification of Diseases coding version in Massachusetts may contribute to the difference in trend. Elective delivery prior to the due date is the most likely explanation for the decrease observed in Europe and Australia. Also, the use of interventions that reduce the risk of pregnancy hypertension and/or progression to pre-eclampsia (low-dose aspirin, calcium supplementation and early delivery for mild hypertension) may have contributed to the decline.

The etiology of preeclampsia: the role of the father

Preeclampsia is often considered as simply a maternal disease with variable degrees of fetal involvement. More and more the unique immunogenetic maternal-paternal relationship is appreciated, and also the specific 'genetic conflict' that is characteristic of haemochorial placentation. From that perspective, pre-eclampsia can be seen as a disease of an individual couple with primarily maternal and fetal manifestations. The maternal and fetal genomes perform different roles during development. Heritable paternal, rather than maternal, imprinting of the genome is necessary for normal trophoblast development. Large population studies have estimated that 35% of the variance in susceptibility to preeclampsia is attributable to maternal genetic effects; 20% to fetal genetic effects (with similar contributions of both parents), 13% to the couple effect, less than 1% to the shared sibling environment and 32% to unmeasured factors. Not one of these large population studies focussed on the paternal contribution to preeclampsia, which is demonstrated by (1) the effect of the length of the sexual relationship; (2) the concept of primipaternity versus primigravidity; and (3) the existence of the so-called 'dangerous' father, as demonstrated in various large population studies. It is currently unknown how the father exerts this effect. Possible mechanisms include seminal cytokine levels and their effect on maternal immune deviation, specific paternal HLA characteristics and specific paternal single nucleotide polymorphisms (SNPs), in particular in the paternally expressed genes affecting placentation. Several large cohort studies, including the large international SCOPE consortium, have identified paternal SNPs with strong associations with preeclampsia.

Postpartum evaluation and long term implications

Hypertension, proteinuria and biochemical changes caused by pre-eclampsia may persist for several weeks and even months postpartum. Hypertension and pre-eclampsia may even develop for the first time postpartum. Care in the six weeks postpartum should include management of hypertension and screening for secondary causes of hypertension including renal disease if abnormalities persist beyond six weeks. Optimal postpartum monitoring for patients with preeclampsia has not been determined, and care needs to be individualized. The postpartum period also provides a window of opportunity for planning for the next pregnancy in addition to discussing long term implications of pre-eclampsia. Increased risk for the development of premature cardiovascular disease is the most significant long term implication of pre-eclampsia. Pre-eclampsia and cardiovascular disease share a common disease pathophysiology. Women who develop pre-eclampsia have pre-existing metabolic abnormalities or may develop them later in life. Women with early onset pre-eclampsia are at the highest risk of ischemic heart disease. Women with a history of pre-eclampsia should adopt a heart healthy lifestyle and should be screened and treated for traditional cardiovascular risk factors according to locally accepted guidelines.

Influence of the couple on hypertensive disorders during pregnancy: A retrospective cohort study

OBJECTIVE

Our study investigates a possible couple predisposition for pregnancy-related hypertensive disorders (PRHDs).

MATERIALS AND METHODS

We selected 350 women with PRHDs and a random control cohort without PRHDs. We analyzed their clinical files and asked them and their partners about clinical information and family history for some common pathologies. Statistical bivariate and multivariate analysis was performed by R, considering significant p<0.05.

RESULTS

Familial history reveals in cases more maternal grandparents hypertension and thrombophilia, and paternal, personal and familial, thrombophilia history than in controls. By multivariate analysis, the occurrence of PRHDs is influenced by stress, maternal BMI, maternal chronic hypertension, pre-pregnancy diabetes mellitus, nulliparity, maternal grandmother and grandfather hypertension; and academic degrees is a protective factor. Selecting only multipara, PRHDs correlate with advanced maternal age, higher maternal BMI, chronic hypertension, longer interpregnancy interval, stress, previous pregnancies affected by PRHDs, and paternal, personal and familial, thrombophilia history. Moreover the multivariate logistic regression models considering parents familial and personal history results are accurate to predict PRHDs with an AUC of 79% in the general population and 82% among multiparous women.

CONCLUSIONS

The couple should be evaluated together for PRHDs risk, both parents familial history should be considered in PRHDs screening programs, and further studies are required, in a society continuously changing its characteristics and habits.

Abnormal placentation, angiogenic factors, and the pathogenesis of preeclampsia

Preeclampsia is a common complication of pregnancy with potentially devastating consequences to both the mother and the baby.It is the leading cause of maternal deaths in developing countries. In developed countries it is the major cause of iatrogenic premature delivery and contributes significantly to increasing health care cost associated with prematurity. There is currently no known treatment for preeclampsia; ultimate treatment involves delivery of the placenta. Although there are several risk factors (such as multiple gestation or chronic hypertension), most patients present with no obvious risk factors. The molecular pathogenesis of preeclampsia is just now being elucidated. It has been proposed that abnormal placentation and an imbalance in angiogenic factors lead to the clinical findings and complications seen in preeclampsia. Preeclampsia is characterized by high levels of circulating antiangiogenic factors such as soluble fms-like tyrosine kinase-1 and soluble endoglin, which induce maternal endothelial dysfunction. These soluble factors are altered not only at the time of clinical disease but also several weeks before the onset of clinical signs and symptoms. Many methods of prediction and surveillance have been proposed to identify women who will develop preeclampsia, but studies have been inconclusive. With the recent discovery of the role of angiogenic factors in preeclampsia, novel methods of prediction and diagnosis are being developed to aid obstetricians and midwives in clinical practice. This article discusses the role of angiogenic factors in the pathogenesis, prediction, diagnosis, and possible treatment of preeclampsia.

Pre-eclampsia: fitting together the placental, immune and cardiovascular pieces

The success of pregnancy is a result of countless ongoing interactions between the placenta and the maternal immune and cardiovascular systems. Pre-eclampsia is a serious pregnancy complication that arises from multiple potential aberrations in these systems. The pathophysiology of pre-eclampsia is established in the first trimester of pregnancy, when a range of deficiencies in placentation affect the key process of spiral artery remodelling. As pregnancy progresses to the third trimester, inadequate spiral artery remodelling along with multiple haemodynamic, placental and maternal factors converge to activate the maternal immune and cardiovascular systems, events which may in part result from increased shedding of placental debris. As we understand more about the pathophysiology of pre-eclampsia, it is becoming clear that the development of early- and late-onset pre-eclampsia, as well as intrauterine growth restriction (IUGR), does not necessarily arise from the same underlying pathology.

Immunology of pre-eclampsia

Pre-eclampsia develops in stages, only the last being the clinical illness. This is generated by a non-specific, systemic (vascular), inflammatory response, secondary to placental oxidative stress and not by reactivity to fetal alloantigens. However, maternal adaptation to fetal (paternal alloantigens) is crucial in the earlier stages. A pre-conceptual phase involves maternal tolerization to paternal antigens by seminal plasma. After conception, regulatory T cells, interacting with indoleamine 2,3-dioxygenase, together with decidual NK cell recognition of fetal HLA-C on extravillous trophoblast may facilitate placental growth by immunoregulation. Complete failure of this mechanism would cause miscarriage, while partial failure would cause poor placentation and dysfunctional uteroplacental perfusion. The first pregnancy preponderance and partner specificity of pre-eclampsia can be explained by this model. For the first time, the pathogenesis of pre-eclampsia can be related to defined immune mechanisms that are appropriate to the fetomaternal frontier. Now, the challenge is to prove the detail.

Pathogenesis of preeclampsia

Preeclampsia is a systemic syndrome that occurs in 3 to 5% of pregnant women and classically manifests as new-onset hypertension and proteinuria after 20 weeks of gestation. Preeclampsia is a leading cause of maternal and neonatal morbidity and mortality. The only known cure is delivery of the placenta. Recent discoveries, however, have led to important advances in understanding the pathogenesis of the condition. Placental antiangiogenic factors are upregulated and disrupt the maternal endothelium. This change in the normal angiogenic balance toward an antiangiogenic state can result in hypertension, proteinuria, glomerular endotheliosis, HELLP (hemolysis, elevated liver enzymes, and low platelets) syndrome, and cerebral edema-the clinical signs of preeclampsia and eclampsia. The regulation of these antiangiogenic factors in the placenta is unknown. The recent discoveries of upregulated antiangiogenic factors provide promise for future testing to predict and diagnose preeclampsia as well as therapeutic targets for amelioration of the clinical disease.

The role of calcium, magnesium, and zinc in pre-eclampsia

Pre-eclampsia is the most common medical complication of pregnancy associated with increased maternal and infant mortality and morbidity. Its exact etiology is not known, although several evidences indicate that various elements might play an important role in pre-eclampsia. This study was carried out to analyze and to compare the concentration of calcium, magnesium, and zinc in the serum of women with pre-eclampsia and in normal pregnant women. Fifty clinically diagnosed patients with pre-eclampsia (25 with mild and 25 with severe pre-eclampsia) and 50 normal pregnant controls were enrolled in this study. The serum calcium, magnesium, and zinc levels were estimated with an atomic absorption spectrophotometer. The mean serum levels of calcium, magnesium, and zinc in normal pregnant group were 2.45 +/- 0.18 mmol/L, 0.79 +/- 0.13 mmol/L, and 15.64 +/- 2.4 micromol/L, respectively, while in mild pre-eclamptic group, these were 2.12 +/- 0.15 mmol/L, 0.67 +/- 0.14 mmol/L, and 12.72 +/- 1.7 micromol/L, respectively. Serum levels in severe pre-eclamptic group were 1.94 +/- 0.09 mmol/L, 0.62 +/- 0.11 mmol/L, and 12.04 +/- 1.4 micromol/L, respectively. These results indicate that reduction in serum levels of calcium, magnesium, and zinc during pregnancy might be possible contributors in etiology of pre-eclampsia, and supplementation of these elements to diet may be of value to prevent pre-eclampsia.

Low birth weight, preterm birth and short interpregnancy interval in Sudan

OBJECTIVE

To investigate whether short interpregnancy interval (IPI) is associated with increased risk of low birth weight and preterm labour.

METHODS

The study was conducted in the labour ward of Khartoum hospital in Sudan during November 2007 through February 2008. Odds ratios (ORs) were adjusted for the confounding factors using multiple logistic regression models.

RESULTS

Compared with IPI of 18-30 months, those women with intervals shorter than 18 months had an increased risk of low birth weight (OR = 1.9, 95% CI = 1.0-3.5, P = 0.04) and preterm labour (OR = 2.3, 95% CI = 1.1-4.7, P = 0.01).

CONCLUSION

In this study, IPI shorter than 18 months are independently associated with increased risk of adverse perinatal outcomes.

Barrier Methods, Length of Preconception Intercourse, and Preeclampsia

BACKGROUND

The immune maladaptation theory suggests that tolerance to paternal antigens, resulting from prolonged exposure to sperm, protects against the development of preeclampsia. We tested whether barrier contraception and shorter sexual experience with the father of the pregnancy would increase the risk of preeclampsia.

METHODS

Of 2211 women delivering singleton births after enrollment in a pregnancy cohort study, 85 (3.8%) developed preeclampsia as defined by antepartum systolic blood pressure > or = 140 or diastolic blood pressure > or = 90 plus proteinuria. At a mean of 10.2 weeks of gestation, all women in the cohort were asked about preconception contraception and timing of first sexual intercourse with the father of the pregnancy. Odds ratios (OR) comparing cases with preeclampsia to the rest of the cohort were adjusted for age, smoking, parity, and body mass index (BMI).

RESULTS

Women using barrier contraception prior to conception were no more likely than women not using barrier contraception to develop preeclampsia (adjusted OR 1.0, 95% CI 0.6-1.6). In unadjusted analyses, a prolonged time to conception was associated with preeclampsia (OR 1.9), however, after adjustment, the association was less prominent (OR 1.6) and after stratification by contraception method, the link between time to conception and preeclampsia was eliminated.

CONCLUSION

These data do not support the immune maladaptation theory of preeclampsia.

Preeclampsia: the role of angiogenic factors in its pathogenesis

Preeclampsia, a systemic syndrome of pregnancy clinically characterized by new onset of proteinuria and hypertension, is associated with significant morbidity and mortality to both mothers and fetuses. The pathogenesis of preeclampsia has been enigmatic; this review will focus on understanding the origins of this disorder. Preeclampsia originates in the placenta, starting with inadequate cytotrophoblast invasion and ending with widespread maternal endothelial dysfunction. Production of placental anti-angiogenic factors, specifically soluble fms-related tyrosine kinase 1 and soluble endoglin, have been shown to be upregulated in preeclampsia. These placental anti-angiogenic factors are released into the maternal circulation; their actions disrupt the maternal endothelium and result in hypertension, proteinuria, and the other systemic manifestations of preeclampsia. The molecular basis for placental dysregulation of these pathogenic factors remains unknown, remains unknown. Hypoxia is likely an important regulator. Other factors such as alterations in the renin-angiotensin-aldosterone axis, immune maladaption, excessive shedding of trophoblast debris, oxidative stress, and genetic factors likely contribute to the pathogenesis of the abnormal placentation. As of 2009, the only successful treatment for preeclampsia is delivery. No definitive preventive strategies have been identified. However, several of the recent observations related to phenotypic causality provide stimuli for the development of novel therapies.

Duration of sexual relationship and its effect on preeclampsia and small for gestational age perinatal outcome

The aim of this study was to determine if women with preeclampsia or delivering small for gestational age (SGA) babies are more likely to have a short duration of sexual relationship compared with those who have uncomplicated pregnancies. In a prospective cohort study, 2507 nulliparous women with singleton pregnancies were interviewed at 15+/-1 weeks gestation about the duration of their sexual relationship with the biological father. Short duration of sexual relationship (< or =6 months, < or =3 months, or first intercourse) was compared between women with preeclampsia (N=131) or SGA babies (N=263) and those with uncomplicated pregnancies (N=1462). Short duration of sexual relationship was more common in women with preeclampsia compared with uncomplicated pregnancies (< or =6 months 14.5% versus 6.9%, adjusted odds ratio [adjOR] 1.88, 95% CI 1.05-3.36; < or =3 months 6.9% versus 2.5%, adjOR 2.32, 95% CI 1.03-5.25; first intercourse 1.5% versus 0.5%, adjOR 5.75, 95% CI 1.13-29.3). Although the total number of semen exposures was lower in SGA, SGA was not associated with a shorter duration of sexual relationship. On post hoc analysis, the subgroup of SGA with abnormal uterine artery Doppler at 20 weeks (N=58) were more likely to have had a short sexual relationship compared with controls (< or =6 months adjOR 2.33, 95% CI 1.09-4.98; < or =3 months adjOR 3.22, 95% CI 1.18-8.79; first intercourse adjOR 8.02, 95% CI 1.58-40.7). We conclude that compared to uncomplicated pregnancies, short duration of sexual relationship is more common in women who develop preeclampsia and women with abnormal uterine artery Doppler waveforms who deliver an SGA baby.

Women in southern Nigeria with change in paternity do not have increased incidence of pre-eclampsia

This was a prospective cohort study of women in their second pregnancies aimed at determining if there was a difference in the incidence of pre-eclampsia between those with changed paternity and those without change in paternity in an entirely black African population. Women in their second pregnancies receiving antenatal care between September 2006 and August 2007 were recruited into the study between 10 and 20 weeks' gestational age and followed up until 37 weeks' gestation. The main outcome measures included incidence of pre-eclampsia in relation to change in paternity at second pregnancy, incidence of pre-eclampsia in relation to duration of sexual cohabitation among those with changed paternity and inter-pregnancy interval. There was no significant difference in the incidence of pre-eclampsia between women who had changed paternity and those without change in paternity (3.5% vs 3.1%, p=0.835). The inter-pregnancy interval was also similar in both groups. The mean duration of sexual cohabitation was similar between women who had changed paternity that developed pre-eclampsia and those that did not develop pre-eclampsia (7.9+/-1.3 vs 7.5+/-2.1 months, p=0.531). It was concluded that Southern Nigerian women with change in paternity in their second pregnancies do not have increased incidence of pre-eclampsia.

Attitudes toward weight gain during pregnancy: results from the Norwegian mother and child cohort study (MoBa)

OBJECTIVE

To explore attitudes toward weight gain during pregnancy in women with and without eating disorders and across eating disorder subtypes, and to examine associations among weight-gain attitudes and actual gestational weight gain, infant birth weight, and infant size-for-gestational-age.

METHOD

Pregnant women (35,929) enrolled in the prospective population-based Norwegian mother and child cohort study (MoBa) provided information at approximately week 18 of gestation regarding eating disorders and weight gain attitudes. We explored these variables in women with anorexia nervosa, bulimia nervosa, eating disorder not otherwise specified, purging type, and binge eating disorder (BED).

RESULTS

The presence of an eating disorderly was associated with greater worry over gestational weight gain. In women without eating disorders, greater worry was associated with higher gestational weight gain, higher infant weights, greater likelihood of a large-for-gestational-age infant, and reduced likelihood of a small-for-gestational-age infant. Women with BED who reported greater worry also experienced higher weight gains during pregnancy.

DISCUSSION

Women with eating disorders tend to experience weight-gain-related worry during pregnancy. Early worry about gestational weight-gain may be a harbinger of high gestational gain.

Is preeclampsia an autoimmune disease?

Preeclampsia is a life-threatening hypertensive disease of pregnancy. The condition is characterized by the presence of autoantibodies that activate the major angiotensin receptor, AT(1). Research conducted during the past decade has shown that these autoantibodies activate AT(1) receptors on a variety of cell types and provoke biological responses that are relevant to the pathophysiology of preeclampsia. The introduction of these autoantibodies into pregnant mice results in hypertension, proteinuria and a variety of other features of preeclampsia including small fetuses and placentas. These findings demonstrate the pathophysiological role of these autoantibodies in preeclampsia. The biological properties of these autoantibodies can be blocked by a 7-amino acid peptide that corresponds to a specific sequence associated with the second extracellular loop of the AT(1) receptor. The fact that autoantibodies from different individuals are directed to a common epitope provides obvious diagnostic and therapeutic opportunities. Research reviewed here raises the intriguing possibility that preeclampsia may be a pregnancy-induced autoimmune condition characterized by the presence of disease-causing angiotensin receptor activating autoantibodies.

Evidence for immune cell involvement in decidual spiral arteriole remodeling in early human pregnancy

Decidual artery remodeling is essential for a healthy pregnancy. This process involves loss of vascular smooth muscle cells and endothelium, which are replaced by endovascular trophoblasts (vEVTs) embedded in fibrinoid. Remodeling is impaired during pre-eclampsia, a disease of pregnancy that results in maternal and fetal mortality and morbidity. Early vascular changes occur in the absence of vEVTs, suggesting that another cell type is involved; evidence from animal models indicates that decidual leukocytes play a role. We hypothesized that leukocytes participate in remodeling through the triggering of apoptosis or extracellular matrix degradation. Decidua basalis samples (8 to 12 weeks gestation) were examined by immunohistochemistry to elucidate associations between leukocytes, vEVTs, and key remodeling events. Trophoblast-independent and -dependent phases of remodeling were identified. Based on a combination of morphological attributes, vessel profiles were classified into a putative temporal series of four stages. In early stages of remodeling, vascular smooth muscle cells showed dramatic disruption and disorganization before vEVT presence. Leukocytes (identified as uterine natural killer cells and macrophages) were apparent infiltrating vascular smooth muscle cells layers and were matrix metalloproteinase-7 and -9 immunopositive. A proportion of vascular smooth muscle cells and endothelial cells were terminal deoxynucleotidyl transferase dUTP nick-end labeling positive, suggesting remodeling involves apoptosis. We thus confirm that vascular remodeling occurs in distinct trophoblast-independent and -dependent stages and provide the first evidence of decidual leukocyte involvement in trophoblast-independent stages.

Pregnancy and birth after kidney donation: the Norwegian experience

Reports on pregnancies in kidney donors are scarce. The aim was to assess pregnancy outcomes for previous donors nationwide. The Medical Birth Registry of Norway holds records of births since 1967. Linkage with the Norwegian Renal Registry provided data on pregnancies of kidney donors 1967-2002. A random sample from the Medical Birth Registry was control group, as was pregnancies in kidney donors prior to donation. Differences between groups were assessed by two-sided Fisher's exact tests and with generalized linear mixed models (GLMM). We identified 326 donors with 726 pregnancies, 106 after donation. In unadjusted analysis (Fisher) no differences were observed in the occurrence of preeclampsia (p = 0.22). In the adjusted analysis (GLMM) it was more common in pregnancies after donation, 6/106 (5.7%), than in pregnancies before donation 16/620 (2.6%) (p = 0.026). The occurrence of stillbirths after donation was 3/106 (2.8%), before donation 7/620 (1.1%), in controls (1.1%) (p = 0.17). No differences were observed in the occurrence of adverse pregnancy outcome in kidney donors and in the general population in unadjusted analysis. Our finding of more frequent preeclampsia in pregnancies after kidney donation in the secondary analysis must be interpreted with caution, as the number of events was low.

Birth outcomes in women with eating disorders in the Norwegian Mother and Child cohort study (MoBa)

OBJECTIVE

We explored the impact of eating disorders on birth outcomes in the Norwegian Mother and Child Cohort Study.

METHOD

Of 35,929 pregnant women, 35 reported broad anorexia nervosa (AN), 304 bulimia nervosa (BN), 1,812 binge eating disorder (BED), and 36 EDNOS-purging type (EDNOS-P) in the six months before or during pregnancy. The referent comprised 33,742 women with no eating disorder.

RESULTS

Pre-pregnancy body mass index (BMI) was lower in AN and higher in BED than the referent. AN, BN, and BED mothers reported greater gestational weight gain, and smoking was elevated in all eating disorder groups. BED mothers had higher birth weight babies, lower risk of small for gestational age, and higher risk of large for gestational age and cesarean section than the referent. Pre-pregnancy BMI and gestational weight gain attenuated the effects.

CONCLUSION

BED influences birth outcomes either directly or via higher maternal weight and gestational weight gain. The absence of differences in AN and EDNOS-P may reflect small numbers and lesser severity in population samples. Adequate gestational weight gain in AN may mitigate against adverse birth outcomes. Detecting eating disorders in pregnancy could identify modifiable factors (e.g., high gestational weight gain, binge eating, and smoking) that influence birth outcomes.

Previous abortions and risk of pre-eclampsia

BACKGROUND

The risk of pre-eclampsia is reduced for second and later births. The causes and mechanisms behind this reduction are unknown. The aim of the study was to estimate the risk of pre-eclampsia in primiparous women according to history of spontaneous and induced abortions, while controlling for several potentially confounding factors.

METHODS

The sample consisted of 20 846 primiparous women participating in the Norwegian Mother and Child Cohort Study (MoBa). Information on abortions and confounders were self-reported in postal questionnaires. The diagnosis of pre-eclampsia was retrieved from the Medical Birth Registry of Norway. Estimation and confounder control was performed with multiple, logistic regression.

RESULTS

One previous induced abortion reduced the risk moderately [odds ratio (OR) 0.84, 95% confidence interval (CI) 0.69-1.02]. Two or more induced abortions reduced the risk more significantly (OR 0.36, 95% CI 0.18-0.73). Adjustment for confounders did not change the estimates.

CONCLUSIONS

The protective effect of two prior induced abortions was similar to what is commonly seen after one birth. Spontaneous abortions may to a larger extent than induced abortions be associated with other factors, such as infertility, that may increase the risk of pre-eclampsia. Normal pregnancies interrupted in early pregnancy may induce immunological changes that reduce the risk of pre-eclampsia in a subsequent pregnancy.

Preeclampsia and the risk of end-stage renal disease

BACKGROUND

It is unknown whether preeclampsia is a risk marker for subsequent end-stage renal disease (ESRD).

METHODS

We linked data from the Medical Birth Registry of Norway, which contains data on all births in Norway since 1967, with data from the Norwegian Renal Registry, which contains data on all patients receiving a diagnosis of end-stage renal disease (ESRD) since 1980, to assess the association between preeclampsia in one or more pregnancies and the subsequent development of ESRD. The study population consisted of women who had had a first singleton birth between 1967 and 1991; we included data from up to three pregnancies.

RESULTS

ESRD developed in 477 of 570,433 women a mean (+/-SD) of 17+/-9 years after the first pregnancy (overall rate, 3.7 per 100,000 women per year). Among women who had been pregnant one or more times, preeclampsia during the first pregnancy was associated with a relative risk of ESRD of 4.7 (95% confidence interval [CI], 3.6 to 6.1). Among women who had been pregnant two or more times, preeclampsia during the first pregnancy was associated with a relative risk of ESRD of 3.2 (95% CI, 2.2 to 4.9), preeclampsia during the second pregnancy with a relative risk of 6.7 (95% CI, 4.3 to 10.6), and preeclampsia during both pregnancies with a relative risk of 6.4 (95% CI, 3.0 to 13.5). Among women who had been pregnant three or more times, preeclampsia during one pregnancy was associated with a relative risk of ESRD of 6.3 (95% CI, 4.1 to 9.9), and preeclampsia during two or three pregnancies was associated with a relative risk of 15.5 (95% CI, 7.8 to 30.8). Having a low-birth-weight or preterm infant increased the relative risk of ESRD. The results were similar after adjustment for possible confounders and after exclusion of women who had kidney disease, rheumatic disease, essential hypertension, or diabetes mellitus before pregnancy.

CONCLUSIONS

Although the absolute risk of ESRD in women who have had preeclampsia is low, preeclampsia is a marker for an increased risk of subsequent ESRD.

Effects of interpregnancy interval on blood pressure in consecutive pregnancies

The lower risk of preeclampsia observed in parous women has prompted a hypothesis that cardiovascular adaptation from a first pregnancy has ongoing benefits which contribute to a reduced risk of preeclampsia in the second pregnancy. However, how the interpregnancy interval affects mean arterial pressure (MAP) as an indicator of cardiovascular adaptation in subsequent pregnancies has not been well studied. The authors examined the effect of interpregnancy interval on MAP in consecutive pregnancies using data from the Collaborative Perinatal Project (1959-1965) and a semiparametric random-effects regression model. Prenatal MAP measurements were available for 533 women with both first and second births. MAP was lower in the second pregnancy (by approximately 2 mmHg) for very short interpregnancy intervals. However, this difference diminished when the interval increased, and it totally disappeared for intervals longer than 2 years. The authors conclude that although MAP is lower in the second pregnancy than in the first pregnancy, the effect persists for only a short time. It is therefore unlikely that mechanisms involving MAP as an indicator of cardiovascular adaptation contribute appreciably to the reduced risk of preeclampsia in subsequent pregnancies. However, it does not rule out the possibility that other mechanisms of cardiovascular adaptation persist longer.

Recurrence of preeclampsia: effects of gestational age at delivery of the first pregnancy, body mass index, paternity, and interval between births

OBJECTIVES

The purpose of this study was to establish estimates for recurrence risk of preeclampsia based on gestational age at delivery of the first pregnancy complicated by preeclampsia and to determine whether interbirth interval, paternity, and body mass index (BMI) modify that risk in women with prior preeclampsia.

STUDY DESIGN

A population-based, cohort study was conducted using data from Missouri maternally linked birth certificates. The cohort included women who had 2 singleton births between 1989 and 1997: 6157 women with preeclampsia and 97,703 women without preeclampsia at the time of their first deliveries. Data were analyzed using the Poisson regression.

RESULTS

At the time of their second delivery, 14.7% women with prior preeclampsia developed recurrent preeclampsia. The risk of recurrent preeclampsia is inversely related to gestational age at the first delivery: 38.6% for 28 weeks' gestation or earlier, 29.1% for 29-32 weeks, 21.9% for 33-36 weeks, and 12.9% for 37 weeks or more. The recurrent preeclampsia risk was fairly constant if both births occurred within 7 years. Obese and overweight women had higher risks of recurrent preeclampsia (19.3% and 14.2%), compared with women with normal BMI (11.2%). The recurrence risk did not differ according to paternity status.

CONCLUSION

The risk of preeclampsia recurrence increases with earlier gestational age at the first delivery complicated by preeclampsia and with increasing maternal BMI.

Male reproductive proteins and reproductive outcomes

Male reproductive proteins (MRPs), associated with sperm and semen, are the moieties responsible for carrying male genes into the next generation. Evolutionary biologists have focused on their capacity to control conception. Immunologists have shown that MRPs cause female genital tract inflammation as preparatory for embryo implantation and placentation. These observations argue that MRPs are critically important to reproductive success. Yet the impact of male reproductive proteins on obstetrical outcomes in women is largely unstudied. Epidemiologic and clinical observations suggest that shorter-duration exposure to MRPs prior to conception may elevate the risk for preeclampsia. A limited literature has also linked sexual behavior to bacterial vaginosis and preterm birth. We offer a clinical opinion that MRPs may have broad implications for successful reproduction, potentially involved in the composition of vaginal microflora, risks of preterm birth and preeclampsia, and success of assisted reproduction.

Preeclampsia and angiogenic imbalance

Preeclampsia is a systemic syndrome of pregnancy that originates in the placenta and is characterized by widespread maternal endothelial dysfunction. Until recently, the molecular pathogenesis of preeclampsia was largely unknown, but recent work suggests a key role for altered expression of placental antiangiogenic factors. Soluble Flt1 and soluble endoglin, secreted by the placenta, are increased in the maternal circulation weeks before the onset of preeclampsia. These antiangiogenic factors produce systemic endothelial dysfunction, resulting in hypertension, proteinuria, and the other systemic manifestations of preeclampsia. The molecular basis for placental dysregulation of these pathogenic factors remains unknown, and the role of angiogenic proteins in early placental vascular development is just beginning to be explored. These discoveries have exciting clinical implications and are likely to transform the detection and treatment of preeclampsia in the future.

Psychosocial factors associated with broadly defined bulimia nervosa during early pregnancy: findings from the Norwegian mother and child cohort study

OBJECTIVE

The purpose of the present study was to investigate the relationship between psychosocial characteristics and broadly defined bulimia nervosa during early pregnancy, including factors associated with continuation, incidence and remission.

METHOD

A total of 41 157 women completed questionnaires at approximately gestation week 18, including items on eating disorders and psychosocial characteristics as a part of Norwegian Mother and Child Cohort Study conducted by the Norwegian Institute of Public Health.

RESULTS

Incident bulimia nervosa during the first trimester was significantly associated with symptoms of anxiety and depression and low self-esteem and life satisfaction, whereas remission was significantly associated with higher self-esteem and life satisfaction. Continuation was not significantly related to any of the psychosocial variables tested.

CONCLUSION

Onset of bulimia nervosa during pregnancy is associated with mood and anxiety symptoms. Remission of bulimic symptoms and new onset of bulimia nervosa are associated with opposite profiles of self-esteem, and life satisfaction measures.

History of Fetal Growth Restriction Is More Strongly Associated With Severe Rather Than Milder Pregnancy-Induced Hypertension

We assessed whether fetal growth restriction without pregnancy-induced hypertension (PIH) is associated with the different clinical subgroups of PIH in the subsequent pregnancy. We also assessed the maternal and paternal contributions to this effect. Pairs of first and second, second and third, third and fourth, and fourth and fifth births were identified among all of the births in Norway: 137 375 pairs with same mother and father, 18 376 pairs with same mother and different fathers, and 18 916 pairs with same father and different mothers. Second births in each pair were restricted to those that occurred in 1998–2005. Odds ratios to predict early onset, severe, and mild preeclampsia and transient hypertension in the second birth from birth weight <1500 g in the first compared with 3500 to 3999 g were 13.8, 7.1, 3.5, and 2.2, respectively. Odds ratios to predict early onset, severe, and mild preeclampsia and transient hypertension from birth weight below the 2.5th percentile compared with percentiles 10.0 to 89.9 were 4.2, 2.5, 2.1, and 1.7, respectively. Men who fathered a child with low birth weight in 1 woman were not more likely to later father a PIH pregnancy in another woman. The results indicate that placental dysfunction and PIH share a genetic factor that can be expressed as fetal growth restriction in 1 pregnancy and PIH in a subsequent pregnancy. Future genetic study is needed to confirm whether the association is caused by delayed genetic expression of endothelial dysfunction and whether the clinical subgroups of PIH have different genetic backgrounds.

HAEMODYNAMIC CONTRIBUTIONS TO THE PATHOGENESIS OF PREECLAMPSIA AND ECLAMPSIA

Current hypotheses regarding the origins of preeclampsia have focused on the “Two stage model”. This model suggests that the primary steps in the pathophysiologic sequence of preeclampsia are initiated by abnormal placentation including the classic finding of abnormal trophoblast invasion of maternal decidual spiral arteries. The second stage of the sequence includes the elaboration of a single or multiple substances from these disordered placentas which contribute to the generalized maternal systemic illness, eventually manifesting as endothelial injury, hypertension and proteinuria. Recent studies have focused on the role of pro and anti-angiogenic peptides as potential placentally derived aetiologic agents in this pathophysiologic sequence, although other placental products have been highlighted in recent research. Despite the fact that this modeling of preeclampsia has widespread support significant limitations to this hypothesis can be identified.

Risk factors for preeclampsia in multiparous women: primipaternity versus the birth interval hypothesis

INTRODUCTION

To determine whether the risk of preeclampsia in multiparous women with a previous normal pregnancy is related to changing paternity or to prolonged birth interval, a retrospective study was conducted at the Lyell McEwin Health Service (University of Adelaide).

METHODS

The study included all multiparous women known to the hospital because of their preceding 1st delivery in the same hospital followed by their 2nd and/or 3rd ongoing pregnancy resulting in a delivery in the period 2001 - 2003. Case records were analyzed for birth interval, pregnancy interval, paternity and recognized risk factors such as booking weight and smoking. For the analysis both the International Society for the Study of Hypertension in Pregnancy (ISSHP) definition and the more recently introduced classification by the Australian Society for the Study of Hypertension in Pregnancy (ASSHP) were used.

RESULTS

In the 656 women in this study cohort, 148 (26.2%) women had a different partner in their 2nd and/or 3rd ongoing pregnancy. Using the ISSHP definition for preeclampsia, changing partners had an odds ratio (OR) of 1.304 (95% CI 0.43 - 3.99); using ASSHP criteria an OR of 1.556 (95% CI 0.6506 - 3721); and looking at the combined group of pregnancy-induced hypertensive disorders an OR of 1.99 (95% CI 1.01 - 3.89). A longer birth interval if anything was associated with a lower risk of preeclampsia (non-significant), whatever definition was used. Also the inter-pregnancy interval did not show a consistent relation with the risk for developing a hypertensive complication.

CONCLUSIONS

The results of this study on risk factors for preeclampsia in multiparous women appear to be in line with the primipaternity hypothesis, but are in direct contrast with the so-called birth interval hypothesis.

Prepregnancy cardiovascular risk factors as predictors of pre-eclampsia: population based cohort study

OBJECTIVE

To examine the effect of cardiovascular risk factors before pregnancy on risk of pre-eclampsia.

DESIGN

Population based prospective study.

SETTING

Linkage between a Norwegian population based study (Nord-Trøndelag health study, HUNT-2) and Norway's medical birth registry.

PARTICIPANTS

3494 women who gave birth after participating in the Nord-Trøndelag health study at baseline; of whom 133 (3.8%) delivered after a pre-eclamptic pregnancy.

MAIN OUTCOME MEASURE

Odds ratio of developing pre-eclampsia.

RESULTS

After adjustment for smoking; previous pre-eclampsia; parity; maternal age, education, and socioeconomic position; and duration between baseline measurements and delivery, positive associations were found between prepregnancy serum levels of triglycerides, cholesterol, low density lipoprotein cholesterol, non-high density lipoprotein cholesterol, and blood pressure and risk of pre-eclampsia. The odds ratio of developing pre-eclampsia for women with baseline systolic blood pressures greater than 130 mm Hg (highest fifth) was 7.3 (95% confidence interval 3.1 to 17.2) compared with women with systolic blood pressures less than 111 mm Hg (lowest fifth). Similar results were found for nulliparous and parous women. Women who used oral contraceptives at baseline had half the risk of pre-eclampsia compared with never or former users (0.5, 0.3 to 0.9).

CONCLUSION

Women with cardiovascular risk factors may be predisposed to pre-eclampsia.

Etiology of preeclampsia: maternal vascular predisposition and couple disease--mutual exclusion or complementarity?

Developed countries represent 20% of the population in the world, but only 12% of human births annually, while 98% of medical publications are issued from these areas. What we can read on preeclampsia is correct, but only for 12% of human pregnancies! In addition, reproductive patterns in the developed world, but only for the last three decades, are different from elsewhere and during the first 70 years of the 20th century. A major difference is in the number of children in families but also, and mainly, in the ages at first pregnancies in primiparae (approaching now 30 years in many developed countries). This is probably why current epidemiological data seem different than that of the 20th century. The purpose of this article is to analyse to what extent the 'primipaternity model' may give clues for the comprehension of epidemiological descriptions past and present--and, indeed, it works in many respects. However, it is evident also that a proportion of preeclampsia cases cannot be explained by paternity patterns, and vascular disease predisposition in women (diabetes, obesity, thrombophilias, etc.) evidently comes into play. For these latter, maternal age is also strongly associated with these complications. Here, we reflect on what can be respective parts of the disease in preeclamptic couples, and on preeclampsia as a marker of subjects susceptible to vascular disease.

Inadequate tolerance induction may induce pre-eclampsia

The fetus is semi-allograft to the maternal host; therefore, a system of tolerance must be present during pregnancy. Epidemiological findings support a relationship between pre-eclampsia and the failure of tolerance induction. For induction of major histocompatibility complex (MHC) class I-specific tolerance, long-term exposure to seminal fluid, which contains paternal soluble MHC class I antigens, may induce paternal MHC class I-specific tolerance. Furthermore, soluble HLA-G1, which induces the deletion of CD8(+) T-cells, and the combination of maternal killer-immunoglobulin-like receptors (KIR) on NK cells and fetal HLA-C, which affects the balance between inhibition and activation signals of NK cells, regulatory CD8(+) T cells, and regulatory NK cells, may play very important roles in the induction of MHC class I-specific tolerance. On the other hand, exposure to sperm, which express paternal HLA-DR, and trophoblastic debris, which contain intracellular fetal HLA-DR, may induce paternal MHC class II-specific tolerance. In this process, CD4(+)CD25(+) regulatory T (Treg)-cells play central roles. In this review, we discuss the relationship between the risk of pre-eclampsia and tolerance induction.

Does the fetal genotype affect maternal physiology during pregnancy?

Conventional wisdom states that associations between fetal growth and diseases in pregnancy, such as pregnancy-induced hypertension (PIH) and gestational diabetes (GDM), result from effects of the mother's genotype or environment acting on her physiology which subsequently affect the fetus. However, recent evidence from human mothers carrying macrosomic offspring with Beckwith Wiedemann syndrome and pregnant mice carrying p57(kip2)-null offspring suggest that variation in the fetal genome can modify maternal physiology to increase fetal nutrient delivery and optimise growth. These are some of the first documented examples of such effects, whereby the genome of one individual directly affects the physiology of another related individual from the same species. We propose that this mechanism is involved in the aetiology of PIH and GDM.

Risk for gastroschisis in primigravidity, length of sexual cohabitation, and change in paternity

BACKGROUND

Maternal epidemiologic similarities between gastroschisis and preeclampsia have led to the objective of evaluating the risk for gastroschisis related to primigravidity, change in paternity, and length of cohabitation, considered as risk factors for preeclampsia.

METHODS

The subjects were 288 newborns with isolated gastroschisis and 576 normal controls, matched by maternal age. They were ascertained in the Estudio Colaborativo Latino Americano de Malformaciones Congenitas hospital network of 10 South American countries between 1982 and 2005. Epidemiologic variables were compared among controls, between primigravidas and multigravidas, between multigravidas who had and had not changed partners, and between mothers with short and long cohabitation times with their partners. Risks associated with primigravidity, short cohabitation time, and changing paternity, as well as their combinations, were calculated. An eventual interaction between maternal age and the three risk factors was assessed.

RESULTS

Only a short cohabitation time showed a significant OR for gastroschisis (OR = 2.36, 95% CI: 1.52-3.66, p < .001), whereas ORs were not significant for primigravidity (OR = 1.40, 95% CI: 0.84-2.35, p = .192) nor for changing paternity (OR = 1.20, 95% CI: 0.49-3.10, p = .752). The risk was highest for multigravidas who had changed partners (OR = 8.71, 95% CI: 2.93-21.12, p < .001), followed by multigravidas who had not changed partners (OR = 3.99, 95% CI: 1.07-15.43, p = .049), and by primigravidas (OR = 3.02, 95% CI: 1.58-5.76, p = .001), all having cohabitated for a short time. Maternal age did not modify these risks.

CONCLUSIONS

Three groups at risk for a child with gastroschisis were identified, all having in common a short cohabitation time. Antigenic or "modern" lifestyle-related factors might be involved in the origin of gastroschisis.

Patterns of remission, continuation and incidence of broadly defined eating disorders during early pregnancy in the Norwegian Mother and Child Cohort Study (MoBa)

BACKGROUND

We explored the course of broadly defined eating disorders during pregnancy in the Norwegian Mother and Child Cohort Study (MoBa) at the Norwegian Institute of Public Health.

METHOD

A total of 41,157 pregnant women, enrolled at approximately 18 weeks' gestation, had valid data from the Norwegian Medical Birth Registry. We collected questionnaire-based diagnostic information on broadly defined anorexia nervosa (AN), and bulimia nervosa (BN), and eating disorders not otherwise specified (EDNOS). EDNOS subtypes included binge eating disorder (BED) and recurrent self-induced purging in the absence of binge eating (EDNOS-P). We explored rates of remission, continuation and incidence of BN, BED and EDNOS-P during pregnancy.

RESULTS

Prepregnancy prevalence estimates were 0.1% for AN, 0.7% for BN, 3.5% for BED and 0.1% for EDNOS-P. During early pregnancy, estimates were 0.2% (BN), 4.8% (BED) and 0.1% (EDNOS-P). Proportions of individuals remitting during pregnancy were 78% (EDNOS-P), 40% (BN purging), 39% (BED), 34% (BN any type) and 29% (BN non-purging type). Additional individuals with BN achieved partial remission. Incident BN and EDNOS-P during pregnancy were rare. For BED, the incidence rate was 1.1 per 1000 person-weeks, equating to 711 new cases of BED during pregnancy. Incident BED was associated with indices of lower socio-economic status.

CONCLUSIONS

Pregnancy appears to be a catalyst for remission of some eating disorders but also a vulnerability window for the new onset of broadly defined BED, especially in economically disadvantaged individuals. Vigilance by health-care professionals for continuation and emergence of eating disorders in pregnancy is warranted.

Options and limitations in studies of successive pregnancy outcomes: an overview

This paper provides a brief overview of options and limitations in studies of successive pregnancy outcomes, largely derived from the author's personal experience on Danish registries. The issues discussed here by no means constitute an exhaustive list, but aim at providing an introduction for researchers interested in this topic.