Partner change and perinatal outcomes: a systematic review

Earlier pregnancies in nulliparous women with current father and lower risks for preeclampsia and low-birth weight newborns

New paternity has been related to placenta-associated complications in pregnancy. We evaluated whether a lack of earlier pregnancies or deliveries with a current father are associated with the pregnancy, prenatal, and early neonatal outcomes after controlling for the most common maternal confounders in prospective birth cohort study. An online questionnaire was used to survey 4459 pregnant women from the Kuopio Birth Cohort in their third trimester. The topics included their history of paternity in current and earlier pregnancies. Data were combined with prenatal, perinatal, and early neonatal information. A multivariable logistic regression analysis was performed to compare the possible associations between selected pregnancy and early neonatal outcomes with respect to paternal change. Pregnant women with changed partners had higher rates of smoking during pregnancy and hypertension before pregnancy. In the adjusted analysis, primigravidas and nulliparous multigravidas with different father had the highest risks for preeclampsia (adjusted odds ratios (aORs) 4.46 and 2.69, respectively), low birth weight (aORs 3.15 and 2.25), and smallness for gestational age (aORs 2.23 and 2.16) compared to the parous controls. Nulliparous women who had earlier pregnancies with the current father had less preeclampsia or gestational hypertension, as well as low birth weight (aOR 0.42, 95 % confidence interval (CI) 0.21-0.82 and aOR 0.26, 95 % CI 0.08-0.87, respectively) compared to other nulliparas. Among parous women, most of the pregnancy, obstetric, and early neonatal outcomes were similar in the adjusted analysis, regardless of new changes in paternity.

Pregnancy induced displacement of preexisting microchimeric cells in the absence of maternal B and T cells

Bidirectional exchange of cells between mother and fetus occurs during pregnancy, and persistence of these genetically foreign cells establishes long-term microchimerism in both individuals after parturition. Since women can have multiple pregnancies, and all mothers were once daughters themselves, the microchimeric milieu in each woman could theoretically contain cells from a variety of origins, including from their own mothers as well as their babies from each pregnancy. Interestingly and in sharp contrast to this prediction, we recently showed preexisting populations of microchimeric cells are lost following pregnancy and associated with seeding of new fetal microchimeric cells. Complete loss of preexisting microchimeric cells in this context draws parallels to immunological rejection with synchronized elimination of cells and tissues that express defined discordant antigens. This perspective evaluates this provocative hypothesis regarding pregnancy induced rejection of microchimeric cells, including new experimental data comparing microchimerism levels in mice simultaneously lacking B and T cells before pregnancy, and after parturition with primary and secondary pregnancies.

Association between interpregnancy interval and hypertensive disorders of pregnancy: Effect modification by maternal age

BACKGROUND

Short and long interpregnancy intervals (IPI) are associated with increased risk of hypertensive disorders of pregnancy, yet whether this association is modified by maternal age remains unclear.

OBJECTIVES

To examine if the association between IPI and hypertensive disorders of pregnancy varies by maternal age at birth prior to IPI.

METHODS

We conducted a population-based cohort study of all mothers who had their first two (n = 169 896) consecutive births in Western Australia (WA) between 1980 and 2015. We estimated the risk of preeclampsia and gestational hypertension for 6 to 60 months of IPI according to maternal age at birth prior to IPI (<20 years, 20-24, 25-29, 30-34 and ≥35 years). We modelled IPI using restricted cubic splines and reported adjusted relative risk (RRs) with 95% CI at 6, 12, 24, 36, 48 and 60 months, with 18 months as reference.

RESULTS

The risk of preeclampsia was increased at longer IPIs (60 months) compared to 18 months for mothers 35 years or older (RR 2.19, 95% confidence interval (CI) 1.14, 4.18) and to a lesser extent for mothers 30- to 34 years old (RR 1.43, 95% CI 1.10, 1.84). Compared to 18 months, the risk of preeclampsia was lower at 12 months of IPI for mothers younger than 20 years (RR 0.74, 95% CI 0.57, 0.96), but not for mothers 35 years or older (RR 0.62, 95% CI 0.36, 1.07). There was insufficient evidence for increased risk of hypertensive disorders of pregnancy at shorter IPIs of <18 months for mothers of all ages.

CONCLUSIONS

Our findings challenge the "one size fits all" recommendation for an optimal IPI, and a more tailored approach to family planning counselling may be required to improve health.

Interpregnancy interval and hypertensive disorders of pregnancy: A population-based cohort study

BACKGROUND

Despite extensive research on risk factors and mechanisms, the extent to which interpregnancy interval (IPI) affects hypertensive disorders of pregnancy in high-income countries remains unclear.

OBJECTIVES

To examine the association between IPI and hypertensive disorders of pregnancy in a high-income country setting using both within-mother and between-mother comparisons.

METHODS

A retrospective population-based cohort study was conducted among 103 909 women who delivered three or more consecutive singleton births (n = 358 046) between 1980 and 2015 in Western Australia. We used conditional Poisson regression with robust variance, matching intervals of the same mother and adjusted for factors that vary within-mother across pregnancies, to investigate the association between IPI categories (reference 18-23 months), and the risk of hypertensive disorders of pregnancy. For comparison with previous studies, we also applied unmatched Poisson regression (between-mother analysis).

RESULTS

The incidence of preeclampsia and gestational hypertension during the study period was 4%, and 2%, respectively. For the between-mother comparison, mothers with intervals of 6-11 months had lower risk of preeclampsia with adjusted relative risk (RR) 0.92 (95% confidence interval [CI] 0.85, 0.98) compared to reference category of 18-23 months. With the within-mother matched design, we estimated a larger effect of long IPI on risk of preeclampsia (RR 1.29, 95% CI 1.18, 1.42 for 60-119 months; and RR 1.30, 95% CI 1.10, 1.53 for intervals ≥120 months) compared to 18-23 months. Short IPIs were not associated with hypertensive disorders of pregnancy.

CONCLUSIONS

In our cohort, longer IPIs were associated with increased risk of preeclampsia. However, there was insufficient evidence to suggest that short IPIs (<6 months) increase the risks of hypertensive disorders of pregnancy.

Association between HLA-A gene polymorphism and early-onset preeclampsia in Chinese pregnant women early-onset

Background

Preeclampsia is an idiopathic disease during pregnancy. This study explores the correlation between HLA-A polymorphism and the onset of preeclampsia.

Methods

The Illumina HiSeq2500 sequencing platform was used to genotyping HLA-A allele in venous blood DNA of 50 preeclampsia pregnant women and 48 normal pregnant women and umbilical cord blood DNA of their children of Han nationality in China. The frequencies and distributions of alleles and genotypes among the mothers and their children were compared between the two groups. The differences of frequencies and distributions of genotypes were compared between the two groups according to the mothers’ genotype compatibility.

Results

Twenty HLA-A alleles were detected in preeclampsia pregnant women and normal pregnant women; 21 HLA-A alleles were found in preeclampsia group fetuses and 22 HLA-A alleles in control group fetuses. There was no statistical difference in the HLA-A genes’ frequency between the two groups of pregnant women and their fetuses. When the sharing antigen was 1, the number of maternal-fetal pairs in the preeclampsia group was more than that in the control group; the difference was statistically significant (P < 0.05). The frequency of neither mother nor fetus carrying the HLA-A * 24: 02 gene in the preeclampsia group was significantly lower than that in the control group (P < 0.05). HLA-A gene homozygosity in fetuses of early-onset preeclampsia group was substantially higher than that of the control group (P = 0.0148); there is no significant difference in pregnant women’s genes homozygosity between early-onset preeclampsia group and the control group.

Conclusions

HLA-A * 24: 02 may be a susceptibility gene for early preeclampsia.

Risk of recurrent preterm birth among women according to change in partner

There is well-established literature indicating change in partner as a risk for preeclampsia, yet the research on the risk of preterm birth after a change in partners has been sparse and inconsistent. Using a population of California live born singletons, we aimed to determine the risk of preterm birth after a change in partner between the first and second pregnancies. The risk of preterm and early term delivery in the second pregnancy was calculated for mothers who did or did not change partners between births with the referent group as women who delivered both pregnancies at term and did not change partners. Adjusted odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated. Relative to women who delivered at 39 weeks or later in the second pregnancy and did not change partners, preterm birth risks were somewhat lower for women who changed partners between the first and second pregnancies compared to those women who did not change partners. For example, 10.6% of women who did not change partners and delivered their second pregnancy before 34 weeks also delivered their first pregnancy before 34 weeks, while 8.5% of women who changed partners delivered before 34 weeks. Findings suggest partner change may alter the risk of preterm birth.

Ectopic Trophoblast Allografts in the Horse Resist Destruction by Secondary Immune Responses

Invasive trophoblast from Day 34 horse conceptuses survives in extrauterine sites in allogeneic recipients that are immunologically naive to donor major histocompatibility complex class I antigens. The ectopic trophoblast retains its in utero characteristics, including similar lifespan, physiologic effect of its secreted product (equine chorionic gonadotropin) upon the recipient's ovaries, and induction of host immune responses. Immunologic memory has not been considered previously in this experimental system. We hypothesized that primary exposure to ectopic trophoblast would affect the recipient's immune status such that the survival time of subsequent transplants would be altered. Secondary transplant lifespans could be shortened by destructive memory responses, as has been observed in ectopic trophoblast studies in rodents, or lengthened, as occurs when male skin grafts follow multiple syngeneic pregnancies in mice. Eight mares received two closely spaced trophoblast transplants. Both grafts for each recipient were obtained from conceptuses sired by the same stallion to provide consistency in histocompatibility antigen exposure. Donor stallions were major histocompatibility complex class I homozygotes. Cytotoxic antibody production was tracked to monitor recipients' immune responses to the transplants. Detection of serum equine chorionic gonadotropin was used as a proxy for transplant lifespan. There was no significant difference between the distributions of primary and secondary transplant lifespans, despite evidence of immunologic memory. These data demonstrate that secondary ectopic trophoblast transplants in horses do not experience earlier destruction or prolonged survival following immune priming of recipients. Mechanisms responsible for the eventual demise of the transplants remain unperturbed by secondary immune responses or chronic antigenic exposure.

Inter-pregnancy interval and risk of recurrent pre-eclampsia: systematic review and meta-analysis

BACKGROUND

Women with a history of pre-eclampsia have a higher risk of developing pre-eclampsia in subsequent pregnancies. However, the role of the inter-pregnancy interval on this association is unclear.

OBJECTIVE

To explore the effect of inter-pregnancy interval on the risk of recurrent pre-eclampsia or eclampia.

SEARCH STRATEGY

MEDLINE, EMBASE and LILACS were searched (inception to July 2015).

SELECTION CRITERIA

Cohort studies assessing the risk of recurrent pre-eclampsia in the immediate subsequent pregnancy according to different birth intervals.

DATA COLLECTION AND ANALYSIS

Two reviewers independently performed screening, data extraction, methodological and quality assessment. Meta-analysis of adjusted odds ratios (aOR) with 95 % confidence intervals (CI) was used to measure the association between various interval lengths and recurrent pre-eclampsia or eclampsia.

MAIN RESULTS

We identified 1769 articles and finally included four studies with a total of 77,561 women. The meta-analysis of two studies showed that compared to inter-pregnancy intervals of 2-4 years, the aOR for recurrent pre-eclampsia was 1.01 [95 % CI 0.95 to 1.07, I(2) 0 %] with intervals of less than 2 years and 1.10 [95 % CI 1.02 to 1.19, I(2) 0 %] with intervals longer than 4 years.

CONCLUSION

Compared to inter-pregnancy intervals of 2 to 4 years, shorter intervals are not associated with an increased risk of recurrent pre-eclampsia but longer intervals appear to increase the risk. The results of this review should be interpreted with caution as included studies are observational and thus subject to possible confounding factors.

Vasopressin: the missing link for preeclampsia?

Preeclampsia is a devastating cardiovascular disorder of late pregnancy, affecting 5-7% of all pregnancies and claiming the lives of 76,000 mothers and 500,000 children each year. Various lines of evidence support a "tissue rejection" type reaction toward the placenta as the primary initiating event in the development of preeclampsia, followed by a complex interplay among immune, vascular, renal, and angiogenic mechanisms that have been implicated in the pathogenesis of preeclampsia beginning around the end of the first trimester. Critically, it remains unclear what mechanism links the initiating event and these pathogenic mechanisms. We and others have now demonstrated an early and sustained increase in maternal plasma concentrations of copeptin, a protein by-product of arginine vasopressin (AVP) synthesis and release, during preeclampsia. Furthermore, chronic infusion of AVP during pregnancy is sufficient to phenocopy essentially all maternal and fetal symptoms of preeclampsia in mice. As various groups have demonstrated interactions between AVP and immune, renal, and vascular systems in the nonpregnant state, elevations of this hormone are therefore positioned both in time (early pregnancy) and function to contribute to preeclampsia. We therefore posit that AVP represents a missing mechanistic link between initiating events and established midpregnancy dysfunctions that cause preeclampsia.

Associations of personal and family preeclampsia history with the risk of early-, intermediate- and late-onset preeclampsia

Preeclampsia encompasses multiple conditions of varying severity. We examined the recurrence and familial aggregation of preeclampsia by timing of onset, which is a marker for severity. We ascertained personal and family histories of preeclampsia for women who delivered live singletons in Denmark in 1978-2008 (almost 1.4 million pregnancies). Using log-linear binomial regression, we estimated risk ratios for the associations between personal and family histories of preeclampsia and the risk of early-onset (before 34 weeks of gestation, which is typically the most severe), intermediate-onset (at 34-36 weeks of gestation), and late-onset (after 36 weeks of gestation) preeclampsia. Previous early-, intermediate-, or late-onset preeclampsia increased the risk of recurrent preeclampsia with the same timing of onset 25.2 times (95% confidence interval (CI): 21.8, 29.1), 19.7 times (95% CI: 17.0, 22.8), and 10.3 times (95% CI: 9.85, 10.9), respectively, compared with having no such history. Preeclampsia in a woman's family was associated with a 24%-163% increase in preeclampsia risk, with the strongest associations for early- and intermediate-onset preeclampsia in female relatives. Preeclampsia in the man's family did not affect a woman's risk of early-onset preeclampsia and was only weakly associated with her risks of intermediate- and late-onset preeclampsia. Early-onset preeclampsia appears to have the largest genetic component, whereas environmental factors likely contribute most to late-onset preeclampsia. The role of paternal genes in the etiology of preeclampsia appears to be limited.

Gadd45 stress sensors in preeclampsia

Preeclampsia is a pregnancy-induced complex of multiple pathological changes. Numerous stresses during pregnancy, including hypoxia, immune activation, inflammatory cytokines, and oxidative stress were reported as contributing factors to the preeclamptic pathology. Seeking common sensors of various stressors in preeclampsia is of new interest and can potentially benefit in disease prevention and treatment. Recent studies have highlighted the role of the Gadd45a protein as a stress sensor in preeclampsia. In response to various pathophysiological stressors, notably hypoxia, inflammatory cytokines, and AT1-AAs, Gadd45a activates Mkk3-p38 and or JNK signaling. This, in turn, results in immunological and inflammatory changes as well as triggering the production of circulating factors such as sFlt-1, which are believed to account for many of the pathophysiological-related symptoms of preeclampsia. Activation of inflammatory/immune responses in preeclampsia may function in a feedback loop to maintain elevated expression of Gadd45a protein.

Small size for gestational age and the risk for infant mortality in the subsequent pregnancy

PURPOSE

To examine the association between small for gestational age (SGA) in the first pregnancy and risk for infant mortality in the second pregnancy.

METHODS

This is a population-based, retrospective cohort study in which we used the Missouri maternally linked cohort dataset for 1978-2005. Analyses were restricted to women who had two singleton pregnancies during the study period. The exposure was SGA in the first pregnancy, whereas the primary outcome was infant mortality in the second pregnancy. Kaplan-Meier Estimate and Cox proportional hazard regression were conducted.

RESULTS

Infant mortality was significantly greater among mothers with previous SGA (P < .01). A persistent association of previous SGA with subsequent infant mortality was observed (adjusted hazard ratio [AHR] 1.35, 95% confidence interval [95% CI] 1.24-1.48). Race-specific data illustrated that black women with a previous SGA birth were 40% more likely to experience infant mortality (AHR 1.40, 95% CI 1.21-1.63) than their counterparts without a history of SGA, but white women with a previous SGA had an increased risk of 31% (AHR 1.31, 95% CI 1.17-1.46).

CONCLUSIONS

Women with previous SGA bear increased risks for subsequent infant mortality, which was greater among black mothers. Hence, SGA plays an important role in the black-white disparity in infant mortality. Women's previous childbearing experiences could serve as important criterion in determining appropriate interconception strategies to improve infant health and survival.

Dynamic proteome in enigmatic preeclampsia: an account of molecular mechanisms and biomarker discovery

The coevolution of genomics and proteomics has led to advancements in the field of diagnosis and molecular mechanisms of disease. Proteomics is now stepping into the field of obstetrics, where early diagnosis of pregnancy complication such as preeclampsia (PE) is imperative. PE is a multifactorial disease characterized by hypertension with proteinuria, which is a leading cause of maternal and neonatal morbidity and mortality occurring in 5-7% of pregnancies worldwide. This review discusses the probable molecular mechanisms that lead to PE and summarizes the proteomics research carried out in understanding the pathogenicity of PE, and for identifying the candidate biomarker for diagnosis of the disease.

Dendritic cells in the circulation of women with preeclampsia demonstrate a pro-inflammatory bias secondary to dysregulation of TLR receptors

Toll-like receptors (TLRs) are central components of the innate immune system that recognize both microbial ligands and host products released during tissue damage. Data from epidemiologic studies and animal models suggest that inappropriate activation of the immune system plays a critical role in the development of preeclampsia. This study evaluates in a systematic fashion the expression and function of TLRs in the circulation of patients with preeclampsia compared to healthy pregnant controls. We evaluated TLR expression and function in primary dendritic cells (DCs) of 30 patients with preeclampsia and 30 gestational age-matched healthy pregnant controls. DCs were stimulated with the different TLR ligands engaging TLR1/2, TLR2/6, TLR3, TLR4, TLR5, TLR7, TLR8 and TLR9. The expression of TLR-induced production of TNF-α, IFN-α, IL-6, and IL-12 were measured by multicolor flow cytometry. Basal expression of TLR3, TLR4 and TLR9 was significantly increased in DCs isolated from women with preeclampsia. Preeclamptic DCs also expressed significantly higher basal levels of cytokines. In contrast, preeclamptic DCs demonstrated a less robust response to stimulation with various TLR ligands as compared with healthy pregnant controls. Under basal conditions, DCs from preeclamptic individuals express higher levels of select TLRs and produce more pro-inflammatory cytokines as compared with healthy controls. As such, the ability of these cells to mount an inflammatory reaction in response to a TLR ligand is limited. These data demonstrate a dysregulated pattern of TLR expression and cytokine production in DCs from PE patients that may limit further activation by TLR engagement.

Influence of previous abortions and new paternity on the risk of hypertension in nulliparous parturients in Ibadan: a cohort study

AIM

This study aims to determine the influence of previous abortions and new paternity on the risk of hypertension in a cohort of nulliparous women.

METHODS

A prospective cohort study was conducted with development of hypertension in pregnancy as outcome variable. Explanatory variables were previous abortions and paternity. Univariate analysis was by t-test, χ(2) test and Fisher's exact test where applicable. Logistic regression was utilized for multivariate analysis. Stata was utilized for all the analyses. The level of statistical significance was set as P < 0.05.

RESULTS

Same paternity abortions reduced the risk of hypertension (OR 0.48, 95% CI 0.31-0.73). Previous abortions did not reduce the odds of hypertension in pregnancy (OR 1.25, 95% CI 0.83-1.88). Rural dwelling reduced the odds of developing hypertension in pregnancy (OR 0.54, 95% CI 0.42-0.70).

CONCLUSION

The result of this study supports the immunological theory of the etiology of hypertension in pregnancy.

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.

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.

Population-based estimate of sibling risk for preterm birth, preterm premature rupture of membranes, placental abruption and pre-eclampsia

Background

Adverse pregnancy outcomes, such as preterm birth, preeclampsia and placental abruption, are common, with acute and long-term complications for both the mother and infant. Etiologies underlying such adverse outcomes are not well understood. As maternal and fetal genetic factors may influence these outcomes, we estimated the magnitude of familial aggregation as one index of possible heritable contributions.

Using the Missouri Department of Health's maternally-linked birth certificate database, we performed a retrospective population-based cohort study of births (1989–1997), designating an individual born from an affected pregnancy as the proband for each outcome studied. We estimated the increased risk to siblings compared to the population risk, using the sibling risk ratio, λ_s, and sibling-sibling odds ratio (sib-sib OR), for the adverse pregnancy outcomes of preterm birth, preterm premature rupture of membranes (PPROM), placental abruption, and pre-eclampsia.

Results

Risk to siblings of an affected individual was elevated above the population prevalence of a given disorder, as indicated by λ_S (λ_S (95% CI): 4.3 (4.0–4.6), 8.2 (6.5–9.9), 4.0 (2.6–5.3), and 4.5 (4.4–4.8), for preterm birth, PPROM, placental abruption, and pre-eclampsia, respectively). Risk to siblings of an affected individual was similarly elevated above that of siblings of unaffected individuals, as indicated by the sib-sib OR (sib-sib OR adjusted for known risk factors (95% CI): 4.2 (3.9–4.5), 9.6 (7.6–12.2), 3.8 (2.6–5.5), 8.1 (7.5–8.8) for preterm birth, PPROM, placental abruption, and pre-eclampsia, respectively).

Conclusion

These results suggest that the adverse pregnancy outcomes of preterm birth, PPROM, placental abruption, and pre-eclampsia aggregate in families, which may be explained in part by genetics.