Association of fetal gender with pregnancy-induced hypertension and pre-eclampsia

Association of fetal gender and the onset and severity of hypertensive disorders of pregnancy

Objective: It was reported that fetal gender was associated with gestational-age related incidence of preeclampsia. However, there is no study to date to evaluate the association of fetal gender differences with all hypertensive disorders of pregnancy. The present study aimed to evaluate the association, if any, between fetal gender differences and the disposition to develop hypertensive disorders of pregnancy and the risk of developing severe features.Methods: This was a single site retrospective cohort that included patients who were diagnosed with either gestational hypertension, preeclampsia without severe features, severe preeclampsia, superimposed preeclampsia, or superimposed preeclampsia with severe features. Patients were divided into two groups based on male versus female fetal gender. Our primary outcome was gestational age (GA) at diagnosis of hypertensive disorder. GA ranges evaluated were <28 weeks, 28-34 weeks, 34-37 weeks, and >37 weeks. Secondary outcomes were maternal morbidity (severe features at delivery, HELLP syndrome, placental abruption, eclampsia, maternal death, and maternal intensive care unit (ICU) admission), GA range at delivery, indication for delivery, and fetal outcomes. Continuous data were analyzed using an unpaired t-test and categorical data was analyzed using Chi-square test. A probability level was <.05 was set as statistically significant.Results: A total of 597 patients were included, 275 with male fetus and 322 with female fetus. Demographic comparison between the two groups showed similar rates in patients complicated with chronic hypertension, but a higher incidence of antihypertensive medication used in the male fetus group, p < .05. All other demographics were similar between the two groups. There were no significant differences in maternal primary and secondary outcomes, including GA range at diagnosis and severe features at delivery, and fetal outcomes, including neonatal intensive care unit (NICU) admission, evaluated between the two groups.Conclusion: Our study did not find significant differences between fetal gender and GA at the diagnosis of hypertensive disorders of pregnancy or development of severe features in the study subjects.

Fetal sex and maternal pregnancy outcomes: a systematic review and meta-analysis

Background

Since the placenta also has a sex, fetal sex–specific differences in the occurrence of placenta-mediated complications could exist.

Objective

To determine the association of fetal sex with multiple maternal pregnancy complications.

Search strategy

Six electronic databases Ovid MEDLINE, EMBASE, Cochrane Central, Web-of-Science, PubMed, and Google Scholar were systematically searched to identify eligible studies. Reference lists of the included studies and contact with experts were also used for identification of studies.

Selection criteria

Observational studies that assessed fetal sex and the presence of maternal pregnancy complications within singleton pregnancies.

Data collection and analyses

Data were extracted by 2 independent reviewers using a predesigned data collection form.

Main results

From 6522 original references, 74 studies were selected, including over 12,5 million women. Male fetal sex was associated with term pre-eclampsia (pooled OR 1.07 [95%CI 1.06 to 1.09]) and gestational diabetes (pooled OR 1.04 [1.02 to 1.07]). All other pregnancy complications (i.e., gestational hypertension, total pre-eclampsia, eclampsia, placental abruption, and post-partum hemorrhage) tended to be associated with male fetal sex, except for preterm pre-eclampsia, which was more associated with female fetal sex. Overall quality of the included studies was good. Between-study heterogeneity was high due to differences in study population and outcome definition.

Conclusion

This meta-analysis suggests that the occurrence of pregnancy complications differ according to fetal sex with a higher cardiovascular and metabolic load for the mother in the presence of a male fetus.

Funding

None.

Impact of gestational hypertension and preeclampsia on fetal gender: A large prospective cohort study in China

BACKGROUND

Recent studies suggested an association between fetal sex preponderance and hypertensive disorders during pregnancy, but the conclusions were inconsistent. Our objective was to investigate whether the occurrence of gestational hypertensive disorders would affect the possibility of delivering boys.

METHODS

Data were obtained from the China-US Collaborative Project for Neural Tube Defects Prevention, a large population-based cohort study. We included participants who were registered in 2 southern Chinese provinces, and whose information of blood pressure and sex delivery were recorded in detailed. Blood pressure was measured during pregnancy by trained health care workers and other health-related information was recorded prospectively. We used log-binomial regression to evaluate the association between gestational hypertension or preeclampsia and the chance of male delivery.

RESULTS

Among 205,605 singleton pregnancy women, the overall incidences of gestational hypertension and preeclampsia were 9.5% and 2.4%, respectively. The prevalence of male delivery was 51.1% and 50.2% in the groups of gestational hypertension and preeclampsia, while in the normotension group was 52.0%. After adjustment for the effects of the main potential confounders, women with gestational hypertension and preeclampsia both showed significantly decreased probability of giving birth to a boy. The adjusted risk ratios (RRs) were 0.98 (95% confidence interval (CI): 0.97-0.99) and 0.96 (95% CI: 0.94-0.99), respectively.

CONCLUSIONS

Our results support a slight but significant association between gestational hypertension or preeclampsia and decreased likelihood of male delivery.

Fetal sex and maternal risk of pre-eclampsia/eclampsia: a systematic review and meta-analysis

BACKGROUND

A preponderance of male fetuses in pregnancies complicated by pre-eclampsia was described over 40 years ago. Since then, however, there has been conflicting evidence in the literature, with some studies supporting a male preponderance, some demonstrating no relationship with fetal sex, and others reporting increased risk in pregnancies bearing females.

OBJECTIVES

In this context, we sought to conduct a systematic review and meta-analysis to objectively evaluate the relationship between fetal sex and maternal risk of pre-eclampsia/eclampsia.

SEARCH STRATEGY

Studies from January 1950 to April 2015 were identified from PUBMED and EMBASE.

SELECTION CRITERIA

This systematic review and meta-analysis evaluated 22 articles reporting data on fetal sex and prevalence of pre-eclampsia/eclampsia.

DATA COLLECTION AND ANALYSIS

Data were extracted by two independent reviewers. Pooled estimates of the relative risk (RR) were calculated by random-effects model.

MAIN RESULTS

Male fetus was considered the exposure and prevalence of maternal pre-eclampsia/eclampsia was the outcome of interest. We identified 534 studies through electronic searches and three studies through manual searches. Twenty-two studies fulfilled the inclusion criteria, yielding data on 3 163 735 women. Pooled analyses of these studies showed no association between male fetal sex and maternal risk of pre-eclampsia/eclampsia (RR 1.01; 95% confidence interval, 95% CI 0.97-1.05); however, a subgroup analysis including only studies that evaluated the non-Asian population (n = 2 931 771 women) demonstrated that male fetal sex was associated with increased maternal risk of pre-eclampsia/eclampsia (RR 1.05; 95% CI 1.03-1.06; I2 = 10%; P = 0.33).

CONCLUSION

Male fetal sex is associated with maternal risk of pre-eclampsia/eclampsia in the non-Asian population.

TWEETABLE ABSTRACT

Fetal sex is associated with maternal risk of pre-eclampsia/eclampsia in the non-Asian population.

The potential impact of the fetal genotype on maternal blood pressure during pregnancy

The heritability of pregnancy-induced hypertension (encompassing both gestational hypertension and preeclampsia) is around 0.47, suggesting that there is a genetic component to its development. However, the maternal genetic risk variants discovered so far only account for a small proportion of the heritability. Other genetic variants that may affect maternal blood pressure in pregnancy arise from the fetal genome, for example wild-type pregnant mice carrying offspring with Cdkn1c or Stox1 disrupted develop hypertension and proteinuria. In humans, there is a higher risk for preeclampsia in women carrying fetuses with Beckwith-Wiedemann syndrome (including those fetuses with CDKN1C mutations) and a lower risk for women carrying babies with trisomy 21. Other risk may be associated with imprinted fetal growth genes and genes that are highly expressed in the placenta such as GCM1. This article reviews the current state of knowledge linking the fetal genotype with maternal blood pressure in pregnancy.

Effect of preeclampsia on placental function: influence of sexual dimorphism, microRNA's and mitochondria

In pregnancy fetal growth and development occur in a sexually dimorphic manner. Male and female fetuses respond differently to the intrauterine environment with males disproportionately suffering from perinatal morbidity and mortality. We have demonstrated placental dysfunction and sexually dimorphic responses in pregnancies complicated by severe preeclampsia. Production of cytokines and apoptosis in the male placenta is heightened relative to that of the female placenta. We also find increased expression and stabilization and a sexual dimorphism in expression of the transcription factor HIF-1α, but a defect in binding to the hypoxia response element with corresponding reduced expression of HIF-1α target genes including VEGF and Glut-1. HIF-1α is involved in crosstalk with the redox sensitive transcription factor NFκB in regulation by cytokines, reactive oxygen species and expression of inflammatory genes. We find increased placental expression and DNA binding of NFκB and a sexually dimorphic response suggesting a role for NFκB in placental dysfunction with preeclampsia. Placental mitochondrial complex III activity and complex I and IV expression are reduced and alterations in mitochondrial morphology are found in preeclampsia and are linked to the hypoxamir miR-210. We propose that with severe PE placental HIF-1α is stabilized by excessive ROS, inflammation and relative hypoxia. This increases the expression of miR-210 in the placenta causing repression of mitochondria-associated target genes, potentially leading to mitochondrial and placental dysfunction. This placental dysfunction may lead to a fetal programming effect that results in disease in later life.

Evidence of sexual dimorphism in the placental function with severe preeclampsia

Preeclampsia (PE) affects 5-8% of pregnancies and is responsible for 18% of maternal deaths in the US, and for long-term complications in mother and child. PE is an inflammatory state and may influence placental function in a sex-specific manner. We determined if there is a sexual dimorphism in the placental inflammatory and apoptotic responses in preeclamptic pregnancies. Placentas were collected from normotensive and preeclamptic pregnancies with either male or female fetuses (MPE and FPE respectively) after c-section at term with no labor. Expression patterns of markers of inflammation measured by ELISA, as well as hypoxia, apoptosis and angiogenesis markers measured by Western blotting were determined in the placenta. Consistent with previous studies, an increase in inflammation, hypoxia, and apoptotic cell death was observed in PE compared to normotensive pregnancies. Levels of TNFα, IL-6 and IL-8, and HIF-1α were significantly greater, whereas the angiogenic marker VEGF was significantly reduced in MPE vs. FPE. Sexual dimorphism was also observed in the activation of cell death: the number of TUNEL-positive cells, and the expression pro-apoptotic markers PUMA and Bax being higher in MPE vs. FPE. We also found an increase in the levels of protein and DNA-binding activity of NFκB p65 in MPE vs. FPE. In summary, we show here that in preeclamptic pregnancies the placentas of males were associated with significantly higher expression of inflammatory, hypoxia and apoptotic molecules but reduced expression of a pro-angiogenic marker compared to placentas of female fetuses. We propose that the transcription factor NFκB p65 might, at least partially, be involved in sexual dimorphism during PE.

Fetal gender and pregnancy outcomes in Libya: a retrospective study

Objective

The relationship between pregnancy outcomes and fetal gender is well reported from different areas in the world, but not from Africa. In this study, we try to understand whether the recorded phenomenon of association of adverse pregnancy outcomes with a male fetus applies to our population.

Materials and methods

A total of 29,140 patient records from 2009 and 2010 were retrieved from Aljalaa Maternity Hospital, Tripoli, Libya. Analysis was carried out to find the correlation between fetal gender and different pregnancy outcomes.

Results

A male fetus was associated with an increased incidence of gestational diabetes mellitus (odds risk 1.4), preterm delivery (6.7% for males, 5.5% for females, odds risk 1.24), cesarean section (23.9% for males, 20% for females, odds risk 1.25), and instrumental vaginal delivery (4.4% for males, 3.1% for females, odds risk 1.48), p<0.005. Preeclampsia was more frequent among preterm females and postterm males, p<0.005. It was also more frequent in male-bearing primigravids, p<0.01.

Conclusion

We confirm the existence of an adverse effect of a male fetus on pregnancy and labor in our population. We recommend further research to understand the mechanisms and clinical implications of this phenomenon.

Fetal ERAP2 variation is associated with preeclampsia in African Americans in a case-control study

Background

Preeclampsia affects 3-8% of pregnancies and is a major cause of maternal and perinatal morbidity and mortality worldwide. This complex disorder is characterized by alterations in the immune and vascular systems and involves multiple organs. There is strong evidence for a genetic contribution to preeclampsia. Two different single nucleotide polymorphisms (SNPs) in the endoplasmic reticulum aminopeptidase 2 (ERAP2) gene were recently reported to be associated with increased risk for preeclampsia in two different populations. ERAP2 is expressed in placental tissue and it is involved in immune responses, inflammation, and blood pressure regulation; making it is an attractive preeclampsia candidate gene. Furthermore, ERAP2 expression is altered in first trimester placentas of women destined to develop preeclampsia.

Methods

A case-control design was used to test for associations between two SNPs in ERAP2, rs2549782 and rs17408150, and preeclampsia status in 1103 Chilean maternal-fetal dyads and 1637 unpaired African American samples (836 maternal, 837 fetal).

Results

We found that the fetal minor allele (G) of rs2549782 was associated with an increased risk for preeclampsia in the African American population (P = 0.009), but not in the Chilean population. We found no association between rs17408150 and risk for preeclampsia in the Chilean population. Association between rs17408150 and risk for preeclampsia was not tested in the African American population due to the absence of the minor allele in this population.

Conclusions

We report an association between fetal ERAP2 and preeclampsia in an African American population. In conjunction with previous studies, which have found maternal associations with this gene in an Australian/New Zealand population and a Norwegian population, ERAP2 has now been associated with preeclampsia in three populations. This provides strong evidence that ERAP2 plays a role in the development of preeclampsia.

Analysis of the S810L Point Mutation of the Mineralocorticoid Receptor in Patients with Pregnancy‐Induced Hypertension

OBJECTIVE

A missense mutation at codon 810 (Ser --> Leu) of the mineralocorticoid receptor was recently observed in a family with early manifestation of hypertension. Our objective was to determine if this mineralocorticoid receptor alterations is prevalent in patients with pregnancy-induced hypertension.

METHODS

Thirty-eight women with hypertension during pregnancy were tested for the mineralocorticoid receptor gene mutation. DNA was extracted out of blood leucocytes. PCR and automated DNA sequencing were used to analyze exon 6 for the S810L missense mutation. Anamnestical data concerning cardiovascular risk factors and family history were evaluated with a questionnaire. Pregnancy course and outcome were documented in all cases.

RESULTS

In 33 patients with pregnancy-induced hypertension and in five patients with exacerbation of preexisting hypertension in pregnancy no point mutations were found at codon 810 in exon 6.

CONCLUSIONS

Our data suggest that the S810L missense mutation of the mineralocorticoid receptor does not play a major role in the etiology of pregnancy-induced hypertension in a German /Turkish population.

A case-control study of polymorphic eruption of pregnancy

BACKGROUND

Polymorphic eruption of pregnancy (PEP) is a pruritic disease that usually occurs in primiparous women, most commonly in the last trimester of pregnancy. The origin and pathomechanisms still remain unknown.

OBJECTIVES

We attempted to determine the parameters that may be associated with or complicate the course of PEP.

METHODS

Data of 200 pregnant women (40 PEP and 160 control) were studied retrospectively and compared statistically using univariable and multivariable analysis.

RESULTS

In multivariate analysis, pregnancy with male fetuses (P = .02) and delivery by cesarean section (P = .012) were overrepresented in the PEP group. A tendency toward more multiple gestation pregnancy in PEP was found (P = .07). The risk of PEP was not related to excessive maternal or fetal weight gain.

LIMITATIONS

This was a retrospective study.

CONCLUSION

This large case-control study confirms the already suspected association of PEP with male fetuses and cesarean deliveries in multivariate analysis. The higher rate of multiple gestation pregnancy was also established.