Fetal sex differences in human chorionic gonadotropin fluctuate by maternal race, age, weight and by gestational age

Associations of Serum Perfluoroalkyl Substances and Placental Human Chorionic Gonadotropin in Early Pregnancy, Measured in the UPSIDE Study in Rochester, New York

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are widely detected in pregnant women and associated with adverse outcomes related to impaired placental function. Human chorionic gonadotropin (hCG) is a dimeric glycoprotein hormone that can indicate placental toxicity.

OBJECTIVES

Our aim was to quantify the association of serum PFAS with placental hCG, measured as an intact molecule (hCG), as free alpha-(hCG α ) and beta-subunits (hCG β ), and as a hyperglycosylated form (h-hCG), and evaluate effect measure modification by social determinants and by fetal sex.

METHODS

Data were collected from 326 pregnant women enrolled from 2015 to 2019 in the UPSIDE study in Rochester, New York. hCG forms were normalized for gestational age at the time of blood draw in the first trimester [multiple of the median (MoM)]. Seven PFAS were measured in second-trimester maternal serum. Multivariate imputation by chained equations and inverse probability weighting were used to evaluate robustness of linear associations. PFAS mixture effects were estimated by Bayesian kernel machine regression.

RESULTS

Perfluorohexane sulfonic acid (PFHxS) [hCG β : 0.29 log MoM units per log PFHxS; 95% confidence interval (CI): 0.08, 0.51] and perfluorodecanoic acid (PFDA) (hCG: - 0.09 ; 95% CI: - 0.16 , - 0.02 ) were associated with hCG in the single chemical and mixture analyses. The PFAS mixture was negatively associated with hCG α and positively with hCG β . Subgroup analyses revealed that PFAS associations with hCG differed by maternal race/ethnicity and education. Perfluoropentanoic acid (PFPeA) was associated with hCG β only in Black participants (- 0.23 ; 95% CI: - 0.37 , - 0.09 ) and in participants with high school education or less (- 0.14 ; 95% CI: - 0.26 , - 0.02 ); conversely, perfluorononanoic acid (PFNA) was negatively associated with hCG α only in White participants (- 0.15 ; 95% CI: - 0.27 , - 0.03 ) and with hCG β only in participants with a college education or greater (- 0.19 ; 95% CI: - 0.36 , - 0.01 ). These findings were robust to testing for selection bias, confounding bias, and left truncation bias where PFAS detection frequency was < 100 % . Two associations were negative in male (and null in female) pregnancies: Perfluoroundecanoic acid (PFUnDA) with hCG α , and PFNA with h-hCG.

CONCLUSIONS

Evidence was strongest for the association between PFHxS and PFDA with hCG in all participants and for PFPeA and PFNA within subgroups defined by social determinants and fetal sex. PFAS mixture associations with hCG α and hCG β differed, suggesting subunit-specific types of toxicity and/or regulation. Future studies will evaluate the biological, clinical and public health significance of these findings. https://doi.org/10.1289/EHP12950.

Mediation Analysis using Semi-parametric Shape-Restricted Regression with Applications

Often linear regression is used to perform mediation analysis. However, in many instances, the underlying relationships may not be linear, as in the case of placentalfetal hormones and fetal development. Although, the exact functional form of the relationship may be unknown, one may hypothesize the general shape of the relationship. For these reasons, we develop a novel shape-restricted inference-based methodology for conducting mediation analysis. This work is motivated by an application in fetal endocrinology where researchers are interested in understanding the effects of pesticide application on birth weight, with human chorionic gonadotropin (hCG) as the mediator. We assume a practically plausible set of nonlinear effects of h C G on the birth weight and a linear relationship between pesticide exposure and hCG, with both exposure-outcome and exposure-mediator models being linear in the confounding factors. Using the proposed methodology on a population-level prenatal screening program data, with hCG as the mediator, we discovered that, while the natural direct effects suggest a positive association between pesticide application and birth weight, the natural indirect effects were negative.

Extreme βHCG levels in first trimester screening are risk factors for adverse maternal and fetal outcomes

Multiples of the normal median (MoM) of free βHCG is a valuable parameter in evaluation of risk of adverse pregnancy outcomes. In the current retrospective study, we assessed the maternal and fetal outcomes in pregnant women having free βHCG MoM levels < 0.2 or > 5 in their first trimester screening (FTS). Relative risk of trisomy 21 was significantly higher in patients having free βHCG MoM > 5. On the other hand, relative risk of trisomies 13 and 18 and Turner syndrome were higher in those having free βHCG MoM < 0.2. Other chromosomal abnormalities were nearly equally detected between those having free βHCG MoM < 0.2 or > 5. Relative risk of hydrocephaly and hydrops fetalis was higher when free βHCG MoM was below 0.2. On the other hand, relative risk of low birth weight was higher when free βHCG MoM was above 5. Moreover, frequency of gestational diabetes mellitus, preeclampsia, preterm delivery and vaginal bleeding increased with levels of free βHCG MoM. However, polyhydramnios had the opposite trend. Frequencies of premature rupture of membranes and pregnancy induced hypertension were highest among pregnant women having levels of free βHCG MoM < 0.2. The current study indicates importance of free βHCG MoM in identification of at-risk pregnancies in terms of both fetal and maternal outcomes. In fact, βHCG MoM < 0.2 or > 5 can be regarded as risk factors for adverse maternal or fetal outcomes irrespective of the presence of other abnormalities in the FTS results.

Application of 4-way decomposition to the analysis of placental-fetal biomarkers as intermediary variables between maternal body mass index and birthweight

Human chorionic gonadotropin (hCG) is a placental hormone measured in pregnancy to predict individual level risk of fetal aneuploidy and other complications; yet may be useful in understanding placental origins of child development more generally. hCG was associated with maternal body mass index (BMI) and with birthweight. The primary aim here was to evaluate hCG as a mediator of maternal BMI effects on birthweight by causal mediation analysis. Subjects were 356 women from 3 U.S. sites (2010-2013). The 4-way decomposition method using med4way (STATA) was applied to screen for 5 types of effects of first trimester maternal BMI on birthweight: the total effect, the direct effect, mediation by hCG, additive interaction of BMI and hCG, and mediation in the presence of an additive interaction. Effect modification by fetal sex was evaluated, and a sensitivity analysis was performed to evaluate the assumption of unmeasured confounding. Additional placental-fetal biomarkers [pregnancy associated plasma protein A (PAPPA), second trimester hCG, inhibin-A, estriol, alpha fetoprotein] were analyzed for comparison. For first trimester hCG, there was a 0.20 standard deviation increase in birthweight at the 75th vs. 25th percentile of maternal BMI (95% CI 0.04, 0.36). Once stratified, the direct effect association was null in women carrying females. In women carrying males, hCG did not mediate the relationship. In women carrying females, there was a mediated effect of maternal BMI on birthweight by hCG in the reverse direction (-0.06, 95% CI: -0.12, 0.01), and a mediated interaction in the positive direction (0.06, 95% CI 0.00, 0.13). In women carrying males, the maternal BMI effect on birthweight was reverse mediated by PAPPA (-0.09, 95% CI: -0.17, 0.00). Sex-specific mediation was mostly present in the first trimester. Second trimester AFP was a positive mediator of maternal BMI effects in male infants only (0.06, 95% CI: -0.01, 0.13). Effect estimates were robust to potential bias due to unmeasured confounders. These findings motivate research to consider first trimester placental biomarkers and sex-specific mechanisms when quantifying the effects of maternal adiposity on fetal growth.

Does foetal gender influence maternal thyroid parameters in pregnancy?

Objective

It is unknown if foetal gender influences maternal thyroid function during pregnancy. We therefore investigated the prevalence of thyroid disorders and determined first-trimester TSH reference ranges according to gender.

Methods

A cross-sectional study involving 1663 women with an ongoing pregnancy was conducted. Twin and assisted pregnancies and l-thyroxine or antithyroid treatment before pregnancy were exclusion criteria. Serum TSH, free T4 (FT4) and thyroid peroxidase antibodies (TPOAb) were measured at median (interquartile range; IQR) 13 (11-17) weeks of gestation. Subclinical hypothyroidism (SCH) was present when serum TSH levels were >3.74 mIU/L with normal FT4 levels (10.29-18.02 pmol/L), and thyroid autoimmunity (TAI) was present when TPOAb were ≥60 kIU/L.

Results

Eight hundred and forty-seven women were pregnant with a female foetus (FF) and 816 with a male foetus (MF). In women without TAI and during the gestational age period between 9 and 13 weeks (with presumed high-serum hCG levels), median (IQR range) serum TSH in the FF group was lower than that in the MF group: 1.13 (0.72-1.74) vs 1.24 (0.71-1.98) mIU/L; P = 0.021. First-trimester gender-specific TSH reference range was 0.03-3.53 mIU/L in the FF group and 0.03-3.89 mIU/L in the MF group. The prevalence of SCH and TAI was comparable between the FF and MF group: 4.4% vs 5.4%; P = 0.345 and 4.9% vs 7.5%; P = 0.079, respectively.

Conclusions

Women pregnant with an MF have slightly but significantly higher TSH levels and a higher upper limit of the first-trimester TSH reference range, compared with pregnancies with a FF. We hypothesise that this difference may be related to higher hCG levels in women pregnant with a FF, although we were unable to measure hCG in this study. Further studies are required to investigate if this difference has any clinical relevance.

Placental Endocrine Activity: Adaptation and Disruption of Maternal Glucose Metabolism in Pregnancy and the Influence of Fetal Sex

The placenta is an endocrine fetal organ, which secretes a plethora of steroid- and proteo-hormones, metabolic proteins, growth factors, and cytokines in order to adapt maternal physiology to pregnancy. Central to the growth of the fetus is the supply with nutrients, foremost with glucose. Therefore, during pregnancy, maternal insulin resistance arises, which elevates maternal blood glucose levels, and consequently ensures an adequate glucose supply for the developing fetus. At the same time, maternal β-cell mass and function increase to compensate for the higher insulin demand. These adaptations are also regulated by the endocrine function of the placenta. Excessive insulin resistance or the inability to increase insulin production accordingly disrupts physiological modulation of pregnancy mediated glucose metabolism and may cause maternal gestational diabetes (GDM). A growing body of evidence suggests that this adaptation of maternal glucose metabolism differs between pregnancies carrying a girl vs. pregnancies carrying a boy. Moreover, the risk of developing GDM differs depending on the sex of the fetus. Sex differences in placenta derived hormones and bioactive proteins, which adapt and modulate maternal glucose metabolism, are likely to contribute to this sexual dimorphism. This review provides an overview on the adaptation and maladaptation of maternal glucose metabolism by placenta-derived factors, and highlights sex differences in this regulatory network.

Maternal steroid levels and the autistic traits of the mother and infant

BACKGROUND

Prenatal sex steroids have been associated with autism in several clinical and epidemiological studies. It is unclear how this relates to the autistic traits of the mother and how early this can be detected during pregnancy and postnatal development.

METHODS

Maternal serum was collected from pregnant women (n = 122) before or during their first ultrasound appointment [mean = 12.7 (SD = 0.7) weeks]. Concentrations of the following were measured via immunoassays: testosterone, estradiol, dehydroepiandrosterone sulphate, progesterone; and sex hormone-binding globulin which was used to compute the free fractions of estradiol (FEI) and testosterone (FTI). Standardised human choriogonadotropin (hCG) and pregnancy-associated plasma protein A (PAPP-A) values were obtained from clinical records corresponding to the same serum samples. Mothers completed the Autism Spectrum Quotient (AQ) and for their infants, the Quantitative Checklist for Autism in Toddlers (Q-CHAT) when the infants were between 18 and 20 months old.

RESULTS

FEI was positively associated with maternal autistic traits in univariate (n = 108, Pearson's r = 0.22, p = 0.019) and multiple regression models (semipartial r = 0.19, p = 0.048) controlling for maternal age and a diagnosis of PCOS. Maternal estradiol levels significantly interacted with fetal sex in predicting infant Q-CHAT scores, with a positive relationship in males but not females (n = 100, interaction term: semipartial r = 0.23, p = 0.036) after controlling for maternal AQ and other covariates. The opposite was found for standardised hCG values and Q-CHAT scores, with a positive association in females but not in males (n = 151, interaction term: r = -0.25, p = 0.005).

LIMITATIONS

Sample size of this cohort was small, with potential ascertainment bias given elective recruitment. Clinical covariates were controlled in multiple regression models, but additional research is needed to confirm the statistically significant findings in larger cohorts.

CONCLUSION

Maternal steroid factors during pregnancy are associated with autistic traits in mothers and their infants.

Sex Differences Are Here to Stay: Relevance to Prenatal Care

Sex differences exist in the incidence and presentation of many pregnancy complications, including but not limited to pregnancy loss, spontaneous preterm birth, and fetal growth restriction. Sex differences arise very early in development due to differential gene expression from the X and Y chromosomes, and later may also be influenced by the action of gonadal steroid hormones. Though offspring sex is not considered in most prenatal diagnostic or therapeutic strategies currently in use, it may be beneficial to consider sex differences and the associated mechanisms underlying pregnancy complications. This review will cover (i) the prevalence and presentation of sex differences that occur in perinatal complications, particularly with a focus on the placenta; (ii) possible mechanisms underlying the development of sex differences in placental function and pregnancy phenotypes; and (iii) knowledge gaps that should be addressed in the development of diagnostic or risk prediction tools for such complications, with an emphasis on those for which it would be important to consider sex.

Second-Trimester Placental and Thyroid Hormones Are Associated With Cognitive Development From Ages 1 to 3 Years

Adequate maternal thyroid hormone (TH) is necessary for fetal brain development. The role of placental human chorionic gonadotropin (hCG) in ensuring the production of TH is less well understood. The objective of the study was to evaluate 1) associations of placental hCG and its subunits, and maternal TH in the second trimester, and 2) the single and joint effects of TH and placental hormones on cognitive development and communication at ages 1 and 3 years. Fifty individuals (5%) were selected from the CANDLE (Conditions Affecting Neurocognitive Development and Early Learning) pregnancy cohort in Memphis, Tennessee, with recruitment from 2006 to 2011, to equally represent male and female fetuses. Participants were 68% Black and 32% White. Hormones measured were maternal thyroid (thyrotropin [TSH] and free thyroxine [FT4]) and placental hormones (hCG, its hyperglycosylated form [hCG-h], and free - [hCG] and -subunits [hCG]) in maternal serum (17-28 weeks). The primary outcome measurement was the Bayley Scales of Infant and Toddler Development. All forms of hCG were negatively associated with FT4 and not associated with TSH. hCG was associated with cognitive development at age 1 year and jointly interacted with TSH to predict cognitive development at age 3 years. This pilot study added insight into the thyrotropic actions of hCG in the second trimester, and into the significance of this mechanism for brain development. More research is warranted to elucidate differences between hCG, hCG, and hCG-h in relation to TH regulation and child brain function.

Gestational Hormone Concentrations Are Associated With Timing of Delivery in a Fetal Sex-Dependent Manner

BACKGROUND

Early delivery remains a significant public health problem that has long-lasting impacts on mother and child. Understanding biological mechanisms underlying timing of labor, including endocrine disruption, can inform prevention efforts.

METHODS

Gestational hormones were measured among 976 women in PROTECT, a longitudinal birth cohort in Puerto Rico. We evaluated associations between hormone concentrations at 18 and 26 weeks gestation and gestational age at birth, while assessing effect modification by fetal sex. Exploratory analyses assessed binary outcomes of overall preterm birth (PTB, <37 weeks gestation) and the spontaneous PTB subtype, defined as preterm premature rupture of membranes, spontaneous preterm labor, or both. Multivariable logistic and linear regressions were fit using visit-specific hormone concentrations, and fetal sex-specific effects were estimated using interaction terms. Main outcome models were adjusted for maternal age, education, marital status, alcohol consumption, environmental tobacco smoke exposure, and pre-pregnancy body mass index (BMI). Exploratory models adjusted for maternal age and education.

RESULTS

We observed reduced gestational age at birth with higher circulating CRH (β: -2.73 days, 95% CI: -4.97, -0.42), progesterone (β: -4.90 days, 95% CI: -7.07, -2.73), and fT4 concentrations (β: -2.73 days, 95% CI: -4.76, -0.70) at 18 weeks specifically among male fetuses. Greater odds of overall and spontaneous PTB were observed among males with higher CRH, estriol, progesterone, total triiodothyronine (T3), and free thyroxine (fT4) concentrations. Greater odds of PTB among females was observed with higher testosterone concentrations.

CONCLUSIONS

Various associations between hormones and timing of delivery were modified by fetal sex and timing of hormone measurement. Future studies are needed to understand differential mechanisms involved with timing of labor between fetal sexes.

A toolkit for the application of placental-fetal molecular biomarkers in epidemiologic studies of the fetal origins of chronic disease

Purpose of review

In this review, we provide essential background knowledge and an analytical framework for the application of placental-fetal molecular biomarkers in fetal origins chronic disease epidemiology. The widely available and highly quantitative placental hormone human chorionic gonadotropin (hCG) is used as an example. hCG is currently used for diagnosing fetal genetic disorders; yet it can and should be expanded to understanding the fetal origins of chronic diseases. We provide justification and methods to do this.

Recent findings

Ten papers published in the last 5 years were identified with supportive findings relevant to the application of biomarkers of hCG in epidemiologic studies on the developmental origins of health and disease (DOHaD).

Summary

There is increasing and consistent evidence that placental-fetal biomarkers may be highly informative in observational studies, as exemplified by hCG, with the correct approaches for measurement and data analysis.

Examining Sex Differences in the Human Placental Transcriptome During the First Fetal Androgen Peak

Sex differences in human placenta exist from early pregnancy to term, however, it is unclear whether these differences are driven solely by sex chromosome complement or are subject to differential sex hormonal regulation. Here, we survey the human chorionic villus (CV) transcriptome for sex-linked signatures from 11 to 16 gestational weeks, corresponding to the first window of increasing testis-derived androgen production in male fetuses. Illumina HiSeq RNA sequencing was performed on Lexogen Quantseq 3' libraries derived from CV biopsies (n = 11 females, n = 12 males). Differential expression (DE) was performed to identify sex-linked transcriptional signatures, followed by chromosome mapping, pathway analysis, predicted protein interaction, and post-hoc linear regressions to identify transcripts that trend over time. We observe 322 transcripts DE between male and female CV from 11 to 16 weeks, with 22 transcripts logFC > 1. Contrary to our predictions, the difference between male and female expression of DE autosomal genes was more pronounced at the earlier gestational ages. In females, we found selective upregulation of extracellular matrix components, along with a number of X-linked genes. In males, DE transcripts centered on chromosome 19, with mitochondrial, immune, and pregnancy maintenance-related transcripts upregulated. Among the highest differentially expressed autosomal genes were CCRL2, LGALS13, and LGALS14, which are known to regulate immune cell interactions. Our results provide insight into sex-linked gene expression in late first and early second trimester developing human placenta and lay the groundwork to understand the mechanistic origins of sex differences in prenatal development.

Genome-wide microRNA expression analysis in human placenta reveals sex-specific patterns: an ENVIRONAGE birth cohort study

There is an increasing interest in microRNAs (miRNAs) as they are of utmost importance in gene regulation at the posttranscriptional level. Sex-related susceptibility for non-communicable diseases later in life could originate in early life. Until now, no data on sex-specific miRNA expression are available for the placenta. Therefore, we investigated the difference by sex of newborn's miRNA expression in human placental tissue. Within the ENVIRONAGE birth cohort, miRNA and mRNA expression profiling was performed in 60 placentae (50% boys) using Agilent (8 × 60 K) microarrays. The distribution of chromosome locations was studied and pathway analysis of the identified sex-specific miRNAs in the placenta was carried out. Of the total 2558 miRNAs on the array, 597 miRNAs were expressed in over 70% of the samples and were included for further analyses. A total of 142 miRNAs were significantly (FDR<0.05) associated with the newborn's sex. In newborn girls, 76 miRNAs had higher expression (hsa-miR-361-5p as most significant) and 66 miRNAs had lower expression (hsa-miR-4646-5p as most significant) than in newborn boys. In the same study population, placental differentially expressed genes by sex were also identified using a whole genome approach. The placental gene expression revealed 27 differentially expressed genes by comparing girls to boys. Ultimately, we studied the miRNA-RNA interactome and identified 14 miRNA-mRNA interactions as sex-specific. Sex differences in placental m(i)RNA expression may reveal sex-specific patterns already present during pregnancy, which may influence physiological conditions in early or later life. These molecular processes might play a role in sex-specific disease susceptibility in later life.

Low serum placental lactogen at term is associated with postnatal symptoms of depression and anxiety in women delivering female infants

BACKGROUND

Placental endocrine insufficiency may increase the risk of depression and anxiety during pregnancy and/or after birth. This study investigated the association between serum human placental lactogen (hPL) and measures of perinatal mental health, accounting for selective serotonin-reuptake inhibitor (SSRI) usage.

METHOD

Caucasian women with singleton, term pregnancies recruited at their pre-surgical appointment prior to an elective caesarean section (ELCS) were studied. Serum hPL levels were measured by ELISA in maternal blood collected at the pre-surgical appointment. Depression and anxiety scores were derived from Edinburgh Postnatal Depression Scale (EPDS) and the trait subscale of the State-Trait Anxiety Inventory (STAI) questionnaires completed at recruitment and three postnatal time points. Data was analysed by unadjusted and adjusted multiple linear regression.

RESULTS

In adjusted linear regressions, term maternal serum hPL levels were negatively associated with postnatal EPDS and STAI score ten weeks postnatal for mothers who had girls (B= -.367, p = .022, 95% CI -.679, -.056; and B= -.776, p = .030, 95% CI -1.475, -.077 respectively). Excluding women prescribed SSRIs strengthened the relationship at 10 weeks and uncovered an earlier association between hPL and mood scores within one week of delivery (EPDS B= -.357, p = .041, 95 % CI -.698, -.015; and STAI B= -.737, p = .027, 95 % CI -1.387, -.086). In mothers who had boys, there were no associations between hPL and mood scores at any time point.

CONCLUSION

Low hPL at term associated with postnatal depression and anxiety symptoms exclusively in mothers of girls. Insufficiency in hPL may contribute to maternal mood symptoms.

Comparison of uterine fibroids' growth pattern during pregnancy according to fetal sex: an observational study

BACKGROUND

To investigate the effect of fetal sex on fibroids' growth during pregnancy according to the hCG serum levels METHODS: Observational study conducted from January 2007 to December 2016 on women with ultrasound identification of uterine fibroids who had a pregnancy within 1 year from diagnosis. The fibroids diameter was determined during the pre-pregnancy ultrasound, early first trimester (5-7 weeks), late first trimester (11-13 weeks), second trimester (19-21 weeks), and third trimester (31-33 weeks). The diameter growth was calculated in each interval between two ultrasounds. The hCG serum levels were determined both in early and late first trimester. The correlation between hCG levels and fibroid diameter was evaluated. Obstetric outcomes collected were gestational weeks at birth and the rate of cesarean section. Neonatal outcomes were birthweight and Apgar score at 1 min.

RESULTS

Eighty-seven of the included women had a male fetus, and 70 had a female fetus. A progressive increase of fibroid diameter was observed from pre-pregnancy to second trimester for both fetal sexes. In third trimester, the mean ± SD fibroid diameter of female fetuses showed a slowdown, while the mean ± SD fibroid diameter of male fetuses continued to grow. Women carrying a female fetus presented a higher fibroid diameter in early first trimester (33.5 ± 13.3 mm vs 27.4 ± 11.0 mm, p < 0.01), late first trimester (40.2 ± 13.9 mm vs 34.6 ± 11.7 mm, p < 0.01), and second trimester (40.5 ± 14.9 mm vs 34.7 ± 10.3 mm, p < 0.01). The hCG serum levels resulted higher in women with a female fetus: 61406 (50554-71760) mU/ml vs 46016 (37160-56744) mU/ml (p < 0.01). A positive correlation between hCG levels and fibroid diameter was found both for male and female fetuses (male r = 0.77, 95% CI 0.71-0.82, p < 0.01 and female r = 0.82, 95% CI 0.76-0.86, p < 0.01).

CONCLUSION

Women with female fetus seem to have a higher growth of fibroids up to second trimester of pregnancy. This process may be mediated by the higher serum hCG levels found in women expecting a female fetus.

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.

The Density of Cell Nuclei at the Materno-Fetal Exchange Barrier is Sexually Dimorphic in Normal Placentas, but not in IUGR

Placental sexual dimorphism is of special interest in prenatal programming. Various postnatal diseases with gender dependent incidence, especially neuropsychiatric disorders like schizophrenia and autism spectrum disorders, have prenatal risk factors established. However, the functional relevance of placental microarchitecture in prenatal programming is poorly investigated, mainly due to a lack of statistically efficient methods. We hypothesized that the recently established 3D microscopic analysis of villous trees would be able to identify microscopic structural correlates of human placental sexual dimorphism. We analyzed the density of cell nuclei of villous trophoblast, i.e. the materno-fetal exchange barrier, in placentas from term pregnancies. The cell nuclei were grouped into proliferative and non-proliferative nuclei by detection of a proliferation marker (PCNA). Normal female placentas showed a higher density of non-proliferating nuclei (PCNA-negative) in villous trophoblast than normal male placentas. The density of PCNA-negative cell nuclei was higher in placentas of pregnancies with intrauterine growth retardation (IUGR) than in control placentas. The data of the present study shows that the density of non-proliferative cell nuclei in the syncytial layer of villous trophoblast is influenced by fetal sex and by IUGR, while proliferation remains unchanged. A novel concept of post-fusion regulation of syncytial structure and function is proposed.

Prenatal Risk for ASD: Fetal Cortisol Exposure Predicts Child Autism-Spectrum Disorder Symptoms

The etiology of autism spectrum disorder (ASD) is multifactorial and complex and likely involves interactions among genetic, epigenetic and environmental factors. With respect to environmental influences, a growing literature implicates intrauterine experiences in the origin of this pervasive developmental disorder. In this prospective longitudinal design, we examine the hypothesis that fetal exposure to maternal cortisol may confer ASD risk. In addition, because ASD is four times more prevalent in males than females and because sexually dimorphic responses to intrauterine experiences are commonly observed, we examine whether or not any associations differ by fetal sex. Maternal plasma cortisol was measured at 15, 19, 25, 31, and 37 weeks' gestation in a sample of 84 pregnant women. ASD symptoms were assessed in their 5-year old children with the Social Communication Questionnaire (SCQ). Fetal exposure to lower levels of maternal cortisol was associated with higher levels of ASD symptoms among boys only. The observed hypocortisolemic profile exhibited by these mothers may indicate a risk factor that precedes the stress of caregiving for a child with ASD and may not be solely a consequence of the stress of caregiving as previously thought. Further, these findings confirm the value of examining prenatal hormone exposures as predictors of ASD risk and support the premise that altered prenatal steroid exposures may play a role in the etiology of ASD.

An Investigation of the Single and Combined Phthalate Metabolite Effects on Human Chorionic Gonadotropin Expression in Placental Cells

BACKGROUND

Observational studies have reported associations between maternal phthalate levels and adverse outcomes at birth and in the health of the child. Effects on placental function have been suggested as a biologic basis for these findings.

OBJECTIVE

We evaluated the effects of phthalates on placental function in vitro by measuring relevant candidate genes and proteins.

MATERIALS AND METHODS

Human trophoblast progenitor cells were isolated at 7-14 wk of pregnancy (two female and three male concepti), and villous cytotrophoblast cells (vCTBs) were isolated at 15-20 wk (three female and four male concepti). Cells were cultured in vitro with four phthalate metabolites and their combination at concentrations based on levels found previously in the urine of pregnant women: mono-n-butyl (MnBP, 200 nM), monobenzyl (MBzP, 3μM), mono-2-ethylhexyl (MEHP, 700 nM), and monoethyl (MEP, 1.5μM) phthalates. mRNA levels of CGA, CGB, PPARG, CYP19A1, CYP11A1, PTGS2, EREG, and the intracellular β subunit of human chorionic gonadotropin (hCGβ) and peroxisome proliferator activated receptor γ (PPARγ) were measured in the cellular extracts, and protein levels for four forms of secreted hCG were measured in the conditioned media.

RESULTS

Previously reported associations between maternal phthalates and placental gene expression were reproduced experimentally: MnBP with CGA, MBzP with CYP11A1, and MEHP with PTGS2. CGB and hCGβ were up-regulated by MBzP. In some cases, there were marked, even opposite, differences in response by sex of the cells. There was evidence of agonism in female cells and antagonism in male cells of PPARγ by simultaneous exposure to multiple phthalates.

CONCLUSIONS

Concentrations of MnBP, MBzP and MEHP similar to those found in the urine of pregnant women consistently altered hCG and PPARγ expression in primary placental cells. These findings provide evidence for the molecular basis by which phthalates may alter placental function, and they provide a preliminary mechanistic hypothesis for opposite responses by sex. https://doi.org/10.1289/EHP1539.