The impact of fetal gender on first trimester nuchal translucency and maternal serum free beta-hCG and PAPP-A MoM in normal and trisomy 21 pregnancies

Cell‑free fetal DNA at 11‑13 weeks of gestation is not altered in complicated pregnancies

Non-invasive maternal cell-free fetal DNA (cffDNA) is a promising biomarker for screening common genetic syndromes. Alterations in the expression levels of cffDNA in the maternal circulation have been demonstrated in abnormal pregnancies. However, the results are conflicting. The present study aimed to investigate whether cffDNA levels are associated with pregnancy complications. The study group comprised pregnant women who presented with pregnancy complications, such as preterm birth, gestational hypertension, intrauterine growth retardation, gestational diabetes, polyhydramnios, oligohydramnios, vaginal bleeding and placental abruption. The control group comprised women who had a normal pregnancy course. Blood samples were obtained from 500 pregnant women between 11-13 weeks of gestation. cffDNA was amplified, sequenced and analyzed using the next-generation aneuploidy test of a Panorama-Natera kit. Nuchal translucency (NT) thickness as well as pregnancy associated plasma protein-A (PAPP-A) and β-human chorionic gonadotropin (β-hCG) levels were also assessed. Statistical analysis was performed in 494 out of the 500 samples collected with SPSS v.26 using non-parametric methods. The parameters were normalized by the multiples of median (MoM) method. The expression levels of PAPP-A, β-hCG, and the NT mean MoM values were significantly different between the study and control groups (P=0.005, P<0.001 and P=0.007, respectively). However, the expression levels of cffDNA and the mean MoM values were not significantly different between these two groups (P=0.687). The findings of the present study support the conclusion that cffDNA expression is not altered in a series of pregnancy complications. The prognostic value of cffDNA in predicting adverse pregnancy outcomes requires further investigation.

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.

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.

Maternal Diabetes and Infant Sex Ratio

PURPOSE OF REVIEW

Evolutionary hypotheses on the ratio of males to females at birth posit that women terminate pregnancies with low likelihood of surviving and producing grandchildren. Thus, females are preferred to males under unfavorable conditions. Much of this literature has focused on catastrophic disruptions that induce maternal stress and result in fewer males. Diabetes may similarly affect the sex ratio.

RECENT FINDINGS

A male bias at birth among infants born to women with GDM is widely recognized; mild hyperglycemia experienced early in pregnancy may signal favorable conditions and warrant investment in males. There are sparse data on women with pregestational diabetes, but some evidence for a female bias born to those with type 1 diabetes and severe hyperglycemia (i.e., requiring insulin). Disease-related maternal stress in these women may lead to the selective termination of male fetuses. Further examination of pregestational diabetes stands to contribute to scientific understanding of the sex ratio.

Exploring Fetal Sex as a Risk Factor for Sleep Disordered Breathing and Its Complications in Pregnancy

Sleep disordered breathing (SDB) is a common, yet under-recognized and undertreated condition in pregnancy. Sleep disordered breathing is associated with pregnancy complications including preeclampsia, gestational diabetes, preterm birth, as well as severe maternal morbidity and mortality. The identification of risk factors for SDB in pregnancy may improve screening, diagnosis, and treatment of SDB prior to the onset of pregnancy complications. The goal of this study was to determine whether fetal sex increases risk of SDB in pregnancy. A cohort of singleton (N = 991) pregnant women were recruited within 24 to 48 hours of delivery and answered questions regarding SDB symptoms by questionnaire. Women who reported frequent loud snoring at least 3 times a week were considered to have SDB. Hospital records were reviewed to extract information on fetal sex and pregnancy complications including preeclampsia, pregnancy-induced hypertension, gestational diabetes, preterm delivery, and low birth weight. Women carrying male fetuses were significantly more likely to have SDB (β = .37, P = .01, OR: 1.45 [95% CI: 1.09–1.94]). Fetal sex was associated with increased risk of hypertensive disorders of pregnancy (defined as preeclampsia and/or pregnancy-induced hypertension) among women with SDB in pregnancy (β = .41, P = .02, OR: 1.51[95%CI:1.08–2.11]).Fetal sex did not increase risk of preterm birth, low birth weight, or gestational diabetes among women with SDB in pregnancy. Women carrying male fetuses were approximately 1.5 times more likely to report SDB in pregnancy compared to women carrying female fetuses, and women with pregnancy-onset SDB carrying male fetuses were 1.5 times more likely to have hypertensive disorders of pregnancy compared to women with SDB carrying female fetuses. Confirmation of fetal sex as a risk factor may, with other risk factors, play a role in identifying women at highest risk of SDB complications in pregnancy.

Fine-tuning of routine combined first- trimester screening: The ratio of serum-free- beta-human chorionic gonadotropin (fβ-hCG) to pregnancy-associated plasma protein-A (PAPP-A) could improve performance of Down syndrome screening program, a retrospective cohort study in Iran

OBJECTIVES

To evaluate the performance of the current national screening policy for Down syndrome (DS) in Iran and suggest a more efficient protocol with a wealth of a large series of first-trimester screening (FTS) data obtained from Nilou medical laboratory. To fulfill this aim, detection rate (DR), positive screening rate (PSR), false negative rate (FNR) and odds of being affected given a positive results (OAPR) were calculated at different cutoff risk. In the latest update of DS screening program in Iran, there is no place for intermediate group to be further investigated. Next, we proposed a novel parameter namely the ratio of fβ-hCG multiple of the median (MoM) value to PAPP-A MoM value to delicately categorize FTS results in a way that reduce FNR without imposing unnecessary anxious and extra money on most families.

METHODS

The present investigation was conducted retrospectively on 197,210 pregnancies undergoing FTS for aneuploidies in Nilou medical laboratory, Tehran, Iran, from March 2015 to February 2016.

RESULTS

Intermediate risk group is important as 23 out of 45 FN fell in the range 1:250 to 1:1100. By applying the proposed index, the ratio of fβ-hCG MoM to PAPP-A MoM and subsequent decision about NIPT, 8 out of 23 FN cases in intermediate group could be detected.

CONCLUSION

Compared with the current policy, our novel proposed approach had better performance and could be applied by the Iran National Health Service to improve the screening program guideline.

Effects of fetal gender and low first trimester aneuploidy screening markers on preterm birth

OBJECTIVE

To show the relation between fetal gender and preterm birth (PTB) in low values of first trimester aneuploidy test markers.

MATERIAL AND METHOD

A total of 29,528 patients included the study of them 7382 was PTB and all patients grouped according to fetal gender. Demographic data and perinatal complications were determined. According low PAPP-A MoM (<0.4) and low free BhCG MoM (<0.5) values PTB subgroup relative risks were calculated for each fetal gender.

RESULTS

The PTB rate and birth weight was significantly higher in male gender. At low PAPP-A MoM values Late PTB in male infant (aRR 95% CI 2.028) and late miscarriage (LM) category with low free BhCG MoM values in female infant (aRR 95% CI 0.907) was determined statistically significant.

CONCLUSIONS

Male gender has an effect on PTB rate. İn low values of first trimester aneuploidy test markers late PTB risk is increasing in male gender and also LM risk is decreasing in female gender. Further studies are required in order to determine the relation between PTB and fetal gender and first trimester aneuploidy screening test.

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.

First trimester ultrasound tests alone or in combination with first trimester serum tests for Down's syndrome screening

BACKGROUND

Down's syndrome occurs when a person has three, rather than two copies of chromosome 21; or the specific area of chromosome 21 implicated in causing Down's syndrome. It is the commonest congenital cause of mental disability and also leads to numerous metabolic and structural problems. It can be life-threatening, or lead to considerable ill health, although some individuals have only mild problems and can lead relatively normal lives. Having a baby with Down's syndrome is likely to have a significant impact on family life.Non-invasive screening based on biochemical analysis of maternal serum or urine, or fetal ultrasound measurements, allows estimates of the risk of a pregnancy being affected and provides information to guide decisions about definitive testing.Before agreeing to screening tests, parents need to be fully informed about the risks, benefits and possible consequences of such a test. This includes subsequent choices for further tests they may face, and the implications of both false positive and false negative screening tests (i.e. invasive diagnostic testing, and the possibility that a miscarried fetus may be chromosomally normal). The decisions that may be faced by expectant parents inevitably engender a high level of anxiety at all stages of the screening process, and the outcomes of screening can be associated with considerable physical and psychological morbidity. No screening test can predict the severity of problems a person with Down's syndrome will have.

OBJECTIVES

To estimate and compare the accuracy of first trimester ultrasound markers alone, and in combination with first trimester serum tests for the detection of Down's syndrome.

SEARCH METHODS

We carried out extensive literature searches including MEDLINE (1980 to 25 August 2011), Embase (1980 to 25 August 2011), BIOSIS via EDINA (1985 to 25 August 2011), CINAHL via OVID (1982 to 25 August 2011), and The Database of Abstracts of Reviews of Effects (the Cochrane Library 2011, Issue 7). We checked reference lists and published review articles for additional potentially relevant studies.

SELECTION CRITERIA

Studies evaluating tests of first trimester ultrasound screening, alone or in combination with first trimester serum tests (up to 14 weeks' gestation) for Down's syndrome, compared with a reference standard, either chromosomal verification or macroscopic postnatal inspection.

DATA COLLECTION AND ANALYSIS

Data were extracted as test positive/test negative results for Down's and non-Down's pregnancies allowing estimation of detection rates (sensitivity) and false positive rates (1-specificity). We performed quality assessment according to QUADAS criteria. We used hierarchical summary ROC meta-analytical methods to analyse test performance and compare test accuracy. Analysis of studies allowing direct comparison between tests was undertaken. We investigated the impact of maternal age on test performance in subgroup analyses.

MAIN RESULTS

We included 126 studies (152 publications) involving 1,604,040 fetuses (including 8454 Down's syndrome cases). Studies were generally good quality, although differential verification was common with invasive testing of only high-risk pregnancies. Sixty test combinations were evaluated formed from combinations of 11 different ultrasound markers (nuchal translucency (NT), nasal bone, ductus venosus Doppler, maxillary bone length, fetal heart rate, aberrant right subclavian artery, frontomaxillary facial angle, presence of mitral gap, tricuspid regurgitation, tricuspid blood flow and iliac angle 90 degrees); 12 serum tests (inhibin A, alpha-fetoprotein (AFP), free beta human chorionic gonadotrophin (ßhCG), total hCG, pregnancy-associated plasma protein A (PAPP-A), unconjugated oestriol (uE3), disintegrin and metalloprotease 12 (ADAM 12), placental growth factor (PlGF), placental growth hormone (PGH), invasive trophoblast antigen (ITA) (synonymous with hyperglycosylated hCG), growth hormone binding protein (GHBP) and placental protein 13 (PP13)); and maternal age. The most frequently evaluated serum markers in combination with ultrasound markers were PAPP-A and free ßhCG.Comparisons of the 10 most frequently evaluated test strategies showed that a combined NT, PAPP-A, free ßhCG and maternal age test strategy significantly outperformed ultrasound markers alone (with or without maternal age) except nasal bone, detecting about nine out of every 10 Down's syndrome pregnancies at a 5% false positive rate (FPR). In both direct and indirect comparisons, the combined NT, PAPP-A, free ßhCG and maternal age test strategy showed superior diagnostic accuracy to an NT and maternal age test strategy (P < 0.0001). Based on the indirect comparison of all available studies for the two tests, the sensitivity (95% confidence interval) estimated at a 5% FPR for the combined NT, PAPP-A, free ßhCG and maternal age test strategy (69 studies; 1,173,853 fetuses including 6010 with Down's syndrome) was 87% (86 to 89) and for the NT and maternal age test strategy (50 studies; 530,874 fetuses including 2701 Down's syndrome pregnancies) was 71% (66 to 75). Combinations of NT with other ultrasound markers, PAPP-A and free ßhCG were evaluated in one or two studies and showed sensitivities of more than 90% and specificities of more than 95%.High-risk populations (defined before screening was done, mainly due to advanced maternal age of 35 years or more, or previous pregnancies affected with Down's syndrome) showed lower detection rates compared to routine screening populations at a 5% FPR. Women who miscarried in the over 35 group were more likely to have been offered an invasive test to verify a negative screening results, whereas those under 35 were usually not offered invasive testing for a negative screening result. Pregnancy loss in women under 35 therefore leads to under-ascertainment of screening results, potentially missing a proportion of affected pregnancies and affecting test sensitivity. Conversely, for the NT, PAPP-A, free ßhCG and maternal age test strategy, detection rates and false positive rates increased with maternal age in the five studies that provided data separately for the subset of women aged 35 years or more.

AUTHORS' CONCLUSIONS

Test strategies that combine ultrasound markers with serum markers, especially PAPP-A and free ßhCG, and maternal age were significantly better than those involving only ultrasound markers (with or without maternal age) except nasal bone. They detect about nine out of 10 Down's affected pregnancies for a fixed 5% FPR. Although the absence of nasal bone appeared to have a high diagnostic accuracy, only five out of 10 affected Down's pregnancies were detected at a 1% FPR.

Combined first-trimester Down syndrome screening in HIV-infected women

OBJECTIVE

To determine if human immunodeficiency virus (HIV) infection or antiretroviral therapy interferes with maternal levels of free human β-chorionic gonadotrophin (hCGβ) and pregnancy-associated plasma protein-A (PAPP-A) and whether any such influence alters first-trimester Down syndrome (DS) screening in HIV-infected women.

STUDY DESIGN

We performed a multicenter 1:2 matched case-control study comparing 84 HIV-infected women with singleton pregnancies with controls randomly selected among uninfected women, delivered and screened in the same center and matched for maternal age, geographical origin and fetal sex.

RESULTS

Groups did not differ significantly in screening results, although case women showed a slightly lower median free hCGβ multiple of the median (MoM) (1.11 versus 1.24 MoM, p=0.32) and higher median PAPP-A MoM (1.45 versus 1.32 MoM, p=0.23) than control women. The false-positive rate was similar in the case and control groups (5% versus 6.5%, p=0.5). Biomarker levels did not differ when comparing treated and untreated patients with their respective controls, and with one another.

CONCLUSION

First-trimester DS combined screening biomarker levels and calculated risk do not seem to be significantly altered by HIV infection or antiretroviral treatment. This screening strategy appears to be suitable for HIV-infected women.

Early maternal serum ß-human chorionic gonadotropin (ß-hCG) levels and sex-related growth difference of IVF embryos

PURPOSE

Maternal serum ß-human chorionic gonadotropin (ß-hCG) represents the trophoblastic cell mass and is an indirect measurement of embryo development at early implantation stage. Studies in animals and human embryos detected sex-related growth differences (SRGD) in favour of male embryos during the pre-implantation period. The purpose of our study was to correlate SRGD and maternal serum ß-hCG at 16 days after embryo transfer.

METHODS

We retrospectively analysed all (fresh and frozen) non-donor, single embryo transfers (SET), elective and not elective, that were performed between December 2008 and December 2013. We included ß-hCG values from day 16 after oocyte collection of pregnancies resulting in live birth. Neonatal gender was retrieved from patient files. Male and female embryos were further grouped to cleavage and blastocyst stage transfers. Regression analysis for confounding variables included maternal age, maternal body mass index (BMI), use of micromanipulation (ICSI), embryo quality (grade), assisted hatching, day of transfer and fresh or frozen embryo transfer.

RESULTS

Seven hundred eighty-six non-donor SETs resulted in live birth. After including only day 16 serum ß-hCG results, 525 SETs were analysed. Neonatal gender was available for 522 cases. Mean maternal serum ß-hCG levels were similar, 347 ± 191 IU/L in the male newborn group and 371 ± 200 IU/L in the female group. The difference between ß-hCG levels remained insignificant after adjusting for confounding variables.

CONCLUSIONS

Early maternal ß-hCG levels after embryo transfers did not represent SRGD in our study.

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

Circulating levels of the placental glycoprotein hormone human chorionic gonadotropin (hCG) are higher in women carrying female v. male fetuses; yet, the significance of this difference with respect to maternal factors, environmental exposures and neonatal outcomes is unknown. As a first step in evaluating the biologic and clinical significance of sex differences in hCG, we conducted a population-level analysis to assess its stability across subgroups. Subjects were women carrying singleton pregnancies who participated in prenatal and newborn screening programs in CA from 2009 to 2012 (1.1 million serum samples). hCG was measured in the first and second trimesters and fetal sex was determined from the neonatal record. Multivariate linear models were used to estimate hCG means in women carrying female and male fetuses. We report fluctuations in the ratios of female to male hCG by maternal factors and by gestational age. hCG was higher in the case of a female fetus by 11 and 8% in the first and second trimesters, respectively (P<0.0001). There were small (1-5%) fluctuations in the sex difference by maternal race, weight and age. The female-to-male ratio in hCG decreased from 17 to 2% in the first trimester, and then increased from 2 to 19% in the second trimester (P<0.0001). We demonstrate within a well enumerated, diverse US population that the sex difference in hCG overall is stable. Small fluctuations within population subgroups may be relevant to environmental and physiologic effects on the placenta and can be probed further using these types of data.

Fetal sex dependency of maternal vascular adaptation to pregnancy: a prospective population-based cohort study

OBJECTIVE

To investigate fetal sex dependency of maternal vascular adaptation to pregnancy as assessed by uteroplacental vascular resistance and maternal blood pressure.

DESIGN

Prospective population-based cohort study.

SETTING

Rotterdam, the Netherlands.

POPULATION

In total, 8224 liveborn singleton pregnancies were included.

METHODS

Maternal vascular adaptation was assessed in all trimesters of pregnancy. Pregnancies were stratified into being either complicated by the placental syndrome (i.e. pre-eclampsia, fetal growth restriction or preterm birth, n = 1229) or uncomplicated (n = 6995).

MAIN OUTCOME MEASURES

First trimester: blood pressures. Second trimester: blood pressures, pulsatility index of the uterine artery (PI-UtA). Third trimester: blood pressures, PI-UtA, presence of notching in the uterine artery.

RESULTS

In women carrying a male fetus PI-UtA was higher than in women with a female fetus in the total group (second trimester P < 0.001, third trimester P = 0.005). Effect estimates differed between women with or without the placental syndrome. In the total group, women with a male fetus more often showed notching in the Doppler resistance pattern (odds ratio 1.42, 95% confidence interval 1.17-1.72). Different blood pressure patterns were observed between pregnant women with a male fetus and pregnant women with a female fetus and between complicated pregnancies and uncomplicated pregnancies.

CONCLUSION

Fetal sex is significantly associated with maternal vascular adaptation to pregnancy with differential effects in uncomplicated pregnancies and in pregnancies complicated by the placental syndrome.

TWEETABLE ABSTRACT

Fetal sex is significantly associated with maternal vascular adaptation to pregnancy.

First trimester PAPP-A MoM values predictive for breech presentation at term of pregnancy

INTRODUCTION

Our aim was to state the role of first trimester pregnancy-associated plasma protein A (PAPP-A)-multiple of the median (MoM) value as a predictor for breech presentation at term of pregnancy.

MATERIALS AND METHODS

In this retrospective study, we present data for 1100 singleton full-term deliveries that took place in a third-level hospital setting in northeast Italy between January 2004 and July 2007. For each case, PAPP-A, free beta-human chorionic gonadotropin and nuchal translucency were measured during prenatal trisomies screening (between 11 weeks and 13 weeks and 6 d). A wide range of predictive factors for breech presentation at term of pregnancy and other confounding elements were considered.

RESULTS

Of the 1100 singleton deliveries at term considered in our study, 40 babies were in breech presentation. Using bivariate analysis and multivariate logistic regression, a lower PAPP-A MoM than 0.63 (first quartile of our distribution) in the first trimester (OR 2.41, CI.95 1.25-4.67), and placental index at term higher than the median value (OR 2.04, CI.95 1.00-4.17) were proven to be associated with breech presentation at term.

CONCLUSIONS

A low PAPP-A during the first trimester was a predictive factor for breech presentation at term of pregnancy. Acknowledging and acting on this predictor could enable improved management of breech foetuses in the future.

Correlation of nuchal translucency and thyroxine at 11-13 weeks of gestation

OBJECTIVE

Nuchal translucency (NT) thickness is one of the major screening markers during the first trimester that could be influenced by several factors. Here, we investigated the association between NT thickness and thyroid related hormones.

METHODS

NT thickness was measured with transabdominal ultrasound in 643 pregnant women between 11 and 13 weeks of gestation. Maternal thyroxine (T4), free thyroxine (fT4) and thyroid-stimulating hormone (TSH) were evaluated. Bivariate correlations were assessed and thyroid profile was subcategorized with regard to the calculated reference ranges.

RESULTS

An inverse relation was found between serum levels of maternal T4 with NT thickness (r = -0.128, p = 0.001) and CRL (r = -0.168, p < 0.001). TSH and hCG were also found to be correlated (Spearman's correlation coefficient = -0.092, p = 0.019). Prevalence of maternal hypothyroidism and subclinical hypothyroidism were 1.1% and 3.7%, respectively.

CONCLUSION

Thyroid function tests are found to independently influence NT measurements in the first trimester. Assessment of hormones such as thyroxine could optimize the interpretation of screening tests for pathological conditions during pregnancy.

Sex differences in developmental programming models

The theory of developmental programming suggests that diseases such as the metabolic syndrome may be ‘programmed’ by exposure to adverse stimuli during early development. The developmental programming literature encompasses the study of a wide range of suboptimal intrauterine environments in a variety of species and correlates these with diverse phenotypic outcomes in the offspring. At a molecular level, a large number of variables have been measured and suggested as the basis of the programmed phenotype. The range of both dependent and independent variables studied often makes the developmental programming literature complex to interpret and the drawing of definitive conclusions difficult. A common, though under-explored, theme of many developmental programming models is a sex difference in offspring outcomes. This holds true across a range of interventions, including dietary, hypoxic, and surgical models. The molecular and phenotypic outcomes of adversein uteroconditions are often more prominent in male than female offspring, although there is little consideration given to the basis for this observation in most studies. We review the evidence that maternal energy investment in male and female conceptuses may not be equal and may be environment dependent. It is suggested that male and female development could be viewed as separate processes from the time of conception, with differences in both timing and outcomes.

Natural selection in utero induced by mass layoffs: the hCG evidence

Evolutionary theory, when coupled with research from epidemiology, demography, and population endocrinology, suggests that contracting economies affect the fitness and health of human populations via natural selection in utero. We know, for example, that fetal death increases more among males than females when the economy unexpectedly contracts; that unexpected economic contraction predicts low secondary sex ratios; and that males from low sex ratio birth cohorts live, on average, longer than those from high sex ratio cohorts. We also know that low levels of human chorionic gonadotropin (i.e., hCG) measured in the serum of pregnant women predict fetal death. We do not, however, know whether male survivors of conception cohorts subjected to contracting economies exhibit, as theory predicts, higher hCG than those from other cohorts. We show, in 71 monthly conception cohorts including nearly two million California births, that they do. We thereby add to the literature suggesting that the economy, a phenomenon over which we collectively exercise at least some control, affects population health. Our findings imply that the effect arises via natural selection - a mechanism we largely ignore when attempting to explain, or alter, how collective choice affects our biology.

Hormonal evidence supports the theory of selection in utero

OBJECTIVES

Antagonists in the debate over whether the maternal stress response during pregnancy damages or culls fetuses have invoked the theory of selection in utero to support opposing positions. We describe how these opposing arguments arise from the same theory and offer a novel test to discriminate between them. Our test, rooted in reports from population endocrinology that human chorionic gonadotropin (hCG) signals fetal fitness, contributes not only to the debate over the fetal origins of illness, but also to the more basic literature concerned with whether and how natural selection in utero affects contemporary human populations.

METHODS

We linked maternal serum hCG measurements from prenatal screening tests with data from the California Department of Public Health birth registry for the years 2001-2007. We used time series analysis to test the association between the number of live-born male singletons and median hCG concentration among males in monthly gestational cohorts.

RESULTS

Among the 1.56 million gestations in our analysis, we find that median hCG levels among male survivors of monthly conception cohorts rise as the number of male survivors falls.

RESULTS

Elevated median hCG among relatively small male birth cohorts supports the theory of selection in utero and suggests that the maternal stress response culls cohorts in gestation by raising the fitness criterion for survival to birth.

Women with chromosomally normal male fetuses are at increased risk of being referred for invasive testing following first-trimester risk assessment

OBJECTIVE

This study investigated the gender distribution in karyotype results from chorionic villus samples and amniocenteses performed due to an increased risk for Down syndrome based on first-trimester combined risk assessment.

METHODS

All prenatal karyotypes performed from 2006-2008 due to a risk assessment above 1:300 were retrieved from the Danish Central Cytogenetic Register. The distribution of gender for all newborns was obtained from Statistics Denmark. The χ(2) test and odds ratios were used for intergroup comparison.

RESULTS

We retrieved 5 157 karyotype results (54.9% male and 45.1% female karyotypes), of which 4 662 were normal. During the same period, 100 112 boys and 94 732 girls were born. Women carrying male fetuses were significantly more often referred for invasive testing than women carrying female fetuses (2.8 vs. 2.5%, p < 0.0001). However, the proportion of chromosomally normal male fetuses was significantly greater than that for female fetuses (92.0 vs. 88.4%, p < 0.0001).

CONCLUSION

A significantly higher proportion of women pregnant with male fetuses compared with female fetuses had an invasive diagnostic test performed prenatally following a risk assessment for Down syndrome.

Determination of fetal chromosome aberrations from fetal DNA in maternal blood: has the challenge finally been met?

The analysis of cell-free fetal nucleic acids in maternal blood for prenatal diagnosis has been transformed by several recent profound technology developments. The most noteworthy of these are 'digital PCR' and 'next-generation sequencing' (NGS), which might finally deliver the long-sought goal of noninvasive detection of fetal aneuploidy. Recent data, however, indicate that NGS might even be able to offer a much more detailed appraisal of the fetal genome, including paternal and maternal inheritance of point mutations for mendelian disorders such as β-thalassaemia. Although these developments are very exciting, in their current form they are still too complex and costly, and will need to be simplified considerably for their optimal translation to the clinic. In this regard, targeted NGS does appear to be a step in the right direction, although this should be seen in the context of ongoing progress with the isolation of fetal cells and with proteomic screening markers.

Early vaginal bleeding has no impact on markers used in first trimester aneuploidy screening

OBJECTIVE

To assess the impact of early vaginal bleeding on the levels of markers used in first trimester screening for aneuploidy.

METHODS

A retrospective analysis was carried out on the free beta human chorionic gonadotrophin (beta-hCG) and pregnancy associated plasma protein-A (PAPP-A) levels and nuchal translucency thickness in 49 653 women with a normal singleton fetus who had first trimester combined screening for Down Syndrome in three centres. Median MoMs and the distribution of log MoMs of the two markers were compared in two groups-7470 women who self-reported vaginal bleeding and 42 183 women who reported no vaginal bleeding at any stage prior to the screening test.

RESULTS

The overall median MoM free beta-hCG and that in the bleeding and non-bleeding group were 0.9854, 1.0012 and 0.9832, and for PAPP-A were 1.0407, 1.0413 and 1.037. There was no significant difference between the bleeding and non-bleeding group by median test (p = 0.080) or by t-test comparing log MoMs (p = 0.1305) for free beta-hCG and for PAPP-A with median test (p = 0.5071) or by t-test comparing log MoMs (p = 0.1740). For delta nuchal translucency (NT) there was also no significant difference between the bleeding and non-bleeding group (p = 0.055).

CONCLUSION

Vaginal bleeding has little or no impact on first trimester marker levels and no correction is necessary.