Low Birth Weight and Male Reproductive Function

The impact of impaired intrauterine growth on male fertility: A systematic review and meta-analysis

BACKGROUND

Adverse intrauterine environment was believed to have deleterious effects on the gonadal function. However, the association between impaired intrauterine growth and fertility in adult males has not been established.

OBJECTIVES

To compare the reproductive rates of males born small for gestational age (SGA), with low birth weight (LBW) or very low birth weight (VLBW) with control groups.

METHODS

The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement was followed to search PubMed, Web of Science, Cochrane Library, and Embase databases from inception to June 16, 2023. Cohort studies investigating the reproductive rates of males born SGA, with LBW or VLBW were included. A random or fixed effects model was used for different exposures.

RESULTS

A total of 10 studies out of 3,801 records were included. Males born SGA showed a higher risk of infertility than the control group (odds ratio, OR = 0.91, 95% confidence interval, 95% CI 0.89-0.93, p = 0.000). The reproductive rates of individuals born with LBW or VLBW were lower than the control group (OR = 0.86, 95% CI 0.78-0.94, p = 0.001; OR = 0.57, 95% CI 0.40-0.81, p = 0.002, respectively). Participants were further divided into two age groups of 18-35 and 35-45 years. In both subgroups, the reproductive rates were lower in males born SGA, with LBW or VLBW compared with controls. Sensitivity analysis showed the robustness of the pooled estimates among LBW and VLBW.

CONCLUSION

In summary, SGA, LBW, and VLBW were associated with a higher risk of male infertility in both early and middle adulthood. Achieving optimal intrauterine growth would be helpful to prevent male infertility.

Reproductive risks in 35-year-old adults born very preterm and/or with very low birth weight: an observational study

Evidence suggests that increased survival over the last decades of very preterm (VPT; gestational age < 32 weeks)- and very low birth weight (VLBW; birth weight < 1500 g)-born infants is not matched by improved outcomes. The objective of our study was to evaluate the reproductive rate, fertility, and pregnancy complications in 35-year-old VPT/VLBW subjects. All Dutch VPT/VLBW infants born alive in 1983 and surviving until age 35 (n = 955) were eligible for a POPS-35 study. A total of 370 (39%) subjects completed a survey on reproductive rate, fertility problems, pregnancy complications, and perinatal outcomes of their offspring. We tested differences in these parameters between the VPT/VLBW subjects and their peers from Dutch national registries. POPS-35 participants had less children than their peers in the CBS registry. They reported more problems in conception and pregnancy complications, including a three times increased risk of hypertension during pregnancy.Conclusion: Reproduction is more problematic in 35-year olds born VPT/VLBW than in the general population, possibly mediated by an increased risk for hypertension, but their offspring have no elevated risk for preterm birth. What is known: At age 28, the Dutch national POPS cohort, born very preterm or with a very low birth in 1983, had lower reproductive rates than the general Dutch population (female 23% versus 32% and male 7% versus 22%). What is new: At age 35, the Dutch POPS cohort still had fewer children than the general Dutch population (female 56% versus 74% and male 40% versus 56%). Females in the POPS cohort had a higher risk of fertility problems and pregnancy complications than their peers in the Dutch national registries, but their offspring had no elevated risk for preterm birth.

Altered umbilical sex steroids in preterm infants born small for gestational age

Background: Boys born small for gestational age (SGA) are at increased risk of testicular dysgenesis syndrome, and girls born SGA face the risk of polycystic ovary syndrome later in life. Our aim was to study whether neonates born SGA have an altered profile of steroid hormones at birth.Materials and methods: A total of 168 singletons (99 boys, 69 girls) born at 32.0-36.9 gestational weeks were recruited to a population-based, university hospital, single-center study. Of these, 31 infants (17 boys, 14 girls) were born SGA. The concentrations of dehydroepiandrosterone sulfate (DHEAS), androstenedione, testosterone, dihydrotestosterone, estrone, estradiol, cortisone, and cortisol were analyzed in umbilical cord serum with mass spectrometry.Results: Girls born SGA had higher levels of androstenedione than girls born appropriate for gestational age (AGA) (4.0 versus 2.6 nmol/L, p = .002). Boys born SGA had lower levels of estrone than boys born AGA (33 822 versus 62 471 pmol/L, p = .038). Infants born SGA had lower levels of cortisone than infants born AGA, both in girls (340 versus 579 nmol/L, p = .010) and in boys (308 versus 521 nmol/L, p = .045). Furthermore, boys born SGA had a higher cortisol/cortisone ratio than boys born AGA (0.41 versus 0.25, p = .028). Gestational age correlated with DHEAS (boys r = 0.48, p = .000, girls r = 0.35, p = .013), and cortisol (boys r = 0.48, p = .000, girls r = 0.29, p = .039).Conclusions: In moderate-to-late preterm infants born SGA, we observed a different steroid hormone profile in cord serum. Girls born SGA show increased levels of androstenedione and boys born SGA show decreased levels of estrone in cord serum, which could be related to placental aromatase deficiency in intrauterine growth restriction.

Placental Weight and Risk of Cryptorchidism and Hypospadias in the Collaborative Perinatal Project

Cryptorchidism and hypospadias are the most common congenital anomalies of the genitourinary tract in males, but their etiology remains unclear. Placental insufficiency has been suggested to be linked to both conditions. Placental weight is a commonly used proxy measure for placental insufficiency; thus, we examined placental weight and other placental characteristics in relation to cryptorchidism and hypospadias in the Collaborative Perinatal Project, a US mother-child cohort study. Pregnant women were recruited between 1959 and 1965. The analysis contrasted boys with cryptorchidism (n = 413) and boys with hypospadias (n = 145) with boys without cryptorchidism (n = 23,799) and boys without hypospadias (n = 22,326). Odds ratios and 95% confidence intervals were calculated using unconditional logistic regression. In categorical analyses in which the middle tertile was the referent, cryptorchidism was inversely associated with placental weight (odds ratio = 0.66, 95% confidence interval: 0.46, 0.95) among white boys and positively associated with the lowest tertile of placental weight among black boys (odds ratio = 1.70, 95% confidence interval: 1.11, 2.59). We conclude that lower placental weight may be related to risk of cryptorchidism. Further investigation of placental functioning may offer insights into the etiology of cryptorchidism.

Amniotic Fluid INSL3 Measured During the Critical Time Window in Human Pregnancy Relates to Cryptorchidism, Hypospadias, and Phthalate Load: A Large Case-Control Study

The period of the first to second trimester transition in human pregnancy represents a sensitive window for fetal organogenesis, particularly in regard to the development of the male reproductive system. This is a time of relative analytical inaccessibility. We have used a large national biobank of amniotic fluid samples collected at routine amniocentesis to determine the impacts of exogenous endocrine disruptor load on specific fetal biomarkers at this critical time. While adrenal and testicular steroids are highly correlated, they are also mostly positively influenced by increasing phthalate load, represented by the metabolites 7cx-MMeHP and 5cx-MEPP, by perfluorooctane sulfonate (PFOS) exposure, and by smoking, suggesting an adrenal stress response. In contrast, the testis specific biomarkers insulin-like peptide 3 (INSL3) and androstenedione are negatively impacted by the phthalate endocrine disruptors. Using a case-control design, we show that cryptorchidism and hypospadias are both significantly associated with increased amniotic concentration of INSL3 during gestational weeks 13-16, and some, though not all steroid biomarkers. Cases are also linked to a specifically increased variance in the Leydig cell biomarker INSL3 compared to controls, an effect exacerbated by maternal smoking. No influence of phthalate metabolites or PFOS was evident on the distribution of cases and controls. Considering that several animal and human studies have shown a negative impact of phthalate load on fetal and cord blood INSL3, respectively, the present results suggest that such endocrine disruptors may rather be altering the relative dynamics of testicular development and consequent hormone production, leading to a desynchronization of tissue organization during fetal development. Being born small for gestational age appears not to impact on the testicular biomarker INSL3 in second trimester amniotic fluid.

Placental surface area mediates the association between FGFR2 methylation in placenta and full-term low birth weight in girls

Background

Fibroblast growth factor receptor 2 (FGFR2) gene encodes a protein of the fibroblast growth factor receptor family. FGFR2 gene expression is associated with the regulation of implantation process of placenta which plays a vital role in fetal growth. DNA methylation is widely known as a mechanism of fetal growth. However, it is unclear whether and how DNA methylation of FGFR2 gene in the placenta is associated with full-term low birth weight. This case-control study aims to explore the links between FGFR2 methylation in placenta and full-term low birth weight and to further examine the mediation effect of placental surface area on this association.

Results

We conducted analyses for each of the five valid CpG sites at FGFR2 in 165 mother-baby pairs (86 FT-LBW vs. 79 FT-NBW) and found that per one standard deviation increase in the DNA methylation of CpG 11 at FGFR2 was associated with 1.64-fold higher risk of full-term low birth weight (OR = 1.64, 95% CI = [1.07, 2.52]) and 0.18 standard deviation decrease in placental surface area (β = - 0.18; standard error = 0.08, p = 0.02). The mediation effect of placental surface area on the association between DNA methylation and full-term low birth weight was significant in girls (OR = 1.38, 95% CI = [1.05, 1.80]) but not in boys. The estimated mediation proportion was 48.38%.

Conclusion

Our findings suggested that placental surface area mediated the association between DNA methylation of FGFR2 in placenta and full-term low birth weight in a sex-specific manner. Our study supported the importance of placental epigenetic changes in placental development and fetal growth.

Gonadotropin levels in urine during early postnatal period in small for gestational age preterm male infants with fetal growth restriction

OBJECTIVE

The objective of this study was to estimate gonadotropin concentrations in small for gestational age (SGA) male infants with the reactivation of the hypothalamic-pituitary-gonadal axis during the first few months of life that is important for genital development.

STUDY DESIGN

We prospectively examined 15 SGA and 15 appropriate for gestational age (AGA) preterm male infants between 2013 and 2014 at Kyoto University Hospital. Gonadotropin concentrations (luteinizing hormone (LH) and follicle-stimulating hormone (FSH)) were measured in serial urine samples from the postnatal days 7 to 168 and compared between SGA and AGA infants using the Mann-Whitney test.

RESULTS

A longitudinal analysis showed that SGA infants had higher LH and lower FSH concentrations (P=0.004 and P=0.006, respectively) than AGA infants.

CONCLUSION

Male infants who are SGA at birth because of fetal growth restriction have gonadotropin secretion abnormalities in the first few months of life.

Men becoming fathers by intracytoplasmic sperm injection were more often born small for gestational age

Being born with nonoptimal birth characteristics decreases the chance of becoming a father. Urogenital malformations as well as metabolic syndrome are more common in men born small for gestational age (SGA) and could be contributing factors to the reduced fertility rate seen in these men. It could imply that men becoming fathers by assisted reproductive technology (ART) more often are born with low birth weight (LBW), preterm, and/or SGA than men conceiving without treatment and also that men where intracytoplasmic sperm injection (ICSI) had to be performed more often are born with nonoptimal birth characteristics than men where conventional in vitro fertilization (IVF) successfully could be used. In this retrospective, case–control study using Swedish national registers, we compared the birth characteristics of 1206 men who have become fathers by ART with a control group consisting of age-matched men who became fathers without treatment. The differences in birth characteristics between men becoming fathers by IVF and ICSI were also assessed. For men becoming fathers by ART, OR of being born with LBW was 1.66 (95% CI = 1.17–2.36) compared with fathers who conceived without treatment. OR of being born prematurely was 1.32 (95% CI = 1.00–1.77). Men becoming fathers via ICSI had a doubled increased likelihood of being born SGA compared with men who became fathers via IVF (OR = 2.12; 95% CI = 1.17–3.83). In conclusion, we have found that men becoming fathers by ICSI treatments had more often been born SGA than men becoming fathers by conventional IVF.

Impact of uteroplacental insufficiency on postnatal rat male gonad

Prenatal events such as intrauterine growth restriction can affect gonadal development of the offspring and have an impact on reproductive health. To investigate the effects of intrauterine growth restriction induced by uterine artery ligation on the postnatal rat testis. Pregnant rats underwent uterine artery ligation at day 19 of gestation. Offspring were killed at 5, 20 and 40 days post-partum (dpp). At killing, one gonad was snap-frozen in liquid nitrogen and processed for RNA and steroid extraction. The other gonad was formalin-fixed for histology. Gene expression was analyzed by TaqMan Low-Density Array. Intratesticular testosterone, estradiol and serum gonadotrophins were measured. Thirty genes were dysregulated in intrauterine growth-restricted rats compared to controls, among which markers of Sertoli cell and Leydig cell function, cell metabolism and growth factors. Testis weights were significantly reduced at 5 and 20 dpp in intrauterine growth-restricted rats and caught-up by 40 dpp Accordingly, Sertoli cell number was significantly lower in 5 dpp intrauterine growth-restricted rats. At 20 dpp, intratesticular testosterone was significantly increased in intrauterine growth-restricted rats, whereas serum gonadotrophins were unchanged. IUGR altered the gene expression in the rat testes up to peripubertal age and reduced testis size and Sertoli cell number in neonatal age. Multiple mechanisms encompassing genetic changes and steroid production by the testis may be involved in the catch-up growth phase that restored testis size by 40 dpp Permanent consequences on organ function and gamete integrity cannot be excluded and deserve further investigations.

Maternal treatment with dexamethasone during lactation delays male puberty and disrupts reproductive functions via hypothalamic-pituitary-gonadal axis alterations

The effects of maternal treatment with dexamethasone during lactation on pubertal timing, serum hormonal profile and sperm indices in the male offspring were assessed. Twenty lactating dams were divided into 4 groups (n=5). Group 1 was administered subcutaneously 0.02ml/100g/day normal saline at lactation days 1-21. Groups 2-4 were administered subcutaneously 100μg/kg/day dexamethasone (Dex) at lactation days 1-7, 1-14, and 1-21 respectively. Results showed that there was significant reduction in serum testosterone in the DexLD 1-7 (p<0.05), DexLD 1-14 (p<0.01) and DexLD 1-21 (p<0.001) relative to control. In addition there was a significant reduction in serum FSH and LH in the DexLD 1-7 (p<0.01), DexLD 1-14 (p<0.001) and DexLD 1-21 (p<0.001) when compared with the control. Treatment with dexamethasone during lactation significantly increased the days of preputial separation in the DexLD 1-7 (p<0.05), DexLD 1-14 (p<0.05) and DexLD 1-21 (p<0.001) relative to control. Maternal treatment with dexamethasone throughout lactation period also significantly reduced sperm counts (p<0.001), motility (p<0.01) and increased percentage abnormal sperm (p<0.001) in the offspring when compared with the control. In conclusion, maternal treatment with dexamethasone during lactation may induce delayed puberty and disrupt reproductive functions by altering activities at hypothalamic-pituitary-gonadal axis in the male offspring.

Reproductive outcomes of women and men born very preterm and/or with a very low birth weight in 1983: a longitudinal cohort study in the Netherlands

The aims of this study were to analyze reproductive outcomes of women and men born very preterm (gestational age <32 weeks) or with a very low birth weight (<1500 g) in 1983 in the Netherlands and to compare their reproductive outcomes with the total population at a similar age of 28 years. Young adults who were born after a pregnancy complicated by very preterm (VP) delivery or with a very low birth weight (VLBW) in the Netherlands in 1983 (Project on Preterm and Small for Gestational Age Infants (POPS) cohort) were invited to complete an online questionnaire at the age of 28. In total, 293 POPS-28 participants (31.6%) completed the questionnaire including 185 female and 108 male participants. Female and male participants who were born VP or with a VLBW had significant reduced reproductive rates compared to the total Dutch population at 28 years of age (female 23.2 vs 31.9% and male 7.4 vs 22.2%). Pregnancies of the female participants were in 14% complicated by preterm delivery in at least one pregnancy.

CONCLUSION

This study indicates that women and men born VP or with a VLBW have reduced reproductive rates at the age of 28 compared to the total Dutch population at a similar age.

Hypospadias: Prevalence, birthweight and associated major congenital anomalies

The aim of this study was to determine the prevalence of hypospadias over 24 years in a Danish population and to describe the relation to birthweight and associated major congenital anomalies. It is a population-based study of all cases (live births, fetal deaths and elective terminations of pregnancy) with hypospadias born in the period 1986-2009 in Funen County and reported to the EUROCAT registry of congenital anomalies. Cases were included only if surgery for hypospadias was performed. 223 cases of hypospadias were registered during the period 1986-2009 with an overall prevalence of 16.9 per 10 000 births. The prevalence was significantly higher in 2000-2009 compared to 1986-1999 (P < 0.001). We found a three times higher occurrence of VLBW (very low birthweight) infants among cases with hypospadias. Infants with isolated hypospadias were more likely to have mild hypospadias (68%) while cases with associated major congenital anomalies were less likely to have mild hypospadias (42%) (P < 0.05). Hypospadias was associated with VLBW and the severity of the defect was related to the presence of major congenital anomalies. The prevalence of hypospadias has increased during the study period. The relation to VLBW could indicate a causal relationship for hypospadias or a shared pathogenic factor.

Possible fetal determinants of male infertility

Although common reproductive problems, such as male infertility and testicular cancer, present in adult life, strong evidence exists that these reproductive disorders might have a fetal origin. The evidence is derived not only from large epidemiological studies that show birth-cohort effects with regard to testicular cancer, levels of testosterone and semen quality, but also from histopathological observations. Many infertile men have histological signs of testicular dysgenesis, including Sertoli-cell-only tubules, immature undifferentiated Sertoli cells, microliths and Leydig cell nodules. The most severe gonadal symptoms occur in patients with disorders of sexual development (DSDs) who have genetic mutations, in whom even sex reversal of individuals with a 46,XY DSD can occur. However, patients with severe DSDs might represent only a small proportion of DSD cases, with milder forms of testicular dysgenesis potentially induced by exposure to environmental and lifestyle factors. Interestingly, maternal smoking during pregnancy has a stronger effect on spermatogenesis than a man's own smoking. Other lifestyle factors such as alcohol consumption and obesity might also have a role. However, increasing indirect evidence exists that exposure to ubiquitous endocrine disrupting chemicals, present at measurable concentrations in individuals, might affect development of human fetal testis. If confirmed, health policies to prevent male reproductive problems should not only target adult men, but also pregnant women and their children.

Maternal medication and herbal use and risk for hypospadias: data from the National Birth Defects Prevention Study, 1997-2007

PURPOSE

To investigate associations between maternal use of common medications and herbals during early pregnancy and risk for hypospadias in male infants.

METHODS

We used data from the National Birth Defects Prevention Study, a multi-site, population-based, case-control study. We analyzed data from 1537 infants with second-degree or third-degree isolated hypospadias and 4314 live-born male control infants without major birth defects, with estimated dates of delivery from 1997 to 2007. Exposure was reported use of prescription or over-the-counter medications or herbal products, from 1 month before to 4 months after conception. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were estimated using multivariable logistic regression, adjusting for maternal age, race/ethnicity, education, pre-pregnancy body mass index, previous live births, maternal subfertility, study site, and year.

RESULTS

We assessed 64 medication and 24 herbal components. Maternal uses of most components were not associated with an increased risk of hypospadias. A new associations was observed for venlafaxine (aOR 2.4; 95%CI 1.0, 6.0) [Correction made here after initial online publication.]. The previously reported association for clomiphene citrate was confirmed (aOR 1.9; 95%CI 1.2, 3.0). Numbers were relatively small for exposure to other specific patterns of fertility agents, but elevated aORs were observed for the most common of them.

CONCLUSIONS

Overall, findings were reassuring that hypospadias is not associated with most medication components examined in this analysis. New associations will need to be confirmed in other studies. Increased risks for hypospadias associated with various fertility agents raise the possibility of confounding by underlying subfertility.

Reproductive patterns among twins--Swedish register study of men and women born 1973-1983

Background

During the last decades there has been a steady increase of twin births. A combination of improved medical treatment of preterm and small-for-gestational age children has contributed to a higher number of surviving twins. Prematurity is known to affect reproduction in a negative way. Few studies have focused on the potential effect twinning may have on future reproduction. Thus, the aim of this study was to investigate the effect of being born a twin compared to being born a singleton have on future reproduction.

Methods

In a national population-based register study, all individuals born between 1973–1983 who were alive and living in Sweden at 13 years of age (n = 1 016 908) constituted the sample. Data on each study subject’s own birth as well as the birth of their first offspring, and parental socio-demographic factors were collected from Swedish population based registers. Hazard ratios and corresponding 95% CI was calculated using Cox proportional hazards model.

Results

Twins, both men and women, had a reduced likelihood of reproducing compared to singletons (women: HR = 0.89, 95% CI = 0.86-0.93; men: HR = 0.92, 95% CI = 0.87-0.97). This difference in birth rates can only partly be explained by diverging birth characteristics. Amongst men and women born very preterm, twins had an increased likelihood of reproducing compared to singletons (women: HR = 1.25, 95% CI = 1.02-1.62; men: HR = 1.34, 95% CI = 1.01-1.78).

Conclusions

Twins have lower reproduction rates compared to singletons, which only to a certain degree can be explained by diverging birth characteristics.

Low birth weight: causes and consequences

During our phylogenetic evolution we have selected genes, the so called thrifty genes, that can help to maximize the amount of energy stored from every consumed calorie. An imbalance in the amount of stored calories can lead to many diseases. In the early 80's the distinguished English epidemiologist David Barker, formulated a hypothesis suggesting that many events that occur during the intrauterine life and early in infancy can influence the occurrence of many diseases that will develop in adulthood. This theory proposes that under-nutrition and other insult or adverse stimulus in utero and during infancy can permanently change the body's structure, physiology and metabolism. The lasting or lifelong effects of under-nutrition will depend on the period in the development at which it occurs. The clues that led Barker to his conclusions started to be discovered when he was studying the temporal trends in the incidence of ischemic heart disease in England and Wales. Examining data found in The Hertfordshire records, collected in the beginning of the last century, he found that the rates of mortality by ischemic heart disease was much higher in children born in less affluent counties and mostly in those with low birth weight. After his initial findings a myriad of diseases have been found to be linked to low birth weight and under-nutrition in utero and in the neonatal period. These diseases were then nominated adult diseases with fetal origin. Epidemiological studies that led to these findings suggest that in utero and early postnatal life have critical importance for long-term programming of health and disease, opening unique chances for primary prevention of chronic diseases.

Spermatogenic defects in F2 mice between normal mouse strains C3H and C57BL/6 without mutation

Genetic disorders are usually considered to be caused by harmful gene mutations, as well as by chromosomal aberrations, including small insertions, duplications and/or deletions. However, as infertile individuals often arise among the offspring of crosses between two fertile mouse strains, we postulate that a certain combination of 'normal' genes with neither gene mutations nor chromosomal aberrations can cause such serious phenotypic alterations as reproductive dysfunction. In this study, we show evidence that a combination of multiple normal genes from two different normal mouse strains manifests a wide range of male reproductive dysfunctions, from benign changes to complete infertility. These abnormal phenotypes are thought to have occurred by epistatic interactions of alleles.

Mechanisms affecting neuroendocrine and epigenetic regulation of body weight and onset of puberty: potential implications in the child born small for gestational age (SGA)

Signaling peptides produced in peripheral tissues such as gut, adipose tissue, and pancreas communicate with brain centers, such as hypothalamus and hindbrain to manage energy homeostasis. These regulatory mechanisms of energy intake and storage have evolved during long periods of hunger in the evolution of man to protect the species from extinction. It is now clear that these circuitries are influenced by prenatal and postnatal environmental factors including endocrine disruptive chemicals. Hypothalamic appetite regulatory systems develop and mature in utero and early infancy, and involve signaling pathways that are important also for the regulation of puberty onset. Recent studies in humans and animals have shown that metabolic pathways involved in regulation of growth, body weight gain and sexual maturation are largely affected by epigenetic programming that can impact both current and future generations. In particular, intrauterine and early infantile developmental phases of high plasticity are susceptible to factors that affect metabolic programming that therefore, affect metabolic function throughout life. In children born small for gestational age, poor nutritional conditions during gestation can modify metabolic systems to adapt to expectations of chronic undernutrition. These children are potentially poorly equipped to cope with energy-dense diets and are possibly programmed to store as much energy as possible, leading to later obesity, metabolic syndrome, disturbed regulation of normal puberty and early onset of cardiovascular disease. Most cases of disturbed energy balance are likely a result of a combination of genetics, epigenetics and environment. This review will discuss potential mechanisms linking intrauterine growth retardation with changes in growth, energy homeostasis and sexual maturation.

Cryptorchidism and hypospadias in a cohort of 934,538 Danish boys: the role of birth weight, gestational age, body dimensions, and fetal growth

Early delivery and low birth weight are strong predictors of the urogenital anomalies cryptorchidism (undescended testis) and hypospadias. Understanding these associations may lead to important etiologic clues. Therefore, the authors revisited the prevailing hypotheses regarding fetal growth restriction as a risk factor for urogenital anomalies. They studied a population of 934,538 Danish boys born alive between January 1, 1980, and December 31, 2008. Cryptorchidism and hypospadias were associated with low weight-for-gestational-age, an indicator of fetal growth restriction, and furthermore the authors observed strong interaction with early delivery. Low birth weight in a singleton compared with the mean birth weight of all singleton brothers in the family or in a twin compared with the male co-twin was associated with higher risk of urogenital anomalies, suggesting an effect of relative fetal growth restriction within families. Contrary to previous reports, newborns' body dimensions assessed independently of birth weight were not associated with urogenital anomalies. The hypothesis that shared factors cause both fetal growth restriction and urogenital anomalies was supported by comparison of urogenital anomaly risks in singletons and twins and by patterns of cryptorchidism and hypospadias co-occurrence in individuals. These novel insights might also extend to other male reproductive conditions with prenatal etiology.

Twinning Rates According to Maternal Birthweight

Dizygotic twinning rates have changed over time, which has been seen as a sign of a decline in fecundity. Since a woman's birthweight has been shown to be a marker of her fecundity, maternal birthweight may correlate with subsequent twinning rates. In the Danish National Birth Cohort (1996–2002), we examined if maternal birthweight, and whether she was born at term or preterm, correlated with her probability of multiple birth. For 20,719 live born infants, we had self-reported information about maternal birthweight, collected during the first wave of the 7-year follow-up, and information on multiple births from record linkage. The association between maternal birthweight and multiple births was investigated by use of logistic regression and presented as odds ratios (ORs) with 95% confidence intervals (CIs). Compared to women born at term with a birthweight of 3001–4000 g, women with a birthweight > 4500 g appeared to have higher chance of multiple birth while women with a birthweight of 4001–4500 had a lower chance, especially if the analysis was restricted to women with a BMI < 25 (Adjusted ORs 2.3 [1.0–5.4] and 0.4 [0.2–0.9] respectively). Odds ratios for dizygotic twinning were of the same magnitude. In women with a BMI ≥ 25, no obvious pattern was present. Our findings do not indicate that twinning is a fecundity indicator. Women with a birthweight that may indicate a pregnancy complicated with gestational diabetes had the highest rate of multiple birth. These findings are new and should be put to a critical test in other data sources.

Premature birth and low birthweight are associated with a lower rate of reproduction in adulthood: a Swedish population-based registry study

BACKGROUND

The aim of this study was to investigate if individuals born with sub-optimal birth characteristics have reduced probability of reproducing in adulthood.

METHODS

Using population-based registries, the authors included 522 216 males and 494 692 females born between 1973 and 1983 and examined their reproductive status as of 2006. Outcome measure was the hazard ratio (HR) of reproducing. Adjustments were made for socio-economic factors.

RESULTS

Males and females born very premature displayed a reduced probability of reproducing [HR = 0.78, 95% confidence interval (CI): 0.70-0.86 for males; HR = 0.81, CI: 0.75-0.88 for females]. Likewise for very low birthweight (HR = 0.83, CI: 0.71-0.95 for males; HR = 0.80, 95% CI: 0.72-0.89 for females). Individuals born large for gestational age (LGA) displayed no significant changes. Males born small for gestational age (SGA) had a 9% lower reproductive rate (CI: 0.89-0.94) and that reduction increased as the individuals aged. Women born SGA tended to start reproducing at an earlier age.

CONCLUSION

The results suggest that being born with low birthweight, premature or SGA (for males) is associated with a reduced probability of reproducing as an adult. LGA shows no statistically significant relationship with future reproduction.

Spermatogenesis in cryptorchidism

Cryptorchidism or undescended testis is the most frequent congenital abnormality in newborn boys. The process of testicular descent to the scrotum is controlled by hormones produced in Leydig cells, insulin-like3, and androgens. Variation in genetic and environmental factors might affect testicular descent. A failure of spermatogenesis and germ cell apoptosis resulting in infertility as well as an increased risk of neoplastic transformation of germ cell are the direct consequences of cryptorchidism in adulthood.

Short- and long-term reproductive effects of prenatal and lactational growth restriction caused by maternal diabetes in male rats

BACKGROUND

A suboptimal intrauterine environment may have a detrimental effect on gonadal development and thereby increases the risk for reproductive disorders and infertility in adult life. Here, we used uncontrolled maternal diabetes as a model to provoke pre- and perinatal growth restriction and evaluate the sexual development of rat male offspring.

METHODS

Maternal diabetes was induced in the dams through administration of a single i.v. dose of 40 mg/kg streptozotocin, 7 days before mating. Female rats presenting glycemic levels above 200 mg/dL after the induction were selected for the experiment. The male offspring was analyzed at different phases of sexual development, i.e., peripuberty, postpuberty and adulthood.

RESULTS

Body weight and blood glucose levels of pups, on the third postnatal day, were lower in the offspring of diabetic dams compared to controls. Maternal diabetes also provoked delayed testicular descent and preputial separation. In the offspring of diabetic dams the weight of reproductive organs at 40, 60 and 90 days-old was lower, as well as sperm reserves and sperm transit time through the epididymis. However the plasma testosterone levels were not different among experimental groups.

CONCLUSIONS

It is difficult to isolate the effects directly from diabetes and those from IUGR. Although the exposure to hyperglycemic environment during prenatal life and lactation delayed the onset of puberty in male rats, the IUGR, in the studied model, did not influenced the structural organization of the male gonads of the offspring at any point during sexual development. However the decrease in sperm reserves in epididymal cauda and the acceleration in sperm transit time in this portion of epididymis may lead to an impairment of sperm quality and fertility potential in these animals. Additional studies are needed in attempt to investigate the fertility of animals with intrauterine growth restriction by maternal diabetes and possible multigenerational effects.

Latin American consensus: children born small for gestational age

BACKGROUND

Children born small for gestational age (SGA) experience higher rates of morbidity and mortality than those born appropriate for gestational age. In Latin America, identification and optimal management of children born SGA is a critical issue. Leading experts in pediatric endocrinology throughout Latin America established working groups in order to discuss key challenges regarding the evaluation and management of children born SGA and ultimately develop a consensus statement.

DISCUSSION

SGA is defined as a birth weight and/or birth length greater than 2 standard deviations (SD) below the population reference mean for gestational age. SGA refers to body size and implies length-weight reference data in a geographical population whose ethnicity is known and specific to this group. Ideally, each country/region within Latin America should establish its own standards and make relevant updates. SGA children should be evaluated with standardized measures by trained personnel every 3 months during year 1 and every 6 months during year 2. Those without catch-up growth within the first 6 months of life need further evaluation, as do children whose weight is ≤ -2 SD at age 2 years. Growth hormone treatment can begin in SGA children > 2 years with short stature (< -2.0 SD) and a growth velocity < 25th percentile for their age, and should continue until final height (a growth velocity below 2 cm/year or a bone age of > 14 years for girls and > 16 years for boys) is reached. Blood glucose, thyroid function, HbA1c, and insulin-like growth factor-1 (IGF-1) should be monitored once a year. Monitoring insulin changes from baseline and surrogates of insulin sensitivity is essential. Reduced fetal growth followed by excessive postnatal catch-up in height, and particularly in weight, should be closely monitored. In both sexes, gonadal function should be monitored especially during puberty.

SUMMARY

Children born SGA should be carefully followed by a multidisciplinary group that includes perinatologists, pediatricians, nutritionists, and pediatric endocrinologists since 10% to 15% will continue to have weight and height deficiency through development and may benefit from growth hormone treatment. Standards/guidelines should be developed on a country/region basis throughout Latin America.

Food availability at birth limited reproductive success in historical humans

Environmental conditions in early life can profoundly affect individual development and have consequences for reproductive success. Limited food availability may be one of the reasons for this, but direct evidence linking variation in early-life nutrition to reproductive performance in adulthood in natural populations is sparse. We combined historical agricultural data with detailed demographic church records to investigate the effect of food availability around the time of birth on the reproductive success of 927 men and women born in 18th-century Finland. Our study population exhibits natural mortality and fertility rates typical of many preindustrial societies, and individuals experienced differing access to resources due to social stratification. We found that among both men and women born into landless families (i.e., with low access to resources), marital prospects, probability of reproduction, and offspring viability were all positively related to local crop yield during the birth year. Such effects were generally absent among those born into landowning families. Among landless individuals born when yields of the two main crops, rye and barley, were both below median, only 50% of adult males and 55% of adult females gained any reproductive success in their lifetime, whereas 97% and 95% of those born when both yields were above the median did so. Our results suggest that maternal investment in offspring in prenatal or early postnatal life may have profound implications for the evolutionary fitness of human offspring, particularly among those for which resources are more limiting. Our study adds support to the idea that early nutrition can limit reproductive success in natural animal populations, and provides the most direct evidence to date that this process applies to humans.

Early life nutrition and metabolic programming

Research investigating the early programming of adult metabolic disease has in recent years provided much mechanistic insight into how the early environment impacts on long-term health. It includes studies addressing the roles of intrauterine nutrient availability, which is determined by maternal nutrition, maternal exposure to oxygen, toxic events, and infection; the placental interface; and also the early postnatal environment. This review will explore the epidemiological evidence for programming of metabolic disease and provide an overview of the various studies using animals to model metabolic phenotypic outcome. It will also discuss evidence for the proposed molecular mechanisms and the potential for intervention.

Low testosterone levels in pre-term newborns born small for gestational age

Previous studies showed that small for gestational age (SGA) newborns have an increased prevalence of hypospadias and other congenital defects of external genitalia. We observed that in the first days of life, SGA male pre-term newborns have reduced testosterone levels compared with adequate for gestational age pre-term newborns, independently from the presence of abnormalities of the external genitalia.

Testicular dysgenesis syndrome: foetal origin of adult reproductive problems

The evidence for the existence of testicular dysgenesis syndrome (TDS) is presented in this review. Several epidemiological studies have shown that conditions like cryptorchidism, impaired spermatogenesis, hypospadias and testicular cancer can be associated as risk factors for each other. Thus, the risk of testis cancer is significantly increased in men with cryptorchidism and/or infertility. Several recent studies point towards early dysgenesis of the foetal testis as the biological link between these disorders. Dysgenesis has been demonstrated in biopsies of the contralateral testis of men with testis cancer and in infertile men. The histological evidence includes immature seminiferous tubules with undifferentiated Sertoli cells, microliths and Sertoli-cell only tubules. Dysgenetic testes often have an irregular ultrasound pattern, where microliths may also be visible. Our current hypothesis is that maternal exposure to endocrine disrupting chemicals may contribute to the pathogenesis of TDS. Animal experiments have shown that all TDS symptoms, except testicular cancer, can be induced by foetal exposure to anti-androgenic chemicals. However, the cause of TDS in humans remains to be determined.

46,XY disorders of sex development (DSD)

The term disorders of sex development (DSD) includes congenital conditions in which development of chromosomal, gonadal or anatomical sex is atypical. Mutations in genes present in X, Y or autosomal chromosomes can cause abnormalities of testis determination or disorders of sex differentiation leading to 46,XY DSD. Detailed clinical phenotypes allow the identification of new factors that can alter the expression or function of mutated proteins helping to understand new undisclosed biochemical pathways. In this review we present an update on 46,XY DSD aetiology, diagnosis and treatment based on extensive review of the literature and our three decades of experience with these patients.

Gestational hypertension, preeclampsia, and risk of testicular cancer

Altered levels of pregnancy hormones have been suggested to initiate testicular cancer prenatally in the male fetus. The placenta is the main source of pregnancy hormones, and pregnancy hypertension and preeclampsia are associated with placental malfunction, including altered levels of hormones such as estrogen and human chorionic gonadotropin. We therefore evaluated fetal exposure to pregnancy hypertension and preeclampsia in relation to risk of testicular cancer in adolescent and adult life. We identified 293 cases of germ cell testicular cancer in the Swedish Cancer Register, and 861 controls in the Swedish Medical Birth Register. The standardized antenatal and delivery charts of the cases and controls were traced in the archives of the delivery units, and information about maternal and pregnancy characteristics such as gestational hypertension, proteinuria, anemia, and glucosuria were extracted. Odds ratios (OR) with 95% confidence intervals (CI) were calculated using conditional logistic regression. We found a strongly decreased risk of testicular cancer among subjects exposed to severe gestational hypertension (OR, 0.29; 95% CI, 0.12-0.74, compared with no hypertension), whereas the risk was increased among those exposed to mild gestational hypertension (OR, 1.62; 95% CI, 0.98-2.69) during the fetal period. The mechanism behind the association between pregnancy hypertension and testicular cancer is unclear, but our findings may reflect a potentially protective effect of the altered pregnancy hormones such as human chorionic gonadotropin that occur in severe gestational hypertension and preeclampsia.

Impact of being born small for gestational age on onset and progression of puberty

Children born small for gestational age (SGA) are at higher risk for perinatal morbidity, mortality and chronic diseases in later life. There is increasing evidence for a link between prenatal growth and pubertal development, but studies concerning the timing, duration and progression of puberty in these children are scarce and the results are difficult to compare due to the various methodologies employed. Most boys born SGA have normal pubertal timing, but often attain an adult height below the target height. In girls, most studies document a relationship between intra-uterine growth retardation and earlier pubertal development or normal timing but with rapid progression. This chapter will discuss the factors that could influence pubertal development in children born SGA and the information reported to date.

Environment, testicular dysgenesis and carcinoma in situ testis

The testicular dysgenesis syndrome (TDS) hypothesis proposes that a proportion of the male reproductive disorders-cryptorchidism, hypospadias, infertility and testicular cancer-may be symptoms of one underlying developmental disease, TDS, which is most likely a result of disturbed gonadal development in the embryo. TDS may be caused by genetic factors, environmental/life-style factors, or a combination of both. Some rare disorders of sex development of genetic origin are among the best-known examples of severe TDS. Among the environmental and life-style factors that are suspected to influence the hormonal milieu of the developing gonad are the endocrine disrupters. A prenatal exposure to commonly used chemicals, e.g. phthalates, may result in a TDS-like phenotype in rats. Currently, this animal model is the best model for TDS. In humans the situation is much more complex, and TDS exists in a wide range of phenotypes: from the mildest and most common form, in which impaired spermatogenesis is the only symptom, to the most severe cases, in which the patient may develop testicular cancer. It is of great importance that clinicians in different specialties treating patients with TDS are aware of the association between the different symptoms.

Current approaches for detection of carcinoma in situ testis

Testicular germ cell tumours have a favourable prognosis if detected early, but are potentially lethal in a subset of patients. Multi-modality treatment is often necessary, thus the preferable time of diagnosis is at the pre-invasive, but unfortunately often asymptomatic precursor stage of carcinoma in situ (CIS). This review describes current possible approaches for the detection of CIS. At present, an open testicular biopsy is the only definitive way of establishing the presence of CIS. The tissue section should be of an adequate size, be properly fixed, and evaluation be supported by at least one solid immunohistochemical marker, for example PLAP, OCT-3/4 or AP-2gamma. Determination of who should be offered testicular biopsies is based on clinical and ultrasonic examination along with the evaluation of risk factors. A surgical biopsy is an invasive procedure with potential complications, although rare. Therefore, a noninvasive and equally reliable method is needed. Testicular ultrasound is risk-free, painless and at present the only noninvasive method of aid for andrologists when CIS is suspected. The presence of testicular microlithiasis is, in some cases, indicative of pre-malignant changes, especially in males with additional risk factors. Promising results have recently been obtained with a novel noninvasive detection method based on immunocytological AP-2gamma-staining of CIS cells in semen. This method could be a supporting method in andrology centres where careful follow-up is possible. In conclusion, one difficulty is to determine in which males CIS should be suspected; secondly, there does not as yet exist an optimal noninvasive method of diagnosis that is more acceptable than an open surgical biopsy.

Managing Q fever during pregnancy: the benefits of long-term cotrimoxazole therapy

BACKGROUND

Q fever is a zoonosis caused by Coxiella burnetii. During pregnancy, it may result in obstetric complications, such as spontaneous abortion, intrauterine growth retardation, intrauterine fetal death, and premature delivery. Pregnant women are exposed to the risk of chronic Q fever.

METHODS

We included 53 pregnant women who received a diagnosis of Q fever. We compared the incidence of obstetric and maternal Q fever complications for women who received long-term cotrimoxazole treatment (n=16) with that for women who did not receive long-term cotrimoxazole treatment (n=37); long-term cotrimoxazole treatment was defined as oral administration of trimethoprim-sulfamethoxazole during at least 5 weeks of pregnancy.

RESULTS

Obstetric complications were observed in 81.1% of pregnant women who did not receive long-term cotrimoxazole therapy: 5 (13.5%) women experienced spontaneous abortions, 10 (27%) experienced intrauterine growth retardation, 10 (27%) experienced intrauterine fetal death, and 10 (27%) experienced premature delivery. Oligoamnios was observed in 4 patients (10.8%). Obstetric complications were found to occur significantly more often in patients infected during their first trimester of pregnancy than in those infected later (P=.032). The outcome of the pregnancy was found to depend on placental infection by C. burnetii (P=.013). Long-term cotrimoxazole treatment protected against maternal chronic Q fever (P=.001), placental infection (P=.038), and obstetric complications (P=.009), especially intrauterine fetal death (P=.018), which was found to be related to placental infection (P=.008).

CONCLUSIONS

Q fever during pregnancy results in severe obstetric complications, including oligoamnios. Because of its ability to protect against placental infection, intrauterine fetal death, and maternal chronic Q fever, long-term cotrimoxazole treatment should be used to treat pregnant women with Q fever.

Cryptorchidism: classification, prevalence and long-term consequences

Undescended testis is a common finding in boys, and the majority of cases have no discernible aetiology. There are unexplained geographical differences and temporal trends in its prevalence. Cryptorchidism, especially bilateral, is associated with impaired spermatogenesis and endocrine function and increases the risk of testicular cancer. There is an urgent need to identify factors that adversely affect testicular development and optimize treatment.

CONCLUSION

Cryptorchidism may reflect a primary testicular maldevelopment with long-term consequences.

Androgen resistance

Androgen resistance causes the androgen insensitivity syndrome in its variant forms and is a paradigm of clinical syndromes associated with hormone resistance. In its complete form, the syndrome causes XY sex reversal and a female phenotype. Partial resistance to androgens is a common cause of ambiguous genitalia of the newborn, but a similar phenotype may result from several other conditions, including defects in testis determination and androgen biosynthesis. The biological actions of androgens are mediated by a single intracellular androgen receptor encoded by a gene on the long arm of the X chromosome. Mutations in this gene result in varying degrees of androgen receptor dysfunction and phenotypes that often show poor concordance with the genotype. Functional characterization and three-dimensional modelling of novel mutant receptors has been informative in understanding the mechanism of androgen action. Management issues in syndromes of androgen insensitivity include decisions on sex assignment, timing of gonadectomy in relation to tumour risk, and genetic and psychological counselling.

Phthalate exposure and male infertility

Phthalates have been used as additives in industrial products since the 1930s, and are universally considered to be ubiquitous environmental contaminants. The general population is exposed to phthalates through consumer products, as well as diet and medical treatments. Animal studies showing the existence of an association between some phthalates and testicular toxicity have generated public and scientific concern about the potential adverse effects of environmental changes on male reproductive health. In particular, prenatal exposure to phthalates seems to play a relevant role in determining these adverse effects given that human exposure has been demonstrated to begin during the intrauterine life. Unprecedented declines in fertility rates and semen quality of antenatal origin have been reported during the last half of the 20th century in developed countries and increasing interest exists on the potential relationship between exposure to environmental contaminants, including phthalates, and human male reproductive health. Here we review the data that support or discounts the evidence existing to date linking phthalate exposure and the decline of human male fertility, especially in developed countries.