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Du T, Xie Q, Ye J, Wang X, Qiu J, Yan Z, Zhang S, Zhao D, Lin J, Li B. Factors affecting male-to-female ratio at birth in frozen-thawed embryo transfer cycles: a large retrospective cohort study. Front Endocrinol (Lausanne) 2023; 14:1188433. [PMID: 37800141 PMCID: PMC10548202 DOI: 10.3389/fendo.2023.1188433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 07/31/2023] [Indexed: 10/07/2023] Open
Abstract
Background ICSI (intracytoplasmic sperm injection) leads to a reduced male-to-female ratio at birth, whereas blastocyst transfer results in an increased male-to-female ratio. However, limited knowledge exists regarding the impact of these factors on the live birth rate for each gender. This study aimed to investigate the influence of patient characteristics and treatment parameters on the live birth rate for each gender, as well as the ultimate male-to-female ratio at birth in frozen-thawed embryo transfer (FET) cycles. Method This retrospective cohort study involved a total of 28,376 FET cycles and 9,217 subsequent deliveries, spanning from January 2003 to December 2015. The study consisted of two parts. First, logistic regression models were constructed to determine the factors influencing the male-to-female ratio among babies born after FET. Second, we aimed to investigate the mechanisms underlying this sex ratio imbalance by analyzing data from all transfer cycles. Generalized estimated equations were employed to assess the impact of risk factors on rates of male and female live births separately. Results ICSI resulted in a lower proportion of male offspring compared to in vitro fertilization (IVF) (50.1% vs. 53.7%, aOR: 0.87, 95% CI: 0.80-0.96). Conversely, blastocyst transfer yielded a higher proportion of male offspring than cleavage-stage embryo transfer (58.7% vs. 51.6%, aOR: 1.32, 95% CI: 1.17-1.48). Analysis of all cycles indicated that ICSI resulted in a reduced likelihood of male live birth in comparison to IVF (19.8% vs. 21.6%, aOR: 0.90, 95% CI: 0.83-0.97). However, the transfer of blastocysts rather than cleavage-stage embryos not only increased the chance of male live birth (26.9% vs. 20.2%, aOR: 1.70, 95% CI:1.56-1.85) but also facilitated female live birth (20.3% vs. 19.3%, aOR: 1.26, 95% CI: 1.15-1.39). Conclusion ICSI was associated with a reduction in the male-to-female sex ratio and a lower rate of male live births, while blastocyst transfer was associated with an increased male-to-female sex ratio at birth and a higher rate of male live births.
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Affiliation(s)
- Tong Du
- Department of Assisted Reproduction, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qin Xie
- Department of Assisted Reproduction, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jing Ye
- Department of Assisted Reproduction, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xindi Wang
- Department of Integrative Physiology and Biochemistry, University of Colorado at Boulder, Boulder, NV, United States
| | - Jiaxin Qiu
- Department of Assisted Reproduction, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zheng Yan
- Department of Assisted Reproduction, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Suqun Zhang
- Department of Assisted Reproduction, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Dong Zhao
- Department of Obstetrics and Gynaecology, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jiaying Lin
- Department of Assisted Reproduction, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Bin Li
- Department of Assisted Reproduction, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Grech V. The Sex Ratio at Birth Is Higher in Māori than in Non-Māori Populations in Aotearoa New Zealand. ACTA MEDICA (HRADEC KRALOVE) 2023; 66:24-27. [PMID: 37384806 DOI: 10.14712/18059694.2023.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/01/2023]
Abstract
AIMS The sex ratio at birth approximates 0.515 (male : total, M/T), with 515 boys per 485 girls. Many factors have been shown to influence M/T including acute and chronic stress. Increasing maternal age is associated with a decline in M/T. In Aotearoa New Zealand, circa 15% of the population identify as of Māori heritage. This populationis generally considered to be socioeconomically disadvantaged. This study analysed M/T for Māori and non-Māori M/T births in Aotearoa New Zealand and relates these to mean maternal age at delivery. METHODS Live births by sex and maternal age at delivery were available from the website of Tatauranga Aotearoa Stats NZ for 1997-2021. RESULTS This study analysed 1,474,905 births (28.4% Māori) Pooled data shows that Māori M/T is significantly higher than non-Māori M/T (chi = 6.8, p = 0.009). Mean maternal age at delivery was less for Māori mothers but this was not statistically significant. CONCLUSIONS Several studies have shown that M/T is decreased in socioeconomically deprived populations, and for this reason Māori M/T is expected to be lower and not higher than non-Māori M/T. A lower mean maternal age at delivery might have explained the M/T differences noted in this analysis but this was not a statistically significant difference.
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Affiliation(s)
- Victor Grech
- Consultant Paediatrician, University of Malta, Malta.
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Fukuda M, Fukuda K, Mason S, Tatsumi K, Shimizu T, Akahori T, Matsumoto T, Tahara M, Andersen CY. Ovulation patterns affect the offspring sex ratios and change with the women's age. Reprod Health 2022; 19:159. [PMID: 35804411 PMCID: PMC9270783 DOI: 10.1186/s12978-022-01462-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 06/21/2022] [Indexed: 11/23/2022] Open
Abstract
Background The aim of this study was to evaluate whether women’s ages at conception and the ratio of male to female infants are associated with various ovulation patterns. Methods An observational clinical study was conducted in private OB/GYN clinics. Infertile women with regular menstrual cycles receiving intrauterine insemination (IUI) and/or in-vitro fertilization (IVF) had their ovulation patterns monitored in three consecutive spontaneous cycles receiving infertility treatment in the third cycle. Ovulation patterns were also observed in women with slight ovulation disorders during IUI and/or IVF in clomiphene citrate stimulated cycles. All the pregnant women’s ages at conception and their respective offspring sex ratios were compared to various ovulation patterns. Statistical evaluation was performed using ANOVA, unpaired t test, χ2 test or Fisher’s exact test, heterogeneity χ2 test, odds ratios at 95% confidence intervals and logistic regression. Results Contralateral ovulation (i.e. ovulation jumping from ovary to the other) was more often observed in relatively younger women, who showed a higher probability of having a boy than after ipsilateral ovulation. There was a significantly higher frequency of boys being conceived following three consecutive ovulations with a left–left–right (LLR) ovulation pattern, while three ovulations from the left ovary (LLL) were associated with a higher frequency of girls. We also found two consecutive menstrual cycles the left–right (LR) ovulation pattern showed a similar significant difference compared to the left-left (LL) ovulation. Both the infertile and infertile + fertile women groups showing right-sided ovulation, regardless of age, showed significantly higher offspring sex ratio compared to left-sided ovulation, which was not observed in the group of fertile women alone. Conclusions LLR, LR and contralateral ovulation happens more often in younger women and favors male offspring in infertile women. Right-sided ovulation favors male offspring in infertile and infertile + fertile women, which was not observed in the group of fertile women. It is of interest to evaluate whether ovulation patterns change with women’s ages at conception and affect offspring sex ratios. An observational clinical study was conducted in private OB/GYN clinics. Infertile women with regular menstrual cycles receiving intrauterine insemination (IUI) and/or in-vitro fertilization (IVF) had their ovulation patterns monitored in three consecutive spontaneous cycles receiving infertility treatment in the third cycle. Ovulation patterns were also observed in women with slight ovulation disorder during IUI and/or IVF in clomiphene citrate stimulated cycles. Women’s ages and offspring sex ratios were compared to various ovulation patterns. The contralateral ovulation was more often observed in relatively younger women, who showed a higher probability of having a boy than following a pregnancy after ipsilateral ovulation. There was a significantly higher frequency of boys being conceived following three consecutive ovulations with after a left-left-right (LLR) ovulation pattern, while three ovulations from the left ovary (LLL) were associated with a higher frequency of girls. Only considering two consecutive menstrual cycles the left-right (LR) ovulation pattern showed a similar significant difference compared to the left-left (LL) ovulation. Both infertile and infertile + fertile women showing right-sided ovulation, regardless of age, showed significantly higher offspring sex ratio compared to left-sided ovulation, which was not observed in the group of fertile women alone. LLR, LR and contralateral ovulation happens more often in younger women and favor male offspring in infertile women. Right-sided ovulation favors male offspring in infertile and infertile + fertile women, which was not observed in the group of fertile women.
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Affiliation(s)
- Misao Fukuda
- M&K Health Institute, 30-9 Kariya, , Ako, Hyogo, 678-0239, Japan.
| | - Kiyomi Fukuda
- M&K Health Institute, 30-9 Kariya, , Ako, Hyogo, 678-0239, Japan
| | - Shawn Mason
- M&K Health Institute, 30-9 Kariya, , Ako, Hyogo, 678-0239, Japan
| | - Kenichi Tatsumi
- Umegaoka Women's Hospital, 1-33-3 Umegaoka, Setagaya-ku, Tokyo, 154-0022, Japan
| | - Takashi Shimizu
- Shimizu Women's Clinic, 2-2-4 Minamiguchi, Takarazuka, Hyogo, 665-0011, Japan
| | | | | | - Masahiro Tahara
- Taniguchi Hospital, 1-5-20 Oonishi, Izumisano City, 598-0043, Japan.,Nomura Clinic, 3-2-28 Chuo-ku Takatsu, Osaka, 542-0072, Japan
| | - Claus Yding Andersen
- Laboratory of Reproductive Biology, Juliane Marie Center, Rigshospitalet, Section 5712, University Hospital of Copenhagen, Blegdamsvej 9, 2100, Copenhagen, Denmark
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Martins ACL, Vaz MA, Macedo MM, Santos RL, Galdino CAB, Wenceslau RR, Valle GR. Maternal age, paternal age, and litter size interact to affect the offspring sex ratio of German Shepherd dogs. Theriogenology 2019; 135:169-173. [DOI: 10.1016/j.theriogenology.2019.06.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 03/25/2019] [Accepted: 06/11/2019] [Indexed: 11/25/2022]
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Carslake D, Tynelius P, van den Berg G, Davey Smith G, Rasmussen F. Associations of parental age with health and social factors in adult offspring. Methodological pitfalls and possibilities. Sci Rep 2017; 7:45278. [PMID: 28345590 PMCID: PMC5366914 DOI: 10.1038/srep45278] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 02/23/2017] [Indexed: 01/06/2023] Open
Abstract
Parental age is increasing rapidly in many countries. Analysis of this potentially important influence on offspring well-being is hampered by strong secular trends and socioeconomic patterning and by a shortage of follow-up data for adult offspring. We used Swedish national data on up to 3,653,938 offspring to consider the associations of parental age with a suite of outcomes in adult offspring, comparing the results from an array of statistical methods for optimal causal inference. The offspring of older mothers had higher BMI, blood pressure, height, intelligence, non-cognitive ability and socioeconomic position. They were less likely to smoke or to be left-handed. Associations with paternal age were strongly, but not completely, attenuated by adjustment for maternal age. Estimates from the commonly-used sibling comparison method were driven primarily by a pathway mediated by offspring date of birth when outcomes showed strong secular trends. These results suggest that the intra-uterine and early life environments provided by older mothers may be detrimental to offspring cardiovascular health, but that their greater life experience and social position may bring intellectual and social advantages to their offspring. The analysis of parental age presents particular challenges, and further methodological developments are needed.
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Affiliation(s)
- David Carslake
- MRC Integrative Epidemiology Unit at the University of Bristol, Bristol, UK
- School of Social and Community Medicine, University of Bristol, Bristol, UK
| | - Per Tynelius
- Department of Public Health Sciences, Karolinska Institute, Stockholm, Sweden
| | - Gerard van den Berg
- School of Economics, Finance and Management, University of Bristol, Bristol, UK
| | - George Davey Smith
- MRC Integrative Epidemiology Unit at the University of Bristol, Bristol, UK
- School of Social and Community Medicine, University of Bristol, Bristol, UK
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Arikawa M, Jwa SC, Kuwahara A, Irahara M, Saito H. Effect of semen quality on human sex ratio in in vitro fertilization and intracytoplasmic sperm injection: an analysis of 27,158 singleton infants born after fresh single-embryo transfer. Fertil Steril 2015; 105:897-904. [PMID: 26738748 DOI: 10.1016/j.fertnstert.2015.12.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 11/18/2015] [Accepted: 12/03/2015] [Indexed: 10/22/2022]
Abstract
OBJECTIVE To evaluate the effect of semen quality on human sex ratio in in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). DESIGN Retrospective cohort study. SETTING Not applicable. PATIENT(S) A total of 27,158 singleton infants born between 2007 and 2012 after fresh single-embryo transfer. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Proportion of male infants among liveborn infants. RESULT(S) There were 14,996 infants born after IVF, 12,164 infants born after ICSI with ejaculated sperm, and 646 infants born after ICSI with nonejaculated sperm. The sex ratio of IVF was 53.1% (95% confidence interval [CI], 52.3-53.9); the sex ratio of ICSI with ejaculated and nonejaculated sperm demonstrated as statistically significant reduction (48.2%; 95% CI, 47.3-49.1 and 47.7%; 95% CI, 43.8-51.6, respectively). In IVF, lower sperm motility, including asthenozoospermia (sperm motility <40%), was associated with a statistically significantly lower sex ratio compared with normal sperm (51.0%; 95% CI, 48.6-53.3 vs. 53.4%; 95% CI, 52.5-54.3). In ICSI with ejaculated sperm, there was no association between sperm motility and sex ratio. Sperm concentration was not associated with sex ratio in both IVF and ICSI. CONCLUSION(S) In IVF, lower sperm motility was associated with a statistically significant reduction in sex ratio; ICSI with either ejaculated or nonejaculated sperm was associated with a statistically significant reduction in sex ratio regardless of semen quality.
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Affiliation(s)
- Mikiko Arikawa
- Division of Reproductive Medicine, Center of Maternal-Fetal, Neonatal and Reproductive Medicine, National Center for Child Health and Development, Tokyo, Japan
| | - Seung Chik Jwa
- Division of Reproductive Medicine, Center of Maternal-Fetal, Neonatal and Reproductive Medicine, National Center for Child Health and Development, Tokyo, Japan; SORA no MORI Clinic, Okinawa, Japan.
| | - Akira Kuwahara
- Department of Obstetrics and Gynecology, School of Medicine, University of Tokushima, Tokushima, Japan
| | - Minoru Irahara
- Department of Obstetrics and Gynecology, School of Medicine, University of Tokushima, Tokushima, Japan
| | - Hidekazu Saito
- Division of Reproductive Medicine, Center of Maternal-Fetal, Neonatal and Reproductive Medicine, National Center for Child Health and Development, Tokyo, Japan
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Kim TB, Oh JK, Kim KT, Yoon SJ, Kim SW. Does the Mother or Father Determine the Offspring Sex Ratio? Investigating the Relationship between Maternal Digit Ratio and Offspring Sex Ratio. PLoS One 2015; 10:e0143054. [PMID: 26575995 PMCID: PMC4648576 DOI: 10.1371/journal.pone.0143054] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 10/30/2015] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE In mammals, high parental testosterone levels present around the time of conception are thought to skew offspring sex ratio toward sons. The second to fourth digit ratio (digit ratio) is now widely accepted as a negative correlate of prenatal testosterone. Thus, we investigated the association between digit ratio and offspring sex ratio. METHODS A total of 508 Korean patients (257 males and 251 females) less than 60 years old who had one or more offspring were prospectively enrolled. The lengths of the 2nd and 4th digits of the right hand were measured by a single investigator using a digital vernier calliper. Next, the patients' lifetime offspring birth sex ratios were investigated. RESULTS Maternal (rather than paternal) digit ratio was significantly associated with the number of sons (r = -0.153, p = 0.015), number of daughters (r = 0.130, p = 0.039), and offspring sex ratio (r = -0.171, p = 0.007). And, the maternal digit ratio was a significant factor for predicting offspring sex ratio (B = -1.620, p = 0.008) on multiple linear regression analysis. The female patients with a lower digit ratio (< 0.95) were found to have a higher offspring sex ratio (0.609 versus 0.521, p = 0.046) compared to those with a higher digit ratio (≥ 0.95). Furthermore, females in the low digit ratio group have a probability 1.138 greater of having sons than females in the high digit ratio group. CONCLUSIONS Maternal digit ratio was negatively associated with offspring sex ratio. Females with a lower digit ratio were more likely to have more male offspring compared to those with a higher digit ratio. Thus, our results suggest that the sex of offspring might be more influenced by maternal rather than paternal factors.
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Affiliation(s)
- Tae Beom Kim
- Department of Urology, Gachon University Gil Hospital, Incheon, Republic of Korea
| | - Jin Kyu Oh
- Department of Urology, Gachon University Gil Hospital, Incheon, Republic of Korea
| | - Kwang Taek Kim
- Department of Urology, Gachon University Gil Hospital, Incheon, Republic of Korea
| | - Sang Jin Yoon
- Department of Urology, Gachon University Gil Hospital, Incheon, Republic of Korea
| | - Soo Woong Kim
- Department of Urology, Seoul National University Hospital, Seoul, Republic of Korea
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Csermely G, Urbán R, Czeizel AE, Veszprémi B. Sex ratio of congenital abnormalities in the function of maternal age: a population-based study. Congenit Anom (Kyoto) 2015; 55:85-91. [PMID: 25354028 DOI: 10.1111/cga.12093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 10/14/2014] [Indexed: 02/04/2023]
Abstract
Maternal age effect is well-known in the origin of numerical chromosomal aberrations and some isolated congenital abnormalities (CAs). The sex ratio (SR), i.e. number of males divided by the number of males and females together, of most CAs deviates from the SR of newborn population (0.51). The objective of this analysis was to evaluate the possible association of maternal age with the SR of isolated CAs in a population-based large dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-1996. First, SR of 24 CA entities/groups was estimated in 21,494 patients with isolated CA. In the next step SR of different maternal age groups was compared to the mean SR of the given CA-groups. The SR of four CA-groups showed some deviation in certain maternal age groups. Cases with anencephaly had female excess in young mothers (<25 years). Cases with skull's CAs particularly craniosynostosis had a male excess in cases born to women over 30 years. Two other CA groups (cleft lip ± palate and valvar pulmonic stenosis within the group of right-sided obstructive defect of heart) had significant deviation in SR of certain maternal age groups from the mean SR, but these deviations were not harmonized with joining age groups and thus were considered as a chance effect due to multiple testing. In conclusion, our study did not suggest that in general SR of isolated CAs might be modified by certain maternal age groups with some exception such as anencephaly and craniosynostosis.
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Mekonen HK, Nigatu B, Lamers WH. Birth weight by gestational age and congenital malformations in Northern Ethiopia. BMC Pregnancy Childbirth 2015; 15:76. [PMID: 25886401 PMCID: PMC4381366 DOI: 10.1186/s12884-015-0507-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 03/19/2015] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Studies on birth weight and congenital anomalies in sub-Saharan regions are scarce. METHODS Data on child variables (gestational age, birth weight, sex, and congenital malformations) and maternal variables (gravidity, parity, antenatal care, previous abortions, maternal illness, age, medication, and malformation history) were collected for all neonates delivered at Ayder referral and Mekelle hospitals (Northern Ehthiopia) in a prospective study between 01-12-2011 and 01-05-2012. RESULTS The total number of deliveries was 1516. More female (54%) than male neonates were born. Birth weights were 700-1,000 grams between 26 and 36 weeks of pregnancy and then increased linearly to 3,500-4,000 grams at 40 weeks. Thirty-five and 54% of neonates were very-low and low birth weight, respectively, without sex difference. Very-low birth-weight prevalence was not affected by parity. Male and female neonates from parity-2 and parity-2-4 mothers, respectively, were least frequently under weight. Sixty percent of newborns to parity -3 mothers weighed less than 2,500 grams, without sex difference. The percentage male neonates dropped from ~50% in parity-1-3 mothers to ~20% in parity-6 mothers. Diagnosed congenital malformations (~2%) were 2-fold more frequent in boys than girls. The commonest malformations were in the central nervous system (CNS; ~1.5% of newborns). Parity, low birth weight, gestational age less than 35 weeks, male sex, and lack of antenatal care were the most significant risk factors for congenital anomalies. CONCLUSION The high prevalence of neonates with low birth weight and CNS anomalies in Northern Ethiopia was very high. The findings may reflect the harsh conditions in the past 2 decades and suggest environmental and/or nutritional causes. Male sex and parity affected the outcome of pregnancy negatively.
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Affiliation(s)
- Hayelom K Mekonen
- Department of Anatomy, College of Health Sciences, Mekelle University, Mekelle, Ethiopia. .,Department of Anatomy & Embryology, Faculty of Health, Medicine, and Life Sciences, Maastricht University Medical Center, Maastricht, The Netherlands.
| | - Balkachew Nigatu
- Department of Gynaecology and Obstetrics, College of Health Sciences, Mekelle University, Mekelle, Ethiopia.
| | - Wouter H Lamers
- Department of Anatomy & Embryology, Faculty of Health, Medicine, and Life Sciences, Maastricht University Medical Center, Maastricht, The Netherlands.
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Schnettler S, Klüsener S. Economic stress or random variation? Revisiting German reunification as a natural experiment to investigate the effect of economic contraction on sex ratios at birth. Environ Health 2014; 13:117. [PMID: 25533777 PMCID: PMC4391084 DOI: 10.1186/1476-069x-13-117] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 12/04/2014] [Indexed: 06/04/2023]
Abstract
BACKGROUND The economic stress hypothesis (ESH) predicts decreases in the sex ratio at birth (SRB) following economic decline. However, as many factors influence the SRB, this hypothesis is difficult to test empirically. Thus, researchers make use of quasi-experiments such as German reunification: The economy in East, but not in West Germany, underwent a rapid decline in 1991. A co-occurrence of a decline in the East German SRB in 1991 has been interpreted by some as support for the ESH. However, another explanation might be that the low SRB in 1991 stems from increased random variation in the East German SRB due to a drastically reduced number of births during the crisis. We look into this alternative random variation hypothesis (RVH) by re-examining the German case with more detailed data. METHODS Our analysis has two parts. First, using aggregate-level birth register data for all births in the period between 1946 and 2011, we plot the quantum and variance of the SRB and the number of births and unemployment rates, separately for East and West Germany, and conduct a time series analysis on the East German SRB over time. Second, we model the odds for a male birth at the individual level in a multiple logistic regression (1991-2010, ~13.9 million births). Explanatory variables are related to the level of the individual birth, the mother of the child born, and the regional economic context. RESULTS The aggregate-level analysis reveals a higher degree of variation of the SRB in East Germany. Deviations from the time trend occur in several years, seemingly unrelated to economic development, and the deviation in 1991 is not statistically significant. The individual-level analysis confirms that the 1991-drop in the East German SRB cannot directly be attributed to economic development and that there is no statistically significant effect of economic development on sex determination in East or West Germany. CONCLUSION Outcomes support the RVH but not the ESH. Furthermore, our results speak against a statistically significant effect of the reunification event itself on the East German SRB. We discuss the relative importance of behavioral and physiological responses to macro-level stressors, a distinction that may help integrate previously mixed findings.
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Affiliation(s)
- Sebastian Schnettler
- Department of Sociology, University of Konstanz, Box 40, Universitätsstr. 10, 78457, Konstanz, Germany.
| | - Sebastian Klüsener
- Max Planck Institute for Demographic Research, Konrad-Zuse-Str. 1, 18057, Rostock, Germany.
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McDonald E, Watterson A, Tyler AN, McArthur J, Scott EM. Multi-factorial influences on sex ratio: a spatio-temporal investigation of endocrine disruptor pollution and neighborhood stress. INTERNATIONAL JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HEALTH 2014; 20:235-46. [PMID: 25000111 PMCID: PMC4070448 DOI: 10.1179/2049396714y.0000000073] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Background: It is suggested the declining male birth proportion in some industrialized countries is linked to ubiquitous endocrine disruptor exposure. Stress and advanced parental age are determinants which frequently present positive findings. Multi-factorial influences on population sex ratio are rarely explored or tested in research. Objectives: To test the hypothesis that dual factors of pollution and population stress affects sex proportion at birth through geographical analysis of Central Scotland. Methods: The study incorporates the use of Geographical Information Systems (GIS) tools to overlay modeled point source endocrine disruptor air emissions with “small-area” data on multiple deprivation (a proxy measurement of stress) and birth sex. Historical review of regional sex ratio trends presents additional data on sex ratio in Scotland to consider. Results: There was no overall concentration in Central Scotland of low sex ratio neighborhoods with areas where endocrine disruptor air pollution and deprivation or economic stress were high. Historical regional trends in Scotland (from 1973), however, do show significantly lower sex ratio values for populations where industrial air pollution is highest (i.e. Eastern Central Scotland). Conclusions: Use of small area data sets and pollution inventories is a potential new method of inquiry for reproductive environmental and health protection monitoring and has produced interesting findings.
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Cheng HH, Ou CY, Tsai CC, Chang SD, Hsiao PY, Lan KC, Hsu TY. Chromosome distribution of early miscarriages with present or absent embryos: female predominance. J Assist Reprod Genet 2014; 31:1059-64. [PMID: 24879519 DOI: 10.1007/s10815-014-0261-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Accepted: 05/13/2014] [Indexed: 11/29/2022] Open
Abstract
PURPOSE The objective of this study is to compare the chromosomal distribution of early miscarriages with or without embryonic poles. MATERIALS AND METHODS It was a retrospective study of 223 women who underwent dilation and curettage (D&C) between 1995 and 2013 for early miscarriages. The presence or absence of a fetal pole was evaluated by abdominal or transvaginal ultrasound. Cytogenetic tests of products of conception following culture were determined in both groups. RESULTS Of the 223 early miscarriages, 143 had embryos and 80 did not. The abnormality rate differed significantly (61.5 % vs. 46.3 %, p < 0.05), with trisomy 18, 21 and 45X found only in miscarriages with embryos. There were no significant differences between groups in rates of triploidy, tetraploidy, mosaicism, structure and double abnormality. The female abortus rate was higher in miscarriages with or without embryonic poles, as well as in groups with normal and abnormal karyotypes. CONCLUSIONS Chromosome distribution differs in miscarriages with or without embryonic poles. The ultrasound findings might offer different direction to determine the causes of early miscarriages. The higher female abortus rate may be associated with early selection.
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Affiliation(s)
- Hsin-Hsin Cheng
- Department of Obstetrics and Gynecology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, 123, Ta-Pei Road, Niao-Sung Dist., Kaohsiung, 833, Taiwan,
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Forgotten fathers: paternal influences on mammalian sex allocation. Trends Ecol Evol 2014; 29:158-64. [DOI: 10.1016/j.tree.2013.12.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 11/25/2013] [Accepted: 12/07/2013] [Indexed: 11/24/2022]
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Venero Fernández SJ, Medina RS, Britton J, Fogarty AW. The association between living through a prolonged economic depression and the male:female birth ratio--a longitudinal study from Cuba, 1960-2008. Am J Epidemiol 2011; 174:1327-31. [PMID: 22038101 DOI: 10.1093/aje/kwr357] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The Trivers-Willard hypothesis suggests that populations respond to scarcity by decreasing the ratio of males to females at livebirth. Cuba experienced an extreme economic depression in the 1990s called the "special period." Using time-series analysis, the authors studied the impact of this event on the male:female sex ratio at birth in Cuba from 1960 to 2008. From 1990 to 1993, the per capita gross domestic product in Cuba decreased by 36%. By use of a definition of the special period from 1991 to 1998, there was a prolonged increase in the male:female ratio of livebirths during this period of economic depression (P < 0.001), from 1.06 at baseline to a peak of 1.18. This association persisted when using alternative definitions of the duration of economic depression in sensitivity analyses. Once the period of economic depression was over, the male:female ratio returned to the baseline value. These data suggest that, in Cuba, contrary to the Trivers-Willard hypothesis, the human population responded to conditions of scarcity by increasing the ratio of males to females at livebirth. These data may be relevant in the modeling of demographic projections in countries that experience prolonged economic depression and in understanding adaptive human reproductive responses to environmental change.
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15
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Rueness J, Vatten L, Eskild A. The human sex ratio: effects of maternal age. Hum Reprod 2011; 27:283-7. [DOI: 10.1093/humrep/der347] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Jia J, Zhou R. The sex ratio of offspring is associated with the mothers' age at menarche. Hum Reprod 2011; 26:2589; author reply 2589-90. [PMID: 21685138 DOI: 10.1093/humrep/der205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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17
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Fukuda M, Fukuda K, Shimizu T, Nobunaga M, Grete Byskov A, Yding Andersen C. The sex ratio of offspring is associated with the mothers' age at menarche. Hum Reprod 2011; 26:1551-4. [DOI: 10.1093/humrep/der107] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Liu Y, Zhi M, Li X. Parental age and characteristics of the offspring. Ageing Res Rev 2011; 10:115-23. [PMID: 20887815 DOI: 10.1016/j.arr.2010.09.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 08/08/2010] [Accepted: 09/16/2010] [Indexed: 11/18/2022]
Abstract
The relations of an offspring to its parents are complex, and the ways in which a parent may influence the characteristics of its offspring are many. This review focuses on the relations of parental age to intelligence, health outcomes, longevity and other characteristics of offspring. Many researchers have demonstrated that children of older parents tend to be more intelligent than do children of younger parents, although there are also some negative findings. Either teenage or advanced parental age is associated with risk of birth and health outcomes in offspring. Parental age at birth displays a negative association with offspring longevity. Parental age can also influence dominant characters, sex ratio, personality and development process of the offspring. To fully analyze the influence of parental age on the offspring is of great significance in deciding the optimal age for parenthood.
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Affiliation(s)
- Yongsheng Liu
- Henan Institute of Science and Technology, Xinxiang, 453003, China.
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