Reduced ratio of male to female births in Japan

Ohmi, Hiroki; Hirooka, Kenzou; Mochizuki, Yoshikatsu

doi:10.1093/ije/28.3.597

Cited by 10 publications

(6 citation statements)

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“…However, this ratio seems to have been lowering worldwide in favor of female births over the past few decades in Europe, the US, and Japan,8,9 probably due to increased prenatal vulnerability of male fetuses after gestational week 12 10,11. Also, in our population, of 72 intrauterine fetal deaths after gestational week 23, 58% were males and 42% were females ( P < 0.05), but these represented only a minority of adverse events (0.5% of deliveries).…”

Section: Discussionmentioning

confidence: 99%

Fetal gender ratio in recurrent miscarriages

Fabro¹,

Driul²,

Anis³

et al. 2011

IJWH

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Background:The purpose of this study was to evaluate the gender ratio and incidence of chromosomal anomalies in the products of conception (POC) from recurrent miscarriages.Methods:We determined the karyotypes of POC from patients with recurrent spontaneous miscarriages between 1999 and 2009.Results:In total, 313 specimens were successfully karyotyped, with a median gestational age of 10 weeks at miscarriage (interquartile range 8–13); 199 (64%) were females and 114 (36%) were males. In total, 121 (39%) had abnormal karyotypes, the most prevalent of which were chromosome 21 and 16 trisomies, triploidy, and monosomy X.Conclusion:Our findings suggest that female POC might be more susceptible to recurrent miscarriages than male ones during embryogenesis, implantation, and initial fetal development.

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Section: Discussionmentioning

confidence: 99%

Fetal gender ratio in recurrent miscarriages

Fabro¹,

Driul²,

Anis³

et al. 2011

IJWH

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“…In his 1712 study, Arbuthnot noted that, for each of the 82 years spanning from 1629 through 1710, the London records for christenings recorded more males than females [Arbuthnot, 1712, discussed in Armitage, 2002. From those early reports through recent epidemiologic studies [Macfarlane and Mugford, 1999;Ohmi et al, 1999], such slight male excess, confirmed also in long time series, has been estimated to center on a sex ratio (ratio of males to females) of approximately 1.04-1.06, with small fluctuations. Researchers have put forth different theories for such male excess, though none of these claims has been conclusively confirmed.…”

Section: Introductionmentioning

confidence: 94%

Sex and congenital malformations: An international perspective

Lisi¹,

Botto

Rittler³

et al. 2005

Am. J. Med. Genet.

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The study evaluated the sex distribution of major isolated malformations and common trisomies among a large and geographically varied sample. Eighteen registries from 24 countries contributed cases, which were centrally reviewed and classified in three clinical types as isolated, associated, or syndromic. We selected cases of 26 major defects (n = 108,534); trisomy 21, 18, and 13 (n = 30,114); other syndromes (n = 2,898); and multiple congenital anomalies (n = 24,197), for a total of 165,743 cases. We observed a significant deviation of sex distribution (compared to a sex ratio of 1.06 or male proportion of 51.4%) for 24 of the 29 groups (a male excess in 16, a female excess in 8), and in 8 of such groups these estimates varied significantly across registries. A male excess was noted for two left obstructive cardiac defects (hypoplastic left heart and coarctation of the aorta) and a female excess for all the main types of neural tube defects. A male excess was seen for omphalocele but not gastroschisis. For neural tube defects the female excess tended to be stronger in areas with historically high prevalence for these defects. For 15 of the 26 birth defects the sex distribution differed among isolated, associated, and syndromic cases. Some of these epidemiologic commonalities are consistent with known or putative developmental processes. Further, the geographic variation for some defects may reflect local prevalence rates and risk factors. Finally, the findings underscore the need for clinical classification (e.g., into isolated, multiple, syndromes) in studies of birth defects.

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“…In the last 2 to 3 decades of the 20 th century, falling sex ratios were noted in a number of countries (Dickinson and Parker, 1996; Marcus et al , 1998; Ohmi et al , 1999; Orvos et al , 2001; Parazzini et al , 1998). Disturbed sex ratios were observed in offspring of parents exposed to toxic environments (Garry et al , 2002; James, 1997b, d, e; Williams et al , 1992) and distressed environments such as during the Iran-Iraq war (Ansari-Lari and Saadat, 2002).…”

Section: Introductionmentioning

confidence: 99%

Live birth sex ratios and father's geographic origins in Jerusalem, 1964–1976

Groeger

Opler

Kleinhaus

et al. 2016

American J Hum Biol

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Objective To examine whether ancestry influenced sex ratios of offspring in a birth cohort before parental antenatal sex selection influenced offspring sex. Methods We measured the sex ratio as the percent of males according to countries of birth of paternal and maternal grandfathers in 91,459 live births from 1964 to 1976 in the Jerusalem Perinatal Study. Confidence limits (CI) were computed based on an expected sex ratio of 1.05, which is 51.4% male. Results Of all live births recorded, 51.4% were male. Relative to Jewish ancestry (51.4% males), significantly more males (1,761) were born to Muslim ancestry (54.5, 95% CI=52.1–56.8, p=.01). Among the former, sex ratios were not significantly associated with paternal or maternal age, education, or offspring’s birth order. Consistent with a preference for male offspring, the sex ratio decreased despite increasing numbers of births over the 13-year period. Sex ratios were not affected by maternal or paternal origins in North Africa or Europe. However, the offspring whose paternal grandfathers were born in Western Asia included fewer males than expected (50.7, 50.1–51.3, p=.02), whether the father was born abroad (50.7) or in Israel (50.8). This was observed for descendents of paternal grandfathers born in Lebanon (47.6), Turkey (49.9), Yemen & Aden (50.2), Iraq (50.5), Afghanistan (50.5), Syria (50.6), and Cyprus (50.7); but not for those from India (51.5) or Iran (51.9). The West Asian group showed the strongest decline in sex ratios with increasing paternal family size. Conclusions A decreased sex ratio associated with ancestry in Western Asia is consistent with reduced ability to bear sons by a subset of Jewish men in the Jerusalem cohort. Lower sex ratios may be due to pregnancy stress, which may be higher in this subgroup. Alternatively, a degrading Y chromosome haplogroup or other genetic or epigenetic differences on male germ lines could affect birth ratios, such as differential exposure to an environmental agent, dietary differences, or stress. Differential stopping behaviors that favor additional pregnancies following the birth of a daughter might exacerbate these lower sex ratios.

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Reduced ratio of male to female births in Japan

Cited by 10 publications

References 0 publications

Fetal gender ratio in recurrent miscarriages

Fetal gender ratio in recurrent miscarriages

Sex and congenital malformations: An international perspective

Live birth sex ratios and father's geographic origins in Jerusalem, 1964–1976

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