Cagnacci A, Renzi A, Arangino S, Alessandrini C, Volpe A
Department of Obstetrics Gynaecology and Paediatric Sciences, Gynaecology Unit, Policlinico of Modena, Via del Pozzo 71, 41100 Modena, Italy.
Hum Reprod. 2004 Feb;19(2):442-4. doi: 10.1093/humrep/deh071.
Less than optimal reproductive conditions may be associated with a secondary sex ratio biased towards females. Body weight represents a critical determinant of reproduction. Accordingly, we evaluated whether preconception body weight and weight gain during pregnancy influence the sex ratio of human offspring.
A retrospective study was performed on 10 239 births in 1997-2001. Time of conception, preconception body weight and net weight gain during pregnancy were obtained for 9284 pregnancies.
The secondary sex ratio of mothers in the lowest quartile of pre-pregnancy body weight (<54.6 kg) was lower than that of the other three quartiles (0.497 versus 0.525; P < 0.01). In contrast, the sex ratio of children born by the women in the highest quartile of weight gain during pregnancy appeared lower than that of the first three quartiles (0.493 versus 0.516; P = 0.054).
A low pre-pregnancy weight and a greater weight gain during pregnancy are both associated with a reduced secondary sex ratio. These data indicate that in women with non-optimal reproductive/metabolic conditions, a greater attrition is exerted on male than on female offspring.
欠佳的生殖条件可能与出生性别比偏向女性有关。体重是生殖的一个关键决定因素。因此，我们评估了孕前体重和孕期体重增加是否会影响人类后代的性别比。
对1997年至2001年的10239例分娩进行了一项回顾性研究。获取了9284例妊娠的受孕时间、孕前体重和孕期净增重。
孕前体重处于最低四分位数（<54.6千克）的母亲的出生性别比低于其他三个四分位数（0.497对0.525；P<0.01）。相比之下，孕期体重增加处于最高四分位数的女性所生孩子的性别比似乎低于前三个四分位数（0.493对0.516；P=0.054）。
孕前体重低和孕期体重增加较多均与出生性别比降低有关。这些数据表明，在生殖/代谢条件欠佳的女性中，男性后代比女性后代受到的损耗更大。
