Bracero L A, Seybold D J, Witsberger S, Rincon L, Modak A, Baxi L V
a Department of Obstetrics and Gynecology , West Virginia University, Charleston Campus , Charleston , WV , USA .
b Center for Health Services & Outcomes Research, Charleston Area Medical Center Health Education and Research Institute , Charleston , WV , USA , and.
J Matern Fetal Neonatal Med. 2016 Mar;29(5):803-6. doi: 10.3109/14767058.2015.1019457. Epub 2015 Mar 10.
To predict the sex of newborns using first trimester fetal heart rate (FHR).
This was a retrospective review of medical records and ultrasounds performed between 8 and 13 weeks of gestation. Continuous variables were compared using Student's t-tests while categorical variables were compared using Chi-square test.
We found no significant differences between 332 (50.7%) female and 323 (49.3%) male FHRs during the first trimester. The mean FHR for female fetuses was 167.0 ± 9.1 bpm and for male fetuses 167.3 ± 10.1 bpm (p = 0.62). There was no significant difference in crown rump length between female and male fetuses (4.01 ± 1.7 versus 3.98 ± 1.7 cm; p = 0.78) or in gestational age at birth (38.01 ± 2.1 versus 38.08 ± 2.1 weeks; p = 0.67). The males were significantly heavier than females (3305.3 ± 568.3 versus 3127.5 ± 579.8 g; p < 0.0001) but there were no differences in the proportion of small for gestational age (SGA), average for gestational age (AGA) and large for gestational age (LGA) infants.
We found no significant difference between the female and male FHR during the first trimester in contrast to the prevailing lay view of females having a faster FHR. The only statistically significant difference was that males weighed more than female newborns.
利用孕早期胎儿心率（FHR）预测新生儿性别。
这是一项对妊娠8至13周期间进行的病历和超声检查的回顾性研究。连续变量采用学生t检验进行比较，分类变量采用卡方检验进行比较。
我们发现孕早期332例（50.7%）女胎和323例（49.3%）男胎的心率无显著差异。女胎的平均心率为167.0±9.1次/分钟，男胎为167.3±10.1次/分钟（p = 0.62）。女胎和男胎的顶臀长（4.01±1.7 vs 3.98±1.7厘米；p = 0.78）或出生时的孕周（38.01±2.1 vs 38.08±2.1周；p = 0.67）均无显著差异。男性新生儿明显比女性重（3305.3±568.3 vs 3127.5±579.8克；p < 0.0001），但小于胎龄（SGA）、适于胎龄（AGA）和大于胎龄（LGA）婴儿的比例没有差异。
与普遍认为女性心率较快的观点相反，我们发现孕早期女胎和男胎的心率无显著差异。唯一具有统计学意义的差异是男性新生儿比女性新生儿体重更重。
